4X6V6 vs 2X6L6

[homesick345]

In a bf/sf fender style amp, what would be the benefits (or the differences) between two power plants as above

What would a quartet of 6V6s bring to the table, assuming same power overall?

Thanks for your input

 

[bluesfordan]

A lot more hassles trying to find 4 good matched 6V6s, for starters. This is true of any amp that uses a quartet of power tubes.

Now, imagine trying to retube an old school Ampeg SVT, with SIX power tubes.

As much as I love 6V6s, if I need more power, I'll go with a pair of 6L6s. If that isn't powerful enough, I'll mic the amp.

 

[jhundt]

4 x 6v6 has never really been a popular amp configuration. Personally, I can only recall the Jim Kelley amp using this lineup.

I guess most amp builders looked at the trade-off 'watts vs complexity' and decided for the 2 x 6L6 design.

I don't know what the sonic difference would be - that is a very good question.

 

[wtk0315]

Maybe we can talk one of our techs into building one and reporting the results. I'm curious as all get out.

 

[Fred Mertz]

The sonic difference between a push/pull pair of 6V6 tubes and a quad of 6V6 tubes using the same operating points amounts to roughly a 3db increase in volume. You get roughly the same volume difference between a pair of 6V6 tubes and a pair of 6L6 tubes. As bluesfordan said, a lot of potential problems for little return.

 

[Jim Kelley]

In a bf/sf fender style amp, what would be the benefits (or the differences) between two power plants as above

What would a quartet of 6V6s bring to the table, assuming same power overall?

Thanks for your input

There have been a few amps that came stock with a quartet of 6V6's. Crate made one I think. And one or two current boutique makers. You're not likely to get the sound of 6V6's from any other kind of tube, so there's that. Four 6V6's draws twice the current of two, and requires an output transformer with half the impedance ratio. I'm partial to the sound of a quartet of 6V6's, and I don't think there's anything quite like it - though a pair of them does come quite close. ;-)

 

[telemnemonics]

There have been a few amps that came stock with a quartet of 6V6's. Crate made one I think. And one or two current boutique makers. You're not likely to get the sound of 6V6's from any other kind of tube, so there's that. Four 6V6's draws twice the current of two, and requires an output transformer with half the impedance ratio. I'm partial to the sound of a quartet of 6V6's, and I don't think there's anything quite like it - though a pair of them does come quite close. ;-)

Welcome to TDPRI Mr Kelley!
(Not that I'm any ambassador for this here Telecaster)

I would look to the sound difference between a 50 and 100w Marshall JMP, softer on the 50 and harder on the 100, if I were trying to imagine a 2 vs 4 6v6 amp.
Not sure about BF Fenders, as they all had various other spec changes along with tube compliment.
I have a 6v6 18w clone which also sounds a little harder than my el84 18watters, so I would fumble a thought that 4 6v6 could get a pretty hard edge to the snarl.
I could be off on that, and have never played or even seen a 6v6 quartet.
I was thinking Ken Fischer built some, maybe not.

 

[twintwelve]

The Vox Tony Bruno designed TB35C1 and C2 amps use 4x6V6's. Sounds like more goodie goodness, IMHO......

(link removed)

 

[Crazy neddie]

DR Z makes a take on a plexi with 4 6v6's. Funny i think the EL84's sound "harder" than the 6v6's.

 

[dmarg1045]

I remember a Bonnie Raitt interview some years ago where she sang the praises of her 4 - 6V6 Jim Kelley amp. Also, doesn't the Victoria Double Deluxe use 4 6V6's?

 

[telemnemonics]

DR Z makes a take on a plexi with 4 6v6's. Funny i think the EL84's sound "harder" than the 6v6's.

It could be we describe what we hear differently, but more likely we're thinking of different amps.
My brown Princeton doesn't sound as hard as my el84 18w clone, but my 6v6 18w does seem to be a bit harder or less creamy, maybe harsher but not in a bad way. Still, they weren't built together and the 6v6 has ppimv and cheaper transformers...
I forgot about the Z plexi amp, was very tempted a while back, but the "Plexi" sound is about as vague as the "Fender" sound.
Bought a (el84 quartet) Stang Ray, which I would say sounds harder than any of my el84 duet amps, but again, different circuit.
I think to truly hear the difference between 2 and 4 6v6s in an amp, you need to double the power supply. Otherwise you compare 2 strong 6v6 to 4 weaker 6v6. Classic Fenders don't have double the power supply filters in quad 6L6 amps, where classic Marshalls do.

