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Why does unplugging/replugging TT leads from tube phono pre-amp reset dead channel?

I have a BAT VK P-10SE with Superpak.  Tubed phono preamp.  When one of the channels drops out (it actually is out when the system powers up), I used to go nuts trying to figure out which tube needed replacing.  I have learned, after much frustration, that simply unplugging the lead from the Turntable - and plugging it back in - solves the problem.  Sometimes it's the left channel.  Sometimes the right.  And if I leave the system on with no music playing for a while, on occasion a channel will drop out.  I have asked at several stereo shops...no one know why this works.  Or what the real underlying cause of the problem is.  When it works...it sounds great.  No indication of a tube issue.  And the cartridge - Shelter 901 - sounds great, too.  Any advice is welcome.  Thanks.

Joe
jmfawdofile
lewm
13,586 posts
 
Al, I did see that.  Perhaps the male pins in question are just thinner than most. Thus, they are not only a misfit for the BAT but also for the adaptors.  You could have a snug ground fitting and never know whether the hot pin is also snug, just due to the nature of an RCA connector.
uberwaltz's avatar
uberwaltz
13,381 posts
 
To the OP
You said in one post that BAT cannot replicate the issue.
Did you mean they cannot get the problem to occur on a similar unit or that they have had your actual unit in for test and could not get this peculiar problem to manifest?


Do you access to another TT to test by any chance as I appreciate the fixed leads syndrome!
jmfawdofile's avatar
jmfawdofile OP
23 posts
 
Hi All...
Lewm -- the male end of the Linn RCA is split, so I gently expanded it...that was a while ago in response to advice from a dealer a few months back.  It has not helped.  Length, though, I cannot change.  I have considered upgrading the cable on the TT.  It might resolve issue. I cannot believe the adaptors also have the issue with the Linn cable.  But who knows.  Thanks.

Al -- I will try that test next time the issue presents.  Thanks.  As to opening the phono stage...that will be done over the weekend...as it has 14 zillion screws and is a major hassle to open.  

Uber -- BAT had the unit in for an upgrade (superpak) and new tubes...the issue existed prior, I believe, and they could not replicate it. (Which is why they say its my TT, not their unit. However, I have another phono preamp...and never had this issue with that unit.)  I don't have access to another TT...but that is worth pursuing.  Especially if I can get it to happen with a different TT!  Thanks for the suggestion.

A mystery.

Joe
lewm
13,586 posts
 
You really don't need to upgrade the cable so much as you need to try a different pair of male RCA plugs at the ends of the cables coming from your Linn. If you have soldering skills, you can buy any pair of aftermarket male RCAs and do it yourself.  I recommend Cardas, for ease of use or WBT. (I am guessing that you have one continuous set of wires from the cartridge all the way to the phono stage, so it would be a big job to change out the wires.  If you are using a traditional pair of ICs with RCA connections at each end, then of course you need to attend to the connectors at the turntable end, as well. Or maybe the wires terminate in a DIN plug at the tonearm end.  DIN plugs can be maddening too.)
lewm
13,586 posts
 
Or by the way, have you ever unscrewed the protective barrels of the male RCAs at the ends of the ICs, to see whether there is an intermittent or cold solder joint to the hot pin?
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