Another thread regarding CCS vs BOOTSTRAP - Page 2 - 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 30th November 2008, 02:36 PM   #11
diyAudio Member
 
Nico Ras's Avatar
 
Join Date: Nov 2005
Location: East Coast of South Africa
Here are the numbers at 100 Hz, again the typical performance is almost identical bar the position and level of odd and even harmonics.

http://digisec.co.za/ras/music/CCS%20THD%20100H.pdf

http://digisec.co.za/ras/music/Boots...THD%20100H.pdf

Again, there are no technical difference really and the sound that the bootstrap makes will be preferred by some and the CCS by others. So there is little room for arguing which outperform the other.

The fact that 7 out of 9 preferred the bootstrap cannot really be explained either. It could have been the type of music that I played.

Nico
  Reply With Quote
Old 30th November 2008, 02:46 PM   #12
diyAudio Member
 
Join Date: Sep 2007
Very interesting Nico.

Have you tried a Fet CCS, it would be interesting to know the results.

André
  Reply With Quote
Old 30th November 2008, 02:55 PM   #13
diyAudio Member
 
Nico Ras's Avatar
 
Join Date: Nov 2005
Location: East Coast of South Africa
Hi guys,

one final thing that could also result in the amps sounding different and that was very interesting. Although both amps has the same bandwidth, the CCS is almost twice as fast as the bootstrap but it has some ringing on the rising edge while the bootstrap is a smooth transistion.

Okay that is it, you are welcome debating these facts and maybe even conclude which is best, the bootstrap or CCS.

Kind regards

Nico
  Reply With Quote
Old 30th November 2008, 03:06 PM   #14
diyAudio Member
 
Nico Ras's Avatar
 
Join Date: Nov 2005
Location: East Coast of South Africa
Quote:
Originally posted by Andre Visser
Very interesting Nico.

Have you tried a Fet CCS, it would be interesting to know the results.

André

No, I did not but you are welcome to play with it. Here are the component values for those interested. The design is loosely based on the quad 303 simplified. I must admit, neither of the amps sound bad at all, in fact I was very surprised at the performance of such a simple design.

Running it with +-50V supplies it will easily give you the magical 100 watts.

http://digisec.co.za/ras/music/CCS%20Schematic.pdf

http://digisec.co.za/ras/music/Boots...0Schematic.pdf
  Reply With Quote
Old 30th November 2008, 03:19 PM   #15
diyAudio Member
 
Nico Ras's Avatar
 
Join Date: Nov 2005
Location: East Coast of South Africa
Quote:
Originally posted by Nico Ras
Hi guys,

one final thing that could also result in the amps sounding different and that was very interesting. Although both amps has the same bandwidth, the CCS is almost twice as fast as the bootstrap but it has some ringing on the rising edge while the bootstrap is a smooth transistion.

Okay that is it, you are welcome debating these facts and maybe even conclude which is best, the bootstrap or CCS.

Kind regards

Nico
Actually what I said here is not quite correct. Have a look at the square wave response and make up your own mind.
Attached Images
File Type: gif ccs overshoot.gif (4.5 KB, 716 views)
  Reply With Quote
Old 30th November 2008, 03:20 PM   #16
diyAudio Member
 
Nico Ras's Avatar
 
Join Date: Nov 2005
Location: East Coast of South Africa
And that of the bootstrap. Depending how you look at it you can argue that the bootstrap is faster.
Attached Images
File Type: gif bootstrap.gif (4.9 KB, 714 views)
  Reply With Quote
Old 1st December 2008, 06:54 AM   #17
AKSA is offline AKSA  Australia
diyAudio Member
 
Join Date: Sep 2001
Location: Melbourne, Australia
Thanks, great work Nico,

I've always used the bootstrap; in listening tests I found it had much less sibilance, and was easier to compensate the amp because of the rapid increase in electrolytic ESR beyond about 200KHz.

I can see it's slower, but that absence of overshoot is a boon.....

According to NP, you get around +/-10% variation in VAS current with a boostrap, and this will make it less linear, particularly at LF.

Swings and roundabouts, perhaps?

Hugh
__________________
Aspen Amplifiers P/L (Australia)
www.aksaonline.com
  Reply With Quote
Old 1st December 2008, 03:08 PM   #18
DRC is offline DRC  United Kingdom
diyAudio Member
 
DRC's Avatar
 
Join Date: Jan 2003
Location: UK (south west)
Nico,
How much voltage is across R25 and Q4 under these signal conditions ? (no voltage is indicated on D3)
Did you try adjusting C13 on the CCS version ? (the bootstrap version looks spot on)

Many thanks for the very interesting results ...

dave
  Reply With Quote
Old 1st December 2008, 08:02 PM   #19
diyAudio Member
 
Nico Ras's Avatar
 
Join Date: Nov 2005
Location: East Coast of South Africa
Quote:
Originally posted by DRC
Nico,
How much voltage is across R25 and Q4 under these signal conditions ? (no voltage is indicated on D3)
Did you try adjusting C13 on the CCS version ? (the bootstrap version looks spot on)

Many thanks for the very interesting results ...

dave
Hi Dave,

sorry about that, D3 is 5V1. Please note that the base bias arrangement for Q1 should be zener stabilized and it is best making R1 variable then off-set can be adjusted for any supply voltage.

Regards
  Reply With Quote
Old 1st December 2008, 08:22 PM   #20
diyAudio Member
 
Nico Ras's Avatar
 
Join Date: Nov 2005
Location: East Coast of South Africa
Quote:
Originally posted by AKSA
Thanks, great work Nico,

I've always used the bootstrap; in listening tests I found it had much less sibilance, and was easier to compensate the amp because of the rapid increase in electrolytic ESR beyond about 200KHz.

I can see it's slower, but that absence of overshoot is a boon.....

According to NP, you get around +/-10% variation in VAS current with a bootstrap, and this will make it less linear, particularly at LF.

Swings and roundabouts, perhaps?

Hugh
Hi Hugh,

thanks for your comments I appreciate it.

This little exercise was prompted after the debate regarding John's Patchworks thread and to be honest I also prefer the bootstrap.

One can see that there are only slight differences in the harmonic order although the harmonic power density is almost identical, thus the THD of both amps would provide identical specification.

Only when one considers the amplitude and position of the harmonic that one may be able to explain the apparent difference in the character of the sound.

I would suggest that liking or disliking one or the other topology is a matter of preference but this decision can only be made if one could audition each under the same circumstances, so the debate probably remains open forever.

Kindest regards

Nico
  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
Why bootstrap? peranders Solid State 69 27th March 2014 02:25 PM
P3A Bootstrap and NFB Capacitors christian.lenci Solid State 16 23rd December 2008 04:36 AM
Aleph amp bootstrap - where to go? Klaus Pass Labs 5 28th May 2003 09:48 AM


New To Site? Need Help?

All times are GMT. The time now is 07:34 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