AudioAficionado.org  

Go Back   AudioAficionado.org > Manufacturers Forums > Audio Research

Audio Research State of the Art Audio Reproduction

Reply
 
Thread Tools Display Modes
  #1  
Old 01-17-2016, 08:23 PM
fgchong fgchong is offline
Senior Member
 
Join Date: Mar 2013
Location: Singapore
Posts: 110
Default HF oscillation or DC trip @ power amplifier

I am using Reference 10 for about 2 years and lately I have this HF oscillation or DC trip @ one of the channel of the Goldmund power-amplifier (either the Telos 250 or 1000+). Fault intermittent i.e. resumed to normal when I reset the power amplifier. This has being going on for a couple of times and each time it trip, the speaker cut off with exploding sound (I am using Alexia).

Send the set to the local agent but their technician could not locate the root of the problem as the fault did not occurred even running for almost 500 hours.

Just wonder any members here have the similar experience to share.

Thank You
Reply With Quote
  #2  
Old 01-17-2016, 11:42 PM
TOGA's Avatar
TOGA TOGA is offline
Member
 
Join Date: Aug 2010
Location: N13E100
Posts: 2,158
Default

I have similar experience.
My suggestion.
1. Can it be related to bad tubes ? Tubes is likely to have slight DC offset higher than SS gears and when tubes gone bad it can get worse I dunno.

2. Moon amplifier shut down in a similar way when I try to play my old Sony CDP X77ES on RCA, but it didnt
Happen when run XLR,also this happened when I liked to have some fun connecting my first ever surr processor
The Yamaha DSP-1 to my current system, the amplifier shut down. This means sometimes the DC leak is from source and can reach power amp. Old source with bad capacitors can do this.

Toga.
Reply With Quote
  #3  
Old 01-18-2016, 05:08 AM
fgchong fgchong is offline
Senior Member
 
Join Date: Mar 2013
Location: Singapore
Posts: 110
Default

Toga,

Appreciate your information. The trip occurred with any of my 3 sources, that should rule them out. Not sure when bad tubes will cause this, will monitor the situation and hopeful the fault can be permanent.
Reply With Quote
  #4  
Old 01-18-2016, 10:02 AM
TOGA's Avatar
TOGA TOGA is offline
Member
 
Join Date: Aug 2010
Location: N13E100
Posts: 2,158
Default

Can you try one channel at a time ?
In case a faulty leak comes from one exact channel.
Is it likely to be caused by power supply 6550 tube ?
Toga
Reply With Quote
  #5  
Old 01-18-2016, 04:18 PM
microstrip's Avatar
microstrip microstrip is offline
Senior Member
 
Join Date: Jun 2011
Posts: 394
Default

The REF10 is capacitor coupled, it should not be a DC problem.

Probably a faulty tube that starts oscillating at ultrasonic frequencies.
The best way to diagnose is connecting an oscilloscope to the output of the amplifier and slightly tapping the tubes with a pencil (including power supply) - sometimes it triggers the oscillation.

You can also swap all the tubes between channels and see if the problem moves to the other channel.

It can also be due to RF pickup - do you use un-screened cables?
Reply With Quote
  #6  
Old 01-18-2016, 08:15 PM
fgchong fgchong is offline
Senior Member
 
Join Date: Mar 2013
Location: Singapore
Posts: 110
Default

Appreciate all the information. I am using a 10m pair PAD XLR cable between the Reference 10 and Telos 1000+. Will first try out my other pair of balance cable this evening before replacing the power tubes.
Reply With Quote
Reply

Thread Tools
Display Modes

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

Audioaficionado.org tested by Norton Internet Security

All times are GMT -4. The time now is 02:08 AM.



Powered by vBulletin® Version 3.8.10
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
ęCopyright 2009-2019 AudioAficionado.org.Privately owned, All Rights Reserved.
Audio Aficionado Sponsors
AudioAficionado Subscriber
AudioAficionado Subscriber
Inspire By Dennis Had
Inspire By Dennis Had
Harmonic Resolution Systems
Harmonic Resolution Systems
Wyred4Sound
Wyred4Sound
Dragonfire Acoustics
Dragonfire Acoustics
GIK Acoustics
GIK Acoustics
Esoteric
Esoteric
AC Infinity
AC Infinity
JL Audio
JL Audio
Acoustic Sciences Corportation
Acoustic Sciences Corportation
Legend Audio & Video
Legend Audio & Video
Audio by E
Audio by E
Canton
Canton
Bryston
Bryston
WireWorld Cables
WireWorld Cables
Stillpoints
Stillpoints
Bricasti Design
Bricasti Design
Furutech
Furutech
Shunyata Research
Shunyata Research
Accuphase
Accuphase