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

Tubes / Valves All about our sweet vacuum tubes :) Threads about Musical Instrument Amps of all kinds should be in the Instruments & Amps forum

Amplifier Distortion (Northern Electric)
Amplifier Distortion (Northern Electric)
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 13th August 2012, 03:37 PM   #1
cthcamaro67 is offline cthcamaro67  United States
diyAudio Member
 
Join Date: Jul 2012
Default Amplifier Distortion (Northern Electric)

So I've run into quite a conundrum here. I've just bought two Northern Electric 4045-C Amplifiers. Powering either one on by itself the amplifier sounds great, little bit of hum but other than that great. However, if I turn them both on at the same time (they are monoblocks so I do need to have them both on for stereo) they start to distort horribly. They'll play fine for five minutes and then start distorting all over the place for thirty seconds, play fine, then distort again. I'm not sure what is causing this distortion. Figured it was a power issue since the amplifiers work fine when only one is on. Any ideas?

Found a schematic here

Last edited by cthcamaro67; 13th August 2012 at 03:48 PM. Reason: schematic added
  Reply With Quote
Old 13th August 2012, 03:58 PM   #2
cancon is offline cancon  Canada
diyAudio Member
 
Join Date: Mar 2011
Haha, I posted that schematic. Crazy amp, HUGE 25hz power transformers. I could never get rid of the background hum in mine. Is yours still running a 5X4 or has it been modified to 5U4?
  Reply With Quote
Old 13th August 2012, 04:00 PM   #3
cthcamaro67 is offline cthcamaro67  United States
diyAudio Member
 
Join Date: Jul 2012
Uses 5U4, that hum isn't too bad on one but the other has hum and a "hizz" that is fairly pronounced that I'm still working on getting rid of. Thanks for the schematic lol I've been using it quite a bit. Replaced/resoldered all the connections to try and alleviate the hum and distortion issue I've been having but to no avail so far.
  Reply With Quote
Old 13th August 2012, 04:05 PM   #4
cthcamaro67 is offline cthcamaro67  United States
diyAudio Member
 
Join Date: Jul 2012
Here's a pic of them, they ain't perfect but they certainly work!
Attached Images
File Type: jpg 4045-C.JPG (241.9 KB, 150 views)
  Reply With Quote
Old 13th August 2012, 04:05 PM   #5
cancon is offline cancon  Canada
diyAudio Member
 
Join Date: Mar 2011
Does the hum go away if you short the balanced inputs together?
  Reply With Quote
Old 13th August 2012, 04:13 PM   #6
cancon is offline cancon  Canada
diyAudio Member
 
Join Date: Mar 2011
Also, are you driving electro-magnetic speakers? if not, have you installed a dummy load to cap the B+ for them?
  Reply With Quote
Old 13th August 2012, 04:55 PM   #7
cthcamaro67 is offline cthcamaro67  United States
diyAudio Member
 
Join Date: Jul 2012
Haven't tried shorting the inputs together, can give that a go tonight. Nope, vintage speakers as well so I've capped the B+. Had these running perfectly in another location, before I took them home, soon as I hooked them up at home this distortion issue arose. I know they work as I can use either independently and they sound just fine, both powered up at the same time sounds like they keep dropping signal intermittently
  Reply With Quote
Old 13th August 2012, 05:08 PM   #8
kevinkr is offline kevinkr  United States
diyAudio Moderator
 
kevinkr's Avatar
 
Join Date: Sep 2004
Location: Boston, Massachusetts
Amplifier Distortion (Northern Electric)
Surprisingly and perhaps a first, but I think this actually belongs in the Tubes / Valves forum since these are apparently being used in a home stereo system. (Usually I'm moving guitar amps from Tubes / Valves to Instruments And Amps)

I think you will have a lot more visibility for this particular issue in Tubes / Valves..

Very odd behavior, I'm wondering if this is some sort of extreme ground loop issue. I'd very carefully check the leakage current from chassis to a good earth ground on each of those amplifiers.. Do they behave this way when they are not connected to the pre-amplifier? How are the various components in your system grounded? (not grounded)
__________________
"To argue with a person who has renounced the use of reason is like administering medicine to the dead." - Thomas Paine
  Reply With Quote
Old 13th August 2012, 05:13 PM   #9
cthcamaro67 is offline cthcamaro67  United States
diyAudio Member
 
Join Date: Jul 2012
haha, I had moved it from that thread originally after reading the rules again. If you'd like to move it back that's fine by me. I'm floating the ground at the moment but will check the leakage current from the chassis, maybe throw in a real good ground. Still baffled why the problem only exists in my house. Hooked these back up in my friends shop and they play without a problem. Seems like the amp isn't the culprit here.
  Reply With Quote
Old 13th August 2012, 05:19 PM   #10
kevinkr is offline kevinkr  United States
diyAudio Moderator
 
kevinkr's Avatar
 
Join Date: Sep 2004
Location: Boston, Massachusetts
Amplifier Distortion (Northern Electric)
My understanding is these are used as part of your stereo system and are not a guitar or instrument amplifier so it may be legitimately be posted to Tubes / Valves. Instruments and Amplifiers is intended for devices that make music not reproduce it.

Grab an AM/FM radio and turn it on, tune across both bands while the amps are misbehaving and see if you hear anything.. Be quick of course so as not to damage anything - hopefully all will be silent - no squeals or odd noises due to amplifier oscillations.

Make sure the AC connections to both amplifiers are wired the same way in the event that leakage current is the cause of this issue. I'd recommend in any event grounding the chassis of both amps for safety..
__________________
"To argue with a person who has renounced the use of reason is like administering medicine to the dead." - Thomas Paine
  Reply With Quote

Reply


Amplifier Distortion (Northern Electric)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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
electric violin - headphones amplifier Amber19 Instruments and Amps 6 20th January 2011 01:14 PM
Cornell-Dubilier Caps Western Electric 91A Amplifier peter hawthorne Parts 2 21st March 2010 06:56 AM
Lighthouse electric amplifier opinions. Stormrider Solid State 1 10th June 2007 08:08 PM
Is Northern Electric the NEW W.E.? rcavictim Tubes / Valves 0 29th May 2007 02:41 PM


New To Site? Need Help?

All times are GMT. The time now is 06:01 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright ©1999-2017 diyAudio
Wiki