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Old Croc
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Post Options Post Options   Thanks (0) Thanks(0)   Quote kedwardsleisure Quote  Post ReplyReply Direct Link To This Post Posted: 12 January 2024 at 12:45pm
Smokey Lab Gruppen LAB1200C module.

Wouldn't be friday without one....

Kevin

North Staffordshire

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Post Options Post Options   Thanks (0) Thanks(0)   Quote EmPro Quote  Post ReplyReply Direct Link To This Post Posted: 07 January 2024 at 11:51am
This blown mosfet kinda looks like a 30 year old woman ready to settle down LOL


Edited by EmPro - 07 January 2024 at 11:55am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote EmPro Quote  Post ReplyReply Direct Link To This Post Posted: 06 January 2024 at 5:55pm
ASHLY FET2000 FET2000m schematic for whoever will need it Smile from ASHLY Technical Service Support.
The O/P devices can be: 2SJ50 and 2SK135,2SJ56 and 2SK176,BUZ901 and BUZ906,BUZ900 and BUZ905,Exicon 10N20 and 10P20 and Exicon 10N16 and 10P16 Smile if you are rich enaugh you can always aim for dual die mosfets BUZ901D and BUZ906D or Exicon 20N20 and 20P20 LOL ofcourse the gate resistors needs to be resized Wink and bias calibrated if dual die O/P are used.


Edited by EmPro - 06 January 2024 at 6:08pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote EmPro Quote  Post ReplyReply Direct Link To This Post Posted: 05 January 2024 at 9:35pm
Yes it is LOL i didn't change the insulators as they shaped already,just cleaned them and changed the paste,i had more than 7 years ago a Lyonforge P400 the model with BK vu-meters and the very same internal amplifier like this one,i did abuse it a lot and i only manage one time to blow one fuse on the output 4A if i recall good due to a short circuit mid bass driver,but that one had Hitachi J50 and K135 in it,never had any oscilation problems,they are quite stabile amps to be honest :) but i think that P400 had a more generous transformer in it.

Edited by EmPro - 05 January 2024 at 9:36pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Xoc1 Quote  Post ReplyReply Direct Link To This Post Posted: 05 January 2024 at 9:23pm
Do the mica insulators actually overlap on the FET bases?
The tracks for the FET gates are very long with the gate resistors at the wrong end of the tracks, not good for stability, especially with Profusion FETs! Has it ever been used in anger? I would expect the output zobel resistors to be fried but they look OK.
Looks like a very minimal amount of transistors. At least it has Zener protection for the gate drive which helps survival with shorted outputs.
Loving the minimal single capacitor on a FET gate per channel, to try & stop any oscillation.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote EmPro Quote  Post ReplyReply Direct Link To This Post Posted: 05 January 2024 at 12:22pm
No excuses for thermal limiting now LOL
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Post Options Post Options   Thanks (0) Thanks(0)   Quote EmPro Quote  Post ReplyReply Direct Link To This Post Posted: 05 January 2024 at 12:20pm
Originally posted by jbl_man jbl_man wrote:

"Lyonforge A400 2x200w (on paper)"

When you have spare time, just run it up, and see what it is actually making at Clipping?


I will,as soon as i get home to my bench test equipment Wink and i will post the results,honestly i don't think will pass more than 100w rms each side LOL the secondary windings of the transformer are 2x42vac
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Post Options Post Options   Thanks (0) Thanks(0)   Quote jbl_man Quote  Post ReplyReply Direct Link To This Post Posted: 05 January 2024 at 11:39am
"Lyonforge A400 2x200w (on paper)"

When you have spare time, just run it up, and see what it is actually making at Clipping?

Be seeing you.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote EmPro Quote  Post ReplyReply Direct Link To This Post Posted: 05 January 2024 at 10:25am
Yes i know them LOL,the outputs are indeed lateral mosfets in this case Exicon 10N16 and 10P16 (160v 8A 125w),it seems that some manufacturers don't quite understand how r.m.s power works LOL adding a poor transformer and 20 reservoir caps will do nothing but haveing a burst power for 1 second and then less power than initial transformer had because he needs to feed the hungry caps as well as the outputs LOL so no,doesn't work like that LOL
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Earplug Quote  Post ReplyReply Direct Link To This Post Posted: 05 January 2024 at 9:58am
Originally posted by EmPro EmPro wrote:

I want to see more transformer as well LOL there is no way this small toy can handle 400w rms LOL also yes,the caps are 6.800uf/63v


Ok.

And are the o/p MOSFETS? In which case they are the thermal switches...  LOL LOL LOL

Are you familiar with AB Precedent amps? Quite well made (US) amps - but also believed that they could use slightly smaller transformers in their amps - as long as they had more than enough filter caps. I had a couple of their amps years ago and sold them as I don't think that their theory quite worked. Even (just) driving mids, never mind subs. You definitely need the copper... 





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Post Options Post Options   Thanks (0) Thanks(0)   Quote EmPro Quote  Post ReplyReply Direct Link To This Post Posted: 05 January 2024 at 9:50am
Real man's don't play with thermal switches mate LOL you have a mirror front panel just to see double the smoke when he comes out LOL
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Post Options Post Options   Thanks (0) Thanks(0)   Quote EmPro Quote  Post ReplyReply Direct Link To This Post Posted: 05 January 2024 at 9:47am
I want to see more transformer as well LOL there is no way this small toy can handle 400w rms LOL also yes,the caps are 6.800uf/63v

Edited by EmPro - 05 January 2024 at 9:49am
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