2. amps-preamps
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ARC PH7

Hello everyone. Just want to run this buy you guys to see what comes out of it. I recently purchased gently used Audio Research PH7 phono preamp. The Preamp had 3 hours on the tubes according to the display. I have had it for a week now and till now it has worked flawlessly. Typically I will mute the preamp to change records, etc. Today I muted changed a record and when I unmated the right channel did not play. turned the unit off and waited for about 10 mins and powered it back up, and the right channel came back. muted/unmuted right channel goes out. According to the seller the PH7 lay dormat for a few years prior to selling it. I am wondering if it could be one of the tubes could simply be failing, but it seems more like a curcuit problem than a tube problem. Any thoughts or experience with this particular issue with the ARC PH7?
barnettk
barnettk OP
410 posts
 
@yogiboy 
Hi Yogiboy. Yea with my other Phono stage that does not have a mute button I just simply roll the volume down. The mute button is very nice to have especially since it has a remote as well. Its not a show stopper however if its a bad circuit I am concerned that it could also cause other things to fail as well. Especially if its a bad Cap, so just to do my diligence I would like to get it resolved, but I appreciate the idea. Thanks



barnettk OP
410 posts
 
@cleeds 

The mute button does work. it actually works a little to good lol.. This problem happens when I "unmute" but I get where  your coming from. If the mute feature has any time of problem its not a good thing as the unit stays in mute during warmup to not allow you to use it till the tubes have gone past a certain power up.

noromance's avatar
noromance
10,057 posts
 
You could try some freeze spray on suspect components. Not the tubes!!


barnettk OP
410 posts
 
@noromance 

I dropped it off at my local guys shop yesterday and we discussed this. It is one of the approaches he is going to take. Hopefully by cooling down whatever component is causing the problem will make for a faster turnaround. Otherwise he will have to trace it down with a meter which will take a little longer. We will see. One of he problems is that if I have the lid off it does not get hot enough to cause it to fail. The good thing is that once it's in the failed state it stays that way until you recycle power. I have a feeling that he will have to trace the schematic and determine where the culprit is. 
barnettk OP
410 posts
 
Hi guys well we found the problem with the PH7. The mute relay was bad. The tech found the problem in about an hour including the time it took to fail. Right under $200 to fix the problem. Hopefully we have had our glitch for this mission. 
Thanks for all the help. Back to the music. 
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