My Amp is Broken - Not Sure What to Do - Any Recommendations?


I went to turn on my Audio Research SD135 amplifier the other day, but it will not turn on. According to the Audio Research service technician I spoke to, the problem is a broken Thermal Trak module chip. He said that it is a temperature sensing component, and that replacements are no longer being manufactured. He said that it is a known problem, and that Audio Research will give me credit to purchase an Audio Research amplifier from an Audio Research authorized dealer. 

I was wondering if Audio Research makes anything powerful enough to drive Vandersteen 3A Signature speakers (which need between 100 - 200 watts of power)? I am using an Audio Research SP8 Mk II as a pre-amp.

I don't really have much of a budget and am not sure what to do. I would appreciate any advice. Thank you.
distortions
Parts go obsolete, I've had to run down a lot of obsolete parts, some companies have made products using discontinued parts, knowing before their production run that the parts had been discontinued!

If you really liked that amp, I'd contact Roy Mottram at tubes4hifi.com, he has designed many tube amps, preamps, and phono preamps. You could also contact Don Sachs, but it's unlikely that he'll do repairs, last I knew he was way behind in making his own amps and preamps. Anyway, those guys are big on tube circuit design and may have already worked on your problem for someone else.
Oh, there is one other option I could suggest. Vandersteens are not the most articulate speakers out there, so you can probably procrastinate doing a bridge rectifier mod to it, but there is a PS Audio 200C amplifier on eBay right now. I think he has come down at least 100, and it may be 100 and free shipping, I don't recall if he was throwing in shipping or not initially. $700 is still a little high for that amp, but it will drive the Vandys with no problems. I have a friend who is borrowing one of my 2 PS amps for his Vandy 2CE Signatures and he loves it. Obviously owning 2 of them, you know that for a transistor amplifier I really like them for the money. BTW, I would try offering him $550, and even that may be high for a stock amp, but no way would I pay more than 600 shipped, and make sure it's insured, clumsy delivery people can destroy an amp with the monster coil it has if they drop it the wrong way.

I think the slew rate is a crazy 400V per millisecond, my tube amp is 60? It owns speakers, back in the day it was one of only a few that could really drive the big Appoge speakers, which went down to 2 ohms. You will fry the amp if you plug or unplug your preamp or speakers while it's turned on though,  and the relay buzzes. A lot of folks think it's the coil, but the relay chatters, if you go that way, there is a company that makes a direct replacement for about 60 dollars. It's one of those, if it bothers you things. It's worth it because you would have to spend a ton to get another transistor amp that sounds as good, much less that can drive a load like the 200C or 200CX.

The other thing is, like most amps of its age, the bridge rectifiers suck! So at some point you really should replace them with Fred's, Hexfreds, or Stealth diodes, I prefer to use IXYS Freds from Partsconnexion, or Michael Percy Audio.  Anyone who can solder should be able to easily replace them for you. It wouldn't hurt to add some nice bypass caps to the power supply. One of mine has a TX2575 resistor on the input, and I am probably going to go through and replace all the resistors in it. I am a detail freak, it is just a shade dark, but like the old Forte F44 preamp, it's actually a pretty awesome viscerally pleasing sound, which is why I have never gone that far with one. I have replaced the caps on the boards with Black Gates, but the bridge rectifiers are what it really needs to fully come into its own. I have been told that some Levenson amps can really control speakers, I can't speak to that, but the PS amp owns what ever I have thrown at them.
 
“Vandersteen’s aren’t the most articulate...”

wait, what?  3A sigs will reveal the differences between whatever you put in front of them. 
Lous is correct, the 3s are warm and hide a lot of warts on the top end. Likely why they’re often used with rock music as a source, esp. CDs
+1 @Bigboltz,
-1 @ glowworm
If anyone finds Vandy's 'warm' or 'not articulate' aren't using the right equipment, or haven't set them up correctly.
Bob