refurbing d200 soundstream amps.

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I have two SS D200 amps. (The early ones) that I have been using for a while. I would like to go through them and freshen them up to get rid of some mechanical power supply noise as well as hopefully clean up the turn on characteristics if possible. I have heard that although these amps sound amazing, the power supply could stand some improvements. I agree currently, but I don't know how these performed when new since I wasn't the original owner.

Anyone here ever worked on these amps? Are there any common things to look for to repair? Any upgrades I can perform while I'm in there? I do have a schematic for these and I'm handy with a soldering iron.

Thanks,

Brian
 
What sort of mechanical power supply noise do you have? The ones I've seen had the transformers clamped to the sink so they couldn't possibly make noise.

I'd suggest changing out all of the radial capacitors (the ones with 2 leads coming out of the bottom of the cap). All of the axial capacitors I've checked in these amps have been OK. If you want to change them, it won't hurt anything but probably isn't necessary. The radial caps tend to have defective seals and leak. Clean up any electrolyte that's leaked before installing the new caps.

How much DC offset do you have across the speaker terminals?
 
I assume the noise is the windings on the transformer in the power supply section. It's a high pitched mechanical noise coming from the chassis of the amps. Since the transformer isn't potted, I don't think the noise is necessarily a bad thing. But it's noticable to me even with the amp under the seat.

The biggest thing I'd like to improve is the power up/shutdown characteristics if possible. After turning on the amp, the sound fades in with a very distorted edge to it until the power supply rail gets up to where it needs to be. There are power down thumps I'd like to get rid of as well.

I haven't made any measurements on the amps at all.

Brian
 
I put them in new in late 80s and do not recall any noise or turn on/off issues....but that was a long time ago. We often used them on mid and highs and LP on mid and lows, so we did not run may on subs or bass playing full range. Not sure why, LP just seemed to have more power and SS clearer. I did do a 260Z with a single 10 on one, it worked fine, is only time I recall running bass on one. Sold a lot more LP and RF than SS at that time, at that place. SS ran hot too as I recall. On the other hand back then turn on/off noises were much more common and accepted, but I don't ever recall one distorting when it came on? I only have a rubicon around here and a newer one.
 
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