Is it the 6SN7 or me? - 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 12th October 2006, 06:24 AM   #1
arnoldc is offline arnoldc  Philippines
diyAudio Member
 
Join Date: Apr 2003
Location: Makati
Send a message via Yahoo to arnoldc
Unhappy Is it the 6SN7 or me?

Last night I played with TubeCAD (I'm lazy) cause I wanted to put my 6SN7 to good use. I configured it in SRPP mode given the following conditions: 320V B+, 8mA

According to the results, I'll get 11.29 Av, -3.9 bias, +-44V Vout

So I went ahead and ripped off the 6SL7 circuit from my 2A3 and wired in the 6SN7

I wire the lower tube's cathode with two LEDs instead of 470R resistor.

When I got to play the amp, I immediately noticed the lack of dynamics and resolution. It was disappointing. Boring sound

What have I done wrong?

I've configured this amp to use the Sun Audio circuit (2 stage 6SN7) but did not like it as well.

  Reply With Quote
Old 12th October 2006, 07:27 AM   #2
EC8010 is offline EC8010  United Kingdom
diyAudio Moderator Emeritus
 
EC8010's Avatar
 
Join Date: Jan 2003
Location: Near London. UK
LED bias works best when the anode load resistance is high - SRPP puts a quite a low load resistance on the lower valve.
__________________
The loudspeaker: The only commercial Hi-Fi item where a disproportionate part of the budget isn't spent on the box. And the one where it would make a difference...
  Reply With Quote
Old 12th October 2006, 07:52 AM   #3
arnoldc is offline arnoldc  Philippines
diyAudio Member
 
Join Date: Apr 2003
Location: Makati
Send a message via Yahoo to arnoldc
aha, i'll change it to a 470R resistor and see what happens.

thanks
  Reply With Quote
Old 12th October 2006, 07:18 PM   #4
diyAudio Member
 
Alastair E's Avatar
 
Join Date: Feb 2004
Location: South Wales
The 6SL7 removed from your amp has a higher Mu of 70 as opposed to the much lower Mu of 20 of the 'SN7.....

I prefer the sound of the 'SL7 to me, Much more dynamic...
__________________
Das Beste Oder Nichts
  Reply With Quote
Old 12th October 2006, 11:31 PM   #5
arnoldc is offline arnoldc  Philippines
diyAudio Member
 
Join Date: Apr 2003
Location: Makati
Send a message via Yahoo to arnoldc
Alastair, yes I was wrong. I thought that having a lower mu tube (I have a preamp) with much more current could improve the dynamics from that of the 6SL7.

I listened to it again last night and it was butchered by my 45 amp with 5842 as drivers.
  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
6SN7 pre-amp Andersen Tubes / Valves 57 17th July 2011 06:00 PM
SE 6SN7 amp.... JandG Tubes / Valves 24 6th March 2011 11:37 AM
6sn7's irishguy170 Swap Meet 0 15th January 2008 07:09 AM
Help me.......What is the 6SN7 ??????? cd149dc Tubes / Valves 10 17th June 2007 04:09 PM
6SN7 CCS Cassiel Tubes / Valves 25 14th February 2006 10:09 PM


New To Site? Need Help?

All times are GMT. The time now is 11:12 AM.


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