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Audio research preamp broken

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Posted on September 28, 2020 at 17:40:48
tunenut
Audiophile

Posts: 9068
Joined: July 18, 2000
So I bought the Reference One preamp new about 20 years ago and it has just worked.

But yesterday it broke in a very weird way. It was powered off but I looked over and saw a number of lights on. The volume and balance knobs have lights to indicate the level, one light on at a time. But the left side of both were all lit, not fully rather dimly but definitely lit. The power light was on dimly as well. I tried toggling power and it had no effect. Finally I removed power cord and plugged it back in. Well the lights are all off but the preamp is dead and does not power on.

I am lucky I live in california and have 2 arc authorized repair places within a reasonable drive.

But I am a bit worried about how expensive this might be. Have any tube experts seen these odd symptoms before and if so what is the best guess of the damage? Thank you.

 

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RE: Audio research preamp broken, posted on September 28, 2020 at 20:00:41
Chip647
Audiophile

Posts: 2315
Location: The South
Joined: December 24, 2012
The fancy-shmancy "electronically regulated automatic 45 second warm/up brown-out mute power supply" would seem to have given up the ghost.

 

That happened to me with an SP-9 years ago, posted on September 29, 2020 at 09:13:34
E-Stat
Audiophile

Posts: 29872
Joined: May 12, 2000
Contributor
  Since:
April 5, 2002
It was failure of an op amp in the mute circuitry. Wasn't especially expensive for ARC to repair.

 

RE: Audio research preamp broken, posted on September 29, 2020 at 13:20:04
airtime
Audiophile

Posts: 10546
Location: Arizona
Joined: February 4, 2003
The joys of having high performance gear - $$ repairs. Others have pretty much giving you the answer. Unfortunately after 20 years that piece is in need a full going over - by a pro!!!

When you buy this level gear, money can't be a concern. It should be part of the decision process when buying this level of gear. A reason I would LOVE to buy somethings of this level, but I can't afford, more like I don't want to afford repairing it.

Rebuild or sell. repairing is simply putting a temporary fix on it for now.

 

Thanks all- some comments..., posted on September 29, 2020 at 15:52:32
tunenut
Audiophile

Posts: 9068
Joined: July 18, 2000
yes I kind of thought the power system might have gone haywire. It's convenient not to worry about sending a loud pulse through your amp, but it's more complex than a simple switch.

I couldn't and can't figure out how multiple lights could go on through what is supposed to be a switch. But while I understand mechanical switches, I don't really know about electronic switches. I wonder if something else got blown out by a power surge? I guess the only way to find out will be to get it looked at.

So for airtime: This was the biggest splurge of my audio life. It was among the top tier of preamps at the time, and I have continued to love it, even as, disconcertingly enough, every new audio research preamp is reviewed as a big step up, and it is now antiquated according to reviewers. Still, if I get it working, it's fine enough for me. And yes, I know expensive preamps eventually need expensive repairs...it's part of the deal...sadly there is never a good time for an expensive repair, but it's all part of life. We'll see what happens.

 

RE: Thanks all- some comments..., posted on September 30, 2020 at 07:32:30
airtime
Audiophile

Posts: 10546
Location: Arizona
Joined: February 4, 2003
Sorry to sound like a wet blanket. I would bet money that your preamp is just as good as any of the new offerings. Me personally - I'd hold onto it and continue enjoying it. Again, being a wet blanket - I haven't gotten much joy from buying new gear in that last decade. I seem to be holding onto and enjoying my older gear MUCH more.

Maybe you can get an estimate to have it restored. It would still be a HELL of a lot cheaper than buying any new preamp.

Best of luck.

Also try posting over on the AudioKarma tube forum. There are one or two guys that specialize in ARC. It costs nothing to ask.

 

RE: Audio research preamp broken, posted on September 30, 2020 at 08:08:27
bouncy ball
Audiophile

Posts: 1095
Location: British Columbia
Joined: July 26, 2003
as you said, there is no good time for any repair. However, if you enjoy this preamp, after 20 yrs, it is worth to have it check, may be an overhaul again. I think it could be one of the op-amp went belly up as E-stat pointed out.

