Help with SRPP pre- - diyAudio
Go Back   Home > Forums > Amplifiers > Tubes / Valves

Tubes / Valves All about our sweet vacuum tubes :) Threads about Musical Instrument Amps of all kinds should be in the Instruments & Amps forum

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 9th October 2003, 10:31 AM   #1
ktigerb is offline ktigerb  South Africa
diyAudio Member
 
Join Date: May 2003
Location: Durban
Talking Help with SRPP pre-

Hi Guys
Attached is a circuit published some 20 yrs ago which I built and had TX made but stalled the finish as the valves were too expensive at that time (for me any how).
I need to know what component values are necessary to change if I substitute V2 and V3 with 12AX7's as in V1 since I have just received a batch of NOS Ediswan 12AX7's.
Thanks
keith birss
Attached Images
File Type: jpg stereo valve preamp2.jpg (50.4 KB, 609 views)
__________________
Keith Birss
  Reply With Quote
Old 9th October 2003, 10:53 AM   #2
diyAudio Moderator Emeritus
 
Bas Horneman's Avatar
 
Join Date: Apr 2002
Location: The Netherlands
Blog Entries: 18
You'll end up with a very different baby if you substitute those tubes all with 12ax7....

first 2 tubes are ofcourse the phono amp the last one the "normal" preamp.

Since it is a phono amp..I would look for a phono amp design that uses all 12ax7 AND THEN build a different preamp...using whatever you fancy or can afford.

Cheers,
Bas

PS..are you the Keith that did dj'ing and rented out sound equipment?
  Reply With Quote
Old 9th October 2003, 11:42 AM   #3
diyAudio Moderator Emeritus
 
Bas Horneman's Avatar
 
Join Date: Apr 2002
Location: The Netherlands
Blog Entries: 18
Please disregard my last question..

I found out that guy was Keith Farr...

Cheers,
Bas
  Reply With Quote
Old 9th October 2003, 03:56 PM   #4
diyAudio Member
 
Join Date: Dec 2000
Location: Germany
Default srpp

Hello,

you can use the amp with 12AX7 in all positions. Make all cathode resistors 1K. The gain will be to high with bypassed cathodes,
35 dB each stage.
Omit the cathode bypass caps, then each stage has a gain of 30dB, good for phono.
The line amp will be a little loud.

Reinhard
  Reply With Quote
Old 9th October 2003, 07:31 PM   #5
diyAudio Senior Member
 
fdegrove's Avatar
 
Join Date: Aug 2002
Location: Belgium
Hi,

That SRPP is a preamp designed by Rainer Zur Linde.

The ECC83 1 2 should be used here for correct gainscaling.
Mu of 100, 60 and 17 respectively.

If not a very noisy pre will result and if only ECC83/12AX7As are used to output impedance will be too high as well.
Not to mention the fact that you'd need to redesign half of the preamp as well.

Surely it must be possible to buy a pair of ECC81s/12AT7As and ECC82s/12AU7As in SA?

Cheers,
__________________
Frank
  Reply With Quote
Old 9th October 2003, 09:55 PM   #6
DrG is offline DrG  South Africa
diyAudio Member
 
Join Date: Aug 2003
Location: Pretoria
Do you require a phono stage? If not then I would buy 2 ECC82's (not too expensive from Mr Valve...) and build the line stage as designed. I did years ago and it sounded pretty damn good!
  Reply With Quote
Old 10th October 2003, 02:31 AM   #7
diyAudio Senior Member
 
fdegrove's Avatar
 
Join Date: Aug 2002
Location: Belgium
Hi,

In case only the line stage is considered an SRPP stage using a 12BH7A would be better still...

Actual results would depend on PS reguation which is tantamount to the SRPP topology.

There's a myriad of other choices for this service one can come up with with too.

Cheers,l
__________________
Frank
  Reply With Quote
Old 10th October 2003, 09:10 AM   #8
ktigerb is offline ktigerb  South Africa
diyAudio Member
 
Join Date: May 2003
Location: Durban
Thanks Frank Reinhard Dr G and Bass
you can stop twisting my arm now (there were no emoticons for tongue in cheek available).
I'll buy the damn things and wait some more for them to arrive ,like I said in an earlier thread with 4 professional students living at home my budget is thinner than the proverbial "....hair"

regards
keith
__________________
Keith Birss
  Reply With Quote
Old 10th October 2003, 09:22 AM   #9
diyAudio Member
 
analog_sa's Avatar
 
Join Date: Aug 2002
Location: Sofia
I also built this circuit (sometime in my youth) and it is largely responsible for my intense dislike of SRPP. Of course it might have been the tubes used
  Reply With Quote
Old 10th October 2003, 05:10 PM   #10
DrG is offline DrG  South Africa
diyAudio Member
 
Join Date: Aug 2003
Location: Pretoria
Quote:
I also built this circuit (sometime in my youth) and it is largely responsible for my intense dislike of SRPP.
Luckily such trauma doesn't seem to have created a permanent aversion to tubes...
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
J-fet Zen Srpp ??? Circlomanen Pass Labs 19 11th April 2010 10:27 PM
Are Srpp's Any Good (please Help) soundbadger Tubes / Valves 6 17th October 2007 10:09 AM
To SRPP or not? duderduderini Tubes / Valves 2 12th March 2007 04:01 PM
mu / srpp / or CF? AudioGeek Tubes / Valves 9 24th April 2004 06:48 PM
SRPP is....? peranders Tubes / Valves 8 19th December 2003 09:38 PM


New To Site? Need Help?

All times are GMT. The time now is 01:35 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2