|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
208.86.125.246
In Reply to: RE: Audio research preamp broken posted by tunenut on September 28, 2020 at 17:40:48
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.
Follow Ups:
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.
Hello Tune, friend of mine has a Reference 1 that exhibited the exact same symptoms going down as yours. The Linestage has been @ Audio Research for 4 months. I would wager is an opamp. I have one of these myself, and thus far I NOW see a pattern. How much?... the old guard is gone and Audio Research has changed hands, again. He can fix it {my friend} but he dislikes working on solid state {inside joke}. Excellent piece that betters the Reference II and III, in my opinion. The 5 SE is definitely better.
The Mind has No Firewall~ U.S. Army War College.
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.
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.
FAQ |
Post a Message! |
Forgot Password? |
|
||||||||||||||
|
This post is made possible by the generous support of people like you and our sponsors: