Look for Single Tube scheme

[mik190]

Hi

I want to build single tube amplifier. Not like ECL82, when there is triod and pentode in one, but real single stage. It have to be like this in my mind:

input transformer--->tube--->output transformer.

Did anybody make sumething like it?

2W output at 8Om will be anough.

As compromise integrated tubes triod+triod is possible (2 stages).

 

[Tom Bavis]

How much output power? What will drive it? A step-up input transformer can provide some voltage gain but will be proportionally harder to drive. A dual triode like 6EM7 (common in MY basement...) will do one watt with PLENTY of gain.

 

[Miniwatt]

My current amps are single tube monoblocks(EL84), but I guess that's not what you mean. And to be fair: they also have a rectifier tube..

 

[astouffer]

You can do it with high GM triodes like the super expensive 437A or the russian 6C45 which is much more reasonable. These tubes don't even need a step up transformer. There are plenty of pentodes too, 12HL7, 6AG7, 6CL6, 8608, etc etc.

 

[tinitus]

ecc99 ?

I suppose it goes without saying that such amps are usually driven with a high gain tube pre ?

there is this one with EML tube, but expencive
http://www.tubeaudiolab.com/id148.html

el84 driving el84 I suppose is only half way there
http://home.comcast.net/~jafix/SakumaEL84.html

 

[artosalo]

I have once seen an amplifier done with a single Russian 6J52P, but can't unfortunately find the link anymore. However, it should not be a top engineering project to design such amplifier. 6J52P has very high gm - 55 mA/V - and max. anode dissipation is 10 W. So these features seem to be very suitable to single tube configuration.

I would try to make it with simple cathode bias and without input transformer. One suitable output transformer would be Hammond 125 ASE.
It has plenty of primary and secondary taps to find the best load impedance for the tube.

 

[Andrewbee]

5842 / 417

 

[rock4016]

abraxasaudio Tube Amplifiers
The 6CL6 with a 8K load does great, and is good for almost 3 watts out.

Hawthorne audio sells a modded kit based on this design.
JerryCurtis Dot Com The Spud Kit

B+ around 300V with about 165V on the screen and around 30 mA through the tube.

 

[banat]

Hi

I want to build single tube amplifier. Not like ECL82, when there is triod and pentode in one, but real single stage. It have to be like this in my mind:

input transformer--->tube--->output transformer.

Did anybody make sumething like it?

2W output at 8Om will be anough.

As compromise integrated tubes triod+triod is possible (2 stages).

Here is Minimalistic Single Tube Set Amp project for You,but with only 1,2W output power.

And here is the link for same project:6S45P-E SE Amp

Best Regards

 

[Wavebourn]

Take one 6Ж52П, and you don't need input transformer. Or, one 6П14П with input transformer.

 

[artosalo]

The 6CL6 with a 8K load does great, and is good for almost 3 watts out.

The problem with this tube is too low gain. Almost 3 Vrms is required to drive to 3W out. Therefore higer gm pentode is more suitable.
(like 6Ж52П, = 6J52P)

 

[Michael Koster]

Here's a single tube parafeed output with active plate "load" that can get 2W out of a 6C45P WITH a decent damping factor. No input transformer needed, and uses a small mains toroid as an OPT.

http://www.diyaudio.com/forums/tube...sist-totem-pole-current-mirror-pp-hybrid.html

Cheers,

Michael

 

[revintage]

Don´t forget 6E5P.
This is something in Swedish, maybe you will understand the essentials.

http://www.goodsoundclub.com/pdf/6E5P_Swedish.pdf

 

[Ty_Bower]

My current amps are single tube monoblocks(EL84), but I guess that's not what you mean.

Something like this "World’s Simplest SE Class-A amplifier", seen about halfway down the page?

John Broskie's Simple SE Amplifiers

 

[indianajo]

single tube amplifier

My Mother's RCA stereo phonograph circa 1961 had two tubes. One for the left, one for the right. The speaker housing was 8"x12"x3.5" but the actual speaker was 2.5" diameter jammed up in one corner. It had a ceramic phono cartridge, a technology known for ripping up records but better than the 78 rpm arm it replaced. If you look up a Sam's photofacts for those years you will find a bunch of those record players. I think she bought the unit with Top Value stamps from Kroger's affiliate Henke & Pilot.
I looked down my nose at RCA consumer electronics after that, although their red seal and dynagroove LP's were superb. The 1968 college library had dynaco ST35's, I followed their lead.

 

[astouffer]

My Mother's RCA stereo phonograph circa 1961 had two tubes. One for the left, one for the right. The speaker housing was 8"x12"x3.5" but the actual speaker was 2.5" diameter jammed up in one corner. It had a ceramic phono cartridge, a technology known for ripping up records but better than the 78 rpm arm it replaced. If you look up a Sam's photofacts for those years you will find a bunch of those record players. I think she bought the unit with Top Value stamps from Kroger's affiliate Henke & Pilot.
I looked down my nose at RCA consumer electronics after that, although their red seal and dynagroove LP's were superb. The 1968 college library had dynaco ST35's, I followed their lead.

The back of the RCA manual shows this design, it uses a 60FX5 for each channel, with b+ coming from the line

 

[dsavitsk]

EML-20A-20B-30A Data sheet. By Emission Labs.

 

[Jaime]

I think the 4L1P can be an interesting alternative (triode or pentode).
Someday I'll try.

 

[Wavebourn]

I think the 4L1P can be an interesting alternative (triode or pentode).
Someday I'll try.

Sounds better than 2A3.

 

[DigitalJunkie]

The 60FX5 will get you about 1watt output from a line level source pretty easily.. The problem is that all of them I've come across were quite microphonic.