Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Keantoken's CFP cap multiplier
Keantoken's CFP cap multiplier
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 27th August 2017, 11:35 AM   #1021
RCruz is offline RCruz  Switzerland
nhinstruments
diyAudio Member
 
RCruz's Avatar
 
Join Date: Sep 2006
Location: Wallis
Keantoken's CFP cap multiplier
Thank you for the tip. I am just experimenting with this type of lytic bypass. Did not realize they could resonate with smaller films. Will change the films to 10u and test.
__________________
RC
  Reply With Quote
Old 27th August 2017, 11:38 AM   #1022
RCruz is offline RCruz  Switzerland
nhinstruments
diyAudio Member
 
RCruz's Avatar
 
Join Date: Sep 2006
Location: Wallis
Keantoken's CFP cap multiplier
Quote:
Originally Posted by keantoken View Post
It really depends on the layout, I think the most important thing is that there is a short path from the driver collectors to the zobel and drain grounds. So much of this is context-dependent, I can only make the most general comments, and I still may be wrong.
I am using separated paths for the zobel gnd and other grounds... they will all join star ground on the psu board. Somehow I believe zobel return should not be connected directly to other gnd. Am I wrong ?

In fact I see the zobel as another load to the power amp and as we normally route speaker return to the psu star, I decided to do the same for the zobel.
__________________
RC

Last edited by RCruz; 27th August 2017 at 11:40 AM.
  Reply With Quote
Old 27th August 2017, 12:48 PM   #1023
RCruz is offline RCruz  Switzerland
nhinstruments
diyAudio Member
 
RCruz's Avatar
 
Join Date: Sep 2006
Location: Wallis
Keantoken's CFP cap multiplier
I rearranged the layout using upright diodes.

Please let me know your opinion.
Attached Images
File Type: png P300 KMult 3.PNG (144.7 KB, 327 views)
__________________
RC
  Reply With Quote
Old 28th August 2017, 09:01 PM   #1024
blmn is offline blmn  Brazil
diyAudio Member
 
blmn's Avatar
 
Join Date: Feb 2001
Location: .
Quote:
Originally Posted by keantoken View Post
This is the current schematic that goes with the current PCB.
Hi Ken,

Im planning to build a 20W class A power amp and I saw you thread and web page on K-mult.

May I use equivalents of D44/5 trannies?

Is the R8/9 use for high current surges in your web page valid in this case?

regards,

Last edited by blmn; 28th August 2017 at 09:18 PM.
  Reply With Quote
Old 29th August 2017, 01:24 PM   #1025
RCruz is offline RCruz  Switzerland
nhinstruments
diyAudio Member
 
RCruz's Avatar
 
Join Date: Sep 2006
Location: Wallis
Keantoken's CFP cap multiplier
Here we have a list of drivers..... maybe some are compatible: http://users.tpg.com.au/gerskine/gre...ransistors.htm
__________________
RC
  Reply With Quote
Old 30th August 2017, 11:59 AM   #1026
RCruz is offline RCruz  Switzerland
nhinstruments
diyAudio Member
 
RCruz's Avatar
 
Join Date: Sep 2006
Location: Wallis
Keantoken's CFP cap multiplier
Found original 2sa1930��
Did a breadboard with the 1930 and bc337-40...
It works but i have .56vdrop on the 47ohm resistor so current in the driver is below 15ma....
The scope shows a clean output without ripple and no oscilations.
Layout is critical
__________________
RC
  Reply With Quote
Old 30th August 2017, 01:05 PM   #1027
keantoken is offline keantoken  United States
diyAudio Member
 
keantoken's Avatar
 
Join Date: Aug 2006
Location: Texas
That webpage was nice more than 5 years ago but I think it is a bit out of date.

PSRR will be fine if your load current is not high enough, but output impedance will be terrible - 2R or higher.

Also, note that the important thing is really that Q2 is turned well on. The 2SA1930 might just have 0.56R Vbe(on), which would be fine. If your load current is more than 25mA, it will be fine.

Quote:
Originally Posted by blmn View Post
Hi Ken,

Im planning to build a 20W class A power amp and I saw you thread and web page on K-mult.

May I use equivalents of D44/5 trannies?

Is the R8/9 use for high current surges in your web page valid in this case?

regards,
My guess is that equivalents will work, but I cannot guarantee it. R8/R9 are not used in the PCB version because I found them to be unnecessary.
__________________
The Kmultiplier rail filter! -=- The Simple Kuartlotron Superbuffer!
Need something built, repaired or modded? PM me and ask what I can do!

