John Curl's Blowtorch preamplifier - Page 13 - 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
Closed Thread
 
Thread Tools Search this Thread
Old 19th January 2006, 11:34 PM   #121
diyAudio Member
 
serengetiplains's Avatar
 
Join Date: Feb 2004
Location: Canada
I understand what you mean by charge retention. It's the out-of-time charge release I'm concerned about, for audio purposes.
 
Old 19th January 2006, 11:45 PM   #122
poobah is offline poobah  United States
diyAudio Member
 
poobah's Avatar
 
Join Date: Nov 2005
Right,

I'm saying that the return effect is sorta DC-ish in nature. I'm just saying that I can't imagine shoving a bunch of AC through a DC biased cap, shorting it, and then expect to see AC (music) coming out in the discharge... what that DC is doing remains to characterised... methinks it does something though... even "disbelievers" (guys with $5 power cords) seems to say something about caps...
 
Old 19th January 2006, 11:52 PM   #123
diyAudio Member
 
serengetiplains's Avatar
 
Join Date: Feb 2004
Location: Canada
I don't question your assumption that you don't see music coming out the discharge. What you will see is an AC voltage (declining or increasing DC = AC) the magnitude of which is correlated with the original voltage which in turn is determined in part by the AC the cap is coupling or some power supply variation caused by AC the amp is amplifying. The discharge *is* related to the AC signal in question, but not in the manner of an echo, which is a naive characterisation.
 
Old 20th January 2006, 12:00 AM   #124
poobah is offline poobah  United States
diyAudio Member
 
poobah's Avatar
 
Join Date: Nov 2005
Right,

I gotta believe to one extent or the another that this would have some "smearing" effect on the audio signal.

 
Old 20th January 2006, 12:45 AM   #125
diyAudio Member
 
serengetiplains's Avatar
 
Join Date: Feb 2004
Location: Canada
Quote:
Originally posted by poobah

I gotta believe to one extent or the another that this would have some "smearing" effect on the audio signal.[/B]
IME I have no doubt it does. I often use the term "smearing" to describe the effect. The effect is subtle, but it's bothersome enough, to me at least, that I find it a good game expunging a circuit of it where I can.
 
Old 20th January 2006, 12:55 AM   #126
diyAudio Member
 
Steve Eddy's Avatar
 
Join Date: Sep 2002
Location: Sacramento, CA
Quote:
Originally posted by serengetiplains
How do you know what you assert? Not anything like ... ? Show me a picture or do your best to describe in words, then we can compare.
I'd be happy to oblige if you can tell me how to show you something which isn't there.

Here, how's this?

Click the image to open in full size.

Quote:
DA, or something to which DA corresponds or correlates---for simplicity's sake, what I'll call DA---smears and/or ghosts and/or adds to and/or subtracts from an audio signal. I hear DA's effects as a form of veiling and grunge, among other descriptions I could throw at it; veiling because DA disrupts my ability to hear clearly into instruments, spaces and dynamics, and grunge because I feel a sense of subtle relaxation or relief when DA is removed as if an irritation has been removed.
Ok, so you've been making objective claims based not on any sort of objective proof or evidence, but on sighted, subjective listening? I'm afraid that won't really get us anywhere if what we're after is what is "*actually*" going on.

se
 
Old 20th January 2006, 01:04 AM   #127
diyAudio Member
 
serengetiplains's Avatar
 
Join Date: Feb 2004
Location: Canada
Steve, here's a subjective claim: almost no one can have a meaningful discussion in this forum with you. I'm sure this is not, in one form or another, news to you. I'm back to ignoring you.
 
Old 20th January 2006, 01:15 AM   #128
diyAudio Member
 
Steve Eddy's Avatar
 
Join Date: Sep 2002
Location: Sacramento, CA
Quote:
Originally posted by serengetiplains
Steve, here's a subjective claim: almost no one can have a meaningful discussion in this forum with you. I'm sure this is not, in one form or another, news to you. I'm back to ignoring you.
Ciao.

se
 
Old 20th January 2006, 01:36 AM   #129
lineup is offline lineup  Sweden
diyAudio Member
 
lineup's Avatar
 
Join Date: Dec 2005
Location: the north
Quote:
Test 2 examined a number of higher value aluminum and tantalum electrolytics. Comparison of units 1 and 2 shows that a higher voltage rated unit of the same value will tend to have a lower relative DA.
This is an interesting point, as this same consideration for selection criteria is also true with regard to DF.
It means that wherever possible,
if you must use an electrolytic, use the highest practical voltage rating.

This applies to either aluminum or tantalum units. Units like number 1 should be avoided at all costs!
Unit three is a 50- u F non-polar aluminum electrolytic of a type often seen in solid-state audio circuits. As can be noted it has a somewhat lower DA. Apparently, a back-to-back connection tends to reduce the DA of a single unit. For example, unit 4, actually a series pair of two units like number 1, shows less DA than a single. This tends to say that nonpolar units or non-polar connected conventional electrolytics will be better in DA relative to a conventional polar cap.
However, this difference is largely academic we feel,
since if you want really high-quality sound,
you cannot tolerate more than a small fraction of a percent DA.
Obviously this rules out all but the best of the film dielectrics.

Unit 6 is an example of one of the better quality aluminum electrolytics (see also Fig. 7).
While studying the DA problem in tantalum and aluminum electrolytics, we also bench-tested .......

-------------------------------------

Acknowledgements
The authors would like to acknowledge private discussions with
John Curl and J. Peter Moncrieff
on the subject of capacitors in audio circuits
and how they might influence subjective testing.
Testing Capacitor DA
__________________
lineup
 
Old 20th January 2006, 01:53 AM   #130
diyAudio Member
 
john curl's Avatar
 
Join Date: Jul 2003
Location: berkeley ca
'Smear' is a pretty good description of DA. I once used the term 'echo' for DA effects, more than 20 years ago in a LTE to 'Wireless World' or 'Hi Fi news'. I never heard the end of it from Doug Self, etc. , but 'echo' is a good first approximation. It is signal AFTER the original input has gone, and there should be only silence.
 

Closed Thread


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



New To Site? Need Help?

All times are GMT. The time now is 10:16 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