6c33c Tube preamp

lawbadman · 12th March 2006, 07:41 AM

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?

Thanks
Lawrence

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.

Shoog

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

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

Hey-Hey!!!,
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...

cheers,
Douglas

fdegrove · 24th March 2006, 10:13 PM

Hi,

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)?

Thanks
Lawrence

rfbrw · 26th March 2006, 04:16 AM

Perhaps it is 6H30.

leadbelly · 26th March 2006, 05:51 AM

Quote:

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:

http://digilander.libero.it/paeng/a_...ine_preamp.htm

12th March 2006, 07:56 AM	#3
SY diyAudio Moderator Join Date: Oct 2002 Location: Austin, TX Blog Entries: 1	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... __________________ “Listening to records is like ****ing a picture of Brigitte Bardot.” - Sergiu Celibidache

24th March 2006, 03:42 PM	#4
commsysman diyAudio Member Join Date: Mar 2006 Location: california	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.

24th March 2006, 05:47 PM	#5
Bandersnatch diyAudio Member Join Date: Jul 2003 Location: Ann Arbor, MI	Hey-Hey!!!, 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... cheers, Douglas __________________ the Tnuctipun will return

24th March 2006, 10:13 PM	#6
fdegrove diyAudio Senior Member Join Date: Aug 2002 Location: Belgium	Hi, 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, __________________ Frank

25th March 2006, 05:35 PM	#7
lawbadman diyAudio Member Join Date: Mar 2003 Location: St. Catherine, Jamaica	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. __________________ <a href="http://www.danasoft.com"><img src="http://www.danasoft.com/sig/lawbadman.jpg" border="0"></a><div style="font-family:arial,sans-serif;font-size:11px;"><p>Sign by Danasoft - <a href="http://www.danasoft.com">For Backgrounds and Layouts</a></p></div>

12th March 2006, 07:48 AM	#2
Shoog diyAudio Member Join Date: Aug 2002 Location: Eire	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. Shoog

25th March 2006, 05:58 PM	#8
lawbadman diyAudio Member Join Date: Mar 2003 Location: St. Catherine, Jamaica	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)? Thanks Lawrence __________________ <a href="http://www.danasoft.com"><img src="http://www.danasoft.com/sig/lawbadman.jpg" border="0"></a><div style="font-family:arial,sans-serif;font-size:11px;"><p>Sign by Danasoft - <a href="http://www.danasoft.com">For Backgrounds and Layouts</a></p></div>

26th March 2006, 04:16 AM	#9
rfbrw diyAudio Member Join Date: Oct 2001 Location: .	Perhaps it is 6H30.

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