A music coming from component. - 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 2nd December 2004, 03:15 PM   #1
diyAudio Member
 
Join Date: May 2004
Location: Taipei, Taiwan
Default A music coming from component.

Dear all,

I recently assembled a 2A3 SE amp. When running in the amp, I used the notebook to play MP3 as the signal source, and connected two 8 ohm, 5W resistor to each output. When I adjusted the volume control into the maximum, there is the small noise coming from the chassis, the MP3 music. My questions are the following:

1. Is the music coming from the components, such as resistor or some kinds of inductance load, transformer?
2. Shall I find it out to change the component? Is it necessary?

Thanks for your time in responding this in advance.
  Reply With Quote
Old 2nd December 2004, 03:18 PM   #2
SY is offline SY  United States
diyAudio Moderator
 
SY's Avatar
 
Join Date: Oct 2002
Location: Chicagoland
Blog Entries: 1
My suspicions would go to any largish coupling caps (especially "designer" caps which often are rather loosely wound) and the output transformer. Try isolating the components mechanically from the chassis- rubber grommets will work for the transformer, some soft hot-melt glue may help with the caps.
__________________
And while they may not be as strong as apes, don't lock eyes with 'em, don't do it. Puts 'em on edge. They might go into berzerker mode; come at you like a whirling dervish, all fists and elbows.
  Reply With Quote
Old 2nd December 2004, 03:50 PM   #3
diyAudio Member
 
Sch3mat1c's Avatar
 
Join Date: Jan 2003
Location: Milwaukee, WI
Send a message via ICQ to Sch3mat1c Send a message via AIM to Sch3mat1c
Pffbt, coupling caps don't have ANY current or voltage through or across them (aside from the DC bias voltage). It's the OPT, especially under clipping when harmonics are more easily heard. Also more easy to hear if the load is disconnected, which is bad mojo at maximum output..

Tim
__________________
Seven Transistor Labs
Projects and Resources
  Reply With Quote
Old 2nd December 2004, 05:01 PM   #4
diyAudio Member
 
cogsncogs's Avatar
 
Join Date: Jul 2003
Location: Wayne, West Virginia
Quote:
connected two 8 ohm, 5W resistor to each output. When I adjusted the volume control into the maximum, there is the small noise coming from the chassis, the MP3 music.
I would think so! Why would you connect resistors to the outputs and crank it all the way up in the first place? The so called "small noise" you are hearing is coming from the OPT's as is to be expected!

Wayne
  Reply With Quote
Old 2nd December 2004, 07:16 PM   #5
diyAudio Member
 
Sch3mat1c's Avatar
 
Join Date: Jan 2003
Location: Milwaukee, WI
Send a message via ICQ to Sch3mat1c Send a message via AIM to Sch3mat1c
Quote:
Originally posted by cogsncogs
Why would you connect resistors to the outputs and crank it all the way up in the first place?
Um....testing?

Even more fun when you have 1uF across it.

Tim
__________________
Seven Transistor Labs
Projects and Resources
  Reply With Quote
Old 3rd December 2004, 01:15 AM   #6
diyAudio Member
 
Join Date: May 2004
Location: Taipei, Taiwan
Default A small noise.

Dear all,

Thanks for your response.

I just attached the photo. The two OPT locates at the upper small compartment, and all other component including the Power Transformer locates in the lower chassis. And the noise comes from the lower chassis.

According to your comments, I will add the rubber gasket between the mounting surface and the transformer.

The reason to run the amp this way is because I just placed the amp in my office. Since the amp was being completed not long time ago, I think for the new mechine it would be better to run it as more as possible. And I also want to know whether it's stable for long time operation. So that I connect two resistors for each output(because in the office) to run the mechine whole day long.

Thanks for all your kind help again....
Attached Images
File Type: jpg dsc-small.jpg (8.2 KB, 190 views)
  Reply With Quote
Old 3rd December 2004, 05:19 PM   #7
diyAudio Member
 
cogsncogs's Avatar
 
Join Date: Jul 2003
Location: Wayne, West Virginia
Quote:
According to your comments, I will add the rubber gasket between the mounting surface and the transformer.
Under normal listening conditions, i.e. not listening to resistors cranked all the way up IMO that would be totally unnecessary. I can duplicate the same on my amp or any tube amp at those conditions! Sooo, don't worry about it! It's normal! You won't hear it! Rubber gaskets won't stop the sound you are hearing at THOSE conditions anyway. Plus it's not a good idea, you need that heat transfer (and electrical) from the OPT to chassis.

Quote:
Um....testing?
Even more fun when you have 1uF across it.
Yeah maybe! And a scope too!

Cheers
Wayne
  Reply With Quote
Old 3rd December 2004, 07:01 PM   #8
diyAudio Member
 
Geek's Avatar
 
Join Date: Sep 2004
Quote:
Originally posted by Sch3mat1c
Pffbt, coupling caps don't have ANY current or voltage through or across them (aside from the DC bias voltage).

Haven't you ever heard a big ol' disc ceramic cap act like a little piezo speaker? The old ones did this quite well. Never heard it in the new ones though.
  Reply With Quote
Old 3rd December 2004, 08:56 PM   #9
diyAudio Member
 
Sch3mat1c's Avatar
 
Join Date: Jan 2003
Location: Milwaukee, WI
Send a message via ICQ to Sch3mat1c Send a message via AIM to Sch3mat1c
Ah, I had a 0.01uF 500V disc on the breadboard once that sang. As I recall t'was the resivoir cap on a flyback supply I was working on; the sound was parasitic oscillations coupled by the PSU rail (oops).

But the whole purpose of a coupling cap is to pass miniscule amounts of current with little voltage change across it, hence it's never going to make a noise.

Tim
__________________
Seven Transistor Labs
Projects and Resources
  Reply With Quote
Old 6th December 2004, 08:57 PM   #10
diyAudio Member
 
Join Date: May 2004
Location: Taipei, Taiwan
Default thanks for all.

Dear all,

Thanks for your kind response. It seems that there is lots of problem never heard of for me, such as ceramic cap. At first, I am afraid that there may be the error in some components.

Thanks for all your kind response. I decided to re-assemble the amp again, not because of the small noise, but for the poor wiring.

Maybe after the re-assemble, I will report to you whether the small noise still exists. Thanks for all.

Charlie
  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
AES coming to NYC Oct 7-10 jackinnj Everything Else 0 14th August 2005 07:00 PM
Zen V7 coming up... Fuling Pass Labs 6 21st October 2004 09:39 PM
JE Labs 300b round 5. MUSIC!! MUSIC!! TubeHound Tubes / Valves 14 11th January 2003 01:02 AM


New To Site? Need Help?

All times are GMT. The time now is 05:38 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