Recommendations for MA-5100 cap replacement.

M Jarve

Audio Geek and NGE Freak
First, I would like to thank Mr. DeWick for his prompt email reply to my MA-5100 repair quote question. For better or worse, it was an easy fix this time, but I will certainly keep you in mind for any future issues I may have.

My 5100 had a problem where it would output varying amounts of DC at the speaker terminals, ranging from 0.2mV all the way to 27(!)VDC. I found the problem to be two fold; a faulty resistor and faulty cap. Although the problem was only in one channel, I replaced the same components in the other channel. The channel that was originally faulty now outputs a mere 0.1mVDC after 10 minuets of warm up, and more or less stabilizes there. The other channel was and still is at a respectable 15.4mVDC.

The question I have has to do with replacing some of the preamp caps. As it is, high-frequency content sounds rolled off compared to any other amp I have when the tone controls are at flat; my reference unit is a h/k 430 receiver, but the Mac sounds rolled off compared to all my other gear too. To remedy this, I have the treble control at the 3-o’clock position and this provided sufficient boost to the treble for my tastes. However, I have read many postings that suggest capacitor replacement in the pre-amp section, especially of the Mallory caps and Sprague “Trans-lytic” caps. Indeed, it was a Sprague Trans-lytic that failed in the power amp section and caused the severe DC offset.

I would like to take recommendations of what new caps to buy, and which ones generally should be replaced. I should say that I have a lot of Elna caps right now, but these are power supply grade caps (I am designing power supplies for a company that sells neon lighting systems for snowmobiles). Every cap that looks like one I would replace (the 4 big Mallory’s and the Sprague pre-amp output caps) I have an Elna replacement for. Would the Elna caps suffice, or it there a brand that is more preferable? Should I stay closely to the original values, or is there somewhere where a different value may “improve” sound?

Thanks for the input.
 
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