6L6GB vs. 6L6GC

[Low_fidelity2100]

Is it bad to use a 6L6GB in an amp that calls For 6L6GC?

I've had some 6L6GB's in my Fender Concert II for about 6 months or so, and haven't had/noticed any problems. But I was just reading up on tube types and all that stuff, and saw that the specs between these two tubes are Way different. So I'm starting to wonder....am I slowly killing my output transformer?

There is quite a pronounced Blue Glow in the tubes. But that was there in the Previous tubes too, and Several people have told me Its normal (been told it just means theres a small amount of oxygen in the tube). So I dunno if that means anything, just thought I'de mention it.

 

[Low_fidelity2100]

Re: 6L6GB vs. 6L6GC

Ok.....Immediately after Posting this. I went and did a search, and The first hit to pop up on google was This....

http://www.harpamps.com/micKtubes/5881=6L6GB.html

....Which is quite Convient Considering it actually Specifically mentions the Tube type (6L6GB), Brand (sovtek), And My specific amp (80's fender concert). Haha. So this basically answers My question, Although If this information is wrong Please lemme know.

This is what it says (I quoted the parts that actually pertains to my question)

I have one of those 80s Concerts (a 2 x 10), those are the Paul Rivera
abortions. Anyway, the BEST output tube for you to use would be for you
to find a NOS American 6L6GC. There are NO REAL, honest to God, 6L6GC
tubes being made today, period, regardless of the lies you hear from
boutique tube sellers.


The best current production 6L6 type tube is the Sovtek 5881, which
electrically is a 6L6GB. (Notice the suffix here.) A GB is not as
powerful as a GC. The GC's had a 30 watt plate dissipation rating and a
higher plate voltage rating (450 or so), while the GB is rated at only 23
watts and 360 volts (as I recall, I don't have a tube manual in front of
me right now). Anyway, the manufacturer's ratings were conservative, and
a GB will handle 450 volts no sweat. But since it's power handling is
lower, your amp will probably lose a bit of power. However, the Sovtek
5881s are very consistent and reliable. They also have decent tone.

If thats incorrect, someone please lemme know. Actually even if it Is correct if someone could verify that for me (i.e. just a second opinion) That would be greatly appreciated too. Thanks!

 

[Curly]

Re: 6L6GB vs. 6L6GC

I would've said yes, but maybe you should read this;
http://www.kcanostubes.com/content/estore_details.asp?category=173&product=132

 

[Low_fidelity2100]

Re: 6L6GB vs. 6L6GC

I would've said yes, but maybe you should read this;
http://www.kcanostubes.com/content/estore_details.asp?category=173&product=132

hmm, Interesting. Thanks for the link.

So ya think its probably fine then? I mean I haven't Noticed any problems with the amp. It actually sounds Better with these than it did with what was in it before. But, I really don't know a Whole lot about tubes and amps.

 

[Gearjoneser]

Re: 6L6GB vs. 6L6GC

I know all the GT's pretty well, and you won't hurt anything using any of them in your amp. They'll all have slightly different quality tones though.

Here's a link of a shootout of the GT 6L6's by legendary tones.
The ones that are the best are the GC's and SV's....Svetlana.
http://www.legendarytones.com/groovetubes.html

 

[Low_fidelity2100]

Re: 6L6GB vs. 6L6GC

I know all the GT's pretty well, and you won't hurt anything using any of them in your amp. They'll all have slightly different quality tones though.

Here's a link of a shootout of the GT 6L6's by legendary tones.
The ones that are the best are the GC's and SV's....Svetlana.
http://www.legendarytones.com/groovetubes.html

Thanks for the link! Now I deffinately know what tubes to try in the future, haha.

Any idea what sovtek that was that he tried? Theres no mention of the type of sovtek 6L6 it was in the artical (not that I saw anyways).

 

[More-Gear-Than-Skill]

Re: 6L6GB vs. 6L6GC

i'd be careful, an amp is a delicate balance of design that expects a certain performance from the chosen valve. Actually amps are designed around the valve. Put a wrong valve in and the voltages and currents could go wrong. And when you're pushing the amp hard, a big failure in a power valve could drag your OT down with it.

But if its working fine, not red plated, sounds good, and the tubes are lasting, then perhaps the design is such that its voltages are lowish, and hence compatible?

 

[Low_fidelity2100]

Re: 6L6GB vs. 6L6GC

i'd be careful, an amp is a delicate balance of design that expects a certain performance from the chosen valve. Actually amps are designed around the valve. Put a wrong valve in and the voltages and currents could go wrong. And when you're pushing the amp hard, a big failure in a power valve could drag your OT down with it.

But if its working fine, not red plated, sounds good, and the tubes are lasting, then perhaps the design is such that its voltages are lowish, and hence compatible?

Yeah the plates aren't "red plateing" at all. The tubes themselves Actually don't seem to even Be any hotter (tempature wise) when running than what was in there before. If anything they seem to run a Tiny bit Cooler. Which is why I was a little confused when I read that 6L6GB's weren't rated to handle The currents of 6L6GC's. Ya know I figured there'de be something obviously wrong (red spots, strange smell, Over heating, sound horrible, etc..), if they were the wrong tube, But I guess not.

 

[Darkness1234]

Re: 6L6GB vs. 6L6GC

Is it bad to use a 6L6GB in an amp that calls For 6L6GC?

I've had some 6L6GB's in my Fender Concert II for about 6 months or so, and haven't had/noticed any problems. But I was just reading up on tube types and all that stuff, and saw that the specs between these two tubes are Way different. So I'm starting to wonder....am I slowly killing my output transformer?

There is quite a pronounced Blue Glow in the tubes. But that was there in the Previous tubes too, and Several people have told me Its normal (been told it just means theres a small amount of oxygen in the tube). So I dunno if that means anything, just thought I'de mention it.

The only damage it could be doing is only if the impedance of the 6L6GC were different to 6L6GB (Which they are). And depending on the Cathode or Fix bias it could vary. The main damage would be to your transformer, your speaker or the tubes themselves. Just remember the impedance will always change between tubes even if they are the same (example is one 6L6GC is never the exact same as another 6L6GC just like everything else in the world). The bias of the amp and power supply voltage can also affect the impedance of the tube. Please Be careful as an amp is costly to repair but your life is also irreplaceable

 

[Low_fidelity2100]

Re: 6L6GB vs. 6L6GC

The only damage it could be doing is only if the impedance of the 6L6GC were different to 6L6GB (Which they are). And depending on the Cathode or Fix bias it could vary. The main damage would be to your transformer, your speaker or the tubes themselves. Just remember the impedance will always change between tubes even if they are the same (example is one 6L6GC is never the exact same as another 6L6GC just like everything else in the world). The bias of the amp and power supply voltage can also affect the impedance of the tube. Please Be careful as an amp is costly to repair but your life is also irreplaceable

Groovy, thanks.

In the decade since I started this thread I have learned a lot, and am much more well informed when it comes to these things.
Regardless, thanks for contributing. Hopefully the info helps someone else reading this in the future.