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Amplifiers Rescue Gods

Printed From: Speakerplans.com
Category: General
Forum Name: Amp Forum
Forum Description: The 'Stopping Jake Fielder moaning constantly' forum description...
URL: https://forum.speakerplans.com/forum_posts.asp?TID=107113
Printed Date: 02 October 2022 at 5:20am
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Topic: Amplifiers Rescue Gods
Posted By: EmPro
Subject: Amplifiers Rescue Gods
Date Posted: 26 May 2022 at 3:37pm
Simple as that,show us what amplifiers you saved from the ,,death'' or you tried hard to LOL

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EmPro Audio



Replies:
Posted By: jbl_man
Date Posted: 26 May 2022 at 4:02pm
You will find quite a few in this thread if you scroll though.
https://forum.speakerplans.com/spot-the-deliberate-mistake_topic89735.html" rel="nofollow - https://forum.speakerplans.com/spot-the-deliberate-mistake_topic89735.html



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Be seeing you.


Posted By: Earplug
Date Posted: 27 May 2022 at 10:48am
Well -- too many to count!   Smile

Latest are a lovely little Inkel hifi thing and an AB Precedent 900.

The owner took them to some other guy that took a look and told him to forget it. In fact the Inkel came with a sticker on the top saying that it was beyond repair! It was really dirty inside, but definitely not beyond hope!  LOL

He got my number from somewhere & brought in a few bits & pieces for me to check. The AB needed new pots and had a couple of burned out resistors, but otherwise ok.

The Inkel, a thorough cleanup of the boards and a several of the input RCA's replacing, but otherwise fine.  Thumbs Up

























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Earplugs Are For Wimps!


Posted By: jbl_man
Date Posted: 27 May 2022 at 1:12pm
The Inkel looks nice Earplug, that's not a brand we ever had here in UK. Looks about 1977-78-ish? About 80w p/ch into 8ohms?


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Be seeing you.


Posted By: EmPro
Date Posted: 27 May 2022 at 7:25pm
https://ibb.co/GPsycFP" rel="nofollow">
https://ibb.co/PDGfjBv" rel="nofollow">
https://ibb.co/41TBc2c" rel="nofollow">
https://ibb.co/sjP3cYk" rel="nofollow">


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EmPro Audio


Posted By: EmPro
Date Posted: 27 May 2022 at 7:28pm
No much info regarding this mixer amplifier,but is proper made and proper 2x150w rms per ch in 4r,just some dead joints on the power supply side and ready to go Big smile

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EmPro Audio


Posted By: EmPro
Date Posted: 27 May 2022 at 7:37pm
https://ibb.co/WWjzWkM" rel="nofollow">
https://ibb.co/HFY31VW" rel="nofollow">
https://ibb.co/n617t1Q" rel="nofollow">
https://ibb.co/6Jz3pNM" rel="nofollow">
https://ibb.co/QfmW3Cy" rel="nofollow">
https://ibb.co/ckt0mtQ" rel="nofollow">
https://ibb.co/HVSXLhd" rel="nofollow">
https://ibb.co/3RTzYT3" rel="nofollow">
https://ibb.co/k2JZYCm" rel="nofollow">
https://ibb.co/9Wz5H7N" rel="nofollow">


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EmPro Audio


Posted By: EmPro
Date Posted: 27 May 2022 at 7:40pm
i couldn't save the original inscription on the front panel as it was way to rusty....right ch was dead (outputs blown) left ch working,now is fully working :) Old School Cloud GS 3002

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EmPro Audio


Posted By: kedwardsleisure
Date Posted: 27 May 2022 at 8:42pm
Quote that's not a brand we ever had here in UK


I've seen a fair few Inkels, though mainly in 100V line models.
They're associated with Inter-M in some way.

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Kevin

North Staffordshire



Posted By: EmPro
Date Posted: 27 May 2022 at 11:28pm
Don't like Inter'm had before two Inter'm M2000 heavy as hell and always tend to go in mighty big bang with loads of expensive sanken outputs,blown traces and holes in heatsinks 😒 also i've seen some Inter'm amplifiers basicaly identical as Samson....now...i've no ideea who's copying who lol

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EmPro Audio


Posted By: EmPro
Date Posted: 27 May 2022 at 11:38pm
McGregor RM1600
2x800w 4r (lateral mosfet dual die)
One ch good,one dead,the fault was one resistor,one to92 transistor and some dead solderings,the amplifier is in full working order now:
https://ibb.co/HF77F81" rel="nofollow">
https://ibb.co/vVPn737" rel="nofollow">
https://ibb.co/wpBnBs5" rel="nofollow">
https://ibb.co/3BS8dqP" rel="nofollow">


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EmPro Audio


Posted By: M4trix
Date Posted: 28 May 2022 at 3:33am
I must admit I have never seen a genuine Motorola MJ15003 with such markings printed at 45° and such font, especially without made in Mexico. If seen on ebay nowadays I would definitely think they're fake. Back in the 80's in miserable ex Yugoslavia, these transistors were hard to come by. The most powerful transistors on Yugo-communist-disaster market was a dodgy 2N3773 and manufactured by EI Nish. Motorola MJ15003/MJ15004 were in my wet dreams. Thank God those days are history. LOL  




Posted By: Lucasdude
Date Posted: 28 May 2022 at 9:22am
Originally posted by EmPro EmPro wrote:

i couldn't save the original inscriptio6n on the front panel as it was way to rusty....right ch was dead (outputs blown) left ch working,now is fully working :) Old School Cloud GS 3002

Graphic needs some new graphics!


Posted By: EmPro
Date Posted: 28 May 2022 at 10:05am
Yeah LOL

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EmPro Audio


Posted By: jbl_man
Date Posted: 28 May 2022 at 10:10am
From a fried HH S500d i rebuilt a couple of years ago. Basically it had 3 shorted output devices,and that then took out every transistor on this driver board, and a dozen passive components too.





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Be seeing you.


Posted By: jbl_man
Date Posted: 28 May 2022 at 10:13am
Rebuilt module.



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Be seeing you.


Posted By: EmPro
Date Posted: 28 May 2022 at 10:36am
Is it true that S500D doesn't have any dc output protection?? If that module was so bad i assume the speakers had no chance Cry
i'm a HH fan,i have: HH V-S Musician combo 2x12,with 100w rms in 4r and quasi comp 2x2n3773 as outputs,HH MA150 amplifier,150w rms with 2XBDY37A as outputs,HH SM200 powered mixer 2x100w rms with two modules with 2x2n3773 on outputs,HH V800 2x400w rms in 4R with 8 lateral hitachi mosfets per ch 4x2SJ50 and 4X2SK135,also i have 6 HH M900 (basicaly HH V800 install version).


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EmPro Audio


Posted By: EmPro
Date Posted: 28 May 2022 at 10:40am
HH MA150,all parts original,no faults on this one:
https://ibb.co/BCn2SQ2" rel="nofollow">
https://ibb.co/DfHYkpF" rel="nofollow">
https://ibb.co/4gXC1GY" rel="nofollow">



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EmPro Audio


Posted By: jbl_man
Date Posted: 28 May 2022 at 10:47am
Originally posted by EmPro EmPro wrote:

Is it true that S500D doesn't have any dc output protection?? If that module was so bad i asume the speakers had no chance Cry



This was common on amps from that era, S500d, Crown DC300a, Phase Linear 700b, MM AP 360, none of them had any DC protection. Speaker fuses need to be fitted in-line.
Martin Audio even fitted big electrolytic caps into their bass cabinets to protect the drivers.


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Be seeing you.


Posted By: EmPro
Date Posted: 28 May 2022 at 10:48am
Here i have a Crown D75,the fault was just one output transistor....yeah...strange..all the other components perfectly fine lol,ofcourse i replaced both outputs,the drivers where totaly fine so no need replace,the amp is working flawless now,tested in heavy load untill the case temperature got 50-55c:

https://ibb.co/MVsxYZ7" rel="nofollow">
https://ibb.co/xhXp9MZ" rel="nofollow">
https://ibb.co/Fz18wsQ" rel="nofollow">


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EmPro Audio


Posted By: EmPro
Date Posted: 28 May 2022 at 10:49am
yeah...i got the point mate,cheers.

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EmPro Audio


Posted By: EmPro
Date Posted: 28 May 2022 at 11:10am
This HH MA100 was a case of some sort of liquid damage as the marked circuits was covered in some sort of sticky thing,C7 was exploded LOL and all the other capacitos where done...strange but true...all the transistors survived,predrivers,drivers and outputs all original,so after full recap and one resistor replaced related to C7 i fired it up and surprise: 47vcc on outputs with all the parts measured with Fluke177 and shows good....then only one remains...the TL741 (UA741)...after replacement 0.037mv on outputs and fully working order,somehow the IC was putting out 6vcc on pin 6 (output pin) but the zenner diodes responsabile with +-15vcc supply were good.
https://ibb.co/80GvQY2" rel="nofollow">
https://ibb.co/bBS5bsG" rel="nofollow">
https://ibb.co/2NtbH6m" rel="nofollow">
https://ibb.co/x3C2Bmj" rel="nofollow">
https://ibb.co/y8tgg6C" rel="nofollow">



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EmPro Audio


Posted By: jbl_man
Date Posted: 28 May 2022 at 11:20am
By the way, those 100w HH pa/guitar amps also had no protection, so will take out a speaker with 47vDC just as easily as a bigger one.


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Be seeing you.


Posted By: EmPro
Date Posted: 28 May 2022 at 11:31am
Originally posted by jbl_man jbl_man wrote:

By the way, those 100w HH pa/guitar amps also had no protection, so will take out a speaker with 47vDC just as easily as a bigger one.

Yeah i know LOL,but not so easy to blow up one LOL


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EmPro Audio


Posted By: Earplug
Date Posted: 28 May 2022 at 11:32am
Originally posted by jbl_man jbl_man wrote:

The Inkel looks nice Earplug, that's not a brand we ever had here in UK. Looks about 1977-78-ish? About 80w p/ch into 8ohms?


Yes - that's about right. I've seen Inkel stuff here go for silly prices. They do have a good reputation among the local hifi buffs.   Smile




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Earplugs Are For Wimps!


Posted By: EmPro
Date Posted: 28 May 2022 at 11:34am
And here is a case of a Matrix UKP1000 removed from Titanic and sold on ebay as faulty due to overheating issues...dunno why LOLLOL
Ater 2kg of dirt removed,and a new case...the amp is up and runnig as new Smile
https://ibb.co/JcWGKxq" rel="nofollow">
https://ibb.co/DYDjZxN" rel="nofollow">
https://ibb.co/LNhHgTd" rel="nofollow">
https://ibb.co/72LRYJs" rel="nofollow">
https://ibb.co/Y03TP5R" rel="nofollow">
https://ibb.co/WPQZ0JV" rel="nofollow">
https://ibb.co/jDgJ42V" rel="nofollow">
https://ibb.co/C7P25DT" rel="nofollow">



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EmPro Audio


Posted By: EmPro
Date Posted: 28 May 2022 at 11:52am
Originally posted by M4trix M4trix wrote:

I must admit I have never seen a genuine Motorola MJ15003 with such markings printed at 45° and such font, especially without made in Mexico. If seen on ebay nowadays I would definitely think they're fake. Back in the 80's in miserable ex Yugoslavia, these transistors were hard to come by. The most powerful transistors on Yugo-communist-disaster market was a dodgy 2N3773 and manufactured by EI Nish. Motorola MJ15003/MJ15004 were in my wet dreams. Thank God those days are history. LOL  



There not fake mate,this are proper MJ15003,i wish i could find more of these...trust me i tryed to kill a pair of those in heavy load with no succes :) so i trust these Motorola MJ15003 with all my heart,on top of that Cloud fitted these outputs on there PA stuff.


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EmPro Audio


Posted By: EmPro
Date Posted: 28 May 2022 at 11:58am
By all means old...i cleaned them to look good LOLLOL
https://ibb.co/VVL1GTr" rel="nofollow">



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EmPro Audio


Posted By: EmPro
Date Posted: 28 May 2022 at 12:11pm
Here we have Vermona Regent 2023 with Tesla KD503 on outputs 2 each ch for i think 100w rms/ch these ,,things'' are loud as hell....as a fault the vu-meters didn't work (some ground wire was reduced to ash somehow) now is fully working with all the parts original from...1980 maybe?!? i did resoldered all the driver boards and changed the thermal paste on the KD503-s just to avoid further problems.Btw....it has dc speaker protection with relays on both ch :D

https://ibb.co/RDQSGT8" rel="nofollow">
https://ibb.co/HhZ4W5b" rel="nofollow">
https://ibb.co/5MNpGSR" rel="nofollow">


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EmPro Audio


Posted By: EmPro
Date Posted: 28 May 2022 at 12:36pm
Soundcraft Powerstation 600 i currently own 2 of these and one 1200,this one in the photos was loosing power at high volumes in 4R loads,so the main supply capacitors 6 of them needed to be replaced so i fitted 6x10.000uf/80v samwha capacitos,increasing a lot the power reserve with no side effects as the rectifier bridge can take the inrush current at start up,now the mixer is acting perfect with a lot of power reserve if needed Wink
https://ibb.co/M5gz90q" rel="nofollow">
https://ibb.co/yWqYhVm" rel="nofollow">
https://ibb.co/qYmMGrp" rel="nofollow">
https://ibb.co/jh4P56t" rel="nofollow">



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EmPro Audio


Posted By: EmPro
Date Posted: 28 May 2022 at 1:05pm
TSR 150X,nice little 1U amps with eq and mic function build in,V-FET toshiba outputs 2 per ch 2x75w rms 8r loads (only) i have three of them Smile all of them needed to be resoldered etc and put back together,no other internal faults founded:
https://ibb.co/3BMPqk5" rel="nofollow">
https://ibb.co/bLC1xPK" rel="nofollow">
https://ibb.co/CbfxBsJ" rel="nofollow">
https://ibb.co/jMnFY0B" rel="nofollow">


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EmPro Audio


Posted By: jbl_man
Date Posted: 28 May 2022 at 1:19pm
^These have cropped up before. TSR was something to do with Bass-Charrington/ Tobysound, they were installed in almost every pub in the UK in the late 80's. From memory, it even has a mic pre-amp in there too, for pub PA.

