Bad Power Tube and other 6V6 Question?

[strat56]

Hi,

I know the first question is probably a long shot that someone will be able to answer but the other ones I'm sure some of you tube gurus will be able to answer.

I have a Class A amp with dual EH 6V6GT tubes. I haven't used in a while and I decided to play it a little today. When I turned it on and took it off standby it had a really bad buzz, even with all the controls turned all the way down. I looked in the back of the amp and I noticed one of the tubes wasn't glowing. I switched the tubes to each others sockets and the same tube still wasn't glowing and the other one still was. Does this sound like just a bad power tube?

I live in a kind of rural area and the only music store with any tubes within 50 miles only has Groove Tube 6V6 tubes in stock. Are 6V6 and 6V6GT the same tube? That guy tried to tell me that the GT meant Groove Tube but I checked a couple tube web sites and that's not true. I checked data sheets on the two tubes and didn't see much difference and the guy at the store told me they were the same but since he was wrong about the GT part I don't trust him about them being the same either.

I went to KCA NOS Tubes and they have TungSol reissues for $40 a pair which is a little more than MF but I've bought some tubes from there before and found the service to be great and for $5 I'll go with the better service.

So this leads me to my next question, at MF they had options for Hard, Medium and Soft for the tubes with no explanation of what that meant but there was no option for Hard, Medium and Soft at KCA. What does Hard, Medium and Soft mean? More headroom for Hard? Is Hard higher gain? I googled "TungSol 6V6GT Hard" and got nothing as far as an explanation.

 

[strat56]

Anybody??

 

[rockon1]

Yes a bad tube. Always stock a spare set. A tube amp must IMO. The Groove tube 6V6GT will work just fine. Its a rebranded tube from another manufacturer.

Hard, medium or soft just refers to the tubes current draw. The higher the rating the higher the idle dissapation will be relatively speaking.

Mike at KCA can give you matched tubes with higher or lower current draw too Im sure. bob

 

[Twin63]

I recently replaced a Groove Tubes GT6V6R with a Tung Sol 6V6GT(reissue) in my Gries 5. No issues so far and it sounds very good. IIRC, I went with "Average Distortion" which I assume would correlate with "Medium".

 

[remedy]

I have NOS Brimar 6V6's in my Germino that sound great & just picked up NOS Pope 6V6's for my deluxe that sounds really good too!
What amp are they going in?

 

[strat56]

They're going in a Rivera Venus 3 1X10.

I went ahead and ordered the Tung Sol's from KCA and got them and put them in today. I would've went with NOS but it's the only 6V6 amp I have and I'm not sure how long I'll be keeping it so I didn't want to put the money in them.

They sound really good, it's been a while since I used the amp so I can't remember what it sounded like with the EH tubes, but I remember I stopped using it because it would sound flubby sometimes. I paid, what for me, is a lot of money for the amp and I really want to like it. It has a pull notch on the middle control which is supposed to change the tone from Tweed to Blackface and I think I'll try that next gig and see if it helps.

Been thinking about changing the speaker, the one in there is advertised as 10" Vintage Gold Speaker but the web site doesn't give the brand and there is no label on the speaker that I can find. I've had the amp for more than a year and there still isn't a manual available on the web site either.

I've had Rivera amps before and had good luck with them, A Quiana, an R30 and an R100, hopefully I can get this one working for me.

 

[jspax7]

They're going in a Rivera Venus 3 1X10.

I went ahead and ordered the Tung Sol's from KCA and got them and put them in today. I would've went with NOS but it's the only 6V6 amp I have and I'm not sure how long I'll be keeping it so I didn't want to put the money in them.

They sound really good, it's been a while since I used the amp so I can't remember what it sounded like with the EH tubes, but I remember I stopped using it because it would sound flubby sometimes. I paid, what for me, is a lot of money for the amp and I really want to like it. It has a pull notch on the middle control which is supposed to change the tone from Tweed to Blackface and I think I'll try that next gig and see if it helps.

Been thinking about changing the speaker, the one in there is advertised as 10" Vintage Gold Speaker but the web site doesn't give the brand and there is no label on the speaker that I can find. I've had the amp for more than a year and there still isn't a manual available on the web site either.

I've had Rivera amps before and had good luck with them, A Quiana, an R30 and an R100, hopefully I can get this one working for me.

If you bought them from Mike you can order a back up pair with the same rating. If you have a tube failure on stage, just pop in a spare. No need to re-bias. (provided that your amp requires a bias adjustment) I prefer to order matched quads when possible.

 

[strat56]

If you bought them from Mike you can order a back up pair with the same rating. If you have a tube failure on stage, just pop in a spare. No need to re-bias. (provided that your amp requires a bias adjustment) I prefer to order matched quads when possible.

Rivera web site says no bias needed. This was the only tube I have in an amp that I didn't have a spare for.

I bring a backup amp when I gig so if something goes bad it's quicker to just swap amps than to swap tubes and I don't take a chance on burning my fingers

I'll ask Mike about ordering another matching pair tho.

 

[ninjaaron]

For 6V6's, I would strongly suggest checking out Eurotubes.com. They will give you a matched pair, and it is my humble opinion that JJ 6V6's are much better sounding than most of the other brands.

 

[rockon1]

If you bought them from Mike you can order a back up pair with the same rating. If you have a tube failure on stage, just pop in a spare. No need to re-bias. (provided that your amp requires a bias adjustment) I prefer to order matched quads when possible.

Cathode biased-there is no need to rebias. That said checking the bias might be a good thing in case they are idling above 100% dissapation. Bo

 

[PepeLeches]

Rivera web site says no bias needed.

Please, where in the web sais that?
I changed today power tubes in my Venus3 (same problem with EHX 6V6) and old tubes were biased for about 35 mA (the broken one measured over 40 mA using a Weber Bias Rite), and the Groove Tubes I used as new ones measured around 35 both too, and were rated as "8" in GT code.
With those similar readings (about 35 mA with both paired tubes old an new ones),I didn't use bias trim but cannot be sure about if it is cathode biased as long as after almost 3 years Mr Rivera hadn't time to hang a manual for Venus amps in his web (sadly bad for Rivera).

Great amp but bad info for this serie in web, no handbook, no schematics, no bias table...

 

[strat56]

I found that info the Rivera Forum in a thread called "tube rolling".

 

[Blue Strat]

BTW, we can provide different tube ratings. Just ask.

 

[PepeLeches]

Sorry for my delay in answer but thank you for info