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 20th October 2003, 12:01 AM   #21
Account Disabled
 
Join Date: Apr 2003
Location: US
well, as long as a device's "peformance", be it electric or physical, is tied to its temperature, warming up will have an impact on its performance.

The question is, for a modern (analog) amp with a lot of feedback, is the performance change audiable? Take Nelson's Class A amp for example. It has considerably less feedback (low gain as well) so it is natural to expect that one is more likely to hear the difference (not that one can). That's assuming the the device performs differently at different frequency.

For a class B amp, or a digital amp, I find it hard to believe that one can hear a 5% drop in beta, etc.
  Reply With Quote
Old 20th October 2003, 01:55 AM   #22
diyAudio Member
 
ashok's Avatar
 
Join Date: Jun 2002
Location: 3RS
Default Need for heat sinks.........

Quote:
Are we to conclude then, that monster heatsinks are bad for sound then because they stop the amp from warming up very much????
Heat sinks of any size are used to keep the operating temperature as low as possible. This is especially critical for (most) class A amps that dissipate lots of heat under normal conditions. Large heatsinks are used also in high power ss amps. The purpose is to keep the temperature down. Apart from avoiding any thermal runaway , it also increases the life of the components. The hotter it gets the shorter it life.

So reaching a stable operating point is not determined by how hot it gets but by achieving a stable operating current / voltage in the circuit. With a large heatsink this could occur at a lower operating temperature !
Cheers.
__________________
AM
  Reply With Quote
Old 20th October 2003, 02:36 AM   #23
diyAudio Member
 
BobEllis's Avatar
 
Join Date: Sep 2003
Location: Upstate NY
Hmm - but a class AB amp will by definition change its dissipation and therefore temperature with the signal. Is the "warm up" effect limited to class A amps only or do AB amps reach a near equilibrium and sound better than when cold?
  Reply With Quote
Old 20th October 2003, 02:39 AM   #24
The one and only
 
Nelson Pass's Avatar
 
Join Date: Mar 2001
More to the point, when the hardware, bias and supply
voltage are all big, audio signal has less effect on these
elements as a percentage, and the resulting performance
is more stable from moment to moment.
  Reply With Quote
Old 20th October 2003, 08:06 AM   #25
EDUM is offline EDUM  Netherlands
diyAudio Member
 
Join Date: Oct 2003
Location: Almere
Hmm-Nelson, do I understand you correct that the audio signal is in fact "disturbing" the optimal setting of an amplifier? It implicates that this coping with the audio signal "disturbance" is a quality parameter of a design. I learned that the insensitivity of a design to changes in component values,current settings, temperatures etc. made a good design. We have to broaden that perspective to insensitivity towards the inputsignal. Hmm- interesting!

Ward
__________________
The vast number of parameters involved in human hearing make imperfect designs certain.
  Reply With Quote
Old 20th October 2003, 08:10 AM   #26
diyAudio Member
 
Join Date: Sep 2002
Location: Sweden
Of course input signals cause trouble for amplifiers. Think of
distorsion, with no input there is no distorsion. I do have a
feeling however that even the most hardcore audiophiles
prefer some distorsion to having no input signal at all.
  Reply With Quote
Old 20th October 2003, 08:14 AM   #27
frugal-phile(tm)
diyAudio Moderator
 
planet10's Avatar
 
Join Date: Oct 2001
Location: Victoria, BC, NA, Sol III
Blog Entries: 5
Quote:
Originally posted by Christer
Of course input signals cause trouble for amplifiers.
This has been coined memory distortion. A French fellow (name something like Lavardian) has done some research and there are some amps whose claim to fame is to pay special attention to this distortion.

dave
__________________
community sites t-linespeakers.org, frugal-horn.com, frugal-phile.com ........ commercial site planet10-HiFi
p10-hifi forum here at diyA
  Reply With Quote
Old 20th October 2003, 08:22 AM   #28
Warp Engineer
On Holiday
 
AudioFreak's Avatar
 
Join Date: Oct 2001
Location: Queensland, Australia
For a given amp, the input signal will have a direct impact on what percentage of the bias is dissipated as heat and what percentage of it gets to the speakers. So, yes the input signal has an effect on the thermal equilibrium of the amplifer, but over any appreciable period of time, it would probably average out quite nicely.

Most components (both active and passive) do change as they warm up and capacitors need time to 'form' when they are first used.
__________________
- Dan
  Reply With Quote
Old 20th October 2003, 09:01 AM   #29
diyAudio Member
 
Join Date: Sep 2002
Location: Sweden
Quote:
Originally posted by planet10


This has been coined memory distortion. A French fellow (name something like Lavardian) has done some research and there are some amps whose claim to fame is to pay special attention to this distortion.

dave
Yes, I read a little bit about that. Actually, my comment was
meant rather as a general one, not specifically regarding
thermal effects, since someone seemed so surprised that the
actual signal could affect the performance.
  Reply With Quote
Old 20th October 2003, 10:56 AM   #30
EDUM is offline EDUM  Netherlands
diyAudio Member
 
Join Date: Oct 2003
Location: Almere
Is there anyone having experience with spectrum analysis-, distortion- or stepresponse measurements with amplifiers just after switching on and say an hour later? Any differences that might explain a this "better" sound?

Strangely enough it seems that the the sound always "improves" I never heard that it became worse.

It is not just the amplifier floating to it correct setting causing less perfect sound during the process. All settings should be more or less on the expected levels directly after switching on (1 minute). If these small differences in settings in the first hour after switching on cause that audible difference I believe a redesign might be appropriate.

Or are we talking about an audio "decanting" ritual that must be performed to appreciate the full audio bouquet?

Ward
__________________
The vast number of parameters involved in human hearing make imperfect designs certain.
  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
TDA1541A - Double Crown - Myth or Fact - How to Test poynton Digital Line Level 9 18th June 2009 11:32 AM
Off topic: SAF........ fact or myth???? rabbitz Multi-Way 19 14th April 2004 10:24 PM
The Solid State Wiki - Your solid state reference guide Jason Solid State 0 25th June 2002 05:26 PM


New To Site? Need Help?

All times are GMT. The time now is 05:00 PM.


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