DIY Audio Projects Forum
 NEW  Matt presents bias and operation data for the 6V6 tube in SE operation - 6V6 Single-Ended (SE) Ultra Linear (UL) Bias Optimization.

DIY Audio Projects Forum

Welcome to the DIY Audio Projects Message Forum. Use these forums to discuss Hi-Fi audio and to share your DIY Audio Projects. Registration is free and required to post messages and view the file attachments. Registration will only take a minute and registered users do not see any advertisements. After you have completed the online registration process, check your email (including spam/junk folder) for the verification email to activate your account. New members are under moderation - so your posts will not be visible until approved by a moderator. See the Read Me 1st, Forum RULES and Forum FAQ to get started on the forum.

It is currently 23 Jun 2018, 05:32

All times are UTC - 6 hours [ DST ]




Post new topic Reply to topic  [ 41 posts ]  Go to page Previous  1, 2, 3, 4, 5  Next
Author Message
PostPosted: 05 Feb 2009, 21:33 
Offline
Moderator
User avatar

Joined: 02 Sep 2008, 14:34
Posts: 527
Location: Rochester, NY
Way To Go Bill, :up:

I can hear your excitement in the post. Keep up the outstanding work!

Alan

_________________
Cheers, Alan
.
Denon POA 2200 | Bottlehead Quickie with PJCCS | Integra CDC 3.1 | SOTA Sapphire-RG301-Grado Gold 1 | Soundwave Soliloquy Series I


Top
 Profile  
 
PostPosted: 05 Feb 2009, 22:13 
Offline

Joined: 26 Aug 2008, 20:57
Posts: 415
Location: Atlanta
Thank you!

I swapped the tubes and it is the tube that has the bright heater.


Top
 Profile  
 
PostPosted: 06 Feb 2009, 13:24 
Offline
Editor
User avatar

Joined: 28 May 2008, 21:53
Posts: 4554
Location: Winnipeg, CANADA
Hey Bill, that looks great. I like to use UF400x didoes. They are dirt cheap and work very well. They recover faster than what you used, but those look fine too.

What size resistor did you use as a bleeder? That will dictate how fast the caps drain.

_________________
[ DIY Mains AC Power Cable Cord ] - [ Gobo LM1875 Amp Kit ] - [ Tang Band D4-1 Horn Speaker Kit ] - [ Monoblock Push-Pull KT88 Tube Amp Kit ]


Top
 Profile  
 
PostPosted: 06 Feb 2009, 13:47 
Offline

Joined: 26 Aug 2008, 20:57
Posts: 415
Location: Atlanta
I didnt thats the weird part.

Though I just looked and maybe it is the humbucking circuit that causes the drain? It comes off the 2nd triode's grid and is connected to B+ and ground via resistors. That will do it won't it as it is basically 2 resistors to ground.


Top
 Profile  
 
PostPosted: 06 Feb 2009, 15:54 
Offline

Joined: 26 Aug 2008, 20:57
Posts: 415
Location: Atlanta
Here is the final circuit with values.
Attachment:
6J6-Hum-Bucking-Common-Cathode-Preamp-Schematic.png


This post has a file attachment. Please login or register to access it. Only Registered Members may view attached files.



Top
 Profile  
 
PostPosted: 08 Feb 2009, 19:41 
Offline

Joined: 26 Aug 2008, 20:57
Posts: 415
Location: Atlanta
Another question:

While I am enjoying this preamp I have found that it is actually too critical with mp3 type material. Seeing as how it has a small form factor and is cheap to build I think its main role would be office and secondary system use.

Is there a good way to actually decrease this? Basically it really brings out the sound of compression. I am thinking a cap that is a little hazy on its own (like a Solen) might do the trick.

Any other suggestions?


Top
 Profile  
 
PostPosted: 08 Feb 2009, 21:57 
Offline
Editor
User avatar

Joined: 28 May 2008, 21:53
Posts: 4554
Location: Winnipeg, CANADA
Yes, less compression or go lossless! :)

How about noisy carbon comp resistors in the signal path?

_________________
[ DIY Mains AC Power Cable Cord ] - [ Gobo LM1875 Amp Kit ] - [ Tang Band D4-1 Horn Speaker Kit ] - [ Monoblock Push-Pull KT88 Tube Amp Kit ]


Top
 Profile  
 
PostPosted: 08 Feb 2009, 22:26 
Offline

Joined: 26 Aug 2008, 20:57
Posts: 415
Location: Atlanta
That might be the way to go.

I will give that a try in Rev 2.

Rin seems like the best candidate.


Top
 Profile  
 
PostPosted: 08 Feb 2009, 23:01 
Offline
Editor
User avatar

Joined: 28 May 2008, 21:53
Posts: 4554
Location: Winnipeg, CANADA
billnchristy wrote:
That might be the way to go.

Yes, lossless. ;)
billnchristy wrote:
Rin seems like the best candidate.

You could also try the 1M and perhaps Ra too.

Here is a good summary of resistor noise: http://www.aikenamps.com/ResistorNoise.htm

Cheers

_________________
[ DIY Mains AC Power Cable Cord ] - [ Gobo LM1875 Amp Kit ] - [ Tang Band D4-1 Horn Speaker Kit ] - [ Monoblock Push-Pull KT88 Tube Amp Kit ]


Top
 Profile  
 
PostPosted: 21 Oct 2009, 21:44 
Offline

Joined: 20 Oct 2009, 21:04
Posts: 1
I may have missed it, but what is the B+ on this preamp circuit, please? :xfingers:


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 41 posts ]  Go to page Previous  1, 2, 3, 4, 5  Next

All times are UTC - 6 hours [ DST ]


Who is online

Users browsing this forum: Google Adsense [Bot] and 6 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  
DIY Tube Projects :: DIY Tube Amp Kits :: DIY Speaker Projects :: DIY Solid State Projects :: DIY IC / Op-amp Projects :: DIY Phono Projects :: DIY Cable Projects :: Hi-Fi Audio Schematics
© diyAudioProjects.com - Terms of Service - Privacy Policy