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 March 2006, 09:59 AM   #1
redzi is offline redzi  Poland
diyAudio Member
 
Join Date: Jul 2004
Location: Gdynia
Default Again, a preamp tube choice.

Hi.
For some time now I've been planning to use the tubes that lay in my cellar, and now, at last I have some spare time, so I decided to build a low mu linestage preamp for my solid state amp.
The construction of this preamp would be the common cathode configuration followed by cathode follower, to decrease the output resistance (however not necessary as my solid state amp has quite high input resistance).

My question is which of the following tubes according to You would be the most appropiate for this design : JJ ECC99, EH 12BH7, EH or Sovtek 6SN7,JJ E88CC / EH or Sovtek 6922,EH 12AU7 or maybe Sovtek 6N30P?

Which of them would be the most linear, the least microphonic, best sounding etc.?

I searched diyaudio forum but i haven't found the anwsers satisfactory.
  Reply With Quote
Old 16th March 2006, 10:42 AM   #2
diyAudio Member
 
Join Date: Nov 2002
I happen to be a 6SN7 fan and highly recommend Franks line stage.

I built this and I am very happy with it. The performance is very good and sonically very pleasing.
Attached Images
File Type: gif 6sn7 line stage.gif (6.9 KB, 739 views)
  Reply With Quote
Old 16th March 2006, 12:24 PM   #3
diyAudio Member
 
Brian Beck's Avatar
 
Join Date: Dec 2004
Location: South Florida, USA
This circuit can probably be improved by simplifying it: remove the coupling cap between the stages, the 220K resistor and the 820 ohm resistor. Directly connect the cathode follower's grid to the first stage's plate. Slight readjustment of the 10K value may be necessary depending on the plate voltage of the first stage. It appears that it can then be increased in value to maintain the 7.15mA shown in the schematic. A higher B+ wouldn't hurt with 6SN7s. A CCS instead of the 10K would be better still, but departs from the inherent simplicity of the design.

This unnecessary AC coupling between a common cathode first stage and CF second stage shows up periodically for some reason. Usually in a well designed common cathode stage the plate sits at roughly 1/2 of the B+ (which can be made higher in this design). This voltage is usually an ideal bias point for the grid of the CF anyway, so why add the colorations of a cap if you don't need to?
__________________
Brian
  Reply With Quote
Old 16th March 2006, 12:34 PM   #4
Giaime is offline Giaime  Italy
diyAudio Member
 
Giaime's Avatar
 
Join Date: Oct 2004
Send a message via MSN to Giaime
Just NOT use ECC82/12AU7
  Reply With Quote
Old 16th March 2006, 10:19 PM   #5
redzi is offline redzi  Poland
diyAudio Member
 
Join Date: Jul 2004
Location: Gdynia
Ok.

So 6SN7 would be nice and ECC82/12AU7 not.

What about the other tubes? Which of them sound better in general (and yes, I know it depends on the used circuit)?

The replies from those of You who have experience and comparison of mentioned tubes would be very helpful.
  Reply With Quote
Old 16th March 2006, 10:36 PM   #6
Ryssen is offline Ryssen  Sweden
diyAudio Member
 
Ryssen's Avatar
 
Join Date: Dec 2003
Location: Sweden--> Here
Quote:
(and yes, I know it depends on the used circuit)?
I like the 6SL7.
  Reply With Quote
Old 16th March 2006, 10:42 PM   #7
lndm is offline lndm  Australia
diyAudio Member
 
Join Date: Mar 2006
Location: nsw
I prefer the 6sn7, it is clean sounding and revealing.

The 12au7 is a more modern equivalent to the 6sn7. A somewhat richer sound, less microphonic. Some sound very good, some don't.

I read in another thread that the EH e88cc is especially non microphonic.
  Reply With Quote
Old 16th March 2006, 10:59 PM   #8
arnoldc is offline arnoldc  Philippines
diyAudio Member
 
Join Date: Apr 2003
Location: Makati
Send a message via Yahoo to arnoldc
I am not a fan of 6SN7. However, based on the list of tubes you have there, I would be tempted to go for the 6SN7.

On the other hand, based on what I have heard on a BAT (Balanced Audio Technologies) pre-amp that uses the 6N30-pi, I might experiment with that, if I were you.
  Reply With Quote
Old 17th March 2006, 10:49 AM   #9
redzi is offline redzi  Poland
diyAudio Member
 
Join Date: Jul 2004
Location: Gdynia
Quote:
I like the 6SL7.
Yes, but it has mu at level of 70 - might be good for RIAA preamp or guitar one, but not a linestage.

Now the 6SN7 starts to be my favourite, but what version to choose EH or Sovtek?

And what about ECC99? I heard it is very linear and also well sounding.

Quote:
I am not a fan of 6SN7. However, based on the list of tubes you have there, I would be tempted to go for the 6SN7.
I've listed just the tubes that are easily accesible in Poland, however I'm open to Your suggestions in this matter. Please tell me about Your favourites.
  Reply With Quote
Old 17th March 2006, 10:53 AM   #10
diyAudio Member
 
Join Date: Nov 2002
Quote:

I prefer the 6sn7, it is clean sounding and revealing.

The 12au7 is a more modern equivalent to the 6sn7. A somewhat richer sound, less microphonic. Some sound very good, some don't.


I don't know how you figure the 12AU7 is a modern equivalent to the 6SN7. Except for use as a phase splitter I can see no other value for it.
  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 tube choice peterr Tubes / Valves 25 12th July 2009 06:46 PM
Tube choice for Class A2 hacknet Tubes / Valves 59 2nd February 2007 06:26 AM
tube choice? andrewe1 Tubes / Valves 3 14th July 2004 01:05 PM
5687 Tube - best choice Alfetta87 Tubes / Valves 5 7th May 2004 02:25 PM


New To Site? Need Help?

All times are GMT. The time now is 11:39 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