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Be seeing you.


Posted By: EmPro
Date Posted: 28 May 2022 at 1:21pm
Originally posted by jbl_man jbl_man wrote:

^These have cropped up before. TSR was something to do with Bass-Charrington/ Tobysound, they were installed in almost every pub in the UK in the late 80's. From memory, it even has a mic pre-amp in there too, for pub PA.

Indeed they have :D


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EmPro Audio


Posted By: EmPro
Date Posted: 28 May 2022 at 1:38pm
Sorry about the quality of the pictures,just ss from an old video,the ideea comes when (as usual for the BK MXF range) the TIP-X vu-meter power stabilizer blows up and smoked the Vu-meters to deathLOL
https://ibb.co/3mR4nQc" rel="nofollow">
https://ibb.co/f4Swkjs" rel="nofollow">
https://ibb.co/9ND0n0L" rel="nofollow">

BK MXF 400
Looks amazing in my home desk Big smile
I also added relay dc speaker protect...for no reason LOLLOL


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EmPro Audio


Posted By: EmPro
Date Posted: 28 May 2022 at 2:14pm
Jbsystems AX200 nice little 1U toy with toshiba 2SC5200/2SA1943 on outputs,i like the way they build these ones,just some loose connections in the psu side and up and running:
https://ibb.co/DPXD4S7" rel="nofollow">


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EmPro Audio


Posted By: EmPro
Date Posted: 28 May 2022 at 2:46pm
Citronic Conquest C12 (V12) same amps by all means,this one faulty on ch1,2 blown BUZ outputs and shorted BTA12 (the 12amps  triac from crowbar protection),remember that these series have smd driver boards that tends to suicide and almost impossibile to repair Cry also the output devices are a mix of single and dual die lateral mosfets...not something i like to much....
https://ibb.co/5kFX78R" rel="nofollow">
https://ibb.co/JqVD85S" rel="nofollow">
https://ibb.co/MMZFpYr" rel="nofollow">


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EmPro Audio


Posted By: Lucasdude
Date Posted: 28 May 2022 at 2:50pm
Originally posted by jbl_man jbl_man wrote:

^These have cropped up before. TSR was something to do with Bass-Charrington/ Tobysound, they were installed in almost every pub in the UK in the late 80's. From memory, it even has a mic pre-amp in there too, for pub PA.


Ah, Tobysound. That takes me back. Didn't they buy a ton of Wharfedale Diamonds with their own badge on?


Posted By: EmPro
Date Posted: 28 May 2022 at 3:04pm
Power Acoustics APK 2240
Output: 2x230w rms 4r
Output devices 2x MJ15001 and 2x MJ15002 per ch
Faults: broken psu capacitors from the main board,cold solderings,so new samwha caps fitted,new thermal paste on all outputs and drivers,and remade all the solderings,the amp is working flawless since:
https://ibb.co/ZN5RB9N" rel="nofollow">
https://ibb.co/mHhWsbS" rel="nofollow">


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EmPro Audio


Posted By: EmPro
Date Posted: 28 May 2022 at 3:21pm
Poor Crest Audio P4000 comes with right ch proper blown up,all the 12 outputs 2SB and 2SD,both drivers,predrivers,emitter resistors,bias diodes,op-amp etc etc Cry so i place it as BER for parts,but one of my friends needed 5-600w of pure mono power for a bass...so...now is working as mono bass amp on the good left ch,so still in service,as is full stabile in 2R loads cand easly drive 2 4R speakers with no problem,and the jumper i made on the output board also activate the vu-meter on the faulty ch as well Clap ps: already removed the right ch when i tooked the photos.
https://ibb.co/cgJv5FD" rel="nofollow">
https://ibb.co/BVbXK7H" rel="nofollow">


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EmPro Audio


Posted By: Earplug
Date Posted: 28 May 2022 at 3:46pm
I am just wondering if all these (wonderful) old amps are old projects, now done & gone - or stuff you still have lying around? And if the latter, how much room do you have in your house for anything else - like furniture - or clothes, etc!  LOL LOL LOL




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Earplugs Are For Wimps!


Posted By: EmPro
Date Posted: 28 May 2022 at 3:51pm
Originally posted by Earplug Earplug wrote:

I am just wondering if all these (wonderful) old amps are old projects, now done & gone - or stuff you still have lying around? And if the latter, how much room do you have in your house for anything else - like furniture - or clothes, etc!  LOL LOL LOL



Well....this 3x4m room now is full....LOLLOL i also sold like 20-30 amps...and i kept like 60-70 of them LOL i like to collect and restore old PA stuff.

https://ibb.co/7vffqRJ" rel="nofollow">
https://ibb.co/dL2Kff5" rel="nofollow">





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EmPro Audio


Posted By: EmPro
Date Posted: 28 May 2022 at 4:01pm
Well...here just for fun and some crazy spl...i fitted two dual concentric speakers 100w rms each 8R in parallel so 4R load 200w into a combo 2x12 speaker cabinet,and the amp to drive them HH MA150 (150w rms) not happy with the weight,but happy with the sound LOLLOL
https://ibb.co/ZhxhP8n" rel="nofollow">
https://ibb.co/st3j06g" rel="nofollow">


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EmPro Audio


Posted By: EmPro
Date Posted: 28 May 2022 at 4:09pm
Crazy Yamaha H5000 bought as untested from Ebay,turns out just the on/off switch was bad (high inrush current) look at the supply voltage per ch Big smile
https://ibb.co/Z6hjxKr" rel="nofollow">


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EmPro Audio


Posted By: EmPro
Date Posted: 28 May 2022 at 5:04pm
Studiomaster Powerhouse Horizon 1208
2X600w rms 4r
Fault: The dsp screen shows: Left Ch Overheating
Turns out the fault has gone after i resolder all the output boards (4 of them) as i din't find any blown parts or dirt in the ventilation tunnel,the fan was working as it should,still own this one Big smile i like the sound,quite strong,the psu does the heavy lifting,10 capacitors and huge transformer.
https://ibb.co/qWR2cgs" rel="nofollow">
https://ibb.co/5strFzq" rel="nofollow">
https://ibb.co/8K9fPvs" rel="nofollow">


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EmPro Audio


Posted By: woody2
Date Posted: 28 May 2022 at 7:38pm
Originally posted by jbl_man jbl_man wrote:

^These have cropped up before. TSR was something to do with Bass-Charrington/ Tobysound, they were installed in almost every pub in the UK in the late 80's. From memory, it even has a mic pre-amp in there too, for pub PA.


They look like the units MAM used.


