Aikido Phono Stage - 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 11th April 2007, 01:36 AM   #1
diyAudio Member
 
Join Date: Apr 2007
Default Aikido Phono Stage

Hi
I have a stereo 5687 Aikido board and would like to build a phono stage around it. Has anyone done this or know of any circuits for it? If not any thoughts as to whether it would even work? Never attempted a phono stage before.

thanks in advance

Bob
  Reply With Quote
Old 11th April 2007, 02:35 AM   #2
JoshK is offline JoshK  Canada
diyAudio Member
 
Join Date: May 2004
Location: Toronto, ON
john broskie has done a little more than ellude to this. basically you will need two aikido stages with the riaa correction between the stages. 5687 should work well for the followers but you will likely need much higher gain tubes for the first spots.

he mentioned that someone at a europeans diy fest got first prize for an aikido phono. so its been done before.
  Reply With Quote
Old 11th April 2007, 02:44 AM   #3
Tweeker is offline Tweeker  United States
diyAudio Member
 
Join Date: Dec 2004
Location: Cincinnati, Ohio
5751 would be a candidate for the first Aikido section.

Tubecad passive RIAA article.

Fourth time constant note.
__________________
Be sure your foil hat has a good low impedance ground.
  Reply With Quote
Old 11th April 2007, 02:56 PM   #4
jduffy is offline jduffy  United States
diyAudio Member
 
jduffy's Avatar
 
Join Date: Oct 2006
Correct me if I'm wrong, but if you use two boards don't you then need eight tubes?
  Reply With Quote
Old 11th April 2007, 03:56 PM   #5
JoshK is offline JoshK  Canada
diyAudio Member
 
Join Date: May 2004
Location: Toronto, ON
yep
  Reply With Quote
Old 11th April 2007, 09:26 PM   #6
Sheldon is offline Sheldon  United States
diyAudio Member
 
Join Date: Dec 2003
Location: San Diego
I did something like this. If you look at the last three triode sections, you will see that they are an Aikido amp with a single triode as the first section. http://www.diyaudio.com/forums/showt...67#post1170667

There's no reason you couldn't use your board and both triode sections, instead of the single triode and cathode resistor. You'd just have to calculate the Rp of the top section.

For the front end, you could use a 6922 cascode, or a hybrid cascode like this:
http://www.diyaudio.com/forums/showt...687#post959687

Sheldon
  Reply With Quote
Old 11th April 2007, 09:53 PM   #7
diyAudio Member
 
Join Date: Apr 2007
Thanks for the responses. Tweaker I read the passive riaa link and Sheldon I have to review your circuit more closely. Wow this is significanly harder than a line stage or a little SE amp! I have to digest all the Bronski stuff to many variables in there and to many things I dont know. Im going to just be running high output ("high output thats a laugh") MM cartridges with it so that should help. Sheldon what kind of accuracy where you able to achieve and how hard is the eq to tweak.
  Reply With Quote
Old 12th April 2007, 12:00 AM   #8
Sheldon is offline Sheldon  United States
diyAudio Member
 
Join Date: Dec 2003
Location: San Diego
Quote:
Originally posted by rhcclark
Thanks for the responses. Tweaker I read the passive riaa link and Sheldon I have to review your circuit more closely. Wow this is significanly harder than a line stage or a little SE amp! I have to digest all the Bronski stuff to many variables in there and to many things I dont know. Im going to just be running high output ("high output thats a laugh") MM cartridges with it so that should help. Sheldon what kind of accuracy where you able to achieve and how hard is the eq to tweak.

It is a bit complicated, but it's manageable. I can help you calculate your eq values and many of the experienced people here are very willing to offer help and advise. If I get the chance, I'll make up a circuit example in the next couple of days.

I built a reverse RIAA circuit don't have the citation with me, but will dig it up when I get home next week. With no changes to my calculated values, I was able to get within a couple tenths of a dB from 40-20kHz. And that was including the step up transformer. It was more than 0.2 off only at the extremes. So I didn't do any tweaking, though it's not hard to add a bit of capacitance or change resistor values. You are welcome to borrow the reverse thingy when you get to that point.

This calculator is much help: http://www.hagtech.com/equalization.html

Sheldon
  Reply With Quote
Old 12th April 2007, 04:18 AM   #9
diyAudio Member
 
Join Date: Jun 2005
Location: Tempe, AZ
Default Love My Aikido Phono

Charlie Butterworth is coming over this weekend to show off his (AT LAST!) totally quiet Aikido and compare it to my full function (yes, EIGHT tubes!) Aikido. (ECC85, 6DJ8, 6SL7, 6SN7) Maybe he will feel like giving his impressions.
  Reply With Quote
Old 12th April 2007, 01:44 PM   #10
Sheldon is offline Sheldon  United States
diyAudio Member
 
Join Date: Dec 2003
Location: San Diego
Here's what an Aikido phono amp might look like with a cascode front end.
Attached Images
File Type: gif riaa aikido cascode.gif (6.8 KB, 2293 views)
  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
Aikido Phono Pre.....any good??? Freecrowder Tubes / Valves 3 21st January 2009 08:02 PM
DIY phono to replace roksan phono stage seroxatmad Analog Line Level 6 14th December 2008 05:46 PM
Aikido line stage - plus phono line stage cjkpkg Tubes / Valves 1 22nd November 2008 09:50 PM
Aikido Phono PCB Modifications Binaural Tubes / Valves 1 9th November 2008 07:47 PM
Should I replace Scott 222C phono stage with Claret phono stage? Bing Yang Analogue Source 0 22nd August 2005 06:41 AM


New To Site? Need Help?

All times are GMT. The time now is 01:55 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