Induced buzz in Hammond 374bx - diyAudio
Go Back   Home > Forums > Amplifiers > Power Supplies

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 11th May 2015, 01:26 AM   #1
diyAudio Member
 
Join Date: Oct 2006
Default Induced buzz in Hammond 374bx

I posted this in the Tubelab forum, but no answers.

The 374bx on my Tubelab SSE has been giving off a mechanical buzz. In order to try to trace the source, I disconnected an optional 85uF Claritycap that is designed for psu smoothing. The buzzing stopped.

The capacitor is glued side-on to the underside of the chassis top plate. The Hammond power trafo sits directly above it on the topside of the aluminum top plate.

To me, it implies some kind of electromagnetic inductive coupling between the trafo and capacitor.

Wonder if anyone has experience of this?

Thanks,
Charlie
  Reply With Quote
Old 11th May 2015, 02:53 AM   #2
rayma is offline rayma  United States
diyAudio Member
 
Join Date: Apr 2011
Location: Upper midwest
Quote:
Originally Posted by cbutterworth View Post
The 374bx on my Tubelab SSE has been giving off a mechanical buzz. In order to try to trace the source, I disconnected an optional 85uF Claritycap that is designed for psu smoothing. The buzzing stopped.
It may be that the large value cap is too much for the power supply. Also, could a rectifier tube be buzzing instead?
  Reply With Quote
Old 11th May 2015, 04:33 AM   #3
diyAudio Member
 
Join Date: Oct 2006
Rayma,

I am pretty sure it's not the rectifier tube as the buzz is gone with the capacitor removed and rectifier tube in place. Also other builders have used 80uF caps in the SimpleSE.

Charlie
  Reply With Quote
Old 11th May 2015, 12:17 PM   #4
Magz is offline Magz  United States
diyAudio Member
 
Join Date: Oct 2009
Location: New Jersey, USA
I don't think it's coupling. Hammonds tend to buzz. Either decrease the cap, go to a choke input design, or slide some Deflex/sorbothane material under the transformer mounting to quiet it down.

I've also had luck jamming some popsicle-stick or other wood into the gap between the bobbin and the center leg of the E laminations. Sounds weird but it works.

.
__________________
On the fast lane of the street I'm driving, sometimes, somewhere, I'm arriving. Every day and every night.

Last edited by Magz; 11th May 2015 at 12:21 PM.
  Reply With Quote
Old 11th May 2015, 01:52 PM   #5
rayma is offline rayma  United States
diyAudio Member
 
Join Date: Apr 2011
Location: Upper midwest
Quote:
Originally Posted by cbutterworth View Post
I am pretty sure it's not the rectifier tube as the buzz is gone with the capacitor removed and rectifier tube in place. Also other builders have used 80uF caps in the SimpleSE.
Ok, then try a similar value cap located a few inches away. This will show whether the problem is the uF value or the location.
Are there bolts on the transformer that you can tighten?

Last edited by rayma; 11th May 2015 at 02:03 PM.
  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
Source of mechanical buzz in Hammond 374bx cbutterworth Tubelab 3 16th May 2015 06:00 AM
FS (UK) Hammond 374BX Power Transformer vinodt1347 Swap Meet 6 23rd November 2014 03:50 PM
FS (UK) - Power Transformer Hammond 374BX vinodt1347 Swap Meet 5 8th October 2013 11:43 AM
Hammond Pwr Trans 374BX Diagnosis Junior Tubelab 19 18th September 2012 03:00 PM
Hammond Power Transformer Buzz... Guiness Tubes / Valves 29 28th June 2008 12:51 AM


New To Site? Need Help?

All times are GMT. The time now is 11:30 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2015 DragonByte Technologies Ltd.
Copyright 1999-2015 diyAudio

Content Relevant URLs by vBSEO 3.3.2