Big valve preamp

[beamnet]

I have once seen a thread about using big oiutput valves in preamps.

Now i have been searching for quite a while and now i am starting to question myself.

So does anyone knuw this tres?

If no, any ideas on the subject?

I have seen designs using el36 vlaves as css for small tubes..

I'd like to make something "way over the top" for my preamp...

[the_manta]

What about using a EL34 as input Valve and the small triode in the EM84 as output ?

Right. That makes no sense. As ist makes no sense to use big output valves in preamps. There are small signal tubes which are especially design for handling small signals :-)

The CSS is for a µ-follower It think..Otherwise it wouldn't make any sense. Now, buy some books about tube engeneering and you will notice that for a µ-follower the Transconductance is the significant criteria.
And a PL36 has only about 14ma/V. This can be done better by physical smaller tubes. (EL802 - 40mA/V, E55L - 45mA/V.......)

Size doesn't matter ! (In that case ;-)

There are also people using old and rare Valves for that job. These are quite big. Here in germany they snap up the old ones like RE084 etc. Fools believe in better sound.

Manta

[beamnet]

Dear manta.

You are reading this _totally_ wrong!

I am just orienting on a good idea for a weird preamp! I once saw this topic and in my memory there were succes stories in it, just wanted to have a look.

Now i remembered it was a dual penthode in that amp that was wired as a css load to a small triode.

I know it's by no means the optimal solution. That's why I called it OVER the top!

[ErikdeBest]

Hi Bas

The other Dutch Bas started a thread on the use of a 300B for preamp duties. In the first post there is a link to a preamp with 6AS7 loaded with EL34 as CCS.

You may laugh..but don't waste your time trying to dissuade me. 300B preamp.

Erik

[soundbrigade]

I've built an amp with mid size tubes (Mapletree Audio Design) - 6J5 and 6R7. I have two pairs of 6R7 and one is the size of 1626 - sexy - with top grid.

[Ryssen]

I tried this one once:http://www.pmillett.com/lowmu_preamp.htm
it sounded thick and boomy,but if it´s just going to be a crazy amp,guess the sound doesn´t matter.

[Bandersnatch]

hey-Hey!!!,
Do a power pentode. You don't want to deal with Miller and a volume pot for the rest of the tone control. Say, a 6CB5A. B+ of 200V, g2 at ~80, and idle current of 75 mA through a 390R plate load.
cheers,
Douglas

[soundbrigade]

Ryssen:

A little OT, but how about the same topology but using smaller tubes like 12B4A and EL84?? Or just a simple ECL82/85/86??

[beamnet]

where's the over the top in that?

[Alastair E]

I saw a preamp by 'Susan-Parker' somewhere on the 'web a while back.....

It used wait for it....

6C33C-B tubes, transformer coupled as I recall....

It apparently DID work reasonably well however according to what Ive read on it...

BUT 6C33C-B...As a Pre...!--Thats just MAD