Audio Research SP9 guilty of screeching sounds! - 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 6th February 2003, 10:47 PM   #1
Eric116 is offline Eric116  United States
diyAudio Member
 
Join Date: Feb 2003
Location: Chicago
Default Audio Research SP9 guilty of screeching sounds!

Hi all,

First of all, please pardon me of my ignorance in all tube matters, as my understanding and manipulation of the Audio Research SP9 Mark II preamplifier that sits in my living room has to this date been limited to turning buttons and flipping switches located on the front of this device.

However, thanks to the help of the speakers people (the "other" forum), I have come to the conclusion that the preamplifier is responsible for screeeeching sounds when the volume is turned up or down As background, the preamplifier is linked to a McCormack Power Drive DNA 0.5 amplifier, and finally to a pair of B&W Nautilus 804 speakers. Current hypotheses on the cause of this problem are (1) the volume knob and (2) the tubes.

Has anyone encountered a similar issue? Is this an "easy" fix or is it a major project? Also, any input on troubleshooting would be greatly appreciated!

Thanks for your help!

Eric
  Reply With Quote
Old 6th February 2003, 11:47 PM   #2
SY is offline SY  United States
diyAudio Moderator
 
SY's Avatar
 
Join Date: Oct 2002
Location: Chicagoland
Blog Entries: 1
If this is happening when you *change* the volume setting, I'd start the troubleshooting process by looking at offset voltages, especially if this is isolated to one channel. And stick a scope on the power supply rails to see if something is oscillating.
  Reply With Quote
Old 6th February 2003, 11:53 PM   #3
diyAudio Senior Member
 
fdegrove's Avatar
 
Join Date: Aug 2002
Location: Belgium
Default SP9.

Hi,

A tube has its' voltage to cathode insulation surpassed and has gone south.

Typical for this circuit really...

Sillly design if you ask me,

Cheers,
__________________
Frank
  Reply With Quote
Old 3rd January 2007, 09:46 AM   #4
diyAudio Member
 
Join Date: Dec 2006
Location: USA
Default ok!

Hi ! You sent me circuit 6h30 (6n6p) please?
I want it! thank you!
  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
Audio Research D-90 rudy129 Tubes / Valves 4 11th June 2010 01:19 PM
Audio Research lawbadman Tubes / Valves 26 2nd November 2007 03:49 PM
Audio Research SP6 E PIERRICK Tubes / Valves 1 26th November 2006 10:03 AM
Ground loop ain't always the guilty one Stabist Pass Labs 1 16th September 2004 11:01 PM
audio research sp6/8--better than sp9? croft Parts 8 16th November 2002 01:25 AM


New To Site? Need Help?

All times are GMT. The time now is 10:02 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