Matrix M-Stage Amp blew out gasket! - diyAudio
Go Back   Home > Forums > Amplifiers > Headphone Systems

Headphone Systems Everything to do with Headphones

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, 05:31 PM   #1
Banned
 
Join Date: Jun 2011
Blog Entries: 1
Default Matrix M-Stage Amp blew out gasket!

a friend of mine bought a Matrix M-Stage headphone amp. it was supposed to be 220V version but 120V version was delivered! and needless to say he put the plug in and used it as a toaster! gave it to me to fix it... power transformer was gone. the power was Toroidal which melted down ... now schematic, no specification, no nothing. I didn't know what is the working voltage of the circuit so I put it in path of signal generator and oscilloscope and power it with a variable power adapter to find the best working voltage. it was ~12V - 970 milliamperes. I winded a 12V/1Ampere power transformer and put it in... everything is ok and it works but when volume is closed, a hum can be spotted... any idea?
  Reply With Quote
Old 26th June 2012, 07:12 PM   #2
diyAudio Member
 
Join Date: Nov 2004
Location: Germany
The M-Stage is supposed to be an "improved copy" of the Lehmann Black Cube Linear. I would expect a center tapped secondary as in most any serious headphone amp, so with some dropping resistors I'd expect about +/- 20 V after rectification, so maybe 2x 15 V~ secondary or so, estimated 10-15 VA.
  Reply With Quote
Old 26th June 2012, 08:56 PM   #3
Banned
 
Join Date: Jun 2011
Blog Entries: 1
Quote:
Originally Posted by sgrossklass View Post
The M-Stage is supposed to be an "improved copy" of the Lehmann Black Cube Linear. I would expect a center tapped secondary as in most any serious headphone amp, so with some dropping resistors I'd expect about +/- 20 V after rectification, so maybe 2x 15 V~ secondary or so, estimated 10-15 VA.
Uh actually you're right. there are two secondary outs with a common center tap. first and center tap go to rectifier to turn into DC and supply whole the circuit and other end goes to earth which is connected to coupling capacitors. so you're telling me that I should try out 2X15V or 2X20V?
  Reply With Quote
Old 26th June 2012, 09:33 PM   #4
diyAudio Member
 
Join Date: Nov 2004
Location: Germany
Basically, yes.

The BCL clone schematic I'm looking at uses a LM317/337 combo to regulate +/-15 V, so you want about +/- 18 V= or slightly higher für the regulators to work properly. This comes out to about 2x 14-15 V~ secondary.

BTW, the center tap is that one that goes to earth.

Last edited by sgrossklass; 26th June 2012 at 09:39 PM.
  Reply With Quote
Old 26th June 2012, 09:39 PM   #5
Banned
 
Join Date: Jun 2011
Blog Entries: 1
Quote:
Originally Posted by sgrossklass View Post
Basically, yes.

The BCL clone schematic I'm looking at uses a LM317/337 combo to regulate +/-15 V, so you want about +/- 18 V or slightly higher für the regulators to work properly.
BTW, the center tap is that one that goes to earth.
Uh you're absolutely right there is LM317 which I think is a voltage stabilizer or regulator but I still don't know what is the problem. I connect 2*12V to circuit (total=24v) but noise is still there I think two separate 12v power transformer will do the justice instead of a toroidal transformer. I think noise is due to the uninsulated EI transformer I winded (I can't isolate it due to the lack of enclosure inner space)
Uh my mistake... the center tap is connected to earth. the other leads are connected to rectifier bridge
  Reply With Quote
Old 27th June 2012, 03:36 PM   #6
Banned
 
Join Date: Jun 2011
Blog Entries: 1
I finally found out what Matrix did. there is no center tap at all... actually there is a center tap on the Matrix transformer but it is common with one of the main outputs. the earth is connect to one of the AC inputs. I winded two separate transformers one 6VA and one 12VA and isolated them to death. all the noise gone. the amp is working in absolute death silence

one thing interesting! I connected my speakers to this amp and it plays them at pretty remarkable decibels I mean wall-shacking levels... I think about 100db/ 1 meter
thanks everybody

Last edited by ARIYAHOOR; 27th June 2012 at 03:57 PM.
  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
Nakamichi pa-7e + B&W 800 Matrix Nonox Pass Labs 10 31st July 2011 11:04 AM
I think I blew up my t-amp...... help! tyler477 Class D 11 27th November 2008 01:34 AM
Matrix Amp? Mike L. Tubes / Valves 1 6th October 2004 05:57 PM
B&W Matrix 803, 804, or 805 Tweeters HELP boisehomes Multi-Way 0 8th February 2004 10:58 PM


New To Site? Need Help?

All times are GMT. The time now is 11:44 AM.


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