Wanted: 6922 / 6DJ8 Preamp Kit / Schematic

[ir33t]

Hi, this is my first post on the board.

Does anyone know where i can get a schematic or kit (very cheap) for 6922 / 6dj8 tube?

The reason i'm asking is..
1. I would like a tube preamp, and use solid state for the rest.
2. I have over 3000 (yes three thousand) of these tubes And the offers I have had for them are a joke and I belive this would be a good value adding venture.

I'll give you some info on the tube, there "National" branded and are made in japan.

Even if nothing comes of this tubes of any make are better then money in the bank and return a better investment.

Oh, if you would like to relive me of some, please leave a message. However, that is not the primary reason for this post and i do not want to be shot down as trying to sell something in this section.

[fdegrove]

Hi,

Welcome,


For a preamp based around the same tube:

6922

I'll give you some info on the tube, there "National" branded and are made in japan.

"National" used be a brandname of Panasonic, I have never seen any tubes branded that way except for Richardson Electronics who still use this brandname mostly on USSR made tubes.
If the branding is red it could that these tubes were made for them.

If you want to sell on the forum than there is the "Trading Post" section on the forum.

Cheers,

[ir33t]

I was hoping for a schematic

[Cobra2]

http://home.c2i.net/semfielec/tubepre1.htm
http://www.mclink.it/com/audiomatica/tubes/6dj8.htm
http://www.vacuumstate.com/various/P..._all_pages.pdf
http://www.users.globalnet.co.uk/~va...PreProject.htm

Arne K

[ir33t]

http://www.users.globalnet.co.uk/~v...ePreProject.htm
<--------

thats a very good site, THANKS!

[Brett]

Originally posted by ir33t
http://www.users.globalnet.co.uk/~v...ePreProject.htm
&lt;--------

thats a very good site, THANKS!

The circuit in fig 2 is easy enough as a first time build, but it will have a gain or 25 which may be too much. Output Z will be about 2.5k.

If you need to attenuate because of too much signal, I'd prefer to do it at the output (for SNR reasons) and use short, low capacitance interconnects. For the same reason, I'd up the cathode R to about 270 ohms (Vg = -2.9V) so that the stage is less likely to clip on most input signals.

The beauty of DIY is you can try it with an atten at the input and output, different biassing etc and see what you think.

The stupidly expnesive CJ ART preamp is only 10 6DJ8's in parallel. You have enough tubes.....

[planet10]

I've seen some people using 6922s for low power (headphone) amps. I wonder if having so many might be an excuse to build a massively parallel OTL amp... Frank?

dave

[fdegrove]

Hi,

I wonder if having so many might be an excuse to build a massively parallel OTL amp... Frank?

LOL, like that amplifier with all those 12AX7s?
The 6922 is far from the ideal candidate for OTL use, you'd need tons of them to get the Zo down to useable levels.

Well, if the tubes were mine I'd put some up for sale/swap and get some tubes that would fit a usefull diy project instead.

Unfortunately they're not mine.

Good use could be:

a preamp,
the headphone amp Dave refers to (actually the headphone amp can easily double as a preamp too),
Input stage or phase splitter in an amp,
output stage in a tube DAC....

Cheers,

[moamps]

Hi,

on www.headwize.com;
http://headwize2.powerpill.org/proje...=cmoy5_prj.htm
is one nice preamp/headphone amp. I was building this, good sound, but very depend of tubes manufacturer. (I make some changes).

Regards

[ir33t]

yea but how much is one of those??? i'm not selling my left nut to get a preamp.