Posted By: EmPro
Date Posted: 29 May 2022 at 12:44pm
Austin Armstrong 403 C Mk 2
Nice lateral mosfet amplifier
2x200w 4r
2 pairs of outputs per ch
Faults: broken connectors and joints (toured way to much i guess)
Also the main board have slots empty for more outputs so..i filled up for more stability Big smile
https://ibb.co/M54KpcF" rel="nofollow">


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EmPro Audio


Posted By: Lucasdude
Date Posted: 29 May 2022 at 12:49pm
Originally posted by EmPro EmPro wrote:

Austin Armstrong 403 C Mk 2
Nice lateral mosfet amplifier
2x200w 4r
2 pairs of outputs per ch
Faults: broken connectors and joints (toured way to much i guess)
Also the main board have slots empty for more outputs so..i filed up for more stability Big smile
https://ibb.co/M54KpcF" rel="nofollow">


I like everything about this post. From the name that sounds like a 60s British car to the unnessecary filling of empty slots. Man's got his Partridge on!


Posted By: EmPro
Date Posted: 29 May 2022 at 1:08pm
Originally posted by Lucasdude Lucasdude wrote:

Originally posted by EmPro EmPro wrote:

Austin Armstrong 403 C Mk 2
Nice lateral mosfet amplifier
2x200w 4r
2 pairs of outputs per ch
Faults: broken connectors and joints (toured way to much i guess)
Also the main board have slots empty for more outputs so..i filed up for more stability Big smile
https://ibb.co/M54KpcF" rel="nofollow">


I like everything about this post. From the name that sounds like a 60s British car to the unnessecary filling of empty slots. Man's got his Partridge on!

Adding an extra 14amp per ch is not quite unnecessary when you play flat in low impedances mate Wink my amplifiers are all bulletproof Smile and if is space for,why not? you gain thermal stability,less thd and stress on the outputs as being connected in parallel they share the total output current,so less current for each output device mean less heat dissipation etc etc


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EmPro Audio


Posted By: EmPro
Date Posted: 29 May 2022 at 1:13pm
As we all know already there's always room for major improvements in any amplifier ever made on this planet,doesn't matter if manufactured in 1960's or 2045 LOLLOL
The only amplifiers i didn't do any sort of modds in them are the Crown Macrotech/Microtech/Powertech series and the ASHLY FET2000m and FTX2001 Series 3,coz i like the way they perform and the ASHLY's are damn overengineered,they play just fine at 1r on outputs,they made these amps to perform in low impedance as the power in 8r is just 250wpc from 16 outputs....a joke isn't it? but as soon as you go under 4r per ch...they show what are capabile of Big smile now imagine to fit dual die lateral fets on these amps....will be like 16 outputs per ch....damn....LOLLOL will be an 0.1r per ch stabile amp (if psu can keep the task) LOLLOL like the old CS800 Comercial Series the 4U monsters with 10 outputs per ch plus 2 drivers that helps as well...if in good working order they play dead short on output at full volume untill the thermal relay kicks in without any sort of internal parts damage Clap and this was tested by me as i have one home,as well as a BGW 750b not the same amps by far btw.
Happy as well with Macrotech's on 2r jobs if proper biased 300-320mvdc on each side of the outputs (2 adjustments per ch needed)


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EmPro Audio


Posted By: simonp1100
Date Posted: 29 May 2022 at 2:10pm
Pretty sure that Austin Armstrong amplifiers were done / designed by someone at C-Audio or an ex-C-Audio engineer (Lee, was it anything to do with you ?) Wink


Posted By: EmPro
Date Posted: 29 May 2022 at 2:36pm
Originally posted by simonp1100 simonp1100 wrote:

Pretty sure that Austin Armstrong amplifiers were done / designed by someone at C-Audio or an ex-C-Audio engineer (Lee, was it anything to do with you ?) Wink

Indeed looks like a combination of RA and ST c-audio's now that you mention it,hmmm Confused
 



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EmPro Audio


Posted By: EmPro
Date Posted: 29 May 2022 at 2:57pm
Boost DA-1000
Bought from ebay as untested,one volume pot has been changed the knob losted,and one binding post broken,after visual inspection i fired it up and is working as it should without any issues,when i will have time i will make it pieces and restore it,no much info about this amp on google,but as the back panel says: 2x300w 8r and 2x400w 4r,judging by the massive psu it has...i beleve the specs are true LOLLOL

https://ibb.co/qszSH87" rel="nofollow">
https://ibb.co/Ks4hN52" rel="nofollow">
https://ibb.co/Xzhmm2X" rel="nofollow">
https://ibb.co/SPHCYV4" rel="nofollow">


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EmPro Audio


Posted By: EmPro
Date Posted: 29 May 2022 at 4:15pm
Sorry about the photo,ss from an old video of an Klynstrom Mosfet 1200 amplifier that i bought as faulty and ideed it was,broken solderings all over the place...i found the dc relay flying around in the case,most of the mosfets with legs off the pcb,he was giveing to me some work to do,the heatsinks are live so isolated from the amp ground case as the mosfets are fitted with no isolation betwin them and heatsink,so after i make it peaces and restore it the amp was working just fine and the sound is amazing,as specs we can say he easly deliver 2x600w rms in 4r,have 10 outputs per ch single die lateral mosfets in my case here 5 Exicon 10N20 and 5 Exicon 10P20 Ps: Still own this one back home Big smile

https://ibb.co/3C0vjLP" rel="nofollow">


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EmPro Audio


Posted By: Earplug
Date Posted: 29 May 2022 at 4:23pm
Originally posted by EmPro EmPro wrote:

Boost DA-1000
Bought from ebay as untested,one volume pot has been changed and knob losted,and one binding post broken,after visual inspection i fired it up and is working as it should without any issues,when i will have time i will make it pieces and restore it,no much info about this amp on google,but as the back panel says: 2x300w 8r and 2x400w 4r,judging by the massive psu it has...i beleve the specs are true LOLLOL

https://ibb.co/SPHCYV4" rel="nofollow">


Man - I do love these old amps with male XLR's on the O/P! A repairman's dream!   LOL









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Earplugs Are For Wimps!


Posted By: Lucasdude
Date Posted: 29 May 2022 at 4:28pm
Originally posted by EmPro EmPro wrote:

Originally posted by Lucasdude Lucasdude wrote:

Originally posted by EmPro EmPro wrote:

Austin Armstrong 403 C Mk 2
Nice lateral mosfet amplifier
2x200w 4r
2 pairs of outputs per ch
Faults: broken connectors and joints (toured way to much i guess)
Also the main board have slots empty for more outputs so..i filed up for more stability Big smile
https://ibb.co/M54KpcF" rel="nofollow">


I like everything about this post. From the name that sounds like a 60s British car to the unnessecary filling of empty slots. Man's got his Partridge on!

Adding an extra 14amp per ch is not quite unnecessary when you play flat in low impedances mate Wink my amplifiers are all bulletproof Smile and if is space for,why not? you gain thermal stability,less thd and stress on the outputs as being connected in parallel they share the total output current,so less current for each output device mean less heat dissipation etc etc5


Don't get me wrong, my friend. I am very much a fan of the over engineered, turbo charged and Top Fuel loaded just for the Hell 'uv it! Maybe next time the Perp should Just dig a deeper hole after he/she has killed something!


Posted By: Lucasdude
Date Posted: 29 May 2022 at 4:29pm
ITS ALIVE!!!


