GU-32/GI-30 tube PP amp - 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 16th October 2008, 02:21 PM   #1
DragosB is offline DragosB  Romania
diyAudio Member
 
Join Date: Jun 2006
Default GU-32/GI-30 tube PP amp

I want to start buiding a PP amp using one of those tubes. I already have two OTP having 2300 turns in primary (plate-to-plate, center taped) and 90+45+45 turns in secondary.

Using the 90 turns secondary with 8ohm speaker, I will have around 5200 ohm plate-to-plate load. Looking to all schematics found for those tubes, that load seems too low. is it possible to use that OTP, and what would be disadvantages of using it?

p.s. power transformer has 300V in secondary.


Thank you

Dragos
  Reply With Quote
Old 16th October 2008, 04:45 PM   #2
diyAudio Member
 
azazello's Avatar
 
Join Date: Aug 2008
Location: Bulgaria
How square surface is the Your transformers ? This is begin to calculate Your Transformer! If You want 10-20 wats per channel, Your
transformer must be equivalent to 100-200 W AC power! Or 12-15-18
sq. sm of coil!
__________________
Projects: OTL-OCL 6AS7 Gen. Electric, SEs 2A3 RCA, 300B JJ, 6S4S, 4P1L, EL11 Telefunken, 6AS7 RCA, 6S33S, 6S41S, 6S19P, E84L Siemens, E236L Telefunken, headphone ampl. OTL Loftin White 6AS7 RCA,... PPs 6005 Gen. Electric, EL34 Mullard, 6L6....
  Reply With Quote
Old 16th October 2008, 05:32 PM   #3
diyAudio Member
 
Wavebourn's Avatar
 
Join Date: Sep 2006
Location: Pleasant Hill, CA
Send a message via Skype™ to Wavebourn
For Gu29 and GI30 you may use a transformer designed for 829, but GU32 is a different beast if I remember right.
Also, there is a "civilian" version of GU-29 called 6R3S-1 that is horrible, though more expensive.
__________________
The Devil is not so terrible as his math model is!
  Reply With Quote
Old 16th October 2008, 11:37 PM   #4
kuroguy is offline kuroguy  Germany
diyAudio Member
 
kuroguy's Avatar
 
Join Date: Sep 2007
I'm sure someone will correct me if I'm wrong. I believe GU-32 is equal to 832. The 832 PP amp likes about 8.5K transformers.
  Reply With Quote
Old 17th October 2008, 07:00 AM   #5
DragosB is offline DragosB  Romania
diyAudio Member
 
Join Date: Jun 2006
Quote:
Originally posted by azazello
How square surface is the Your transformers ? This is begin to calculate Your Transformer! If You want 10-20 wats per channel, Your
transformer must be equivalent to 100-200 W AC power! Or 12-15-18
sq. sm of coil!
The transformer has around 8 square cm in section.


Quote:
Originally posted by kuroguy
I'm sure someone will correct me if I'm wrong. I believe GU-32 is equal to 832. The 832 PP amp likes about 8.5K transformers.
I know tha 832 PP amp likes 8.5k transformers. My question was: what are the effects of using my 5.2 k transformers with 832 tube
? Would be that transformer more suitable for 829 PP amplifier?
  Reply With Quote
Old 17th October 2008, 08:08 AM   #6
Colt45 is offline Colt45  Serbia
diyAudio Member
 
Join Date: Feb 2002
Location: Canada
Send a message via ICQ to Colt45
Yes it's equivalent to a 832.

GI-30 is odd though, intended for HF pulse stuff.. low dissipation iirc.



Quote:
I know tha 832 PP amp likes 8.5k transformers. My question was: what are the effects of using my 5.2 k transformers with 832 tube ? Would be that transformer more suitable for 829 PP amplifier?
If you don't change the operating point, and just the iron to a lower load, generally, power is up, distortion is up.

5k sounds about right for GU-29, as it's basically a pair of 6L6's, and that's near what they like...
  Reply With Quote
Old 18th October 2008, 06:55 AM   #7
vladn is offline vladn  United States
diyAudio Member
 
Join Date: Feb 2008
You may want to check this thread - I've run some numbers for 829B PP AB1 at various plate voltages:

budget xformer for 829B pentode mode PP (class AB) ?

I couldn't resist grabbing a pair of RCA 829B from ebay for the looks alone so this is my current project.
  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
need diy tube preamp (line-stage) recommendation and general tube advice Musiclover4 Tubes / Valves 16 18th May 2013 03:19 PM
FS tube tuner, Active filter kit, tube amp, amp3 Josephjcole Swap Meet 9 20th July 2007 04:05 PM
SS or tube voltage amplifying stages in an amp with tube output? ray_moth Tubes / Valves 14 4th July 2007 03:09 AM
tube driving the same tube - whats the collective word? zobsky Tubes / Valves 3 13th June 2005 06:47 AM


New To Site? Need Help?

All times are GMT. The time now is 05:51 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