#26 pre amp - Page 310 - 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 30th March 2013, 04:20 PM   #3091
euro21 is offline euro21  Hungary
diyAudio Member
 
Join Date: Sep 2004
Location: Budapest
Quote:
Originally Posted by merlin el mago View Post
.. change OPT to output cap, I left the OPT
Felipe, I think you giving up too soon.

Using anode resistor and cap. coupling (B+:220V, Ra:10K) the easiest method, but the poorer sound.

If you compensate OPT, you get much better result.
  Reply With Quote
Old 30th March 2013, 04:22 PM   #3092
diyAudio Member
 
merlin el mago's Avatar
 
Join Date: Sep 2009
Location: Catalonia - Europe
Quote:
Originally Posted by euro21 View Post
Felipe, I think you giving up too soon.

Using anode resistor and cap. coupling (B+:220V, Ra:10K) the easiest method, but the poorer sound.

If you compensate OPT, you get much better result.
Many thanks for the info
  Reply With Quote
Old 30th March 2013, 05:35 PM   #3093
diyAudio Member
 
Join Date: Sep 2003
Location: London
Using an anode resistor is a very poor idea. I would forget it. Various solid state anode loads are interesting - I tried these at some point and preferred the OPT, but haven't revisited this lately. I would simply use the transformer and forget about output caps. Try it as it is first.

My experiences with the 26 is that it has good sound at several different operating points. I have run it at 90v and 3mA and it sounds surpringly good at that operating point. You are not going to have poor sound within the range 90-180v

Filepe - you have now practically built your 26 preamp. I think this is the time to stop agonising over possible choices and just listen to it. You will need a reference listening test for any future modifications anyway. Experiment later and then see if it sounds better or worse or the same as it is with the OPT and VR150. This is exactly what I'm listening to as I write, and it's a perfectly good sound. Have a good Easter and enjoy your build. Play some music!

Andy
  Reply With Quote
Old 30th March 2013, 06:07 PM   #3094
FRUGIVO is offline FRUGIVO  Spain
diyAudio Member
 
Join Date: Feb 2010
Location: Burgos
Quote:
Originally Posted by andyjevans View Post
Filepe - you have now practically built your 26 preamp. I think this is the time to stop agonising over possible choices and just listen to it. You will need a reference listening test for any future modifications anyway. Experiment later and then see if it sounds better or worse or the same as it is with the OPT and VR150. This is exactly what I'm listening to as I write, and it's a perfectly good sound. Have a good Easter and enjoy your build. Play some music!

Andy
Andy wise example
care
DIY is highly addictive
must take breaks
  Reply With Quote
Old 30th March 2013, 06:57 PM   #3095
diyAudio Member
 
merlin el mago's Avatar
 
Join Date: Sep 2009
Location: Catalonia - Europe
Quote:
Originally Posted by andyjevans View Post
Using an anode resistor is a very poor idea. I would forget it. Various solid state anode loads are interesting - I tried these at some point and preferred the OPT, but haven't revisited this lately. I would simply use the transformer and forget about output caps. Try it as it is first.

My experiences with the 26 is that it has good sound at several different operating points. I have run it at 90v and 3mA and it sounds surpringly good at that operating point. You are not going to have poor sound within the range 90-180v

Filepe - you have now practically built your 26 preamp. I think this is the time to stop agonising over possible choices and just listen to it. You will need a reference listening test for any future modifications anyway. Experiment later and then see if it sounds better or worse or the same as it is with the OPT and VR150. This is exactly what I'm listening to as I write, and it's a perfectly good sound. Have a good Easter and enjoy your build. Play some music!

Andy
Thanks for kind advice Andy, I will folow your advice, I wish you happy Easter.

Felipe
  Reply With Quote
Old 30th March 2013, 08:42 PM   #3096
diyAudio Member
 
merlin el mago's Avatar
 
Join Date: Sep 2009
Location: Catalonia - Europe
Quote:
Originally Posted by iko View Post
It's what I have, a VR150 in series with a VR75 for B+. Gyrator as load, and I end up with 150V DC on the plate of the 26.
That's a good idea, I only need one VR75 and few resistors
  Reply With Quote
Old 2nd April 2013, 01:22 PM   #3097
diyAudio Member
 
merlin el mago's Avatar
 
Join Date: Sep 2009
Location: Catalonia - Europe
Listened the 26 with OPTs, no hum only sound, for my Borbely monos 75W enough power: my loudspeakers 94dB/W/m
  Reply With Quote
Old 2nd April 2013, 01:25 PM   #3098
iko is offline iko  Canada
diyAudio Moderator
 
iko's Avatar
 
Join Date: May 2008
Location: Toronto
And? Any impression on the sound? Any difference from what you had before?
  Reply With Quote
Old 2nd April 2013, 01:31 PM   #3099
diyAudio Member
 
merlin el mago's Avatar
 
Join Date: Sep 2009
Location: Catalonia - Europe
Yes, very different I used SS Borbely balanced preamp, the 26 is silent like a tomb, I was afraid that it did not have sufficient gain but now I believe still can play vinyl with TT and 26: that's will do tomorrow.

Last edited by merlin el mago; 2nd April 2013 at 01:35 PM.
  Reply With Quote
Old 2nd April 2013, 01:34 PM   #3100
diyAudio Member
 
merlin el mago's Avatar
 
Join Date: Sep 2009
Location: Catalonia - Europe
VR150 is very low noise I'm not sure when installed, 26 is the most musical preamp I have listened and I listened several (40 years).
  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



New To Site? Need Help?

All times are GMT. The time now is 05:36 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