Amplifier Issues.... - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

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 26th June 2012, 08:25 PM   #1
diyAudio Member
 
Join Date: Nov 2009
Default Amplifier Issues....

The amplifiers are Rod Elliott's P3A
The preamp is Rod Elliott's P97

100W x 2 stereo amplifier, the power supply is a 300VA toroidal transformer with a 35A bridge rectifier and 2 15000uf, the preamp has Rod Elliott's P05 as its power supply and a small standard transformer for it (not toroidal)

Before I put it in the aluminum chassis it was working perfectly, low noise, high stability. After i put it in the chassis i get noise and the transistors seem to try to go into a thermal runaway when have an input connected but nothing playing and raise the volume high. i hook my ipod directly to the input of the amplifier, not through the preamp, and it works perfectly
I've checked for shorts there seems to be none

i notice i get more hum when i hook the house's earth to the chassis, and most of the noise goes away when i don't hook the house's earth to the chassis and hook just the amplifier's ground to the chassis

  Reply With Quote
Old 26th June 2012, 08:33 PM   #2
Did it Himself
diyAudio Member
 
richie00boy's Avatar
 
Join Date: Nov 2003
Location: Gloucestershire, England, UK
Are your RCA sockets isolated from the chassis?
__________________
www.readresearch.co.uk my website for UK diy audio people - designs, PCBs, kits and more.
  Reply With Quote
Old 26th June 2012, 08:36 PM   #3
diyAudio Member
 
Join Date: Nov 2009
the ground of the RCAs are tied to the chassis and the positive is insulated, i disconnected the RCA and don't use them and i still have these issues
  Reply With Quote
Old 26th June 2012, 09:41 PM   #4
jaycee is offline jaycee  United Kingdom
diyAudio Member
 
Join Date: Apr 2004
Location: Norwich, UK
It's definitely a ground loop. Make sure signal ground is not connected to the chassis at all. Make sure you connect signal ground and power ground at only one place
  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
We described a 500W amplifier in the August, September & October 1997 issues of SILIC jamesfeline Solid State 7 26th January 2011 05:25 AM
Kenwood Amplifier KA 7020 Starting up Issues! emsee Solid State 19 1st June 2008 07:17 PM
amplifier issues andyb21 Class D 2 26th June 2005 03:50 AM


New To Site? Need Help?

All times are GMT. The time now is 07:52 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