Problem with amp - 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 10th February 2007, 10:36 AM   #1
diyAudio Member
 
Join Date: Sep 2006
Default Problem with amp

Sometimes my brother will stop by and we will talk audio and test various recordings with various pieces of equipment. Well one day he brought over his homemade headphone amp named Big Ugly to test it against my Technics V85a. After a few switches back and forth we both noticed that there was information missing when playing the music through my amp. I guess you could say there were symmetrical holes in the soundstage. I have made a crappy diagram to further explain the problem.


Click the image to open in full size.

Imagine the red dots as headphones and the blue arch as the soundstage.

The yellow sections are where I believe the information is lost.
It became even more apparent when I was listening to the intro to Pinball Wizard where (in this particular mastering) the acoustic guitar starts off in the right ear cup and the echo travels over to the left cup. With my amp the echo cuts in and out at those points along its travel.


Does anyone know what could be happening "under the hood" to cause this?
  Reply With Quote
Old 10th February 2007, 02:03 PM   #2
honsten is offline honsten  United Kingdom
diyAudio Member
 
Join Date: Feb 2004
Location: london
sounds like it could be a capacitor issue, odds are that the "holes" were there all along and the tests that you and your bro have been doing have brought these characteristics out somewhat.obviously his headphone amp is pretty good!
anyway, back to solving your problem... try replacing the caps in the output stage with ones rated with a broader frequency range, you dont need to go all out on blackgates or nuffin...you know the score.
  Reply With Quote
Old 10th February 2007, 03:22 PM   #3
diyAudio Member
 
Sonusthree's Avatar
 
Join Date: Dec 2005
Location: Sussex, UK
Hi Mox00,

I can't get see the picture
I can't tell if your comparing the headphone amp to your amp and speakers or your amp connected to headphones.

I think that you're trying to describe a soundstage problem rather than a frequency response problem so I doubt that the caps are the issue. Output caps pass all frequencies above a certain point that is related to its capacitance (and sometimes connected components such as resistors and Coils,and following equipment)

Honsten: I'm not sure what you mean by output capacitors on this amplifier. Does it even have any? Do you mean input caps?

"Ones rated with a broader frequency range" would have a larger capacitance which may only serve, if anything, to pass more low frequencies. These frequencies generally are not involved in the soundstage since they usually go to both channels (and are very hard to locate below ~200Hz in speakers).

I can't see your diagram but, and this a complete guess, it would seem that the two channels are somehow being summed together at certain frequencies and cancelling out.
I'll say it again: This is just a complete guess and I cannot see your diagram!!

As a first step I would check the wiring of your setup to make sure that nothing is out of phase: Speakers or input cabling or maybe even the headphones connector if this is what you are using. I have had problems with these connectors in the past but the symptoms have been more pronounced.

Maybe later I will be able to see the pic...... and stop guessing. Sorry about that but it is an interesting problem and I couldn't help it.

Cheers,
Martin.
  Reply With Quote
Old 10th February 2007, 08:41 PM   #4
diyAudio Member
 
Join Date: Sep 2006
Thank you for your comments

Martin, I have attached the file. Perhaps you will have better luck with it.
Attached Images
File Type: jpg untitled2uq8op.jpg (75.7 KB, 59 views)
  Reply With Quote
Old 10th February 2007, 10:01 PM   #5
diyAudio Member
 
Sonusthree's Avatar
 
Join Date: Dec 2005
Location: Sussex, UK
Hi Mox00,
I appreciate you taking the time to repost the pic and I can see it now. Yippee!!!

Hmmm, a very strange problem. I stand by most of earlier comments as possible causes. Since you are comparing to such a good (I assume) headphone amp then maybe it is just that your amp has poor channel separation. Have you got any other headphone amps to compare with? May well be that any ordinary amp would have similar results or is it more pronounced than that?

It would be very interesting to make some test tones at different frequencies. Static and also ones that pan from side to side to hear the problem under controlled conditions? Perhaps these identical wave forms may cancel out slightly when panned across the problematic areas.
This is what I'd do but I'm no expert.

I was kind of hoping that someone else would have had this problem specifically or personal experience with this series of Technics amps. My ideas are based purely on theories.

Is it really noticeable or do you have to really listen hard to hear the differences?

Cheers,
Martin.
  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
mtx amp problem [[help!!]] fuzzypinkhat45 Car Audio 3 8th July 2008 05:34 AM
CDM 2/29 Problem HELP! Bassivus Digital Source 29 23rd December 2007 10:00 AM
FRD/ZMA Problem Twisted85 Multi-Way 5 4th December 2006 01:19 PM
p3a problem MaXiZ Solid State 17 16th July 2005 07:14 AM


New To Site? Need Help?

All times are GMT. The time now is 05:30 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