24v tube buffer & line stage schematic - Page 2

plovati · 3rd May 2007, 11:00 AM

http://www.audiofaidate.it/forum/upl...cario_srpp.jpg

Simpleton · 3rd May 2007, 12:00 PM

Simple grounded cathode line amplifier stage using ECC86:

R(grid bias): 100k
Rk: 160Ohm (or closer)
Cathode bypass cap: 50uF
Ra:2.5k
B+: 25V

Vin: 1Vpp
Vout: 10.25Vrms
Ia: 3.1mA
Ia max: 3.5mA
Calculated distortion (2nd hamonic): 1%

plovati · 4th May 2007, 09:15 AM

Quote:

Originally posted by Simpleton
Simple grounded cathode line amplifier stage using ECC86:

R(grid bias): 100k
Rk: 160Ohm (or closer)
Cathode bypass cap: 50uF
Ra:2.5k
B+: 25V

Vin: 1Vpp
Vout: 10.25Vrms
Ia: 3.1mA
Ia max: 3.5mA
Calculated distortion (2nd hamonic): 1%

Ra*Ia = 7.75V
Shouldn't possible to get 10.25V rms out (that means 14.45V peak) beacuse on the anodic resistor there is no enough volatge headroom.
The distortion of 1% seems too optimistic, in practice I think will be 1% at few volts rms.

Bem-bem · 4th May 2007, 10:05 AM

congratulation Plovati ! AC MILAN (3) - MU (0)
in SRPP schematic if i use 100k ohm potensio for input are it too big?
i try to build for line level preamp and what the sound ?

Shoog · 4th May 2007, 10:31 AM

The SRPP doesn't make a good preamp. It can only be optimised for a fixed lowish load. Its is a circuit that need optimisation to give of its best.
I suggest any other type of circuit will do far better.

Shoog

Simpleton · 4th May 2007, 11:48 AM

Thanks for pointing that out Plovati

It seems I have to review my notes (I made these calculations many months ago) and theory

Bem-bem · 5th May 2007, 02:28 AM

Shoog, what preamp circuit in your opinion is the best?

Shoog · 5th May 2007, 07:14 AM

The low voltage Aikido. Plenty of people have built it and liked the result. I have heard no-one complain.

Shoog

plovati · 16th December 2009, 01:13 PM

Quote:

Originally Posted by plovati

This one works from a 12V battery:

http://www.audiofaidate.it/forum/upl...tem_lowres.JPG

gain 13.7
BW (-1dB) 12Hz .. 250kHz
clipping Vout max 3Vrms on 27Kohm load
THD at 2Vrms 1%, 2nd harmonic only
THD at 1Vrms 0,78%, 2nd harmonic only ( -50dB)
output resistance less than 600ohm

We re-organized all the AUDIOFAIDATE forum, noe we're on www.audiofaidate.org Il sito indipendente degli audiocostruttori.
Please take note of the new link to PREcario low voltage tube preamplifier
New link:

http://www.audiofaidate.org/uploaded...tem_lowres.JPG

3rd May 2007, 11:00 AM	#11
plovati diyAudio Member Join Date: Mar 2005 Location: near Milan	and the SRPP version too http://www.audiofaidate.it/forum/upl...cario_srpp.jpg __________________ Piergiorgio

3rd May 2007, 12:00 PM	#12
Simpleton diyAudio Member Join Date: Jan 2005 Location: Lisboa	Simple grounded cathode line amplifier stage using ECC86: R(grid bias): 100k Rk: 160Ohm (or closer) Cathode bypass cap: 50uF Ra:2.5k B+: 25V Vin: 1Vpp Vout: 10.25Vrms Ia: 3.1mA Ia max: 3.5mA Calculated distortion (2nd hamonic): 1% __________________ "There's something organic about a happy cloud of electrons" - Neutron Bob

4th May 2007, 11:48 AM	#16
Simpleton diyAudio Member Join Date: Jan 2005 Location: Lisboa	Thanks for pointing that out Plovati It seems I have to review my notes (I made these calculations many months ago) and theory __________________ "There's something organic about a happy cloud of electrons" - Neutron Bob

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4th May 2007, 10:05 AM	#14
Bem-bem diyAudio Member Join Date: May 2006	congratulation Plovati ! AC MILAN (3) - MU (0) in SRPP schematic if i use 100k ohm potensio for input are it too big? i try to build for line level preamp and what the sound ?

4th May 2007, 10:31 AM	#15
Shoog diyAudio Member Join Date: Aug 2002 Location: Eire	The SRPP doesn't make a good preamp. It can only be optimised for a fixed lowish load. Its is a circuit that need optimisation to give of its best. I suggest any other type of circuit will do far better. Shoog

5th May 2007, 02:28 AM	#17
Bem-bem diyAudio Member Join Date: May 2006	Shoog, what preamp circuit in your opinion is the best?

5th May 2007, 07:14 AM	#18
Shoog diyAudio Member Join Date: Aug 2002 Location: Eire	The low voltage Aikido. Plenty of people have built it and liked the result. I have heard no-one complain. Shoog

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