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 18th November 2012, 10:30 PM   #61
diyAudio Member
 
vinylkid58's Avatar
 
Join Date: May 2005
Location: Victoria, B.C.
Quote:
Originally Posted by pancaQe View Post
Actually this will be a pair of mono-blocks.
If you're trying to economize, why not go with a single chassis amp?

Quote:
Originally Posted by pancaQe View Post
I like the schem you showed earlier, but was put off by the filter chokes.
You could build it without the chokes, but they're there for a reason. Personally, I'd use one in a CLC config., but your PS trans should be no more the 300vAC, otherwise you're going to end up with way too much B+.

Quote:
Originally Posted by pancaQe View Post
And it doesn't look complex, compared to a couple other designs I've built it actually looked fairly simple.
As Kevin points out, the Williamson has issues, and could result in an exercise in frustration. 6V6's are easy to drive with a concertina, and you can get away with cheaper OPT's.

What circuit were the other amps you built based on?

jeff
  Reply With Quote
Old 18th November 2012, 11:33 PM   #62
pancaQe is offline pancaQe  United States
diyAudio Member
 
pancaQe's Avatar
 
Join Date: Jan 2011
Location: Los Angeles, CA
[QUOTE=vinylkid58;3246929]If you're trying to economize, why not go with a single chassis amp?

Good point, Vanity, I've always wanted a mono-block pair and there seems to be some advantages I'm curious to explore.



You could build it without the chokes, but they're there for a reason. Personally, I'd use one in a CLC config., but your PS trans should be no more the 300vAC, otherwise you're going to end up with way too much B+.

My power xfrmr is 350vAC

The first amp I built was the little 6BM8 SE, 3watt stereo below
And then the 6AQ5 SE below
Also just finished the 12AT7 audio generator
Attached Images
File Type: gif tiny3W.gif (10.7 KB, 83 views)
File Type: jpg 6AQ5 amplifier 2.jpg (60.2 KB, 81 views)
File Type: gif AudioGenerator-1.gif (37.5 KB, 77 views)
  Reply With Quote
Old 19th November 2012, 02:43 AM   #63
diyAudio Member
 
vinylkid58's Avatar
 
Join Date: May 2005
Location: Victoria, B.C.
Quote:
Originally Posted by pancaQe View Post
I've always wanted a mono-block pair and there seems to be some advantages I'm curious to explore.
Yes, it usually involves space for more iron, hence a better power supply for each amp.

Quote:
Originally Posted by pancaQe View Post
My power xfrmr is 350vAC
That's really 6L6 territory.

Quote:
Originally Posted by pancaQe View Post
The first amp I built was the little 6BM8 SE, 3watt stereo below
And then the 6AQ5 SE below
Which one sounds better?

jeff
  Reply With Quote
Old 19th November 2012, 06:26 AM   #64
pancaQe is offline pancaQe  United States
diyAudio Member
 
pancaQe's Avatar
 
Join Date: Jan 2011
Location: Los Angeles, CA
The ps transformers came out of a couple of weird Moviola mdl#565. I have no idea what they were for but they had 1-5Y3, 2-6V6, 2-6J5, 1-5879, 1-OC3. A couple of 1/4" jacks labeled "OPT" and "MAG". So I figured they would be good for a 6V6 amp.
I liked the 6BM8 3-watt (which I just realized I posted the wrong schem, correct one below). I'm no audiophile and I've been doing living sound engineering for so long my hearing probably wouldn't pickup most of the anomalies talked about on this forum. But both amps seemed to be thin, lacking in low end 200hz and below maybe. And just not very loud. I listen to rock n roll and so a little volume is desirable.
Attached Images
File Type: jpg 6BM8A.jpg (69.2 KB, 66 views)
  Reply With Quote
Old 19th November 2012, 07:43 AM   #65
EssB is offline EssB  United Kingdom
diyAudio Member
 
Join Date: Jan 2009
FYI: "OPT" and "MAG" refers to Optical and Magnetic sound pickup heads on film projectors. The preamps may have some eq networks to give the correct academy response curves, that might be causing the thin sound.
  Reply With Quote
Old 19th November 2012, 08:17 AM   #66
Jaap is offline Jaap  Netherlands
diyAudio Member
 
