SilverSport Posted September 9, 2007 Share Posted September 9, 2007 okay...this is a question I should know the answer to but I don't seem to get it... I am having a channel dropp off or at least...most the sound is going away (I can hear it still playing with a bit of static) on my two channel set up...I don't abuse my gear (knowingly) and there are some oddities to the set up but here it is: Pair of NOSValves VRD monoblocks powered by Ei KT-90s instead of the stock Tubes (Craig has warned me that these can get unstable but they are the best sounding Tubes in my applications. Juicy Music BlueBerry MkI with all original Tubes but I do have a Pinch Waist in spot 6DJ8/V4 that has been giving me trouble (microphonic) Heart Tube CD player... Last week this happened and the power Tubes on the offending channel were high (over 100 instead of the 72 or so I leave them at) so I rebiased and it was fine the rest of last weekend...turned them on today...let them settle in and a few hours later...the left channel was all static with little music. I plan to wait for everything to cool down and replace those KT-90s with the original style KT-88s unless you guys point me in another direction... Thanks and I apologize for the unworthyness of this question but I'm stumped at the moment (and not looking forward to moving everything out to change Tubes on the BlueBerry or open that Heart CDP...but...[] Bill Quote Link to comment Share on other sites More sharing options...
Audible Nectar Posted September 9, 2007 Share Posted September 9, 2007 Go ahead and roll in the KT88s, especially if you know that quad works well electrically in your amplifers. Turn JUST the amplifers on and bias them, and see if you hear any noise. Make sure tube sockets are properly tensioned. You should turn your bias pots down before rolling, then dial them up once the amplifiers warm up a bit. Also allow the amps time to cool before repowering (easier on the rectifier). If it is true that you had such an issue recently and the bias was suddenly way off from the norm, I might suspect the power tubes. Stuff like that is NOT normal. I don't care how they sound.....if that tube brand/type is known to be problematic, you really should look for another alternative. I really like the reissue Genelex KT88...it is my current tube for my VRDs after much frustration with the Shuguangs. The new Genelex sounds excellent. If the amps are quiet, then we move to the rest of the system, and if after playing that through the amps you still get noise, then we work up the chain through the pre and CD. Quote Link to comment Share on other sites More sharing options...
SilverSport Posted September 9, 2007 Author Share Posted September 9, 2007 Audible thanks...before seeing your response this was what I planned to do...my mistake was not turning the bias pots way down...I got to them before I heated the whole room and we'll give that a try...I agree with you on the power Tubes not being worth it if they lose bias...and they do...Craig warned me that they may sound sweet to me but they can be unstable (I am paraphrasing of course) so this will be my first try...I have the new to me but "original equipment" type Valve Art KT88s warming up (or cooling down as in this case...[:$])... As always...thanks, this Forum and its people are great... Bill Quote Link to comment Share on other sites More sharing options...
Audible Nectar Posted September 9, 2007 Share Posted September 9, 2007 Just curious, Bill - what is it that you like about the EI's sonically vs. the Valve Arts? Quote Link to comment Share on other sites More sharing options...
SilverSport Posted September 9, 2007 Author Share Posted September 9, 2007 they seemed to have more bass a clearer highs albeit at some expense of a midsection...saying that, it may just be that these were the Tubes that came with mine (I bought my VRDs second hand) so it was the sound I was most used to...I had a second set of EH KT88s and I don't really care for them...then I bought some of the Original Equipment Valve Arts but only put a short time in with them... Bill Quote Link to comment Share on other sites More sharing options...
SilverSport Posted September 9, 2007 Author Share Posted September 9, 2007 2 hours to the minute of making this plea, I am listening to Diana Krall The Girl in the Other Room (familiar CD) and have sound coming evenly from both monoblocks...I will monitor of course but perhaps the reportedly unstable KT90s from Ei have become exactly that...I did have a problem with one power Tube not lighting unless I moved it a bit...I checked the pin connections, sockets, as well as DeOxit'ing them last weekend thinking this might be the problem...Today, all four power Tubes lit fine but as I mentioned...static and no real volume from one channel... Thanks for the helps again Audible...it is ver much appreciated. Bill Quote Link to comment Share on other sites More sharing options...
Audible Nectar Posted September 9, 2007 Share Posted September 9, 2007 The Valve Arts do sound good in the VRDs, but I really like the Genelex reissues. Just a clean and balanced tube all around - no emphasis on any one aspect, just a tube that does everything well. Solid bass, extended and smooth highs, and a clean and warm midrange. From all accounts, these seem to be the current production KT88 king, and I cannot argue that. These are a bit more pricey ($200 per quad), but should drop in price a bit more as dealers get better stock on them. They were $300 at issue, and sold as soon as most dealers got them, but once dealers are well stocked should be more affordable. Once you pick this tube up in your hand, you'll see how it's easily worth more than a Valve Art - this new Genelex is a very well made and finished tube - superb for current production. Something to think about when it comes time to retube. Quote Link to comment Share on other sites More sharing options...
