Power tube substitution

[ryognbass]

Hi all,
I have a relatively simple question that I've been toying with for a while. I recently bought a VHT special 6 ultra, which is an INCREDIBLE amp for only $280. excellent for clean and dirty guitar, as well as for recording bass!

The only drawback is that the 6V6 power tube putting out 6 watts might not cut it for some of my gigs. I'm aware that some tubes (such as a 12ax7 and 12au7) are interchangeable, and some are not... but, are there tubes available that could replace the 6v6 and yield more power? whether it be a direct replacement that fits in the same socket, or a different tube all together that can be used by replacing the current socket. I'm not concerned yet about a different power tube altering the tone, so any insight as to the feasibility of such a switch would be much appreciated!

[fuzzy beard]

This may not help much but when reading about the epiphone valve Jr. I read that upgrading the transformer with a larger one from hammond that you almost double your watts! It is also better for bass with the larger transformer. This is all stuff I read so take it for what its worth.

[RickenBoogie]

Yeah, you'd need to change more than just tubes if you want more power. Output transformer for one, plus it would need alot more work. Not worth the effort. If you need more power, you need a different amp.

[BassmanPaul]

Originally Posted by ryognbass

are there tubes available that could replace the 6v6 and yield more power?

Simple answer is no.

More complicated answer is yes BUT you would have to replace both the power and output transformers. You might also need to redesign the circuit to provide the higher drive needed.

[Ed Storer]

A 6L6 can be plugged in to the socket (same size and pinout). It will add a little power (20 to 30 percent), but nothing like double. To use the full potential of the 6L6 you would need new transformers.

A 6L6 wants to see half the impedance of a 6V6; if you are presently running an 8 Ohm speaker, you should add an 8 Ohm extension to get the impedance to 4 Ohms.

The last hurdle. The bias current for a 6V6 should be in the 22-28 mA range; a 6L6 should draw 32 - 37. I don't know if your amp's bias is self-adjusting; if it is, you may not be able to get into the usable range with a 6L6.

I don't know if you've ever looked at TDPRI.com, but the amp forum there is really good for tube amp questions.

[T-Bird]

Hi.

Yet another vote for no.

You can of course slap an EL84 there with the VHT adapter, but it's not likely that it'll squeeze any more watts from it.

I'd look for a more efficient cab, like a BFM horn loaded, or at least one with more/bigger speakers. You might, gasp, even use a bass speaker instead of the guitar one.

BTW, not to rain on Your parade, but the 6W figure is most likely for around 100Hz, the guitar designed OT will probably handle about 2W on the bass frequencies. Not that it matters much if You dig the tone .

Regards
Sam