Last edited by keantoken; 30th August 2017 at 01:09 PM.
  Reply With Quote
Old 30th August 2017, 01:52 PM   #1028
keantoken is offline keantoken  United States
diyAudio Member
 
keantoken's Avatar
 
Join Date: Aug 2006
Location: Texas
Quote:
Originally Posted by RCruz View Post
I am using separated paths for the zobel gnd and other grounds... they will all join star ground on the psu board. Somehow I believe zobel return should not be connected directly to other gnd. Am I wrong ?

In fact I see the zobel as another load to the power amp and as we normally route speaker return to the psu star, I decided to do the same for the zobel.
I see the issue of layout as a bunch of intersecting and nesting current loops. You look at which current loops are both important for operation and sensitive to layout (or current loops which would emit large EMI if not controlled). The Zobel current loop is one such important loop. This loop goes through the MOSFETs, through the rails and through the closest decoupling cap to the zobel ground which completes the loop. A physically small loop here is good for stability. Feedback should come directly from the zobel, otherwise the amp sees the zobel as inductive, which is also bad for stability.

I see the layout of a power amp as a 2-wire system. The wires should stay together. The two wires start at the feedback resistor and the feedback ground. Next the pair of wires goes to the zobel (which is connected to the output stage and decoupling). Then the pair of wires go to the speaker. I think the zobel ground makes a good star point.

Sometimes people think it's better to put one ground away from another thinking if it's "over there" that it won't get the other one dirty. The real solution tends to be the opposite when we are talking about stuff on a power amp PCB. It is often better to put such a node in the center of the design, where nothing is too far away and it can be controlled.
__________________
The Kmultiplier rail filter! -=- The Simple Kuartlotron Superbuffer!
Need something built, repaired or modded? PM me and ask what I can do!

Last edited by keantoken; 30th August 2017 at 02:04 PM.
  Reply With Quote
Old 31st August 2017, 10:38 PM   #1029
blmn is offline blmn  Brazil
diyAudio Member
 
blmn's Avatar
 
Join Date: Feb 2001
Location: .
Quote:
Originally Posted by keantoken View Post
That webpage was nice more than 5 years ago but I think it is a bit out of date.

PSRR will be fine if your load current is not high enough, but output impedance will be terrible - 2R or higher.

Also, note that the important thing is really that Q2 is turned well on. The 2SA1930 might just have 0.56R Vbe(on), which would be fine. If your load current is more than 25mA, it will be fine.

My guess is that equivalents will work, but I cannot guarantee it. R8/R9 are not used in the PCB version because I found them to be unnecessary.
Tks, Ken!
Best regards,
  Reply With Quote
Old 1st September 2017, 06:26 PM   #1030
RCruz is offline RCruz  Switzerland
nhinstruments
diyAudio Member
 
RCruz's Avatar
 
Join Date: Sep 2006
Location: Wallis
Keantoken's CFP cap multiplier
Quote:
Originally Posted by keantoken View Post
I see the issue of layout as a bunch of intersecting and nesting current loops. You look at which current loops are both important for operation and sensitive to layout (or current loops which would emit large EMI if not controlled). The Zobel current loop is one such important loop. This loop goes through the MOSFETs, through the rails and through the closest decoupling cap to the zobel ground which completes the loop. A physically small loop here is good for stability. Feedback should come directly from the zobel, otherwise the amp sees the zobel as inductive, which is also bad for stability.

I see the layout of a power amp as a 2-wire system. The wires should stay together. The two wires start at the feedback resistor and the feedback ground. Next the pair of wires goes to the zobel (which is connected to the output stage and decoupling). Then the pair of wires go to the speaker. I think the zobel ground makes a good star point.

Sometimes people think it's better to put one ground away from another thinking if it's "over there" that it won't get the other one dirty. The real solution tends to be the opposite when we are talking about stuff on a power amp PCB. It is often better to put such a node in the center of the design, where nothing is too far away and it can be controlled.
Thank you.... I must modify the layout according to your input.

I have been studying the circuit corresponding to your boards. I have built those and they do perform very well indeed.

Can I use the same circuit in my power amp (+- 62v rails) ?

I breadboarded the high voltage circuit (the one in your site with a lot of diodes) and it works also but I am having trouble including it in the power amp board... (too many components) so I would like to use your board circuit instead.
Attached Images
File Type: jpg kmult board sch_edited.jpg (154.5 KB, 227 views)
__________________
RC
  Reply With Quote

Reply


Keantoken's CFP cap multiplierHide 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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Vbe multiplier - bypass cap Donk Solid State 7 22nd January 2008 02:55 AM
Question(s) about CFP. Justcallmedad Solid State 94 20th September 2005 11:08 AM
cap multiplier or not? PederBass Solid State 13 23rd March 2004 07:26 PM
Cap. multiplier or regulated supply ? Buhl Pass Labs 1 8th October 2003 11:51 PM


New To Site? Need Help?

All times are GMT. The time now is 09:07 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Copyright ©1999-2019 diyAudio
Wiki