OTL's and aircraft transformers - 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 14th September 2006, 03:19 PM   #1
vp36kv is offline vp36kv  United States
diyAudio Member
 
vp36kv's Avatar
 
Join Date: Aug 2006
Default OTL's and aircraft transformers

Hello all,
Anyone out there messed with the RCA OTL design? http://www.k-amps.8m.com/cgi-bin/i/P...uum/rcaotl.gif Looks pretty straightforward but something has to be done about that power supply altho having a tube amp without any iron is an interesting idea. maybe hide away an isolation transformer somewhere.
Speaking of transformers curious of others experiance repurposing 400 cycle transformers for 60 cycle use? Ive tried a couple for the heck of it 120V on the 130V tap. The idle current seems a bit high but not seeing any signs of core saturation or overheating at ~rated load.
Austin
  Reply With Quote
Old 14th September 2006, 07:29 PM   #2
diyAudio Member
 
tubelab.com's Avatar
 
Join Date: Jul 2005
Location: West Virginia panhandle
Quote:
Speaking of transformers curious of others experiance repurposing 400 cycle transformers for 60 cycle use? Ive tried a couple for the heck of it 120V on the 130V tap. The idle current seems a bit high but not seeing any signs of core saturation or overheating at ~rated load.
A few zillion years ago when 400 Hz surplus transformers were common, I found a magazine article that said to use them on 400 Hz, wire the primaries and secondaries of two identical transformers in series. I tried it and it worked. Haven't tried this in years though.

I think that using a 400Hz transformer on 60Hz will invite the fire gods to dance on your project.
__________________
Too much power is almost enough! Turn it up till it explodes - then back up just a little.
  Reply With Quote
Old 15th September 2006, 02:21 AM   #3
diyAudio Member
 
sorenj07's Avatar
 
Join Date: May 2006
nah actually for best results, just switch the primaries for the secondaries to counteract the phase imbalance... fire gods, indeed
  Reply With Quote
Old 15th September 2006, 03:29 AM   #4
vp36kv is offline vp36kv  United States
diyAudio Member
 
vp36kv's Avatar
 
Join Date: Aug 2006
Parallel the secondaries out of phase
Its too bad about these things some would be really nice transformers if they were for 60 cycle. Ive been digging thru an old junkyard and coming up with neat stuff, getting ate up by mosquitos in the process. potted transformers arnt fun to burn up that smell lingers for days. Minus the power transformers these old avionics remotes still have some cool parts and are built like a brick dog house.
  Reply With Quote
Old 15th September 2006, 05:16 AM   #5
diyAudio Member
 
Miles Prower's Avatar
 
Join Date: May 2005
Location: USA
Blog Entries: 7
Default Re: OTL's and aircraft transformers

Quote:
Originally posted by vp36kv
Hello all,

Speaking of transformers curious of others experiance repurposing 400 cycle transformers for 60 cycle use? Ive tried a couple for the heck of it 120V on the 130V tap. The idle current seems a bit high but not seeing any signs of core saturation or overheating at ~rated load.
Austin
Don't do that.

At 60Hz, the 400Hz will have a volts/turn ratio that's way too high. The voltage has to come down at the lower frequency. If the winding is rated at 120Vac @ 400Hz, it'll have to be reduced to 18Vac @ 60Hz. If you try to run it at 120Vac @ 60Hz, it will poof.

Either that, or build a 400Hz inverter.
__________________
There are no foxes in atheistholes
www.dolphin-hsl.com
  Reply With Quote
Old 16th September 2006, 04:18 AM   #6
diyAudio Member
 
Join Date: Jan 2006
Location: SAO PAULO - SP
Hi vp36kv ,

Miles Prower is correct . Don’t do that !!!

When you increase the working frequency of any
power tranny , the calculation shows up that you can
decrease the “ quantity of iron “ on the core .

So if you connect a power tranny at a lower frequency ( 60 Hz )
than the specified ( 400 Hz ) , the “ lack “ of iron core , will
increase the current a lot , then the tranny will overheat and ...
... ( probably ) burn out .

Regards ,

Carlos
  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
Loudspeaker magnet and aircraft safety Ipanema Multi-Way 9 6th July 2009 08:30 PM
Aircraft Fasteners Selling Dark Shadow Swap Meet 1 25th March 2009 11:33 AM
Audio switch like in aircraft chair arm tmd1 Parts 0 29th June 2006 01:38 PM
Military aircraft reminiscences BobEllis Everything Else 12 23rd June 2006 08:25 AM
End of a long and beautiful aircraft story Netlist The Lounge 7 26th October 2003 04:03 PM


New To Site? Need Help?

All times are GMT. The time now is 10:03 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