WMD or Big Freakin Power Supply - 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 30th November 2008, 02:26 PM   #1
diyAudio Member
 
tubelab.com's Avatar
 
Join Date: Jul 2005
Location: South Florida
Default WMD or Big Freakin Power Supply

Those who follow my (sometimes excessive) experiments know that I have found myself up against the limitations of my old Fluke 407D power supply. There have been several experiments where I could not find the "maximum power output" or "turn it up till it explodes". I had 4 days off of work (rare lately) and I had to take the customary trip to my mom's for Thanksgiving. Sherri wanted to visit a friend in Orlando for some of the extreme retail stupidity that occurs on "Black Friday" so off we went. I had no desire to hit the mall, so I visited my old high school friend who is in the surplus business, and there it was. A HP 6448B power supply. 0 to 600 volts at 1.5 AMPS! I had visions of brightly glowing melted tubes, so a deal was struck.

I got home last night and I was sure that the power supply was hungry since it had been sitting outside in the Florida rain for several months in a scrapyard. I decided to feed it and test it at the same time. How quickly could it "eat" one of those gassy 6V6's that I had. Well I guess that it wasn't so hungry after all since it chewed on that 6V6 for 15 minutes until the bench breaker blew. The light show and fireworks display was awesome but I had accidentally hit the manual focus button on my camera so there no pictures of the action.

The photo shows the meaning of "excessive grid current". Note the warping of the cathode rod.
Attached Images
File Type: jpg 6v6_a.jpg (76.2 KB, 614 views)
__________________
Too much power is almost enough! Turn it up till it explodes - then back up just a little.
  Reply With Quote
Old 30th November 2008, 02:33 PM   #2
diyAudio Member
 
Join Date: Nov 2002
I wish I could have seen that
  Reply With Quote
Old 30th November 2008, 02:36 PM   #3
diyAudio Member
 
tubelab.com's Avatar
 
Join Date: Jul 2005
Location: South Florida
I was about to turn the bench off when I remembered the box of bad tubes that I got from the AES tube sale. Would my new power supply like the taste of a vintage GE 6BQ6GA with a little gas? You know it. Same deal as before, the fun ended when the bench breaker blew. It blew because the tube failed to a dead short. I have never seen that happen before.

OK, autopsy revealed the cause of the dead short. The screen grid support rod had melted and touched the beam plate. Now that is some excessive screen dissipation.

All this fun is over now, but this power supply will be used to design some big amps in the future. I must revisit my cathode follower, hybrid amp, and screen drive experiments since all of them were limited by lack of power. None of this will happen until early next year due to work and travel commitments.
Attached Images
File Type: jpg 6bq6ga_no_plate_a.jpg (74.4 KB, 542 views)
__________________
Too much power is almost enough! Turn it up till it explodes - then back up just a little.
  Reply With Quote
Old 30th November 2008, 04:32 PM   #4
Banned
 
Join Date: Jan 2005
No vid
  Reply With Quote
Old 30th November 2008, 05:34 PM   #5
diyAudio Member
 
vitalstates's Avatar
 
Join Date: Jan 2006
Location: uk
one of the little idiosyncrosies that us brits notice when we're watching American movies is the way two people will leave each other with the remark ' take it easy'.......This parting remark would be completely wasted on George


take it easy

Ed
  Reply With Quote
Old 30th November 2008, 10:57 PM   #6
diyAudio Member
 
Join Date: Apr 2003
Location: Portland,Oregon
Blog Entries: 4
Send a message via AIM to DigitalJunkie
Bwahahahah!

Gotta love it.
  Reply With Quote
Old 1st December 2008, 02:49 AM   #7
diyAudio Member
 
Richard Ellis's Avatar
 
Join Date: Sep 2006
Location: Mar del Plata, a BIG seasonal getaway city, can see the Ocean from our residence.
George, you have too much fun!..........
Like me back in Tech school playing with an old B&W TV, ran a 12 Gauge to ground & playing with an arc off the HV....the screen would shrink with the "load".
Makes you think if one could use ultra high temp internals for screen, anode, cathode components....what was that material? Iconel X????
___________________________________Rick........... .
  Reply With Quote
Old 1st December 2008, 09:16 PM   #8
diyAudio Member
 
Join Date: Jul 2003
Location: Ann Arbor, MI
let's see you bring a 750TL to its knees...
cheers,
Douglas
__________________
the Tnuctipun will return
  Reply With Quote
Old 2nd December 2008, 02:34 AM   #9
diyAudio Member
 
tubelab.com's Avatar
 
Join Date: Jul 2005
Location: South Florida
Quote:
let's see you bring a 750TL to its knees
Sorry, only otherwise worthless tubes are accepted into my "testing program". I have a fair quantity of 833A's that are going to "meet the power supplies". Don't worry, a current limited power supply can be used to safely test and measure large tubes like these. I plan to stash away a few good ones for myself, and sell the extra good ones on Ebay. Now if I find a bad tube that still conducts current............


Quote:
No vid
I have attempted to take video of some of my "experiments" but so far have not been successful. Things just don't blow up when they are being watched. I tested out one of my other power supply acquisitions on a similar gassy 6V6. I have 20 minutes of video of it quietly glowing bright blue with no fireworks. Cathode current was at the 200 mA limit of the power supply. Sooner or later I will catch one.
__________________
Too much power is almost enough! Turn it up till it explodes - then back up just a little.
  Reply With Quote
Old 2nd December 2008, 06:27 AM   #10
diyAudio Member
 
wrenchone's Avatar
 
Join Date: Feb 2004
Location: Silicon Valley
No picture of the monster?
  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
Split Voltage Switching Power Supply for Power Amp vectorplane Swap Meet 2 23rd April 2011 11:48 PM
LTspice tool for power amp power supply component evaluation andy_c Software Tools 2 23rd August 2009 05:10 PM
is there a circuit for a power supply to power the differant add on clocks frank2395 Digital Source 1 30th June 2005 09:33 AM
selling high current power supply for power amps. ericpeters Swap Meet 0 14th January 2005 02:21 PM
heater supply (xformer specs are 6.3V 2.5A) as supply for a power LED? jarthel Tubes / Valves 10 21st July 2003 01:30 PM


New To Site? Need Help?

All times are GMT. The time now is 10:15 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