Posted By: EmPro
Date Posted: 29 May 2022 at 9:39pm
Originally posted by Earplug Earplug wrote:

Originally posted by EmPro EmPro wrote:

Boost DA-1000
Bought from ebay as untested,one volume pot has been changed and knob losted,and one binding post broken,after visual inspection i fired it up and is working as it should without any issues,when i will have time i will make it pieces and restore it,no much info about this amp on google,but as the back panel says: 2x300w 8r and 2x400w 4r,judging by the massive psu it has...i beleve the specs are true LOLLOL

https://ibb.co/SPHCYV4" rel="nofollow">


Man - I do love these old amps with male XLR's on the O/P! A repairman's dream!   LOL



Yeah....hate this one too LOLLOL 99% of the output devices failure comes from this LOLLOL





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EmPro Audio


Posted By: EmPro
Date Posted: 29 May 2022 at 9:40pm
Originally posted by Lucasdude Lucasdude wrote:

Originally posted by EmPro EmPro wrote:

Originally posted by Lucasdude Lucasdude wrote:

Originally posted by EmPro EmPro wrote:

Austin Armstrong 403 C Mk 2
Nice lateral mosfet amplifier
2x200w 4r
2 pairs of outputs per ch
Faults: broken connectors and joints (toured way to much i guess)
Also the main board have slots empty for more outputs so..i filed up for more stability Big smile
https://ibb.co/M54KpcF" rel="nofollow">


I like everything about this post. From the name that sounds like a 60s British car to the unnessecary filling of empty slots. Man's got his Partridge on!

Adding an extra 14amp per ch is not quite unnecessary when you play flat in low impedances mate Wink my amplifiers are all bulletproof Smile and if is space for,why not? you gain thermal stability,less thd and stress on the outputs as being connected in parallel they share the total output current,so less current for each output device mean less heat dissipation etc etc5


Don't get me wrong, my friend. I am very much a fan of the over engineered, turbo charged and Top Fuel loaded just for the Hell 'uv it! Maybe next time the Perp should Just dig a deeper hole after he/she has killed something!

Got you mate Clap


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EmPro Audio


Posted By: EmPro
Date Posted: 30 May 2022 at 11:10am
FBT Evolution 400E
2x200w 4r
Output modules are STK,this one comed as faulty due to a permanent background noise and a bad cosmetic shape,so after a full recap on the output board (5-6 capacitors) fully resoldered (toke me like 3hr to do it) including the mixer side,fixed the zobbel network as it was blown (i suspect some HF oscilation) fitted binding posts on outputs (original were jack's 6.35mm) and a full body paint the mixer is working great,the job was done 3yrs ago and is working since without any issues on two wharfedale pro evp12's Big smile and i must say..this toy have some guts.
https://ibb.co/WBmfSKk" rel="nofollow">


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EmPro Audio


Posted By: EmPro
Date Posted: 30 May 2022 at 11:36am
Here is my beloved HH SM200 bought from Ebay faulty,and the faults was:
-Blown Output devices 2N3773HG
-Blown Drivers/predrivers
-Blown op-amp
-Blown supply op-amp zenners
-Blown bias superdiode transistors
-Blown psu capacitors
-Blown vu-meters lights
-And a dozen of resistors

What i did:
-Fitted new MJ21194G (OnSemi) Outputs
-Fitted new BD911/BD912 Driver and predriver transistors plus more efficient heatsinks on drivers
-Fitted new DIP 8 socket plus new op-amp (if my memory doesn't screw me i think it was LF351) and supply zenners
-Changed all the small transistors from the boards with MPSA42 MPSA92
-Replaced all the burnt resistors
-Fitted new samwha capacitors made for this from MAJ Electronics
-I moved the inputs on the back panel (looks more nice like this)
-Fitted binding posts on outputs
-Fitted output dc relay protection and coupling delay (no thumb anymore)
-Fitted white LED's in the vu-meteres
-New thermal paste were was needed
The mixer is working ice cold since then even if i run flat all day long in 4r load. Big smile still own it.

https://ibb.co/tbfT20Y" rel="nofollow">
https://ibb.co/5Lfb6nw" rel="nofollow">



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EmPro Audio


Posted By: EmPro
Date Posted: 30 May 2022 at 12:00pm
Is currently driveing two full range 15inch tops 200w rms each 150w lf driver 50w Hf driver,and damn is loud as hell Big smile
https://ibb.co/4S3T28j" rel="nofollow">
https://ibb.co/KhZjFf7" rel="nofollow">
https://ibb.co/wMHmc0f" rel="nofollow">
https://ibb.co/X4gQ4fN" rel="nofollow">


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EmPro Audio


Posted By: EmPro
Date Posted: 30 May 2022 at 12:45pm
Well...you don't do that on a 600w rms module CryCry
Studiomaster Powerhouse Horizon 1208 this was human mistake that could cost a lot,happened when was inspected i presume.
https://ibb.co/r3svxff" rel="nofollow">
https://ibb.co/X84P31s" rel="nofollow">
https://ibb.co/dJDyxdy" rel="nofollow">


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EmPro Audio


Posted By: EmPro
Date Posted: 30 May 2022 at 1:24pm
Poor HH VX-900 rusted to death...driver board with parts exploded...left ch outputs rusted and shorted to case,i rebuilded half of it and then due to cosmetic condition i just donate it to a guy who have a same one with a faulty ch,so the guy just stripped out my good ch and fitted in his one,now he enjoys a fully working HH VX-900 with a dozen of original spares Big smile
https://ibb.co/dmBMMNN" rel="nofollow">
https://ibb.co/FwH191b" rel="nofollow">


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EmPro Audio


Posted By: EmPro
Date Posted: 30 May 2022 at 2:05pm
This happens when you run flat bridge and the fan stops spinning (not on my watch) CryCry Matrix UKP1300,all mosfets done...all drivers,dozen of resistors,small caps etc etc so obviously BER,he became donnor parts for my ex rusted UKP1000 and the other working UKP1300 i own. Wink

https://ibb.co/fMRGYV3" rel="nofollow">
https://ibb.co/YdMpcvr" rel="nofollow">
https://ibb.co/zQFHvxX" rel="nofollow">


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EmPro Audio


Posted By: jbl_man
Date Posted: 30 May 2022 at 2:33pm
"This happens when you run flat bridge and the fan stops spinning"

Is there not a thermal cut-out on the heatsink? I'm looking hard, but can't see one from here?  


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Be seeing you.


Posted By: EmPro
Date Posted: 30 May 2022 at 3:22pm
Well,Andy calaims that all his amps are thermal protected and indeed this one have 4 thermal sensing ,,things'' looks like PTC-s straight in the heatsink filled with thermal paste but they didn't do nothing to prevent this amplifier to get hot to his destruction...the temperature was so big as the maiboard under the heatsink becomed yellow and the insulator was black from brown....so more then 120c were there....i pointed with the red arrows were the thermal ,,things'' are located,but no any mechanical thermal relay if you looking for one LOLLOL those 4 thermal tracking things (i call them things as i didn't even bother to measure them to see what they are,resistors,diodes etc etc)suppose to track the temperature of the heatsink and cut the speaker relay out...but somehow that didn't work...i'm sorry about the amp as it was well mentained,almost new Cry
If i'm wrong someone please enlight me,as no schematics available for these old UKP Series,and my other UKP1300 is still in good working order after 7 years of service on my watch,mainly used in stereo mode 4r per ch on full range,and i like what i hear Smile

https://ibb.co/JsRsbyk" rel="nofollow">


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EmPro Audio


Posted By: jbl_man
Date Posted: 30 May 2022 at 5:06pm
How daft. Would have been so simple to just fit a $2 thermal switch, to chop the power at 70c or 90c etc. 

