valve preamp criticisms?

lt cdr data · 29th December 2005, 07:00 PM

whaddya think?

analog_sa · 29th December 2005, 08:25 PM

Criticisms:

1. ECC82
2. ECC82
3. ECC82
4. Cathode follower
5. Cap coupled
6. Sand in PSU
7. It just can't compete with a good passive if gain or impedance matching is not an issue.
8. Not even the 'finest silver RCA' will help it

Steve Eddy · 29th December 2005, 08:43 PM

Quote:

Originally posted by lt cdr data
whaddya think?

I'd just say don't let other peoples' prejudices discourage you or get you down. At the end of the day you're the one who has to be satisfied with it. And the only person who can tell you whether you've achieved that is you.

se

bigwill · 29th December 2005, 08:57 PM

Quote:

Originally posted by analog_sa
Criticisms:
6. Sand in PSU

How on earth is that a bad thing? Anyway, tubes have more sand in them than solid state devices

Giaime · 29th December 2005, 09:05 PM

It's good.

Said that, here's the things I would do:

1) ECC88

2) sand regulator in the PSU. Trust me.

3) CCS under the tubes, throw away that led.

Practically that's my preamplifier, you can find detailed schematics on my site.

Robski666 · 30th December 2005, 12:50 AM

Hi

I would have to agree with Giaime on the led, other then that its all fairly arbitrary

Robert

fdegrove · 30th December 2005, 03:21 AM

Hi,

Yet another preamp that nobody really needs.

If you want to experiment and learn what valves are all about why waste the opportunity by throwing in all that semi-conductor trash?

I'm afraid I'll have to agree with Analog_SA's analysis.

Steve Eddy still hasn't caught up on tubes yet either so what else is new?

You want a preamp?
You want a little gain?
Reasonable output impedance?
Not too expensive?
Sound you won't believe was possible?

Get yourself a pair of 12B4A's and build Brett's little circuit, it's in the forum's archives and probably has been mentioned in the recent 12B4A thread by Mark Gulbrandsen.

Oh, pay attention to the PS.
Not a single circuit sounds better than its PS.

Thank us later,

Bryan · 30th December 2005, 03:39 AM

I'm with Frank on this one. 12B4A, simple and sweet

lt cdr data · 30th December 2005, 09:58 AM

the psu is actually tube rectified, but there was no tube rectifier on the drawing package

dave dove · 30th December 2005, 11:17 AM

are you building
or buying?

dave dove

30th December 2005, 03:21 AM	#7
fdegrove diyAudio Senior Member Join Date: Aug 2002 Location: Belgium	Hi, Yet another preamp that nobody really needs. If you want to experiment and learn what valves are all about why waste the opportunity by throwing in all that semi-conductor trash? I'm afraid I'll have to agree with Analog_SA's analysis. Steve Eddy still hasn't caught up on tubes yet either so what else is new? You want a preamp? You want a little gain? Reasonable output impedance? Not too expensive? Sound you won't believe was possible? Get yourself a pair of 12B4A's and build Brett's little circuit, it's in the forum's archives and probably has been mentioned in the recent 12B4A thread by Mark Gulbrandsen. Oh, pay attention to the PS. Not a single circuit sounds better than its PS. Thank us later, __________________ Frank

30th December 2005, 03:39 AM	#8
Bryan diyAudio Member Join Date: Jun 2003 Location: Reading MA	I'm with Frank on this one. 12B4A, simple and sweet __________________ Dont take life too seriously, you will never get out alive!

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29th December 2005, 08:25 PM	#2
analog_sa diyAudio Member Join Date: Aug 2002 Location: Sofia	Criticisms: 1. ECC82 2. ECC82 3. ECC82 4. Cathode follower 5. Cap coupled 6. Sand in PSU 7. It just can't compete with a good passive if gain or impedance matching is not an issue. 8. Not even the 'finest silver RCA' will help it

29th December 2005, 09:05 PM	#5
Giaime diyAudio Member Join Date: Oct 2004	It's good. Said that, here's the things I would do: 1) ECC88 2) sand regulator in the PSU. Trust me. 3) CCS under the tubes, throw away that led. Practically that's my preamplifier, you can find detailed schematics on my site.

30th December 2005, 12:50 AM	#6
Robski666 diyAudio Member Join Date: Sep 2005	Hi I would have to agree with Giaime on the led, other then that its all fairly arbitrary Robert

30th December 2005, 09:58 AM	#9
lt cdr data diyAudio Member Join Date: Dec 2003 Location: earth	the psu is actually tube rectified, but there was no tube rectifier on the drawing package

30th December 2005, 11:17 AM	#10
dave dove diyAudio Member Join Date: Mar 2005 Location: mid wales	are you building or buying? dave dove

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