EL84 Amp - Baby Huey - Page 71 - 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 9th March 2009, 08:57 AM   #701
jkeny is offline jkeny  Ireland
Banned
 
Join Date: Feb 2007
Location: Dublin
Where's the plate to plate feedback?
  Reply With Quote
Old 9th March 2009, 09:01 AM   #702
diyAudio Member
 
Join Date: May 2007
Jaaps type of feedback must be better than "plate to plate" when dealing with triodes.

There are other "features" that are questionable, though. One of them is that you can not use a pot at input. Must be fed from a lowZ source! Best would be to feed differential through a transformer.

Also, as far as I know, the LND150 is a low voltage device and the whole circuit around it looks mystic...........

  Reply With Quote
Old 9th March 2009, 09:54 AM   #703
jkeny is offline jkeny  Ireland
Banned
 
Join Date: Feb 2007
Location: Dublin
I just wondered about it being called a baby huey without the plate to plate feedback with shunt - I thought that's what defined a BH.
LND150 is a high voltage part - up to 400V, I think
  Reply With Quote
Old 9th March 2009, 10:22 AM   #704
diyAudio Member
 
Join Date: May 2007
No trace of Baby Huey in it. Think Jaap was thinking of killing the Baby with this one ......

About LND150, my mistake(was thinking of the Lovoltech LU1014) ! Still I think its a waste of time&effort to insert the stuff here. The ECL82 triode has less than half Ri and almost double Gm of ECC83.
  Reply With Quote
Old 9th March 2009, 10:23 AM   #705
Jaap is offline Jaap  Netherlands
diyAudio Member
 
Jaap's Avatar
 
Join Date: Dec 2002
Location: Netherlands
Quote:
Originally posted by revintage
Jaaps type of feedback must be better than "plate to plate" when dealing with triodes.

There are other "features" that are questionable, though. One of them is that you can not use a pot at input. Must be fed from a lowZ source! Best would be to feed differential through a transformer.


I will try with transformer in the future. I have now a 10K pot in use, but i draw a 100K because I thought it would be the right value.

Quote:
Originally posted by jkeny
I just wondered about it being called a baby huey without the plate to plate feedback with shunt - I thought that's what defined a BH.
LND150 is a high voltage part - up to 400V, I think
I suppose it is a family member of the BH.
Therefore I first posted here: http://www.diyaudio.com/forums/showt...04#post1766804

More important: I have only 88 db speakers and my cd-player has low voltage-output. For that reason I connected a pre-amp a few moments ago. Pre-amp has 5842 tube and LL1630 transformer; 0A2/ccs PSU as here: http://www.ecp.cc/SSS.html . Must say that this BH cousin sounds very very good ! Thundering bass and nice highs (cymbals), and that with a small sized OPT and disastrous layout. Problem is I cannot compare to the original BH, it is possible (but unlikely ) BH sounds even better.
  Reply With Quote
Old 9th March 2009, 10:40 AM   #706
diyAudio Member
 
Join Date: May 2007
OT:

Jaap,

If you have a transformer preamp, why in the world do you do like this????

Ground the CT of your transformer secondary and feed from the first winding(+) into the 27k input and lift the second 27k from ground and feed the other winding(-) into this.

Probably you could also short(bypass) the caps from the pentode plates.

Still even a 10k pot it will be less than good as lowZ (600ohm) feeding is necessary.
  Reply With Quote
Old 9th March 2009, 10:52 AM   #707
Jaap is offline Jaap  Netherlands
diyAudio Member
 
Jaap's Avatar
 
Join Date: Dec 2002
Location: Netherlands
Quote:
Originally posted by revintage
OT:

Jaap,

If you have a transformer preamp, why in the world do you do like this????

I am just testing for the best topology for a stand alone small amp (for my son). That IT coupled amp will certainly be made in some time.

By the way, the BH-cousin sounds so good that I cannot stop listening ( and jumping around ) while I have more important things to do. And I am listening only to 1 channel of the stereo signal. I can only wonder what great amp this can become with the el84 in stereo!
  Reply With Quote
Old 9th March 2009, 11:01 AM   #708
diyAudio Member
 
Join Date: May 2007
OT:

Jaap,
Make it simple and use XLR as interconnects.
  Reply With Quote
Old 12th March 2009, 04:09 PM   #709
Banned
 
Join Date: Dec 2004
Location: Zemun
Default PLATE TO PLATE OR NOT

Quote:
Jaaps type of feedback must be better than "plate to plate" when dealing with triodes.
Not necessarily. Actually, that is feedback as we know it. Why would it be better?

If you calculate everything correctly and do a lot of sims, you will see that the plate to plate feedback (if I have not gotten everything wrong, that is the type of feedback I use in RH amps) gives better results, sonically at least (if the math is not important to you).

Correct me if I'm wrong.

Regards,
Alex
  Reply With Quote
Old 12th March 2009, 04:51 PM   #710
diyAudio Member
 
Join Date: May 2007
Hi Alex,
When adopted to triodes the "plate-to plate" should give a lot worse results with higher THD. This due to a heavier load on the driver. Think this was explained in detail by our norwegian friend Svein earlier in this or Jaaps thread.

http://www.diyaudio.com/forums/showt...03#post1729903

But it is up to the listener to decide whats best IRL.
  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
Red Light District/Baby Huey (EL84 P-P) Output Iron dsavitsk Tubes / Valves 3 14th February 2009 01:21 AM


New To Site? Need Help?

All times are GMT. The time now is 03:50 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