Grounded Grid Trafo question - 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 7th November 2003, 04:02 PM   #1
diyAudio Member
 
Join Date: Jan 2002
Location: Puget Sound
Default Grounded Grid Trafo question

I'd like to build Rosenblit's grounded grid preamp and am not sure what an acceptable transformer entails.

He specifies a 120V-50MA and 12V-1A. I did a search on Digi-Key and came up with the following:

229A12D misspelled as 229A120

and

3FL24-500

This guy used toroids so I checked Plitron. They don't have 120V-1A but do have 117V-1A. However the price for three transformers is over $120 which is about four times higher than Digi-Key's.

Any recommendations?

Thanks.
  Reply With Quote
Old 7th November 2003, 05:00 PM   #2
diyAudio Member
 
Join Date: May 2003
Location: Morton, Illinois
Default Transformers

Hi Ultrachrome,

Could go with Allied Electronics, part no. 704-9090 isolation transformer. It runs on both 120 and 240 vac. Easy to mount, but must position and place away from the circuit. Cost is $15.42

Separate filament transformer necessary. 227-0016 is 6.3vac at 1 amp or 227-0045 is rated 1.2 amps. Costs are $7.14 and $7.04 respectively.

Another choice is: 704-5715, which is a 190,160,0,160,190 at 70 ma, capacitive input rating and a 6.3 vac at 3 amps. Cost is $29.58.
Simply use the 160 taps, center tapped (seal off the 190 vac leads). Drop the DC voltage from there. Again, have to position from circuit and probably mount core perpendicular to the circuit for minimum hum.

Hope this helps.
Steve
  Reply With Quote
Old 21st November 2003, 03:34 AM   #3
agent.5 is offline agent.5  United States
diyAudio Member
 
Join Date: Aug 2003
Location: San Francisco, CA
How is the quality of the Allied filament transformer? The price seems good; but is the quality there? Thanks.
  Reply With Quote
Old 21st November 2003, 03:53 AM   #4
diyAudio Member
 
Join Date: May 2003
Location: Morton, Illinois
Default Quality

Quality doesn't seem bad from my experience. Pretty quiet.

I always put a piece of tough, temp resistant rubber between the tranny and chassis to reduce any hum that might happen to be present. Doesn't take much thickness to help.
  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
Hum in Grounded Grid Pre g(f(e)) Tubes / Valves 4 18th March 2008 02:28 AM
Grounded Grid jswen Tubes / Valves 0 17th May 2006 11:48 PM
Grounded Grid Help gelder Tubes / Valves 8 11th December 2005 02:00 AM
Grounded Grid wiring question ultrachrome Tubes / Valves 4 17th October 2004 03:36 PM
Grounded Grid pre amp-- help please andrewe1 Tubes / Valves 10 17th April 2004 02:37 PM


New To Site? Need Help?

All times are GMT. The time now is 11:58 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