Favorite pentode circuits

[jcat5503]

EF86 seems to be the norm

Just curious what people like and why

Cheers!

[JamesHealey]

I've never made an amp using anything but dual triodes 12ax7 only!

I know i should try others but why spoil a good thing? I like how they sound!

[10thTx]

My favorite pentode is the 5879 & have gotten a fat tone out of it that I have not been able to get from a 12A_7 tube. It has both a fat and slightly chimey tone and is low on microphonics. Not as much gain as the EF86

Of all the amps I have built, the Tweed Overdrive Special is my favorite and I think the most versatile for my style of playing.

On the 56T, I also tried a 6AU6 and a 5654 in the V1 position and they also sounded very good to me. The 56T is my version of Geezer's HoSo56.

Soundbit for 56T is here:
http://www.soundclick.com/player/single ... i&newref=1

Soundbit for the Tweed Overdrive Special is here:
http://www.soundclick.com/player/single ... i&newref=1

With respect, 10thtx

[da Geezer]

Yep, love those 5879's.

10thTX & I have designed several amps around that pentode.

Here's a copy of the HoSo56 schematic (not a clone, but trying to imulate the tone of the 65Amps Soho.....got pretty close)

Still my main "go to" amp.

Geezer

[David Root]

5879 gets my vote. Play a '57 Gibson GA-40, that will convince you!

[KindaFuzzy]

5879 gets my vote. Play a '57 Gibson GA-40, that will convince you!

+1, that's a pretty cool amp.

[tkdrew]

Not exactly your typical preamp tube but I've used the 6GH8A in a few amps and really like them, plus they are dirt cheap. It is a pentode/triode in one bottle and was mainly used in TV circuits. Here's a link to a few clips of a Voxy kind of amp I used it in, I've got a high gain amp design I used in too but don't have any clips at the moment.

http://www.smittytoneamps.embarqspace.c ... 4526251690

[Phil_S]

Look at the Gibson GA-20 with 6SJ7 input. This thing is not real loud but has about the richest tone I've heard. You can buid a single input one channel of it in a relatively small chassis. If you omit the tube rectifier (which probably adds very little, if anything to the circuit), it is a 4 tube amp. IMO, there is nothing special about the design beyond the 6SJ7 input stage. You could probably couple that to just about any amp with similar results. It is elegantly simple. You just need to feed it enough voltage to get some clean headroom out of it. I modified the B+ ladder to maximize plate and screen voltage. It sounded like poo at first.

[jcat5503]

I've used the 5879 in a project with great success

Anyone experimented with a 6au6?

I know divided by uses the 5879 cascaded into a triode of a 12ax7 for their click channel and it has tons of useable gain on tap

I love ef86 tubes, they're just so picky and fickle

[10thTx]

Anyone experimented with a 6au6?

from my previous post earlier on this same thread below:

On the 56T, I also tried a 6AU6

I also used a 6Au6 to provide vibrato for a 6L6 cathode based push/pull amp. (Similar to Silvertone amps)

with respect, 10thtx

[Cliff Schecht]

I liked the 6AU6 myself. It has a natural bloom to it under heavy load conditions which is pretty neat.


Also my '54 Silvertone 1331 is a single 6SJ7 into a 6V6. Makes for a dynamic amp that plays the blues well.

[diode]

Yep, love those 5879's.

10thTX & I have designed several amps around that pentode.

Here's a copy of the HoSo56 schematic (not a clone, but trying to imulate the tone of the 65Amps Soho.....got pretty close)

Still my main "go to" amp.

Geezer

Do you have a layout for this? I tried following the 2009 thread but there is a million schems and layouts in them.

[10thTx]

Do you have a layout for this

This really is a nice sounding amp that DaGeezer's come up with.

Editable schematic and layout are here:

http://www.el34world.com/Forum/index.php?topic=10999.0

CHECK for errors and compare schematic with layout. If there is a difference, go with the schematic.

With respect, 10thtx

[Darkbluemurder]

Built two versions of the HoSo, both with the 5879. I also built an amp based on the Stang Ray but with 6V6s in the power amp. I used an EF86 in that one.

Cheers Stephan

[tictac]

I just got a blue-screen-of-death by clicking on one of the pictures in this thread....

TT