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Be seeing you.


Posted By: EmPro
Date Posted: 30 May 2022 at 5:33pm
Originally posted by jbl_man jbl_man wrote:

How daft. Would have been so simple to just fit a $2 thermal switch, to chop the power at 70c or 90c etc. 

Indeed,simple as that....i don't know why Andy didn't do that...a 2$ 90c thermal switch would saved this poor amplifier from total destruction easly...you know what? i will do this mood for my other UKP1300 and UKP1000 to make sure that don't end up like this one if fan's go out.


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EmPro Audio


Posted By: njw
Date Posted: 30 May 2022 at 5:55pm
Originally posted by EmPro EmPro wrote:

Boost DA-1000
Bought from ebay as untested,one volume pot has been changed the knob losted,and one binding post broken,after visual inspection i fired it up and is working as it should without any issues,when i will have time i will make it pieces and restore it,no much info about this amp on google,but as the back panel says: 2x300w 8r and 2x400w 4r,judging by the massive psu it has...i beleve the specs are true LOLLOL

https://ibb.co/qszSH87" rel="nofollow">
https://ibb.co/Ks4hN52" rel="nofollow">
https://ibb.co/Xzhmm2X" rel="nofollow">
https://ibb.co/SPHCYV4" rel="nofollow">
  

 I'm sure I can remember Terralec selling those in the late 90's.


Posted By: njw
Date Posted: 30 May 2022 at 6:14pm
Originally posted by EmPro EmPro wrote:

This happens when you run flat bridge and the fan stops spinning (not on my watch) CryCry Matrix UKP1300,all mosfets done...all drivers,dozen of resistors,small caps etc etc so obviously BER,he became donnor parts for my ex rusted UKP1000 and the other working UKP1300 i own. Wink

https://ibb.co/fMRGYV3" rel="nofollow">
https://ibb.co/YdMpcvr" rel="nofollow">
https://ibb.co/zQFHvxX" rel="nofollow">
   

 Coincidentally, I had an STR2000 that suffered a dodgy fan, that also kept chugging away until it got very, very hot, luckily I noticed the electrical burning smell coming from the amp rack and shut it off before too much damage was done. If I recall correctly the only blown components were a couple of driver transistors so the amp still worked but was down on power. I was a big fan of the STR amps having owned or used every model over the years from the 600 right up to the 3000 but as they got older they became very 'needy' and there always seemed to be one of them away for repair.


Posted By: EmPro
Date Posted: 30 May 2022 at 6:21pm
,,I'm sure I can remember Terralec selling those in the late 90's.''

These amps are build like a tank,if proper mentained will serve for another 32 years Big smile


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EmPro Audio


Posted By: EmPro
Date Posted: 30 May 2022 at 6:33pm
,,Coincidentally, I had an STR2000 that suffered a dodgy fan, that also kept chugging away until it got very, very hot, luckily I noticed the electrical burning smell coming from the amp rack and shut it off before too much damage was done. If I recall correctly the only blown components were a couple of driver transistors so the amp still worked but was down on power. I was a big fan of the STR amps having owned or used every model over the years from the 600 right up to the 3000 but as they got older they became very 'needy' and there always seemed to be one of them away for repair.''




Well mate,every amp made in good days that have more then 10 years on service needs to be 100% restored,all the way down to pieces and rebuild back with proper resolderings all over the boards,thermal paste changed if no pads ofcourse,all capacitors checked,power resistors were big currents are flowing checked,and i ensure you that you have a nice and proper amp running for another 10 years easly,but most of the people don't do that so that's why old amps keeps falling,most of the people don't even clean the dust out of them....not to mention about bias and offset adjustments....from hundreds and hundreds of amps that i fixed,checked etc not even one been in correct bias value....and we all know what happens if you play with wrong bias Confused


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EmPro Audio


Posted By: EmPro
Date Posted: 30 May 2022 at 6:56pm
I have STR3000 as well in working order but tired,and i don't use it anymore untill i make him pieces,full recap,full resolderings,new thermal paste and a full check of all the rest of the parts Big smile

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EmPro Audio


Posted By: EmPro
Date Posted: 30 May 2022 at 7:18pm
Speaking of thermal protection,4 years ago i bought from Ebay a Peavey XR886 powered mixer faulty ofcourse....heavy unit with two transformers,6 TO3 outputs per ch and the smallest heatsink i've ever seen on a 2x300w rms unit so far,so it was tottaly dependent of the 120mm force air cooling fan to stay cool,the fan is fitted right under the unit blowing straight in the middle of the small heatsink were the 12 To3 outputs are....the fault was blown outputs (has been repaired before as i found 10 types of bjt's there lol) so no wonder why he exploded again,after i replaced all the outputs with capabile MJ21194G/MJ21193G and the 4 psu capacitors (just to avoid future problems) the mixer worked as new and all nice and good,so i pack it in a nice box and send it 3000km away,on arrival i've pluged it on a pair of Peavey HiSys 2,4ohm hungry 4inch coil drivers,so i push it in 0Db and the sound was fine...for 10min only,then total silence....i went straight to the mixer and it was in protect mode!!! Total shock for me as i know when i do something i do it for 20 years...not for 2 months...so i unpluged the speakers and start to check the mixer as no smoke or smell in the air...when i touched underneath where the fan is my skin from the fingers almost sticked on the body lol....a damn small piece of carboard entered in the fan and block it from spinning...so the mixer was playing those 10min at full load without any cooling so the 90c mechanical thermal relay had kicked in and saved the mixer...after i unblock the fan and let it cool for 10min all was back to normal and the mixer is working great since.
Not mine in the photo,but same:
 
https://ibb.co/RY51JzM" rel="nofollow">


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EmPro Audio


Posted By: njw
Date Posted: 30 May 2022 at 7:48pm
 I once saw one of the older XR300's get fed half a pint of lager whilst it was running at full power, after letting it dry out for a while and giving the insides a squirt of isopropyl it carried on working just fine much to our surprise, tough amps, Peaveys! Smile


Posted By: EmPro
Date Posted: 30 May 2022 at 8:00pm
I still own two CS800x the 3U ones,fully restored as new,one CS1000X as well restored as new piece by piece and an old CS800 Comercial Series 4U heavy monster that can be used as wellding machine LOLLOL

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EmPro Audio


Posted By: jbl_man
Date Posted: 30 May 2022 at 8:08pm
Love the 1980's  Peavey CS series amps, and quite easy to overhaul, once you get your head around the fact than Americans can put a man on the moon, but cant standardise case screws! There must be, (not exagerating here) 40 screws holding it together, a mixture of machined screws, (cross head and slotted) self tappers, torx screws, bolts and washers, all mostly random sizes. Bonkers. 

