Tube Amps / Music Electronics
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|5/9/1999 12:46 PM|
||Re: The Best 6V6?...opinion|
I hate to be the party pooper by I've been working on an amp with 6V6's for a couple of months and using Sovtek 6V6's and have had no problems. In fact what nos 6V6's I have I elected to save them while I was pounding the Sovteks. As long as I've kept plate voltage under 410 volts I haven't fried any. I've been using these tubes for about four years and have only lost a half a dozen. I agree that they aren't like they used to be but they will work fine when set-up with enough load (30-35ma.) I have friend with a BFSR and because he had a lot of nos 6L6's he prefers to run them in that amp instead of 6V6's.
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|5/9/1999 10:40 PM|
||Re: The Best 6V6?...party poopin Bob|
Hold on Bob, the party is not quite over yet... didn't we blow a pair of my new Sovtek 6V6s on my work bench with one of your amps... or was it one of mine? I forgot now!
Remember that nasty little hi freq fizzy scruntch sound on top of the loud high notes and I said I think you just blew one of my Sovtek 6V6 tubes?
That's the sound of a typical Sovtek 6V6 about to cave in and that's why I was sure we'd have to change them.
I think I warned you that we'd probably blow my new Sovteks with this high plate voltage! :>) But since I don't use them, it's OK.
Also, remember your amps are mostly cathode biased and that little resistor on the power tube's cathodes can blow a lot of plate voltage when you're playing your amp like screamin' monkey. ha ha.
I wonder if that helps save your tubes?
Maybe someone else has a thought on that too.
If you're still on speaking terms with K. Fischer you should ask him.
Oh, by the way, Larry loved the yellow Ohua SE 6V6 amp I showed you! He has not called me back about the 5V4.
Can you restate the Super Reverb thing, I didn't quite understand it.
Wait...did you mean a BF Deluxe Reverb?
|5/10/1999 9:00 AM|
Do I still have to party Bruce? I'm tired and I want to go home. Sorry I couldn't resist. Don't forget my fine Wavetek meter dc voltage was way off and when we measured the plate voltage it was at 435 volts not the 411 volts I thought. I can't believe they lasted that long. When I've kept reasonable voltages I have'nt had a problem. Now I have to come by because my other Wavetek is reading within one volt of the other one. Both your meters are about 25 volts higher than mine. I'm going to go buy a Fluke and call it a day!!!!!
|5/13/1999 7:58 PM|
||Any updates on your meters, Bob?|
It's possible that Bruce's Fluke meter was reading high (I've seen them go back to the factory for recalibration.) Before dumping your Waveteks you might get a few second opinions (one of you must have a Simpson analog meter- right?)
For some reason measuring B+ on tube plates can throw off meters that otherwise seem to work just fine. I keep a Radio Shack DMM as a spare, and it seems to handle eveything fairly well... except for the B+ on tube plates! Maybe there is an ac component in there that wreaks havoc on the innards, but my meter will change modes and even go blank... but only when I'm measuring the B+ on tube plates and screens!
P.S. Let us know the verdict on your Waveteks! If they are indeed off almost 6% (25volts/ 435vdc) the rest of us Wavetek-heads better check ours, too! (They have been recommended here often as a less-expensive alternative to a Fluke.)
|5/13/1999 9:31 PM|
One meter is bad and one is still ok. The good meter is within a volt of his fluke. The amp I'm working on reads about 411 volts on the plate with 6V6's in it. The day we blew up a 6V6 there was 435 volts on the plate.
When I work on my amps at my place I voltage them through a variac @ 120 volts and I know Bruce has told me he's had as much as 126 volts on tap so that's what probably happened that day.
As for Wavetek's, I'm sure they're accurate until they get zapped one too many times but so far I've had two out three go bad one way or another, and I'm not a thrasher, but in the middle of deep tweaking I do ask a lot of my meters. I'm not sure at this point they're up to the tasks, so for now I'm hanging loose til I figure out what I'm going to do. Maybe I'll find a high dollar Fluke at some pawn shop for a song and a dance.
|5/13/1999 11:23 PM|
I'm not sure how old your bad Wavetek meter is but I believe that they are now offering a 3 year warranty on their meters, which will be honored at any Wavetek dealer. If your meter goes bad within the warranty period any Wavetek dealer is supposed to exchange it for a new one.
But it sure would be nice to have a nice Fluke...
P.S. Almost all of my meters seem to do just fine measuring 120 to 240vac; it seems to be the B+ voltages over 400v that are the real test of a good meter... at least IMHO. Thanks!
|5/15/1999 6:48 AM|
I've heard a few stories about failures of Wavetek meters. I find this surprising because Wavetek is a respected brand name, although they're better known for stuff like pulse generators. Perhaps these are isolated incidents.
Many of the Flukes--like the trusty model 87, beloved by so many professional techs--are expensive, but even the cheaper models like the 70-series are pretty nice. I have a model 73 which has served me very well over the past couple of years.
Multimeters and soldering irons (preferably soldering stations) are two areas where it doesn't pay to skimp. I recommend buying the best ones you can afford. I struggled for years with cheap soldering irons and DMMs before realizing this.
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