Voltage source decoupling cap - 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 26th March 2005, 07:50 PM   #1
IVX is offline IVX  Russian Federation
diyAudio Member
 
IVX's Avatar
 
Join Date: Jul 2003
Location: Everywhere (Buddhist's context)
Default Voltage source decoupling cap

I'm sure that voltage source decoupling .1-1uF cap is quite enough, and film cap type it's good choice. However, i have advice coming from some high end people to use 470uF/16 nonpolar Black Gate. Someone can explain why? I can't find any reason so far.. BS?
Attached Images
File Type: png 470uf.png (1.6 KB, 223 views)
__________________
Best regards,
E1.
  Reply With Quote
Old 26th March 2005, 07:59 PM   #2
Mr Evil is offline Mr Evil  United Kingdom
diyAudio Member
 
Join Date: Aug 2004
Location: Behind you
Its purpose is to keep the Vbe multiplier's impedance low at high frequencies, but as long as the transistor is suitable, the impedance will already be low to beyond the audio band, so only a smallish capacitor should be needed.

The only possible reason I can think of to go higher is if the Vbe multiplier is not perfectly stable into a particular value of capacitance, but still 470uF seems very high.
__________________
https://mrevil.asvachin.eu/
  Reply With Quote
Old 26th March 2005, 11:43 PM   #3
anatech is offline anatech  Canada
diyAudio Moderator
 
anatech's Avatar
 
Join Date: Jun 2004
Location: Georgetown, On
I agree with Mr. Evil. You are further ahead with polerized capacitors. These will never see a reversed polarity unless the rest has gone completely south. So part of the advise given is BS at best. I have had good luck with film caps around 1uF.
Best thing to do is try it and see. The caps are cheap in this range.
-Chris
  Reply With Quote
Old 27th March 2005, 05:28 AM   #4
IVX is offline IVX  Russian Federation
diyAudio Member
 
IVX's Avatar
 
Join Date: Jul 2003
Location: Everywhere (Buddhist's context)
BTW, those 470uF BG around $20. High end people = magic people, they talk - we heard it, and no any tech comments. Well, if noone said that 470uF nonpolar BG will be worse vs 1uF polyester Wima, then i'll take BG, but i've still feeling about BS:-)
__________________
Best regards,
E1.
  Reply With Quote
Old 27th March 2005, 06:03 AM   #5
djk is online now djk
diyAudio Member
 
djk's Avatar
 
Join Date: Feb 2001
Location: USA
Nelson Pass used 47F in many of his Threshold designs.

Post #31
Point of interest: The Vbe multiplier affects amplifier sonics, not so much of itself as it's a DC voltage source, but via its bypassing capacitor, the size and quality of which is very important, particularly in the ubiquitous Class AB amplifiers most of us use.

Too small a cap will cost strong, tight bass. The wrong cap type will confer a 'grainy' sound on the amp, as the top and bottom halves of the output stage are out of step with one another. You want something with good frequency response and very low dielectric absorption, less than 0.05.

Essentially, all caps in an audio amplifier will have huge effect on the sonics. Use the best you can find everywhere and LISTEN HARD! Even the feedback shunt electro has strong influence on the sonics. Differences in amps all too often can be traced to capacitor choices.

Cheers,

Hugh


__________________
Hugh R. Dean
  Reply With Quote
Old 27th March 2005, 04:07 PM   #6
anatech is offline anatech  Canada
diyAudio Moderator
 
anatech's Avatar
 
Join Date: Jun 2004
Location: Georgetown, On
Hi Hugh,
I will agree with that. But a bipolar electrolytic cap will have higher ESR for no advantage. It will never see a reversed polarity. I do like the sound of a nice big film cap.
-Chris
  Reply With Quote
Old 27th March 2005, 11:15 PM   #7
djk is online now djk
diyAudio Member
 
djk's Avatar
 
Join Date: Feb 2001
Location: USA
That was a cut-and-paste from an old hard-to find thread, not real time (post#31).
  Reply With Quote
Old 28th March 2005, 06:53 AM   #8
IVX is offline IVX  Russian Federation
diyAudio Member
 
IVX's Avatar
 
Join Date: Jul 2003
Location: Everywhere (Buddhist's context)
BTW, I had measured ESR for the nonpolar BG 470uF/16v at 1A square wave current ~20mOhm
__________________
Best regards,
E1.
  Reply With Quote
Old 29th March 2005, 12:18 AM   #9
anatech is offline anatech  Canada
diyAudio Moderator
 
anatech's Avatar
 
Join Date: Jun 2004
Location: Georgetown, On
Hi IVX,
Try them and post the results. Empirical evidence is everthing at the end of the day.
-Chris
  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
calculating b+ voltage drop, decoupling? jimytheassassin Tubes / Valves 7 10th November 2007 12:02 AM
source for high voltage diodes. tade Planars & Exotics 3 4th July 2005 04:07 PM
2MHz, High voltage source? bigparsnip Tubes / Valves 21 2nd October 2004 05:12 AM
Safety thought regarding low voltage caps for DC-decoupling roibm Parts 4 25th April 2004 10:46 PM
Voltage on TDA1541s decoupling pins... weissi Digital Source 4 14th January 2004 07:34 PM


New To Site? Need Help?

All times are GMT. The time now is 08:41 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