diyAudio (
-   Tubes / Valves (
-   -   6c33c Tube preamp (

lawbadman 12th March 2006 07:41 AM

6c33c Tube preamp
2 Attachment(s)
Hello all,
I know this is a real waste of power tubes, but I feel the itch to build the 6c33c tube pre amp I have attached to this post.

Apart from the crazy use/waste of this tube, what do you guys think its performance might be compared to other tube preamps?
As much as I want to build this I dont want to build something that wont sound good.

How do I calculate output impedance and power output?

Also has anyone tried the Tube Zen amp, I have never read any discussion about it?


Shoog 12th March 2006 07:48 AM

I didn't think the 6c33c was know for its linearity. Also there are better circuits availble than the SRPP. If you really need to drive 50meters of cable then go for it - otherwise forget it.

Just my opinion.


SY 12th March 2006 07:56 AM

The SRPP is totally unneccessary if you're only swinging a couple of volts. The rp is so low for this tube that you don't gain any real advantage in output impedance, either.

Just for fun, I breadboarded a phono input with a 6528 a couple months ago. Microphonic as hell. And not terribly quiet, so the old 2.5/gm rule is not exactly universal. OTOH, at ETF05, I saw someone who used high gm sweep tubes as phono preamps and the preamp was reasonably quiet, so there could be something to the idea of using grossly oversized tubes...

commsysman 24th March 2006 03:42 PM

tube choice
If the parameters are what I suspect they are, a 6C30 might be a better choice. It has excellent linearity. The new Audio Research preamps all use the 6C30, and the sound is an incredible step up from the earlier designs that used the 6922/6DJ8.

Bandersnatch 24th March 2006 05:47 PM

I'd suggest setting it up with a slightly smaller valve to start...6C19 for one...6C41 for another. If these pan out, then move on up to the Big One...:)

fdegrove 24th March 2006 10:13 PM


With a powertube like that count an hour for the thing to settle, deal with cracks, clicks, pops and microphony as well...

The schematic is an SRPP using a dual triode iso of a twin where mu is virtually non-existant and not a design priority either.
On top of that the SRPP cuts mu in half, what is this thing designed for I wonder?

It sports a 22 microFarad bipolar cap on the output as well, great....

Could it be a headphone amp perhaps?

Cheers, ;)

lawbadman 25th March 2006 05:35 PM

Well so much for that idea.
I was thinking that it would be kind of fun to use those big ole power tubes for a line-stage since I dont have the money right now for a full power amp, and I have a fetish for big tubes.

lawbadman 25th March 2006 05:58 PM

I looked up 6C30 tube and the descriptions say 'Delay Relay', what does that mean, a delay relay vacuum tube?????

Also how would I substitute the 6C33C for the 6C30 (I have zero experience in designing tube equipment)?


rfbrw 26th March 2006 04:16 AM

Perhaps it is 6H30.

leadbelly 26th March 2006 05:51 AM


Originally posted by lawbadman
Also how would I substitute the 6C33C for the 6C30 (I have zero experience in designing tube equipment)?
They don't substitute. Just look for published 6H30 designs such as this one:

All times are GMT. The time now is 12:19 PM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 18.75%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio