meagain Posted May 21, 2007 Author Share Posted May 21, 2007 Someone might ask since you can bias each tube individually with the VRD's, why do you need matched tubes? That's what I was wondering. But what about the push-pull thing? (I call this the pushmepullyou ala Dr. Doolittle).... If the 2 tubes were far off from each other, wouldn't the push/pull action be tricky? Quote Link to comment Share on other sites More sharing options...
NOSValves Posted May 21, 2007 Share Posted May 21, 2007 Someone might ask since you can bias each tube individually with the VRD's, why do you need matched tubes? Dean, Read my post above I answered that. Quote Link to comment Share on other sites More sharing options...
NOSValves Posted May 21, 2007 Share Posted May 21, 2007 I like them over .71 I will say I had them at .57 on Saturday and couldn't listen to it. If something else was at play besides bias, then IDK. But that was a bad number. At 125V on the wall and you wonder why your tubes fry............. Quote Link to comment Share on other sites More sharing options...
meagain Posted May 21, 2007 Author Share Posted May 21, 2007 I used to keep them at .72 because the manufacturer says in the manual that that's where he runs his. Quote Link to comment Share on other sites More sharing options...
Coytee Posted May 21, 2007 Share Posted May 21, 2007 For a non-tech like me, if she's biased at .71 and you say "at 125V on the wall", does that imply .71x125=88.75 volts and when she's biased at .57, it's .57x125=71.25 volts? so she's using a 17.5 volt differential? Just trying to comprehend how some of these things interrelate Quote Link to comment Share on other sites More sharing options...
NOSValves Posted May 21, 2007 Share Posted May 21, 2007 For a non-tech like me, if she's biased at .71 and you say "at 125V on the wall", does that imply .71x125=88.75 volts and when she's biased at .57, it's .57x125=71.25 volts? so she's using a 17.5 volt differential? Just trying to comprehend how some of these things interrelate Short and quick answer.........no LOL!! The higher the wall voltage is the higher the plate voltages are on the output tubes so in turn the plate dissipation rises which in turn lowers the life span of the output tubes. Pretty simple stuff. But the math is not done from the wall voltage. With 125V on the wall the output tubes are most likely experiencing 525V so you take that times the bias current and you come up with the plate dissipation. 525 x 72 mils = 37.8 watts of plate dissipation. The KT-88 are rated at 35 watts of idle plate dissipation but they can take a bit more it just lowers the life span of the tube. Craig Quote Link to comment Share on other sites More sharing options...
NOSValves Posted May 21, 2007 Share Posted May 21, 2007 I used to keep them at .72 because the manufacturer says in the manual that that's where he runs his. And you can bias them to .72 go right ahead. If your going to run them for the extended periods like you did before you will buy new tubes every six months. Your not going to hurt the amps a bit which has already been proven. It's your money not mine. Normal music lovers run their amps an average of maybe 2, 3 maybe 4 hours a night and most likely more on the weekends. You ran your amps at least 10 hours a day and often 24/7. Even if you lower the bias and keep running them like that plan on retubing the amps at least once a year simple as that. Craig Quote Link to comment Share on other sites More sharing options...
meagain Posted May 21, 2007 Author Share Posted May 21, 2007 Why would any even remotely sensible person run them 24/7 without darned good reason? Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted May 22, 2007 Share Posted May 22, 2007 "The higher the wall voltage is the higher the plate voltages are on the output tubes so in turn the plate dissipation rises which in turn lowers the life span of the output tubes." Don't forget filament windings. Correct heater voltages are important, too, but often seem to play second chair to B+. Are the heater supplies regulated DC or AC? Erik Quote Link to comment Share on other sites More sharing options...
NOSValves Posted May 22, 2007 Share Posted May 22, 2007 "The higher the wall voltage is the higher the plate voltages are on the output tubes so in turn the plate dissipation rises which in turn lowers the life span of the output tubes." Don't forget filament windings. Correct heater voltages are important, too, but often seem to play second chair to B+. Are the heater supplies regulated DC or AC? Erik Erik, Your right! The heaters are all unregulated AC so the higher the wall voltage the higher the filament voltage will be. But not to such an extreme degree like it does with the B+. You know me old school all the way. The more little parts you install the more parts to fail. The best solution to high wall voltage in this situation is a voltage regulator which benifits your entire audio system not just the amps. Heck I've been darn impressed with the sonic improvementys my system has receieved since putting the Furman in and I didn't have a high wall voltage problem here (mostly with digital sources). But we have beat this subject to death around here if you ask me. Craig Quote Link to comment Share on other sites More sharing options...
NOSValves Posted May 22, 2007 Share Posted May 22, 2007 Why would any even remotely sensible person run them 24/7 without darned good reason? You tell me? Quote Link to comment Share on other sites More sharing options...