SilverSport Posted September 9, 2007 Author Share Posted September 9, 2007 Stop it!...[]...teasin'...thanks for the help... Bill Quote Link to comment Share on other sites More sharing options...
mikebse2a3 Posted September 9, 2007 Share Posted September 9, 2007 2 hours to the minute of making this plea, I am listening to Diana Krall The Girl in the Other Room (familiar CD) and have sound coming evenly from both monoblocks...I will monitor of course but perhaps the reportedly unstable KT90s from Ei have become exactly that...I did have a problem with one power Tube not lighting unless I moved it a bit...I checked the pin connections, sockets, as well as DeOxit'ing them last weekend thinking this might be the problem...Today, all four power Tubes lit fine but as I mentioned...static and no real volume from one channel... Thanks for the helps again Audible...it is ver much appreciated. Bill Hey Bill I would suggest that if you continue to have the problem that you actually try to isolate which piece of equipment is having the problem. I would swap the Left and Right Amps to begin with to see if the problems moves with that amp (if it does then that amp is where your problem is and can proceed from there). If it doesn't then the amps are OK and I would suggest you swap the left and right input from the CD Player to the Pre-Amp. If the problem stays in the same channel/speaker (your Pre-Amp is where the problem is located) and if the problem changes channels/speakers (then the CD Player has the problem). Of course keep in mind the interconnects along with the equipment could cause the problem when watching for the problem to change channels/speakers just in case. mike tn[] Quote Link to comment Share on other sites More sharing options...
mikebse2a3 Posted September 9, 2007 Share Posted September 9, 2007 My first double post[:^)] Quote Link to comment Share on other sites More sharing options...
SilverSport Posted September 10, 2007 Author Share Posted September 10, 2007 double post or not...I appreciate the help...it seems to have been those KT90s...but when I re-tensioned the sockets and cleaned and lubed with DeOxit and DeOxit Gold, the problem seemed to go away as well...be that as it may, I had the "new" KT88s on all day and no drop off...they settled in nicely at 72 or so...thanks for the feedback Mike and Audible...[]...I'll have to change my avatar since my VRDs pictured have the KT90s in them... Bill Quote Link to comment Share on other sites More sharing options...
SilverSport Posted September 10, 2007 Author Share Posted September 10, 2007 well...it is not those power tubes...no problems for the rest of the night last night...I tried it today and was fine for about 20 minutes...then the left channel cut out...I quickly started a record on the Turntable to check if it was that and the left channel was still out...I will wait for everything to cool again and change the left and right channel connection to see if the channel drop follows the amp...if not...I need to pull the PreAmp and take out that 6DJ8 I think... Bill Quote Link to comment Share on other sites More sharing options...
pauln Posted September 10, 2007 Share Posted September 10, 2007 You mentioned Craig's warnings... was that early on or have you sought his help on this problem? Quote Link to comment Share on other sites More sharing options...
SilverSport Posted September 10, 2007 Author Share Posted September 10, 2007 nope...I talked to Craig last year about the KT90s...no more dropouts since I fiddled with the connections... Bill Quote Link to comment Share on other sites More sharing options...
SilverSport Posted September 11, 2007 Author Share Posted September 11, 2007 Well...it seems to be on a 24 hour delay...I switched the left channel connection to the right side and the right to the left side and the drop out just occurred in the right channel... I have changed out the power Tubes so it is not them I have checked and re checked all connections so it is not that I have ruled out the CDP as this has also dropped out when playing the Turntable so... Bill Quote Link to comment Share on other sites More sharing options...
mikebse2a3 Posted September 11, 2007 Share Posted September 11, 2007 Well...it seems to be on a 24 hour delay...I switched the left channel connection to the right side and the right to the left side and the drop out just occurred in the right channel... Bill just so we are on the same page, Which connections did you switch? If you just changed the L & R input connections of the Amps then your problem is in the Pre-Amp. If you changed both the Input and Speaker Connections of the Amps at the same time then the Amp is the problem. I have changed out the power Tubes so it is not them I have checked and re checked all connections so it is not that Depending on whether you isolate the problem to the Amp or Pre-Amp you might look at the small tubes in either the Amp or Pre-Amp to see if their heaters are staying on? You might need to look with the lights down low to see them. Of course with just the info we have so far I can't say for sure but one of the most likely causes could be a bad solder connection acting intermitent but no way to say for sure without more trouble shooting. I have ruled out the CDP as this has also dropped out when playing the Turntable so... Bill mike tn Quote Link to comment Share on other sites More sharing options...
SilverSport Posted September 11, 2007 Author Share Posted September 11, 2007 Mike, I'll stay with this for sure...all I did was change the Interconnects to the amps from the preamp...I will have to pull out the pre and check it out...If I recall correctly, I should have one 6DJ8 in there that was troublesome in the past (Pinch waist or Bugle Boy) perhaps it has gone to the great Tube Preamp in the sky... Small Tubes in the Amps are all burning pretty much evenly...there are NOS Tubes in there as well so I will keep an eye on those as well... Thanks for staying with me on this. Bill Quote Link to comment Share on other sites More sharing options...
NOSValves Posted September 12, 2007 Share Posted September 12, 2007 Bill, First try a new set of IC's between amp and preamp. While doing so check closely for a damaged RCA jack on your preamp outputs. I'd be surprised if this is a 6DJ8 problem unless it's connection related. One way or the other this sounds like a connection problem either the RCA cables, RCA jacks or the tube pins at the preamp (6DJ8). You may be able to track it down just by carefully working these connections while the channel is experiencing the problem. Craig Quote Link to comment Share on other sites More sharing options...
SilverSport Posted September 12, 2007 Author Share Posted September 12, 2007 thanks Craig...when I get home I'll give that a try... [] Bill Quote Link to comment Share on other sites More sharing options...
SilverSport Posted September 12, 2007 Author Share Posted September 12, 2007 I pulled stuff out and took a look...somewhere in all my times of changing Tubes and A/B'ing two BlueBerrys (BlueBerries?) I seem to have pulled the "little feet" out on the right side channel of the main interconnect...(where the amp for the right channel attaches to the PreAmp)...I will give Craig's "cure" a try when it drops out again. Thanks guys, Bill Quote Link to comment Share on other sites More sharing options...
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