#26 pre amp - Page 44 - 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 7th May 2010, 09:40 PM   #431
Sheldon is offline Sheldon  United States
diyAudio Member
 
Join Date: Dec 2003
Location: San Diego
Quote:
Originally Posted by coolzero View Post
Sheldon,

I tried just a simple en. mode FET follower (similar to the schematic you provide). But results were not that impressive to me. Certainly it reduces the distortion but I felt that it reduces the liveliness of the music as well. The instruments I could hear before seems diminished or sound thin. Not sure this is because I had set the FET to run in low current (7ma). Any suggestions you could give?


If you are comparing it to a heavily loaded 26, then it will have much less distortion, and probably reduced top end. A lot of second and third harmonics will make the sound seem full. You can try higher current, no harm there. Listen for a few sessions before you decide. Make sure you can listed for a long time without tiring.

Sheldon
  Reply With Quote
Old 7th May 2010, 10:17 PM   #432
diyAudio Member
 
coolzero's Avatar
 
Join Date: Sep 2009
Location: UAE
Quote:
Originally Posted by Sheldon View Post
If you are comparing it to a heavily loaded 26, then it will have much less distortion, and probably reduced top end. A lot of second and third harmonics will make the sound seem full. You can try higher current, no harm there. Listen for a few sessions before you decide. Make sure you can listed for a long time without tiring.

Sheldon
Hmm..what I felt was bit confirmed. Top end had lost it's strength Which I didn't like. I personally felt it is one of the strength of 26 tube of having the smoothest and live top end. However FET follower improves the low end a bit. Anyway, I will try with higher current and also the dep. mode FET follower as well. I will post my findings as it progress.
  Reply With Quote
Old 8th May 2010, 10:21 AM   #433
regal is offline regal  United States
diyAudio Member
 
Join Date: Jan 2004
Location: MD
Quote:
Originally Posted by coolzero View Post
Hmm..what I felt was bit confirmed. Top end had lost it's strength Which I didn't like. I personally felt it is one of the strength of 26 tube of having the smoothest and live top end. However FET follower improves the low end a bit. Anyway, I will try with higher current and also the dep. mode FET follower as well. I will post my findings as it progress.
Also may try feeding the #26 with more current. Guessing you may be running it too lean?
  Reply With Quote
Old 8th May 2010, 03:28 PM   #434
Sheldon is offline Sheldon  United States
diyAudio Member
 
Join Date: Dec 2003
Location: San Diego
Quote:
Originally Posted by coolzero View Post
Hmm..what I felt was bit confirmed. Top end had lost it's strength Which I didn't like. I personally felt it is one of the strength of 26 tube of having the smoothest and live top end. However FET follower improves the low end a bit. Anyway, I will try with higher current and also the dep. mode FET follower as well. I will post my findings as it progress.
I didn't say it very clearly, but I would expect the loaded 26 to have more roll off at the high end. But with more distortion products, the top end could be perceived as more pronounced. In the end it comes down to taste. For me, a certain kind of distortion sounds nice, but over time I don't like it as much.

Sheldon
  Reply With Quote
Old 10th May 2010, 01:12 PM   #435
diyAudio Member
 
coolzero's Avatar
 
Join Date: Sep 2009
Location: UAE
Quote:
Originally Posted by Sheldon View Post
I didn't say it very clearly, but I would expect the loaded 26 to have more roll off at the high end. But with more distortion products, the top end could be perceived as more pronounced. In the end it comes down to taste. For me, a certain kind of distortion sounds nice, but over time I don't like it as much.

Sheldon
Agree with you complete. It is all about the personal preference of the sound. I liked a bit of forward sound and it well mate with my other equipments use, especially with my mellow sounding speakers. That could be the reason the loaded 26 sound is more pleasing to my ears. This may not be true in case the other equipment use with 26 pre is behaving differently I believe. This is why I like DIY. You can always get what you like, not someone else prefer. But in the meantime you could experience both the sides in case if you want to compare. Thanks Sheldon for all your education provided. I actually learnt something which I didnít know much before.
  Reply With Quote
Old 10th May 2010, 01:15 PM   #436
diyAudio Member
 
coolzero's Avatar
 
Join Date: Sep 2009
Location: UAE
Quote:
Originally Posted by regal View Post
Also may try feeding the #26 with more current. Guessing you may be running it too lean?
I could do this and test too. But will it not damage the tube in long run?
  Reply With Quote
Old 13th May 2010, 08:38 AM   #437
diyAudio Member
 
Join Date: Sep 2009
Location: Vietnam
Blog Entries: 2
Send a message via Yahoo to quanghao Send a message via Skype™ to quanghao
Default Rod Coleman DHT

Hi Rod Coleman!

I use your design for my amli ( HQ-DHT) 26-45-6C4C (2A3).
The filament is exelent, my amli not hum not noise.
But i lost many time for 6 filament: 2 for tube 26, 2 for tube 45, 2 for tube 6C4C

Thank you very much!
__________________
Group buy DAC-END R (ES9018) full assembled board
update 06/14/2013 :http://www.audiodesignguide.com/DAC32/index2.html
  Reply With Quote
Old 17th May 2010, 08:10 AM   #438
diyAudio Member
 
Join Date: Sep 2009
Location: Vietnam
Blog Entries: 2
Send a message via Yahoo to quanghao Send a message via Skype™ to quanghao
audiodesign and me have new design am li use all DHT tube
26-45-2A3.
Use filament design by Rod Coleman

HQ-DHT (All tube DHT amli) 26-45-2A3
__________________
Group buy DAC-END R (ES9018) full assembled board
update 06/14/2013 :http://www.audiodesignguide.com/DAC32/index2.html
  Reply With Quote
Old 17th May 2010, 09:26 AM   #439
работник
diyAudio Member
 
Rod Coleman's Avatar
 
Join Date: Jul 2004
Location: Warwickshire UK
Quote:
Originally Posted by quanghao View Post
audiodesign and me have new design am li use all DHT tube
26-45-2A3.
Use filament design by Rod Coleman

HQ-DHT (All tube DHT amli) 26-45-2A3
Quanghao, thanks for sharing! looking good!

You have Fans on the filament circuit heatsink?

Please post the filament circuit, if you changed anything.
  Reply With Quote
Old 17th May 2010, 09:52 AM   #440
diyAudio Member
 
Join Date: Sep 2009
Location: Vietnam
Blog Entries: 2
Send a message via Yahoo to quanghao Send a message via Skype™ to quanghao
Quote:
Originally Posted by Rod Coleman View Post
Quanghao, thanks for sharing! looking good!

You have Fans on the filament circuit heatsink?

Please post the filament circuit, if you changed anything.
Yes! because i buye heasick from degike, but now not arrive!
It is very hot! but it is exelent, no hum no noise.
in my Amli, I put my handphone to head tube 26, so i can listen some microphonic!
__________________
Group buy DAC-END R (ES9018) full assembled board
update 06/14/2013 :http://www.audiodesignguide.com/DAC32/index2.html
  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 10:55 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