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.

Blackstar combo 20 that squeals
Blackstar combo 20 that squeals
Blackstar combo 20 that squeals 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 21st October 2014, 04:09 PM   #11
turk 182 is offline turk 182  Canada
diyAudio Member
 
Join Date: Oct 2012
any effects patched in inline or on the loop or is this just the amp with your guitar(which is what a Strat or...) and have you tried another signal source as in low level audio?
you should try Enzo's suggestion about the tubes.
also is this happening on both the clean and dirty channels?

Last edited by turk 182; 21st October 2014 at 04:12 PM.
  Reply With Quote
Old 21st October 2014, 04:15 PM   #12
brewback is offline brewback  United States
diyAudio Member
 
Join Date: Jul 2014
Location: Pearl River, New York USA
No effects- Just a Fender/Gretch slid guitar and a Tele with Di Marizio "Twang Thang". Same problem. Tubes where swapped with new and biased. Low level audio, I havn't tried......thanks
  Reply With Quote
Old 22nd October 2014, 02:30 PM   #13
Jarno is offline Jarno
diyAudio Member
 
Join Date: Sep 2002
Location: Rosmalen, The Netherlands
To repeat my previous question, does it have a SMPS B+ supply or a linear B+ supply?
__________________
Oemptempa petoempetapap
  Reply With Quote
Old 22nd October 2014, 06:14 PM   #14
brewback is offline brewback  United States
diyAudio Member
 
Join Date: Jul 2014
Location: Pearl River, New York USA
Sorry- I'm not that knowledgeable. I'm somewhat of a beginner/intermediate.
How do I tell?
  Reply With Quote
Old 22nd October 2014, 09:12 PM   #15
Jarno is offline Jarno
diyAudio Member
 
Join Date: Sep 2002
Location: Rosmalen, The Netherlands
Did you open it up already? (mains lead unplugged, and left for a while to make sure capacitors are drained)
If so, could you post some pictures of the insides and particularly the main PCB?

Some of the newer guitar/ bass amplifiers have SMPS PSU's for the B+ voltage as these are more compact (lighter!) than conventional PSU's. There's a big Fender bass amp which has this, and probably a few others. And I believe some/ all of the blackstar amps have SMPS PSU's.
These work by (attention: extremely non-engineeringlike description) creating a alternating current, with a much higher frequency than regular mains voltage (50Hz, 60Hz). The reason for this is that transformers can be made a lot more compact and work better for these higher frequencies. The drawback is that these high frequencies can find their way to the audio path, which leads to a whining noise. Careful layout, grounds in particular, and proper filtering can keep this from happening. But if there's a not so nice ground somewhere, or caps going bad, this can cause trouble.
__________________
Oemptempa petoempetapap
  Reply With Quote

Reply


Blackstar combo 20 that squealsHide 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
Which combo XP-30/XA100.5 or XP-20/XA160.5 LTo Pass Labs 3 5th June 2013 11:32 PM
Blackstar Amps mains connection? eem2am Instruments and Amps 1 14th July 2012 11:18 PM
Maximum power of Blackstar ID series? eem2am Instruments and Amps 19 21st June 2012 08:05 PM
where can i buy a replacement PSU for my Blackstar pedal? mondogenerator Instruments and Amps 6 24th December 2010 02:41 AM
No output and Loud squeals! Help! skid20 Tubes / Valves 5 2nd May 2010 05:07 AM


New To Site? Need Help?

All times are GMT. The time now is 03:07 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Copyright ©1999-2019 diyAudio
Wiki