5902 subminiature audio pentode

[Glass_painter]

Hello everyone,

I would like to build a small tube amp with 6021 as dirver / phase splitter and 5902 push pull in the output for driving an electret stax headphones.

The motivation is to fit it into the existing adapter box and use the trasformers for this project.

What do you think of the project in general and any part in particular.

Any info will be welcome.

Thanks.

Glass_painter

[fdegrove]

Hi,

I would like to build a small tube amp with 6021 as dirver / phase splitter and 5902 push pull in the output for driving an electret stax headphones.

Hard to tell without knowing the electrical characteristics of the Stax adapter you have in mind.

Cheers,

[Glass_painter]

Hi Frank

I am refering to the SRD type adapter which has two step up transformers inside only.

The idea is to use these transformers as output transformers connected to push pull 5902, connect two capacitors to the transformer primary and to the headphones stators.

In addition, when the eletret headphones are not connected, it can still drive regular headphones as well.

What do you think?

Thanks.

Glass_painter

[845]

Hi Glass_painter!

Very pleasantly to meet the compatriot at this forum. I too Tube fanatic for the last 22 years. Be with me in touch.

845

[djmiddelkoop]

Glass_painter,

I also own a Stax electret headphone, the step-up transformers in the adapterbox are not that great that they deserve a seperate tube amp driving them.

I have made a tubeamp driving the Stax direct without transformer. The improvement in soundquality is quite alot.

So I would suggest if you want to make a seperate tubeamp for your Stax, do it the same way.

You can find projects at: headwize

Dick

[Glass_painter]

Hi 865,

Yes, it can be real nice to exchange views and opinions. You are more then welcome to contact me at glavi6@walla.co.il.

Hi Dick,

Can you tell me which one of them did you use in the headwise project section?

Second, I would like to use the transformers only as loads to the tubes, the sound is going directly from the tubes to the stators via a cupling cupacitor, this way the quality of the transformer is less of importance???

What do you think?

Glass_painter

[Brett]

Originally posted by djmiddelkoop
Glass_painter,

I also own a Stax electret headphone, the step-up transformers in the adapterbox are not that great that they deserve a seperate tube amp driving them.

I have made a tubeamp driving the Stax direct without transformer. The improvement in soundquality is quite alot.

So I would suggest if you want to make a seperate tubeamp for your Stax, do it the same way.

You can find projects at: headwize

Dick

Absolutely! If you're going to go to all the effort to build a tube headphone driver, ditch the crap STAX transformers. Not sure they'll be suitabe for anode loads either, but I doubt they will. I've been direct drive since I bought my first set of Lambda Pro's in the mid 80's and wouldn't go back.

There's also a decent little design on Tubecad, somewhere around 2001 in the archives there.

[djmiddelkoop]

Can you tell me which one of them did you use in the headwise project section?

headwize project

The first schematic (figure 1).

Dick.

[Glass_painter]

Hello everyone,

Thanks for the information so far.

Can you direct me to additional schematics of direct drive amps for electret headphones?

I was able to find very little information other the Gilmore designs.

Thanks.

Glass_painter

[Brett]

Originally posted by Glass_painter
Can you direct me to additional schematics of direct drive amps for electret headphones?

http://www.tubecad.com/november99/page2.html
http://www.tubecad.com/december99/page2.html