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Audio Research Gamble

sirianni

sirianni

AK Subscriber
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I just bought an Audio Research D-100B from the bidding site, the seller stated that when he bought it it did not work because it keeps blowing fuses.I will be taking this to my tech in Buffalo for servicing, but was just wondering if anyone knows what might be causing this to happen.
 
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I hope you got a good deal on it. The D-100 is an amp I would personally steer clear of. Some of the parts for this amp are no longer available. ARC actually wants owners of this amp to contact them before sending in a unit for service to prevent the shipping costs associated with a non-repairable unit.
 
Blown fuses in solid state amps are usually caused by shorted output transistors. There can be a lot of other reasons, like bad power supply caps, rectifiers, even the transformer, but shorted outputs are the most likely.

Your tech will be able to figure it out quickly. If you are lucky, replacing the outputs and maybe the drivers will get you going again. The bad news is that in some designs an output transistor failure will cause everything upstream to fail, in which case you apparently have a boat anchor on your hands. Fingers crossed - good luck!
 
Several of the potted modules have been reverse engineered by somebody over at diyAudio. Unless the main transformer is bad, it can likely be fixed. Economically fixed is another story.
 
For most of my music-listening and technician life,I have always loved and endorsed Audio Research.In fact,most of my systems are using ARC gear.

But,in the case of this series of equipment that used modules that are servicable by replacemnent only,they oughta be ashamed of themselves:rant:
It would be a nice gesture if someday they would publish the schematics for these,in order that these units don't all land (NEEDLESSLY!) in a dump.......

I believe Conrad is correct in that some of the modules have been reverse-engineered,but re-creating one will not be a task for a novice.

Good luck,and I hope you have a really savvy tech:)
 
I always was scared of ARC. They always seem to use three times as many components trying to make their design perform the best it can be. Their early tube amps all oscillated above 35,000 HZ when pushed near clipping which could eat tweeters quickly and interfere with the sound of percussive instruments . Our techs would think they had a unit repaired but then upon burn in and final check out it seemed quite a few amps would either fail again or not perform as we felt they should. So we stopped accepting them for repair. Even the local dealer in town sent all the units back to the factory unless it was a simple tube replacement.
 
Thanks for all the info, it is sad that ARC doesen't have a fix for these Modules, a lot of metal in the scrape yard. My Tech in Buffalo is very good, I have never taken him anything yet that he couldn't fix, he is old school military trained.
 
I have found over the years it isn't so much where they were trained but how they apply their knowledge from school and the school of hard knocks. Two years on a work study program and if the unit said Professional Ampex I had it conquered. Same for A-77 and B-77 revox. Tape a thon and Ampex home decks were easy 99 % of the time. When reel to reel went away I never looked back. I stuck with designing and installing Discos, Commercial PA systems and communication systems. and helping the guys out with HTsystems that just didn't sound the way everyone thought they should. B&K electronics were a real pain, almost as bad as Yamaha, and some other brands. It seemed like every time time I turned around there was this new format or other change that kept HT a continuous learning experience. Now streaming has come along further complicating the modern HT system. I am glad I bailed when I did.
 
Does any have or know where I can find a manual for this ARC D-100B? I have the manual for the 100 it may be the same but not sure.
Thanks
 
sirianni said:
Does any have or know where I can find a manual for this ARC D-100B? I have the manual for the 100 it may be the same but not sure.
Thanks
Click to expand...

The manual you have is fine. The B version offered slightly better performance specs...damping factor, distortion, etc...
 
That was definitely not one of ARC's better units. Look at it this way. If it turns out to be too costly to repair you have a very nice case to build a DIY amp.
 
Old-School said:
That was definitely not one of ARC's better units. Look at it this way. If it turns out to be too costly to repair you have a very nice case to build a DIY amp.
Click to expand...

Eh...if that turns out to be the case, he would be better off parting it out to reclaim some of the original purchase costs.
 
I doubt the used parts market for these is very good as the modules are the main item of value. Well, also the output transistors, if they are all good. If it's blowing fuses I wouldn't bet on that. Theyre in matched sets.
Caps are definitely on the watch list due to age.
Though I guess a couple good used modules may go a long way to the purchase price if sold used. .
These are a pain to work on.. no joke. I really like ARC, but this is surely the bastard child if ever there were one.
 
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