SE TESLA E34L - 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 December 2010, 09:08 AM   #1
diyAudio Member
 
merlin el mago's Avatar
 
Join Date: Sep 2009
Location: Catalonia - Europe
Question SE TESLA E34L

I have 2 tubes Tesla E34L without use & want to do two SE triode mono amps with only 1 tube per channel, I am looking nice design & schematics, any help will welcome.
  Reply With Quote
Old 11th December 2010, 03:21 PM   #2
diyAudio Member
 
artosalo's Avatar
 
Join Date: Feb 2010
Quote:
I am looking nice design & schematics, any help will welcome.
Here You are:


Click the image to open in full size.


But I do not suggest triode connection as you wanted to build.

This circuit is an UL-connected output stage. It's sensitivity is some 0,5 Vrms for 50 mW out. So with a CD-player having 2 Vrms output voltage you can get some 0,5...0,6 W, while full capability of this circuit is some 10 to 11 W out. This requires some 8,7 Vrms input voltage.

If this circuit were triode connected the sensitivity would be much lower.
To get 50 mW out, some 1,7 Vrms input voltage is needed.
The full power of triode connection is about 6 W. To get this, you would need almost 19 Vrms input voltage.

To get a real SE-amplifier, a voltage amplifying stage must be added before the EL34. Then the triode connection would have some sense.
  Reply With Quote
Old 11th December 2010, 05:47 PM   #3
diyAudio Member
 
merlin el mago's Avatar
 
Join Date: Sep 2009
Location: Catalonia - Europe
Quote:
Originally Posted by artosalo View Post
Here You are:


Click the image to open in full size.


But I do not suggest triode connection as you wanted to build.

This circuit is an UL-connected output stage. It's sensitivity is some 0,5 Vrms for 50 mW out. So with a CD-player having 2 Vrms output voltage you can get some 0,5...0,6 W, while full capability of this circuit is some 10 to 11 W out. This requires some 8,7 Vrms input voltage.

If this circuit were triode connected the sensitivity would be much lower.
To get 50 mW out, some 1,7 Vrms input voltage is needed.
The full power of triode connection is about 6 W. To get this, you would need almost 19 Vrms input voltage.

To get a real SE-amplifier, a voltage amplifying stage must be added before the EL34. Then the triode connection would have some sense.
Thanks for help, you are right will do a SE-amplifier with a 1st voltage amplifying stage so can be SE triode? I have on hand:

2 tubes Sovtek 12AX7WXT
2 tubes Sovtek 12AXTWA
2 tubes Sovtek 6922
4 tubes RSD ECC83
2 tubes Siemens E283CC
1 tube National ECC82
3 tubes EI long anode ECC81
4 tubes EI long anode ECC83
3 tubes EI long anode ECC82

Any suggestion will welcome, thanks.
  Reply With Quote
Old 11th December 2010, 06:31 PM   #4
diyAudio Member
 
azazello's Avatar
 
Join Date: Aug 2008
Location: Bulgaria
ECC82 is more suitable for prestage with very good sound.
  Reply With Quote
Old 11th December 2010, 06:50 PM   #5
diyAudio Member
 
artosalo's Avatar
 
Join Date: Feb 2010
Quote:
Any suggestion will welcome, thanks.
Below is one option.


Click the image to open in full size.


I calculated this amplifier with 12AX7 / ECC83. Connected as above the amplification of 1st stage is about 51. Therefore the sensitivity becomes 8,7 V / 51 = 170 mV. Then there is also some gain reserve to add suitable amount of negative feedback. I selected the input sensitivity of 0,5 Vrms for full output. Then the amount of feedback would be 20 log (0,5 V / 0,17 V) = 9,4 dB. This will give reasonable low output impedance, lower distortion and improved frequency response.

Quote:
ECC82 is more suitable for prestage with very good sound.
ECC82 is also a good voltage amplifying tube, but in this case it's low gain
would lead to worse final result. The required input voltage would be essentially higher or there would be no spare gain to utilize NFB.
  Reply With Quote
Old 11th December 2010, 10:21 PM   #6
diyAudio Member
 
azazello's Avatar
 
Join Date: Aug 2008
Location: Bulgaria
I, prefer IMO, tube with good sound, than tube with good gain....
For me, sound is more important than gain! And ECC82 is sounding
better and its gain is enough to drive E34L from every CD or cassette player or RIAA....

Last edited by azazello; 11th December 2010 at 10:23 PM.
  Reply With Quote
Old 12th December 2010, 07:39 AM   #7
diyAudio Member
 
artosalo's Avatar
 
Join Date: Feb 2010
Quote:
And ECC82 is sounding
better and its gain is enough to drive E34L from every CD or cassette player or RIAA....
You hereby invited to present your version of the voltage amplifying stage. Please let us also know the input sensitivity and possible NFB your desing applies.
  Reply With Quote
Old 12th December 2010, 12:07 PM   #8
diyAudio Member
 
merlin el mago's Avatar
 
Join Date: Sep 2009
Location: Catalonia - Europe
Quote:
Originally Posted by azazello View Post
I, prefer IMO, tube with good sound, than tube with good gain....
For me, sound is more important than gain! And ECC82 is sounding
better and its gain is enough to drive E34L from every CD or cassette player or RIAA....
Could you post the schematic with ECC82?
  Reply With Quote
Old 12th December 2010, 01:00 PM   #9
diyAudio Member
 
artosalo's Avatar
 
Join Date: Feb 2010
Quote:
Could you post the schematic with ECC82?
I am waiting that too.

But the fact is that the gain of single ECC82-half is not sufficient.
The input sensitivity would be some 0,65 Vrms without negative feedback.
Although the 1 Vrms input level would be acceptable, there would be only some 3 dB left for NFB. This would lead to insufficient loudspeaker damping
and just average linearity.

However, as such, somebody could say that it sounds great.
But for me, the amplifier must sound good and perfomd good at tests.
  Reply With Quote
Old 12th December 2010, 04:35 PM   #10
diyAudio Member
 
nicoch58's Avatar
 
Join Date: Oct 2004
el84 but some idee....

Audio Asylum Thread Printer
__________________
Sic58
  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
Tesla ARN930 jurda8 Swap Meet 4 2nd October 2012 02:26 PM
Tesla Guitar culture Instruments and Amps 8 18th March 2008 09:19 PM
JJ E34L failure(s) cogsncogs Tubes / Valves 24 30th December 2004 08:37 AM
Is Tesla still going? Hesky Tubes / Valves 4 18th July 2004 11:42 AM


New To Site? Need Help?

All times are GMT. The time now is 11:35 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright Đ1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2