HarryO Posted May 22, 2007 Share Posted May 22, 2007 Craig, The subject may be beat to death but maybe NOW notice will be taken of the importance of proper power feed. A simple surge protector will Not help. The proper voltages are a must. Excellent exclammation on the power input problems. Readers take notice! Important things can be simple. Harry Quote Link to comment Share on other sites More sharing options...
Strabo Posted May 22, 2007 Share Posted May 22, 2007 .... Heck I've been darn impressed with the sonic improvementys my system has receieved since putting the Furman in and I didn't have a high wall voltage problem here (mostly with digital sources). But we have beat this subject to death around here if you ask me. Craig Sorry to sidetrack this, could someone point me to the thread where you discussed the actual results of the Furman? I remember reading that you picked one up from ebay. Is it in the same thread? Quote Link to comment Share on other sites More sharing options...
meagain Posted May 22, 2007 Author Share Posted May 22, 2007 Why would any even remotely sensible person run them 24/7 without darned good reason? You tell me? You know why. (hugs) Quote Link to comment Share on other sites More sharing options...
meagain Posted May 22, 2007 Author Share Posted May 22, 2007 STrabo - http://forums.klipsch.com/forums/thread/910769.aspx Quote Link to comment Share on other sites More sharing options...
meagain Posted May 22, 2007 Author Share Posted May 22, 2007 Craig - Re the Furman...... Do you know if it allows some type of nifty shut off method for the gear attached to it? Are you able to turn off the Furman and have it properly shut down the gear? I know some conditioners do this but IDK about this gadget. My husband asked me this this morning. BTW - So far, it looks like you got the last one from that guy. I almost pulled the trigger on it but opted to wait the few days till you got yours to run the tests. He emailed me on the 10th to tell me he has more but has yet to post them or respond to further emails from me. Grrr. I keep waiting for him to throw more up but nothing yet. I'm also searching around for a good price on a used Monster AVS-2000 with blue lights. Missed a nice deal on A-gon. Even more frustrating was a missed local Craigslist for the type Dean has for $225-250. That one almost made me cry. Not as good as yours but surely would've gotten me through this dry spell. The bias is set to .60 till I find something. I 'think' that should be ok. My wall is averaging 124.5-124.9 ish. I'm thinking this slow-start tweek is a good thing all the way around. Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted May 22, 2007 Share Posted May 22, 2007 Craig: "You know me old school all the way. The more little parts you install the more parts to fail." Believe me, I can also appreciate that very traditional way of feeding filaments; and it can be very, very quiet. Are you grounding the center tap of the filament winding (or separate filament transformer) or possibly connecting it to a DC source to raise them above ground? Just curious in terms of how your doing that; no trade secret interest! No need to share that if you'd rather not. I was just thinking that, depending on how out of tolerance those filaments might be (maybe not at all), there can be some other problems that come about. And yeah, I agree that the actual voltage difference won't be as influenced as B+ by the higher AC house supply, but heaters need to be fairly close to spec. for the tube. All of this you know. Erik Quote Link to comment Share on other sites More sharing options...
NOSValves Posted May 22, 2007 Share Posted May 22, 2007 The center tap of the 6.3V winding is attached to ground VIA coupling cap. Craig Quote Link to comment Share on other sites More sharing options...
NOSValves Posted May 22, 2007 Share Posted May 22, 2007 Craig - Re the Furman...... Do you know if it allows some type of nifty shut off method for the gear attached to it? Are you able to turn off the Furman and have it properly shut down the gear? I know some conditioners do this but IDK about this gadget. My husband asked me this this morning. BTW - So far, it looks like you got the last one from that guy. I almost pulled the trigger on it but opted to wait the few days till you got yours to run the tests. He emailed me on the 10th to tell me he has more but has yet to post them or respond to further emails from me. Grrr. I keep waiting for him to throw more up but nothing yet. I'm also searching around for a good price on a used Monster AVS-2000 with blue lights. Missed a nice deal on A-gon. Even more frustrating was a missed local Craigslist for the type Dean has for $225-250. That one almost made me cry. Not as good as yours but surely would've gotten me through this dry spell. The bias is set to .60 till I find something. I 'think' that should be ok. My wall is averaging 124.5-124.9 ish. I'm thinking this slow-start tweek is a good thing all the way around. The furman has a main power switch on the front that you could shut your entire system down at one time. Works fine on my system not a noise to be heard... at shut off or at turn on (except the little click/pop when the BBX delay circuit turns on. The only thing I don't like about the on/off switch is it's rather large and lit up bright red. I took electrical tape and neatly covered it because the light is just plain annoying. The other lights on the unit look nice and the front looks much better with out the ugly red switch lit or not. In fact the light/switch is only negative I have found with the Furman it just gives it that commercial/pro look. Craig Quote Link to comment Share on other sites More sharing options...
meagain Posted May 22, 2007 Author Share Posted May 22, 2007 Cool - Thanks! I'd also have to do something about the red light. If it was blue - I'd be happier. Quote Link to comment Share on other sites More sharing options...
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