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Be seeing you.


Posted By: EmPro
Date Posted: 30 May 2022 at 9:15pm
Indeed mate LOLLOL you need to be a mechanic first to have all the tools from the planet if you wanna fix CS series from Peavey LOLLOL once you have the tools to take a CS800 apart...you can take apart any amplifier ever made LOLLOL

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EmPro Audio


Posted By: EmPro
Date Posted: 31 May 2022 at 9:20am
My CS1000x next to my Peavey UL15's,ss from old video,however i do have all the photos from when i restored this amplifier as new on my other laptop (not with me right now) but i will post them in the future:
https://ibb.co/X8YZc9n" rel="nofollow">


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EmPro Audio


Posted By: Earplug
Date Posted: 31 May 2022 at 9:32am
Originally posted by jbl_man jbl_man wrote:

Love the 1980's  Peavey CS series amps, and quite easy to overhaul, once you get your head around the fact than Americans can put a man on the moon, but cant standardise case screws! There must be, (not exagerating here) 40 screws holding it together, a mixture of machined screws, (cross head and slotted) self tappers, torx screws, bolts and washers, all mostly random sizes. Bonkers. 



Hahaha - that is so true. I had a couple of old Peaveys and working on them was an adventure. But they were amazing workhorses and rarely needed any serious tinkering.  Smile

I guess that the newer Chinese stuff is an improvement there - as all the screws in those now tend to be the same - even if something larger or a bit longer is needed!  LOL LOL LOL





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Earplugs Are For Wimps!


Posted By: EmPro
Date Posted: 31 May 2022 at 9:34am
Speaking of devil LOLLOL one of my fully restored CS800x:
https://ibb.co/vxpfpTv" rel="nofollow">
https://ibb.co/HDx8mFj" rel="nofollow">
https://ibb.co/JB6TcmD" rel="nofollow">
https://ibb.co/mzhmrMf" rel="nofollow">
https://ibb.co/w44wFdD" rel="nofollow">


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EmPro Audio


Posted By: EmPro
Date Posted: 31 May 2022 at 9:38am
,,I guess that the newer Chinese stuff is an improvement there - as all the screws in those now tend to be the same - even if something larger or a bit longer is needed!''

Now you see why i like 1980's/90's stuff LOLLOL


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EmPro Audio


Posted By: EmPro
Date Posted: 31 May 2022 at 10:05am
Avitec Beta 500 amplifier,4 outputs per ch (2xK135 2xJ50) from factory,the red dot marked outputs were added by me later on for more stability,the amplifier still use all the original parts,no issues,still own it,got as well the Beta 800 basically same amplifier but with 4 pairs of outputs per ch from factory and obviously a more capabile transformer,one of my good friends is useing it.
This Beta 500 runs ice cold no matter what and how long Big smile

https://ibb.co/hHVSjmM" rel="nofollow">


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EmPro Audio


Posted By: EmPro
Date Posted: 31 May 2022 at 10:22am
Still own this Avitec Pro Beta 1200 Seven Series
Bought as faulty,the left ch was makeing big thumb at start in speaker and i couldn't hear the 30A dc protection relay kick in,so i suspected a faulty relay always coupled...when i removed the module...surprise....i found a 2.5mm copper bar soldered betwin relay legs on output...so no more dc protection or coupling delay,i removed the bar and checked the relay and was good...the fault was if i recall good a 22r resistor in the supply of relay circuit..after resistor replace the relay kicks in as the other one perfectly,no more thumb at start LOLLOL,ofcourse i made all the amplifier pieces and rebuild back,also changed all the vu-meter led's to custom colours LOLLOL
The amplifier have 12 outputs per ch 6-K135 and 6-J50 and a power of 2x600w 4r all day and night long,never seen this amp to get barely warm even.
And yeah,the soft start resistor has been changed by someone and bolted to case,good ideea so i left it like that,no other faults with this amplifier,the psu capacitors 4 per ch still good by that time,but now will need new ones to avoid bigger problems,as the Hitachi's are obsolete these days.
https://ibb.co/G5kx3SF" rel="nofollow">


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EmPro Audio


Posted By: EmPro
Date Posted: 31 May 2022 at 11:23am
RAM AUDIO MB 1500
2x1100w 2r
2x700w 4r
Bought as left ch faulty (why is always left ch dunno LOLLOL) the ch was stuck in protect mode,so i toke the module apart and start with the outputs...and good...drivers good...no burnt marks....went to connectors and here is the design flow in these amplifiers..they put the main connectors of the modules right in the spinning blades of the 120mm fan..so all the crap and moisture and god knows what more is going straight in the connectors...after i cleaned the connectors and remade some almost corroded circuits and solderings the amplifier was still in protect mode on left ch,the fault was the the low negative voltage TO220 regulator shorted to death (crap betwin his legs as both regulators are next to connectors)...after i replaced both of them the amplifier is working great,still in use now,ofcourse new thermal paste was added on all the outputs,stabilizers etc etc,all soldering remade etc etc i don't like to open one amp 10 times,so i just do proper job from beginning and no headache later on LOLLOL
https://ibb.co/2S89b5r" rel="nofollow">
https://ibb.co/C2JW7nS" rel="nofollow">
https://ibb.co/0Bwhs8m" rel="nofollow">
https://ibb.co/Z6hY50Z" rel="nofollow">


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EmPro Audio


Posted By: EmPro
Date Posted: 31 May 2022 at 12:01pm
Philips AH 594 bought as faulty (first photo not mine,just to show the internal) no sound on outputs...turns out that the old TO3 Motorola's were shorted to death,so i replace them with proper MJ21194/MJ21193 and the drivers with TIP29/TIP30c,no resolderings needed as it was like new lol,i added binding posts on outputs,jack's on inputs,and a relay coupling delay as i didn't liked the start thumb in the speakers,also a nice autocolant over the wood top cover Big smile still own this one.
https://ibb.co/nn8nB0d" rel="nofollow">
https://imgbb.com/" rel="nofollow">
https://ibb.co/F4h4KPK" rel="nofollow">


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EmPro Audio


Posted By: EmPro
Date Posted: 31 May 2022 at 1:30pm
This Crown XLS602 bought from ebay as faulty unit (not power on) was a case of head scratching....the amplifier looked so good in photos,almost new,so i was tempted and i bougt it,when i open it i was shocked....every single wire from it was cutted in half,starting with power supply and finish with speakers cables....god know's why and by who,as the amplifier had no faults and looks new internal as well as external...after full rewiring the amplifier was working just perfect and i still own it.
I also had three C Audio GB602's basically same amps as XLS602 but in a 3U case,ugly as hell,bigger heatsinks and 120mm fan cooling,however they do good job in stereo mode 4R per ch on mid-tops duty beeing pushed in soft clip all day and night trouble free.
https://ibb.co/rtmc2Cv" rel="nofollow">