 

[muchxs]

It could be we describe what we hear differently, but more likely we're thinking of different amps.
My brown Princeton doesn't sound as hard as my el84 18w clone, but my 6v6 18w does seem to be a bit harder or less creamy, maybe harsher but not in a bad way.

Even though they seem nominally similar with similar characteristics 6V6s and EL84s are dramatically different tubes.

A 6V6 is a beam power tube like a 6L6.

An EL84 is a power pentode.

An EL84 takes less input to drive it to full power than a 6V6.

An EL84 makes more power when driven hard than a 6V6.

 

[jhundt]

@ Jim Kelley - are you the same one who builds the amps with 4 6v6's? If so, they sure do look nice.

 

[homesick345]

There have been a few amps that came stock with a quartet of 6V6's. Crate made one I think. And one or two current boutique makers. You're not likely to get the sound of 6V6's from any other kind of tube, so there's that. Four 6V6's draws twice the current of two, and requires an output transformer with half the impedance ratio. I'm partial to the sound of a quartet of 6V6's, and I don't think there's anything quite like it - though a pair of them does come quite close. ;-)

Your name rings a bell

 

[WrapAround]

4 power tube configuration would always sound more "complex" than 2. Older (?) Tone King amps has/had 6v6 power tubes with an option of turning off 2 as I recall.

 

[filmix2]

Hey.. Here is an amp with 4 6v6 power tubes.

(link removed)

 

[homesick345]

Well; I'm so happy an innocent thread about 4X6V6 brought in such a fine amp builder!...

I think I deserve a TDPRI t-shirt

 

[telemnemonics]

Or at least some good karma to you homesick.
Seems I misread your OP, was thinking 2 or 4 6v6...
Given how common quad el84 vs duet el34 varieties are, it's curious that there aren't more quad 6v6 amps.
Maybe Communist el84 production so far exceeded Capitalist 6v6 production that el84 quads cost less than el34 or 6L6 duets.
Or the 9 pin sockets take up so little space compared to four big 8 pins?
Regarding the OQ, I would guess that a 6v6 quad would sound a little more snarly and toothy distorted than a 6L6 duet, and think the clean sound might be nearer to indistinguishable. It would be interesting to hear the two, with otherwise truly comparable circuits.

 

[Jim Kelley]

4 power tube configuration would always sound more "complex" than 2. Older (?) Tone King amps has/had 6v6 power tubes with an option of turning off 2 as I recall.

That is also how I would describe it. Difficult to put your finger on; it's subtle, but I would say four tubes in parallel push-pull does seem to create a more complex harmonic structure (in overdrive) than two.

I can't explain it, and I don't know why it would be the case. But in my amps I know that I do like it better.

Obviously, in the case of an amp that can switch two of its output tubes in and out of circuit, the loading is different in each mode, and this also has an effect on the sound and the feel. In addition, even well matched tubes do have slight differences, and the sum of the two in parallel creates a unique waveshape, with each tube making its individual contribution.

A few years ago I built a new prototype of the JK amp using amp using four EL84's in the output. Roughly 38 watts. It sounded good - but quite different than the same amp with 6V6's in it. The most noticeable difference in overdrive was in the top end harmonics. I think most would describe it as having more grind; more of an edge. But in a different amp, with different drive and different loading, without negative feedback, etc. the results could possibly be quite different.

Guys - I appreciate the all kind words, and warm welcome into your group. I have followed along with interest for a few years now. I really like to see the mutual enthusiasm for the instrument, and the high level at which the discourse here takes place. It's very nice. Thanks.

 

[homesick345]

Guys - I appreciate the all kind words, and warm welcome into your group. I have followed along with interest for a few years now. I really like to see the mutual enthusiasm for the instrument, and the high level at which the discourse here takes place. It's very nice. Thanks.

Most welcome - it's sincerely a pleasure, & a great honor.