REf 1 is a very good preamp, I particularly enjoy the front panel design, it still has the classic ARC feel.

 

+1, posted on September 30, 2020 at 10:06:19
Mick Wolfe
Audiophile

Posts: 2517
Joined: October 10, 1999
Contributor
  Since:
September 4, 2000
NT

 

RE: Audio research preamp broken, posted on September 30, 2020 at 10:59:49
fredtr
Audiophile

Posts: 1311
Location: Phoenix
Joined: January 4, 2005
I have a couple of older ARC preamps, an SP3 and SP11. I like working on equipment so when I have had problems with these I repair and update them myself. I haven't seen a problem that matched yours, but the SP11 did have a PS problem that caused the lights to do unusual things, and no sound. It was just a capacitor, cheap, quick fix. I didn't post this because of that, it is to pass along the impressions I have of the ARC equipment, which is excellent design, build quality and components. I doubt you will ever have to replace the coupling capacitors, about the only thing that I have seen age in mine are the tubes and electrolytic capacitors.

The schematics are very good, and my experience is that the equipment has been very easy to repair. ARC uses currently produced tubes, the SP11 uses 6922/6DJ8's and I would not use the currently produced 6922's that ARC will try to sell you. I found the Philips and other older tubes sound better. I have a friend that has a pile of these from old oscilloscopes and I'm sure there are other sources of inexpensive good sounding 6922's. Sorry I couldn't find the reference 1 at the ARC schematics download site to see what tubes and FET's it uses, and to guess at the source of your problem. I can see the other Reference preamps, is it also known under a different name?

So if cost is your concern, either ARC authorized repair, of anyone else that does electronic repair, but tell them what you want done. First the repair, which most likely will be inexpensive and then discuss with them replacing any electrolytics, I just measure ESR to decide what to replace if any. And for tubes, buy some, replace them yourself and listen.

I have had very few problems with these older ARC preamps. I did do a lot of experimentation on the SP3 to see what changes did what, meaning I would change something and then listen. I'm mentioning this because I would not be concerned that this will be the first of many fixes. Get fixed what is wrong, and do a bit of updates if needed and you should be fine for a long time.

I mention this from time to time. I go to hamfest's mainly for the entertainment factor. These are almost all old nerd's that like working on equipment and know electronics. Many of these guys would diagnose and fix your preamp for almost nothing.




 

schematics, posted on October 2, 2020 at 17:01:09
tunenut
Audiophile

Posts: 9068
Joined: July 18, 2000
I very much appreciate your advice. I went to the Audio Research site and could not find any download for my preamp. So I dug around the Internet for a while. On the site I linked below, there are 2 pdf files, Audio-Research-REF-1-Rev-21-Sch and Audio-Research-REF-1-Schematics. These are about 2/3 of the way down the page.

If you get some free time to look at these, that would be great, but don't go to any trouble. I am going to dig through these myself, although a professional will repair this, it is always good to know as much as you can about things.

 

RE: schematics, posted on October 2, 2020 at 17:37:51
fredtr
Audiophile

Posts: 1311
Location: Phoenix
Joined: January 4, 2005
You mentioned initial LED problem, I would first check the PS voltages. It is a separate LED supply which comes from the digital 5 volt supply. All you need to do it is a voltmeter. The supplies are separate enough that it is probably a low voltage only problem. If you want to give it a try, take the cover off and take pictures and post them.

If you want a guess, it would be bad filter cap in the digital 5 volt supply. My guesses are usually wrong, but so many times, problems are immediately visible by just taking off the covers. Look for a bulging capacitor in the PS section, particularly ones that show on them voltage ratings less than 100 volts.

 

RE: schematics, posted on October 3, 2020 at 12:03:20
Mendel
Audiophile

Posts: 1060
Location: GTA
Joined: January 17, 2009
If your preamp is full of those yellow wondercap capacitors, a sizeable increase in performance can be had by replacing them with modern film caps, particularly the coupling caps. I changed them out for Vcaps in my SP14 about 10 years ago and it made a big difference.

 

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