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EmPro Audio


Posted By: EmPro
Date Posted: 31 May 2022 at 2:30pm
Under the XLS602 is a C Audio ST400i,and this one by all means new,i got it like from the factory gates,not even a scratch or dust in or on it,this was the good part...the bad part was that he only played like 5 minutes before goes in thermal protect..doesn't matter the output power or output impedance,i start to check parts..and check and double check...all good....at the end of my patience i removed the 12 output mosfets 6x 2SK1058 and 6x 2SJ162 and start to check them...all good....damn..i fit just one ch back 3 pairs of random mosfets from the 12's and the amp was cool and working good...after i fixed the remaining 3 pairs the thermal problem started again....so i removed the last 3 pairs and fitted 3 other pairs i had for spares at home and surprise...the amp was running ice cold....after more testing i found just one mosfet bad from the 3 pairs that shows good on any device you test but somehow in the circuit is causing big trouble for the whole bunch leading to thermal cut-out,after the issue was solved i filled up the remaining 2 empty slots per ch with good mosfets,so from 6 per ch now has 8 per ch as his big brother ST600i Big smileBig smile and it runs ice cold since,still own this one as well. (photo not mine,but same amp)
https://ibb.co/yF28M0c" rel="nofollow">


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EmPro Audio


Posted By: GAZ.
Date Posted: 31 May 2022 at 2:39pm
http://forum.speakerplans.com/poor-ppx_topic100483_page4.html?KW=Poor+ppx" rel="nofollow - Dead PPX

Here’s one of mine. Couldn’t be brought back from the dead

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100% Earth Moving Bass


Posted By: EmPro
Date Posted: 31 May 2022 at 2:56pm
Never had any citronic good old stuff,i do however want to get my hands on a PPX900 Big smile i like those monsters.

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EmPro Audio


Posted By: EmPro
Date Posted: 31 May 2022 at 3:09pm
Now from the same era..i had two Cloud CV1000,both faulty,both of them had two big feeding resistors blown to death that i replace them with double stronger ones (less heat) one of it have the supply dc relay circuits cracked but no visibile....i needed to trace the circuits to find out witch one is bad,after these two faults one was good working on both ch,all the Toshiba V-Fet's were good 8 per ch,the other one ch1 faulty but just one V-Fet blown...after i remove the faulty one the ch1 starts to work just fine...so i ordered one (original recovered fully working) v fet to solve the problem...when arrived and fitted i start the amp and surprise....the ordered v-fet must been fake as he destroyed all the remaining good fet's from the ch.....i was so pissed off,i've sent some ,,congrats'' to the seller then went to farnell and order 4-IRFP240 and 4-IRFP9240.....fitted in the amp and is working great ever since,ch1 hexfet ch2 V-Fet LOLLOL i've measured the output power and is only couple of mv difference betwin them.
https://ibb.co/QD0TTrW" rel="nofollow">
https://ibb.co/RSpwkhx" rel="nofollow">


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EmPro Audio


Posted By: jbl_man
Date Posted: 31 May 2022 at 3:17pm
A little earlier this one, RSD Studiomaster 800c from 1978. Built like a tank, and weighs about the same. 8x RCA mj15003, plus 2 drivers per channel. Access to the devices is by removing the two 5-inch fans.







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Be seeing you.


Posted By: EmPro
Date Posted: 31 May 2022 at 3:21pm
Originally posted by jbl_man jbl_man wrote:

A little earlier this one, RSD Studiomaster 800c from 1978. Built like a tank, and weighs about the same. 8x RCA mj15003, plus 2 drivers per channel. Access to the devices is by removing the two 5-inch fans.








Daamn mate....this is beauty....i'd like to get one home with me LOLLOL


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EmPro Audio


Posted By: EmPro
Date Posted: 31 May 2022 at 4:14pm
Here i have a ,,Macrotech from Japan'' LOL Pioneer M V-3000,not mine in the photos but i have the same one and same condition,bought it in working order,i made it peaces and restore it to full glory,this beast is only 2U in height but has two power transformers,another small one for the pre-amp board,two 15.000uf capacitors,16 Sanken outputs per ch and a mix of aluminum and copper heatsinks (visibile only when you remove the output modules out) in terms of output power 2x500w in 4r with a total power consumption of 2200w,the sound is superb,punchy and strong,seems to have endless power like all the good Pioneer stuff,still own it Big smile,this beast is heavy as hell (22.5kg) and almost keeps up with a Crown Macrotech 2400
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EmPro Audio


Posted By: jbl_man
Date Posted: 31 May 2022 at 4:26pm
Never seen one before, didn't know they were even made. Certainly never seen one in the UK. Looks very well built inside. Clap

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Be seeing you.


Posted By: kedwardsleisure
Date Posted: 31 May 2022 at 4:48pm
I've got a couple of the Pioneers here, they run stinking hot and draw in so much air they need monthly cleaning otherwise they fall over. Nicely made though, if somewhat complicated . They date from the mid 1990's.

The Cloud CV range need matched v-fets as the threshold voltage varies widely. There are also a few factory mods to prevent repeat blowups.



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Kevin

North Staffordshire



Posted By: EmPro
Date Posted: 31 May 2022 at 5:08pm
Originally posted by jbl_man jbl_man wrote:

Never seen one before, didn't know they were even made. Certainly never seen one in the UK. Looks very well built inside. Clap

The're overengineered,still working perfect after 20-22 years old with all the original parts,the only problem my one had was cold solderings on the output boards,loads of them...most of the outputs were basically doing nothing in the circuit,the amp is thermally tracked and he keeps playing with the remain outputs like a hero with less power and more heat ofcourse LOL


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EmPro Audio


Posted By: EmPro
Date Posted: 31 May 2022 at 5:27pm
Originally posted by kedwardsleisure kedwardsleisure wrote:

I've got a couple of the Pioneers here, they run stinking hot and draw in so much air they need monthly cleaning otherwise they fall over. Nicely made though, if somewhat complicated . They date from the mid 1990's.

The Cloud CV range need matched v-fets as the threshold voltage varies widely. There are also a few factory mods to prevent repeat blowups.



Did you check for cold joints on the output boards?? As my pioneer was full of them,after that sorted,the amp is ice cold on 4R duty as long as i want,even do good job in 2.66R mate.

Yeah,v-fet's are nasty if more then 2 outputs are used LOLLOL


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EmPro Audio


Posted By: kedwardsleisure
Date Posted: 31 May 2022 at 6:27pm
no, the amps were known to me from the day they were new and they always ran hot...in the real world of course, 4r per side and in clip all night.

I got an after hours call out to one that was going thermal and it was on a stage with the cabaret act in progress. Felt a right plonker on my hands and knees on the stage with a paint brush and vacuum cleaner trying to clear the dust as it was still playing......

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Kevin

North Staffordshire



Posted By: EmPro
Date Posted: 31 May 2022 at 6:58pm
I'm sorry to hear that mate,if you push in clip all night any amplifier will be warm,but a good one will do the job without problems and a bad one will explode,i didn't used my one in a rack, just in open space and it barely gets warm in 2.66r per ch,not in clip ofcourse,i don't like to drive amps in full clip,so maybe that's why you have thermal issues with them i presume,you cannot kill these amps with heat as are fully protected against Big smile

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EmPro Audio



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