Perreaux 2150B & SM2 issues

gyurika · 18th January 2012, 01:37 AM

Greetings to all from Canada,
I have recently acquired a Perreaux 2150B amp and SM2 preamp to drive my fully restored Gale GS401 speakers and I’m seeking advice on three issues:

Power switch: the amp will switch on but will not switch off normally. If I hold the switch depressed for several seconds the amp may power down when I release the switch. It can take several attempts to achieve this and if all fail I just pull the power cord out! Not a good idea.

Preamp gain: the output of the preamp is so high that I can reach maximum tolerable levels by advancing the volume control only to 7:00 o’clock position, where 6:00 is zero. Is this normal for this preamp? [/FONT][/SIZE]

The sound: I would characterize the sound of my system as clean, articulate, powerful and exhilarating for the first half hour. From that point on, however, it gradually becomes a joyless “music-in-your face” experience. Which is not only a great disappointment but entirely inconsistent with MOSFET design from a highly reputable source.

What can I do about the power switch? Do I need a different preamp? Can I tame the beast by changing interconnect and speaker cables or am I facing a major restoration project? And, if so, is it worth it? Your comments and suggestions would be very much appreciated.

Monte Verdi · 18th February 2012, 05:26 AM

These fine units were produced in the early to Mid 80"s so there powersupply caps, and Wima film caps are likely tired and exhausted, that has been my experience with Perreaux from this time period. The 2140B is a really fine amp when it is set up properly.

Problem with gain (preamp) could be Alps pot gone south, no good anymore.

On off switch (amp) likely needs replacing etc.

If your going to own an 80's Perreaux or any Class A Solid State from the 1980's you must be prepared to replace parts, and newer finer engineered parts today make these amps compete with some of the finest (IMO)! Solid State circuit design has not evolved that far from the the 1980's.

Luke · 18th February 2012, 07:24 AM

read this about the switch, they are known to fail...

Perreaux_Amps

I think the sm2 was pre cd, it was designed for lower gain sorces. You may need to use a voltage divider to reduce the gain.

18th January 2012, 01:37 AM	#1
gyurika diyAudio Member Join Date: Jul 2011	Perreaux 2150B & SM2 issues Greetings to all from Canada, I have recently acquired a Perreaux 2150B amp and SM2 preamp to drive my fully restored Gale GS401 speakers and I’m seeking advice on three issues: Power switch: the amp will switch on but will not switch off normally. If I hold the switch depressed for several seconds the amp may power down when I release the switch. It can take several attempts to achieve this and if all fail I just pull the power cord out! Not a good idea. Preamp gain: the output of the preamp is so high that I can reach maximum tolerable levels by advancing the volume control only to 7:00 o’clock position, where 6:00 is zero. Is this normal for this preamp? [/FONT][/SIZE] The sound: I would characterize the sound of my system as clean, articulate, powerful and exhilarating for the first half hour. From that point on, however, it gradually becomes a joyless “music-in-your face” experience. Which is not only a great disappointment but entirely inconsistent with MOSFET design from a highly reputable source. What can I do about the power switch? Do I need a different preamp? Can I tame the beast by changing interconnect and speaker cables or am I facing a major restoration project? And, if so, is it worth it? Your comments and suggestions would be very much appreciated.

18th February 2012, 07:24 AM	#3
Luke diyAudio Member Join Date: Sep 2001 Location: Wellington NZ	read this about the switch, they are known to fail... Perreaux_Amps I think the sm2 was pre cd, it was designed for lower gain sorces. You may need to use a voltage divider to reduce the gain. __________________ If you give a man a fish he will eat for a day. But if you teach a man to fish he will buy an ugly hat. And if you talk about fish to a starving man then you are a consultant. Dilbert

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18th February 2012, 05:26 AM	#2
Monte Verdi diyAudio Member Join Date: Oct 2008 Location: Santa Fe,NM	These fine units were produced in the early to Mid 80"s so there powersupply caps, and Wima film caps are likely tired and exhausted, that has been my experience with Perreaux from this time period. The 2140B is a really fine amp when it is set up properly. Problem with gain (preamp) could be Alps pot gone south, no good anymore. On off switch (amp) likely needs replacing etc. If your going to own an 80's Perreaux or any Class A Solid State from the 1980's you must be prepared to replace parts, and newer finer engineered parts today make these amps compete with some of the finest (IMO)! Solid State circuit design has not evolved that far from the the 1980's.

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