Jaap's Avatar
 
Join Date: Dec 2002
Location: Netherlands
Quote:
Originally Posted by pancaQe View Post
The ps transformers came out of a couple of weird Moviola mdl#565. I have no idea what they were for but they had 1-5Y3, 2-6V6, 2-6J5, 1-5879, 1-OC3. A couple of 1/4" jacks labeled "OPT" and "MAG". So I figured they would be good for a 6V6 amp.
Why don't you just stick with your original idea ? Buy 2 7-pin sockets that fit into a 9-pin sockethole and you are done. If you don't like the result change it into something else. In the mean time try this design to change your 6BM8 amp. I tried it and it sounds really good.
Attached Images
File Type: png 6bm8_2sk30.png (24.7 KB, 60 views)
  Reply With Quote
Old 19th November 2012, 09:30 AM   #67
pancaQe is offline pancaQe  United States
diyAudio Member
 
pancaQe's Avatar
 
Join Date: Jan 2011
Location: Los Angeles, CA
@EssB: I didn't use anything but the power transformers from the Moviola chassis. I was just describing what I pulled the trannys out of in hopes that somebody knew what they were purely out of curiousity. thanks though

@Jaap: I've decided to save my stock of 6AU6 tubes for another build. I really want to find a design using 6SN7's and 6V6's. Thanks for the the upgrade, I think that's just what I need cause I really want to get to work on something.
  Reply With Quote
Old 19th November 2012, 10:04 AM   #68
Jaap is offline Jaap  Netherlands
diyAudio Member
 
Jaap's Avatar
 
Join Date: Dec 2002
Location: Netherlands
Quote:
Originally Posted by pancaQe View Post
@EssB: I didn't use anything but the power transformers from the Moviola chassis. I was just describing what I pulled the trannys out of in hopes that somebody knew what they were purely out of curiousity. thanks though

@Jaap: I've decided to save my stock of 6AU6 tubes for another build. I really want to find a design using 6SN7's and 6V6's. Thanks for the the upgrade, I think that's just what I need cause I really want to get to work on something.
You can exchange the 12au7 for the 6SN7 without any problem, at least that is what I am going to do in the near future (with CCS and led on first tube). I prefer local feedback in all cases to global feedback, that is one reason why I want to try this design.
In a RCA handbook I saw that you can also scale this design up with parallel 6V6 in het outputstage and get 20 Watts from it.
  Reply With Quote
Old 19th November 2012, 10:50 AM   #69
pancaQe is offline pancaQe  United States
diyAudio Member
 
pancaQe's Avatar
 
Join Date: Jan 2011
Location: Los Angeles, CA
Quote:
Originally Posted by Jaap View Post
You can exchange the 12au7 for the 6SN7 without any problem, at least that is what I am going to do in the near future (with CCS and led on first tube). I prefer local feedback in all cases to global feedback, that is one reason why I want to try this design.
In a RCA handbook I saw that you can also scale this design up with parallel 6V6 in het outputstage and get 20 Watts from it.
Are you talking about the schematic below?
With the CCS, are you going to use the LED's voltage drop to derive the constant voltage for the CCS? What about using an LM317 regulator.
I posted a schema for what was identified as a Williamson type design with 2-6sl7 and 2-6v6. But I was informed it was not a good choice. So I'm still looking
Attached Images
File Type: gif 6v6_2.gif (33.7 KB, 40 views)
  Reply With Quote
Old 19th November 2012, 11:23 AM   #70
Jaap is offline Jaap  Netherlands
diyAudio Member
 
Jaap's Avatar
 
Join Date: Dec 2002
Location: Netherlands
Just use the 6SN7 where you had 12au7 in your original RCA-design. Take other component values, for instance from post 56. If it works you can try to use a (v)ccs on top of the first tube and a led for the cathode resistor. You can find a lot of info on this forum.
  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
6au6 for stereo? TechnoBeaver Tubes / Valves 5 9th April 2010 03:11 PM
6AU6 pentodes TGRANT Tubes / Valves 20 6th March 2009 12:22 AM
6au6 Cf mashaffer Tubes / Valves 3 21st April 2008 10:19 AM
better 6au6 alternative nhuwar Tubes / Valves 6 6th February 2007 06:10 PM
6AU6 Varieties wrenchone Tubes / Valves 2 13th January 2007 10:49 PM


New To Site? Need Help?

All times are GMT. The time now is 10:41 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