Are Srpp's Any Good (please Help) - 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 16th October 2007, 08:24 AM   #1
diyAudio Member
 
soundbadger's Avatar
 
Join Date: Sep 2007
Default Are Srpp's Any Good (please Help)

hello
me again,,,
i want a driver stage for kt88 and was thinking of using both sections of an e88cc the first section as common cathode, then the output from this going in to the grid of the second section which would be run as a cathode follower.

but then i saw this e88cc srpp schematic and thought id ask about it.

i have heard srpp may not sound that good, could someone explain the pros and cons of srpp, and tell me if it would be suitable for use in a high quality hi-fi amp .

also if someone could explain how to calculate the total gain and output resistance of an srpp it would be really usefull.

cheers
soundbadger
Attached Images
File Type: png 6dj8-srpp-tube-preamp.png (12.8 KB, 417 views)
  Reply With Quote
Old 16th October 2007, 08:53 AM   #2
diyAudio Member
 
Alastair E's Avatar
 
Join Date: Feb 2004
Location: South Wales
There is nothing wrong with the SRPP....Preferable to the straight common-cathode IMO...

But--As with many things in life, its quite a personal thing.....

If I was to do summit similar I would probably go for a Mu Stage, followed by maybe a cathode-follower to the KT88....

They say that the Mu stage goes some way nearer to the 'perfect' CCS for the lower gain stage....I like the sound, but some prefer the SRPP for its simplicity, although the Mu stage only has a couple of extra parts and appears 'similar'
__________________
Das Beste Oder Nichts
  Reply With Quote
Old 16th October 2007, 10:51 AM   #3
SY is offline SY  United States
diyAudio Moderator
 
SY's Avatar
 
Join Date: Oct 2002
Location: Chicagoland
Blog Entries: 1
It depends on the application. For swinging large voltages into reactive loads, they are excellent. For normal sorts of voltage amplification, their linearity is inferior to a simple common cathode stage. This, of course, has not prevented its use in totally inappropriate applications because of the fascination it holds for hobbyists. For driving KT88, the swing requirements are pretty nominal, so SRPP would not be optimum. The badger's recommendation is a better one and, frankly, a plain vanilla 6SN7 with a 50k plate load and a 450V supply will give outstanding results with much lower parts count and complication.

The basics and the trade-offs of SRPP are discussed in "Valve Amplifiers," 3rd edition.

edit: I meant Alastair's, not sb's suggestion. Too early in the morning.
__________________
You might be screaming "No, no, no" and all they hear is "Who wants cake?" Let me tell you something: They all do. They all want cake.- Wilford Brimley
  Reply With Quote
Old 16th October 2007, 11:17 AM   #4
Gordy is offline Gordy  United Kingdom
diyAudio Member
 
Join Date: Nov 2006
There is also a lot of stuff (pros and cons) about SRPP over at tubecad.com
  Reply With Quote
Old 16th October 2007, 12:15 PM   #5
18thell is offline 18thell  United Kingdom
diyAudio Member
 
Join Date: Jan 2007
Default SRPP

From my point of view,SRPP had been using by Luxman products, but no more on the market today, due to the sound reproduction is " too hard " and not that much Audiophile likes it. From the HI-Fi review mag. suggested " Williamson " sounds much better. take 12ax7 for front pre. and phase splitter, 12bh7 for after phase driver, then push a pair of kt88. This combination is employed by amp. manufacturer like fisher, Scott, Radford, H,J, Leak----.
  Reply With Quote
Old 16th October 2007, 01:26 PM   #6
diyAudio Member
 
soundbadger's Avatar
 
Join Date: Sep 2007
i did a bit of reading of valve amps 3rd and decided i think id be beter of with a mu folower.
however after reading some articles here on diy audio it seems that using a pentode as the constant current source / cf would yeild much better results.


ive attached the formula for voltage gain of a mu follower. could someone explain, which tubes do the values for this formula come from.
Attached Images
File Type: gif uk_tubesinfo_1_formula_1.4a.gif (4.1 KB, 275 views)
  Reply With Quote
Old 17th October 2007, 09:09 AM   #7
diyAudio Member
 
Alastair E's Avatar
 
Join Date: Feb 2004
Location: South Wales
Check out this from Allan Kimmel --

http://www7.taosnet.com/f10/mustage.html

Its a description of exactly how to work out the circuit values, as well as the pro's and cons of various 'active-loaded' triode stages. It examines the SRPP, the Triode Mu, Pentode Mu and if you're not allergic to silicon,
it describes a MOSFET active load....
__________________
Das Beste Oder Nichts
  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 09:27 PM
To SRPP or not? duderduderini Tubes / Valves 2 12th March 2007 03:01 PM
mu / srpp / or CF? AudioGeek Tubes / Valves 9 24th April 2004 05:48 PM
SRPP is....? peranders Tubes / Valves 8 19th December 2003 08:38 PM
Help with SRPP pre- ktigerb Tubes / Valves 11 10th October 2003 10:40 PM


New To Site? Need Help?

All times are GMT. The time now is 05:58 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