Now for something different...

[kevin gilmore]

2 people asked for the gerber files, so here they are.

this still needs checking for errors.

http://gilmore.chem.northwestern.edu/ll.zip

[El_Doug]

I LOVE it! Bet it would go completely over the A10-lovers' heads though...

So the LL boards are pretty much ready for production and I've ordered boxes for my version of the A-10. How about "Pyrite" for a name...

[kevin gilmore]

So there is absolutely NO way we are going to do an A10 board due to all the issues we know about.

But it would be nice to do something simple that anyone can build. So i'm looking for tubes

that can handle at least 500 volts, anything there is bunches of that does not have stupid pricetags

attached. And its not going to be SRPP either, because done right, you need at least 5 seperate

filament supplies. 6s4's don't seem to be in plentiful supply any more. Otherwise its a circuit

board that is bigger than it should be with multiple 6ca7's...

Any ideas?

[livewire]

EL-34 as a triode strapped pentode? Or would that be too noisy?

EDIT: Doh! Just checked - 6CA7 = EL34.

Edited March 15, 2012 by livewire

[FrankCooter]

6P14P-EV. Tough as a boot Russian version of a 7189. Guitar guys push the voltage ratings all the time. If you were interested in octals, lots of TV vert. amp types still around. My favorite is the 6AH4.

[Clarkmc2]

The 6P14P-EV is also dirt cheap, plentiful and ultra quiet. -EB is the same tube, in cyrllic. (6 Pi 14 Pi EB more or less) But why am I preaching to the choir? Typing practice, I guess. For NOS fans, they are all NOS.

Edited March 15, 2012 by Clarkmc2

[chinsettawong]

How about 6BL7? It can take 500V easily.

Wachara C.

[mrarroyo]

From my day playing guitar I love the sound of the 6V6 tube as in an old Ampeg amp. Also the 7591 but those have gotten quite expensive.

[kevin gilmore]

I'm definitely liking the 6bl7 as it is a dual triode. So we could do an amp

that is 3 octals per channel. Slightly bigger than i want, but ok

if the tubes are cheap. Looking into 6p14 now.

[Beefy]

You can do it Kevin!

As 'bad' as the Exstata is seen around here, it was very compact. I would love to see another compact alternative.

[kevin gilmore]

Yeah, it was compact. And yes it blew up. Evidently quite often.

i'm thinking 3 x 6bl7 per channel, +/-400 power supplies, gilmore

triode amp style with cathode bias and DC coupled output.

Local feedback on the input, and local feedback on the output.

unbalanced input only. (i'm thinking about this last bit)

10 amps of filament current.

[spritzer]

For a small amp then we could do ECC83 input and 6CM7/6CS7 for the second and third stages. Can be made quite small indeed.

I know Kevin doesn't like them much, but the differential amp (aka. Egmont) is bloody tiny, fully balanced too.

[deepak]

For a small amp then we could do ECC83 input and 6CM7/6CS7 for the second and third stages. Can be made quite small indeed.

I know Kevin doesn't like them much, but the differential amp (aka. Egmont) is bloody tiny, fully balanced too.

Nice, I would be interested in something small like this. Need an amp for my SR-Lambdas at work.

[kevin gilmore]

how about 12ax7,12ax7,6cm7. won't be much bigger than that.

The power supply however is going to be at least that size or

bigger.

[FrankCooter]

I built an Egmont with 6BL7 output. Worked quite well. Maybe it was just my luck, but out of 20+ tubes no two had anywhere close to matching sections and no two samples matched each other in thier differences. I was quite surprized actually. Same with the 6BX7. One the other hand, I had no problem coming up with a pretty good quad of 6P14P out of a dozen samples on hand.

I would love to see a professionally updated small/cheap all tube electrostatic amp along the lines of a "hot-rodded" Egmont.

[spritzer]

Glad I looked at those PCB's since I can't understand what I was thinking with the psu caps...

how about 12ax7,12ax7,6cm7. won't be much bigger than that.

The power supply however is going to be at least that size or

bigger.

That would work. 6CM7's appear to be in plentiful supply too. We could always do a CRC psu...

[kevin gilmore]

anyone going to be upset if i insist on the teflon sockets?

[Beefy]

anyone going to be upset if i insist on the teflon sockets?

6 tubes runs it at ~$120 for just the sockets? But so long as nothing else in the amp is too exotic, it would seem pretty reasonable to me.

[deepak]

Teflon works for me, noval teflon sockets are cheap on Ebay... like $11 shipped each

[spritzer]

The ceramic units are only about 2$ each and the quality isn't that bad.

[El_Doug]

"Something simple everybody can do" is a great idea... but does it have to be cheap or tube-based? This would be a great time to use pa89's

Edited March 15, 2012 by El_Doug

[kevin gilmore]

no one seems in the mood to do the pa89 group buy.

I already have mine.

So what do people think of this

http://gilmore.chem.northwestern.edu/bate.pdf

Edited March 15, 2012 by kevin gilmore

[spritzer]

Silly people people who don't want to fork out for 300+$ opamps...

[kevin gilmore]

Try this one on for size... specifically 7.6 x 6.25 inches

http://gilmore.chem....rn.edu/bate.jpg

4 x 12ax7

2 x 6BL7

same teflon sockets as the T2.

Edited March 16, 2012 by kevin gilmore

[chinsettawong]

no one seems in the mood to do the pa89 group buy. I already have mine. So what do people think of this http://gilmore.chem.northwestern.edu/bate.pdf

I like it! It should be simple enough to even hard wire.

Wachara C.