Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Instruments and Amps Everything that makes music, Especially including instrument amps.

Heater voltage too low
Heater voltage too low
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 12th January 2019, 01:25 PM   #1
vinceg is offline vinceg
diyAudio Member
 
Join Date: Jan 2019
Default Heater voltage too low

Hi, I have a 5F6A clone whit a heater voltage too low. PT is a Hammond 290DEX wich has a primary winding 240VAC and heater 6.7VAC nominal voltage unloaded.

In my house wall voltage is a range of 205-220 VAC and I measured 6.2 VAC heater voltage at PT wires. When I connect heater wires to tube sockets I measured 5 VAC heater voltage. I think this volage drop is too much considering that all tubes absorb about 2.7A and PT secondary heater has 4A
  Reply With Quote
Old 12th January 2019, 02:07 PM   #2
Printer2 is offline Printer2  Canada
diyAudio Member
 
Join Date: Apr 2010
What is the 5V winding putting out?
  Reply With Quote
Old 12th January 2019, 02:28 PM   #3
vinceg is offline vinceg
diyAudio Member
 
Join Date: Jan 2019
In this moment, with 220V wall voltage, it is 4.8V unloaded. Heater voltage is 6.2V unloaded and 5.6V loaded. Anyway I do not use 5V out because I use solid state rectifier instead tube rectifier.

It is 4.8V unloaded
  Reply With Quote
Old 12th January 2019, 03:11 PM   #4
Printer2 is offline Printer2  Canada
diyAudio Member
 
Join Date: Apr 2010
You can get a supply of 5V6GT and run them on the 6V, put the 6 and 5V in series, rectify and filter for the 12A*7 tubes. Just took a quick peek in EBay in Europe and not a bad deal for NOS tubes, I would buy all I think I could use.



5 x 5V6GT WESTINGHOUSE TUBE ELECTRONIQUE | eBay
  Reply With Quote
Old 12th January 2019, 03:55 PM   #5
vinceg is offline vinceg
diyAudio Member
 
Join Date: Jan 2019
Sorry, I'm afraid I did not understand.
  Reply With Quote
Old 12th January 2019, 04:29 PM   #6
vinceg is offline vinceg
diyAudio Member
 
Join Date: Jan 2019
Default 5F6A 50Hz Hum?

Hi, can you help me to identify this hum? It is very annoying and it is not affected by controls.


YouTube
  Reply With Quote
Old 12th January 2019, 04:36 PM   #7
Galu is offline Galu  Scotland
diyAudio Member
 
Join Date: Apr 2018
Running at a reduced primary voltage reduces the power in the secondary. This not only reduces the secondary voltage, but also the secondary current.

Whether the reduced power you are getting in the heater secondary is consistent with a drop in primary voltage of 20V remains the question!

https://www.hammfg.com/files/parts/pdf/290DEX.pdf
  Reply With Quote
Old 12th January 2019, 04:40 PM   #8
jazbo8 is offline jazbo8
diyAudio Moderator
 
jazbo8's Avatar
 
Join Date: Jan 2011
Location: In Transient
Heater voltage too low
@vinceg - please don’t start multiple threads for the same project, your threads have been merged.
  Reply With Quote
Old 12th January 2019, 05:06 PM   #9
vinceg is offline vinceg
diyAudio Member
 
Join Date: Jan 2019
Quote:
Originally Posted by jazbo8 View Post
@vinceg - please donít start multiple threads for the same project, your threads have been merged.

Sorry
  Reply With Quote
Old 12th January 2019, 05:16 PM   #10
vinceg is offline vinceg
diyAudio Member
 
Join Date: Jan 2019
Quote:
Originally Posted by Galu View Post
Running at a reduced primary voltage reduces the power in the secondary. This not only reduces the secondary voltage, but also the secondary current.

Whether the reduced power you are getting in the heater secondary is consistent with a drop in primary voltage of 20V remains the question!

https://www.hammfg.com/files/parts/pdf/290DEX.pdf

Ok, this is. I calculated same percentage value between reduced primary voltage and unloaded secondary voltage.
But how much should the heater voltage drop be? (unloaded vs loaded)
  Reply With Quote

Reply


Heater voltage too lowHide 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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
DC voltage leaking into AC voltage heater rail jimmy74 Tubes / Valves 20 1st July 2018 02:30 PM
Elevating Heater Voltage with multiple Transformer Heater Secondaries mbeards Tubes / Valves 5 26th June 2013 05:32 PM
heater voltage Jaap Tubes / Valves 3 19th November 2008 12:39 AM
Too low heater voltage? jkeny Tubes / Valves 6 26th August 2008 01:08 AM
heater voltage: why ac, and not dc? alex278 Tubes / Valves 18 7th October 2005 01:21 PM


New To Site? Need Help?

All times are GMT. The time now is 02:12 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Copyright ©1999-2019 diyAudio
Wiki