Pumpkin preamp - ordered by Steen , official making thread - Page 112 - diyAudio
Go Back   Home > Forums > Amplifiers > Pass Labs

Pass Labs This forum is dedicated to Pass Labs discussion.

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 19th January 2008, 08:45 AM   #1111
Zen Mod is offline Zen Mod  Serbia
diyAudio Member
 
Zen Mod's Avatar
 
Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
Quote:
Originally posted by hershann
Cookbook says EI transformer is preferred - I supposed due to better noise characteristics and ability to withstand DC etc.

For my Pumpkin the transformer is going to be mounted near the front panel and the audio circuit right at the back (the pot probably actuated via an extension rod).

So should I go for the old EI transformer 250VA, 42VCT x2 (pic 1) or the toroidal transformer 600VA 90VCT (pic 2). They are similar in price - with the EI at $20 and toroidal at $29.5.

BTW how easy is it to shield the EI's stray magnetic field?

her shann

use that EI and place it in separate box ; 600VA donut is really overkill ....... even for Pumpkin

both transformers you show are probably too large ( physically and inducing hum wise) to be in same box with active electronic
__________________
my Papa is smarter than your Nelson !
clean thread; Cook Book;PSM LS Cook Book;Baby DiyA ;Mighty ZM's Bloggg;Papatreasure;Papa...© by Mighty ZM
  Reply With Quote
Old 19th January 2008, 10:18 AM   #1112
Zen Mod is offline Zen Mod  Serbia
diyAudio Member
 
Zen Mod's Avatar
 
Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
Default last last watt F4

you can probably drive it balanced ........ with omitting few last resistors in Pumpie , you can also omit input resistors and big input caps on this last last watt F4 .......

or I'm missing something ....... as usual .........
__________________
my Papa is smarter than your Nelson !
clean thread; Cook Book;PSM LS Cook Book;Baby DiyA ;Mighty ZM's Bloggg;Papatreasure;Papa...© by Mighty ZM
  Reply With Quote
Old 19th January 2008, 10:40 AM   #1113
cviller is offline cviller  Denmark
diyAudio Member
 
cviller's Avatar
 
Join Date: Dec 2005
Location: Copenhagen
Blog Entries: 2
Default last last F4

Interesting drawing, but I think you'll still need something for balanced to single ended conversion, because the input you have shown on your last F4 must have identical phased inputs, only with 8V dc difference...

I bet pumpkin will kill those tl431 very fast!
  Reply With Quote
Old 19th January 2008, 11:58 AM   #1114
Zen Mod is offline Zen Mod  Serbia
diyAudio Member
 
Zen Mod's Avatar
 
Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
Default Re: last last F4

Quote:
Originally posted by cviller
Interesting drawing, but I think you'll still need something for balanced to single ended conversion, because the input you have shown on your last F4 must have identical phased inputs, only with 8V dc difference...

I bet pumpkin will kill those tl431 very fast!

dunno ......... I'm still fuzzy - flue ....... dumb ( that last like always )

I'll think more maybe tomorrow .........
__________________
my Papa is smarter than your Nelson !
clean thread; Cook Book;PSM LS Cook Book;Baby DiyA ;Mighty ZM's Bloggg;Papatreasure;Papa...© by Mighty ZM
  Reply With Quote
Old 19th January 2008, 01:06 PM   #1115
diyAudio Member
 
jacco vermeulen's Avatar
 
Join Date: Oct 2004
Location: At the sea front, Rotterdam or Curaçao
Send a message via Yahoo to jacco vermeulen
My Shunty trannie pickings.

Single 44Vac secondary, means 2 trannies per channel, 4 total.
Split-bobbin type, primary winding in the bottom section and the secondary on top, metal shielding.
NOS Cheapo. (of course)
__________________
The buck stops Here
  Reply With Quote
Old 19th January 2008, 01:25 PM   #1116
diyAudio Member
 
mpmarino's Avatar
 
Join Date: Jun 2004
Location: Crunchville, where I don't fit in.
Quote:
means 2 trannies per channel, 4 total.
That's a lot of wires! Too complicated, no?
__________________
Crazy Yankee.
  Reply With Quote
Old 19th January 2008, 01:35 PM   #1117
Formerly "jh6you". R.I.P.
 
Babowana's Avatar
 
Join Date: Jul 2006
Default Re: last last watt F4

Quote:
Originally posted by Zen Mod



this last last watt F4 .......

When you are out of flue and find yourself fine, I hope you will
look back into the last last circuit . . .

Papa feeds F4 with the one phase input to the all FETs



  Reply With Quote
Old 19th January 2008, 02:09 PM   #1118
diyAudio Member
 
jacco vermeulen's Avatar
 
Join Date: Oct 2004
Location: At the sea front, Rotterdam or Curaçao
Send a message via Yahoo to jacco vermeulen
Quote:
Originally posted by mpmarino
a lot of wires
4 times 4 is 16 wires.
2 transformers with 2*115Vac primaries and dual secondaries count up to....16 wires.

These are so small that they'll fit in a 3 1/2 " high case.
(burp, same height my Aleph-J cases will have)
__________________
The buck stops Here
  Reply With Quote
Old 19th January 2008, 02:44 PM   #1119
diyAudio Member
 
mpmarino's Avatar
 
Join Date: Jun 2004
Location: Crunchville, where I don't fit in.
Ya know,

I had a hard time deciding whether or not to put the trafo in the pre case. In the end I decided to chicken out and keep it outside. I've been having cr@p luck with noise lately - I think it's the 106dB horns' fault.

That is, when I can get back to work on this stuff - I had to put the pumpy on a high shelf

edit: Aleph J? is that anything like the Babelfish?
__________________
Crazy Yankee.
  Reply With Quote
Old 19th January 2008, 02:52 PM   #1120
Zen Mod is offline Zen Mod  Serbia
diyAudio Member
 
Zen Mod's Avatar
 
Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
Quote:
Originally posted by mpmarino
.......

edit: Aleph J? is that anything like the Babelfish?

dunno ............. will it drive F4 ?

__________________
my Papa is smarter than your Nelson !
clean thread; Cook Book;PSM LS Cook Book;Baby DiyA ;Mighty ZM's Bloggg;Papatreasure;Papa...© by Mighty ZM
  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 01:50 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