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Amp Internals 2

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kedwardsleisure View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote kedwardsleisure Quote  Post ReplyReply Direct Link To This Post Posted: 24 July 2019 at 9:50am
Can't remember the voltage but it was a 5kw loadbank at approx 5R resistive around 500hz
Kevin

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Post Options Post Options   Thanks (0) Thanks(0)   Quote jbl_man Quote  Post ReplyReply Direct Link To This Post Posted: 24 July 2019 at 12:12pm
Liking the dummy load in the video....4 cooker grill elements?  Smile
Be seeing you.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote kedwardsleisure Quote  Post ReplyReply Direct Link To This Post Posted: 24 July 2019 at 3:21pm
actually 5 industrial lab washer elements but that's another story
Kevin

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Post Options Post Options   Thanks (0) Thanks(0)   Quote kedwardsleisure Quote  Post ReplyReply Direct Link To This Post Posted: 24 July 2019 at 3:29pm
Quote Ken, Kevin you have no fear of things going bang



Yes I should charge danger money

Kevin

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JJax View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote JJax Quote  Post ReplyReply Direct Link To This Post Posted: 24 July 2019 at 7:59pm
REC PFM-3602 MOSFET
Made in Europe (Ukraine)
From their catalogue:

Power amplifiers series "Millennium" designed for high-quality amplification of audio signals as part of the professional sound reinforcement equipment complexes. Specifications: Power amplifier 2x1800 / 2 Ohm; 2x1000 / 4 ohms; 2x650 / 8 Ohm; 3600/4 ohms bridge; 2000/8 Ohm bridge, S / N 103 dB Weight 28 kg. 


Works fine at lower volumes but at higher volumes/bass hits, the "DC/TEMP" light lights up for a brief sec and then it trips it's mains relay until the input signal drops down or you lower the volume. At lower volumes it sounds good. Nothing seems to get hot, everything is clean, no signs of damage, filter caps measure good. Does this on both channels at the same level. Any ideas? No schematics for it anywhere, e-mailed REC UA today, let's see if they are willing or able to provide a schematic.



Edited by JJax - 24 July 2019 at 8:05pm
When life gives you lemons, sell them and use the money to buy more audio gear.
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kedwardsleisure View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote kedwardsleisure Quote  Post ReplyReply Direct Link To This Post Posted: 25 July 2019 at 9:57am
If that's the soft start resistor, it looks like it's been burning, suggesting the bypass relay isn't working, so I'd investigate that.
Kevin

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Post Options Post Options   Thanks (0) Thanks(0)   Quote JJax Quote  Post ReplyReply Direct Link To This Post Posted: 27 July 2019 at 1:04pm
Soft start delay works great. 
Fixed it yesterday. It was tripping early. Saw one of the small electrolytics had been leaking slightly so I pulled a bunch of them and many tested way out of spec. Changed them all and now it works great. Good sounding amp but real heavy, maybe a good amp to drive subs in an install.


Edited by JJax - 27 July 2019 at 1:05pm
When life gives you lemons, sell them and use the money to buy more audio gear.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote kedwardsleisure Quote  Post ReplyReply Direct Link To This Post Posted: 01 August 2019 at 3:38pm
Electro-Voice Q99, aka Dynacord SL1800.
Smoke fluid, beer, fine wine, who knows but it doesn't like it up it.



Edited by kedwardsleisure - 01 August 2019 at 4:51pm
Kevin

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Earplug View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Earplug Quote  Post ReplyReply Direct Link To This Post Posted: 13 August 2019 at 11:38am
Another lovely old skool (MOSFET) amp:-














1Kw of real power - and made locally:-






These amps seem to go on forever. This one just needed a good clean - one pot replacing...   Smile



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Post Options Post Options   Thanks (0) Thanks(0)   Quote bruce@bluff Quote  Post ReplyReply Direct Link To This Post Posted: 13 August 2019 at 1:16pm
OOH ultra high velocity that's a new one
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Post Options Post Options   Thanks (0) Thanks(0)   Quote jbl_man Quote  Post ReplyReply Direct Link To This Post Posted: 13 August 2019 at 1:27pm
A new one on me too. Looks like someone saw the front panel on an HH V800 and copied it.  Not seeing how that fan on the back is cooling those heatsinks on the sides though?
Be seeing you.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Earplug Quote  Post ReplyReply Direct Link To This Post Posted: 13 August 2019 at 2:02pm
Originally posted by bruce@bluff bruce@bluff wrote:

OOH ultra high velocity that's a new one


Haha, yes - but MOSFETS are supposed to be "faster" than BJT´s...   LOL


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