Swordfishy/ASPEN FETZILLA power amp - Page 11 - diyAudio
Go Back   Home > Forums > Commercial Sector > Manufacturers > AKSA

AKSA Builders of market proven kits and modules at sound quality to rival the best in high end

Reply
 
Thread Tools Search this Thread
Old 8th July 2011, 04:55 AM   #101
diyAudio Member
 
Join Date: Jun 2009
to ian i can supply you with sinks sent directly to your door just mail me when the time comes and you know i`ll give you at the best price
  Reply With Quote
Old 8th July 2011, 06:32 AM   #102
AKSA is offline AKSA  Australia
diyAudio Member
 
Join Date: Sep 2001
Location: Melbourne, Australia
HI George,

Please post, I would be interested - though the soft start is not actually required.

Thanks for the legwork, appreciated,

Hugh
__________________
Aspen Amplifiers P/L (Australia)
www.aksaonline.com
  Reply With Quote
Old 8th July 2011, 09:24 AM   #103
diyAudio Member
 
chlorofille's Avatar
 
Join Date: Jul 2008
Location: Malaysia
Can't wait to start building this amp! (Once Greg gives the "go ahead")
I already have a 44,000uF per channel PS using Evox Rifa PEH169 caps so all I need is to connect the +/- 35V to the board!! Currently running a P3A amp - I'm certain the Aspen Fetzilla will be more musical.
  Reply With Quote
Old 8th July 2011, 12:39 PM   #104
AKSA is offline AKSA  Australia
diyAudio Member
 
Join Date: Sep 2001
Location: Melbourne, Australia
Dinesh,

I really would discourage you from building a huge power supply. It will not sound so good.

I have done extensive testing with Class AB amps on this issue and found again and again that the very high charge pulses found in high cap power supplies actually militate against good sonic performance. The problem is that these very high charge pulses interfere with the voice coil earth return through the filter caps, causing intermodulation.

I find it's never necessary to go much more than 4,700uF on a 50W amplifier.

The FETzilla uses two 3,300uF caps separated by interelectrode resistors, each of 0.15 ohms. This quarantines the charge pulses principally to the first cap after the rectifier, with the second cap handling much reduced charge pulse and all of the speaker return current. This arrangement gives palpably better sound.

Cheers,

Hugh
__________________
Aspen Amplifiers P/L (Australia)
www.aksaonline.com
  Reply With Quote
Old 8th July 2011, 01:12 PM   #105
diyAudio Member
 
chlorofille's Avatar
 
Join Date: Jul 2008
Location: Malaysia
Hugh,

Noted, will follow your recommendation.
  Reply With Quote
Old 8th July 2011, 03:30 PM   #106
JKC is offline JKC  Canada
diyAudio Member
 
Join Date: Jun 2011
Location: Calgary
Hugh

Here is schematics for separate PSU. This is only a general idea if you are planing to use separate power supply instead of the one included on amp PCBs. You can change all the major components to your personal taste. I used here 24VAC 300W transformer. 24VAC is more common than 25VAC and is much easier to get. You don't need 300W transformer for this project, 160W will probably be enough. I used 300W for economical reasons, it costs only $15 more and is bigger by 7mm than 160W one. Soft start circuit is optional in case you plan to use large filtering capacitors to prevent blowing fuses on start-up.

Fetzilla PSU.jpg

Regards
George
  Reply With Quote
Old 8th July 2011, 11:22 PM   #107
AKSA is offline AKSA  Australia
diyAudio Member
 
Join Date: Sep 2001
Location: Melbourne, Australia
Lovely work, George, many thanks.

Agree about the 24Vac trafos, plenty around, some at disposals prices.

I do feel you might have too much capacitance there, which incidentally can be mounted onboard at the pcb. I have found that onboard caps improve the sound since the connection to the output devices is not so inductive as a long wire.

Thank you for your excellent contribution!

Hugh
__________________
Aspen Amplifiers P/L (Australia)
www.aksaonline.com
  Reply With Quote
Old 9th July 2011, 01:03 AM   #108
diyAudio Member
 
Join Date: Nov 2010
Location: Marblehead Ma
put me down for 4+P

2+P JoMo Adelaide SA Australia
2+P Ian Finch Coffs Harbour NSW Australia
2+P Gennaji Hyderabad India
2 Ken Lewis LA USA
2 Ron Russell Kent UK
2+P John Kenny Dublin Ireland
2+P Francis Morrin Dublin Ireland
2+P Vitalica Bucharest Romania
2+P Erik Deinum Groningen Netherlands
2+P Keith Correa ? India
2 Igor Polyakov California (city?) USA
2 Steve (aka SRH) Whangarei New Zealand
2+P George (aka JKC) Calgary Canada
2+P Anthony Mills Gold Coast Australia
2+P Dinesh (aka Chlorofille) Christchurch New Zealand
2+P Colin S. (?) (city?) NSW Australia
2 Chris Powell Sydney Australia
2+P Danny (?) Lierde Belgium
2 Sonnya (?) City (?) Denmark
4+P Jozua Cape Town South Africa
2 JT (? aka Sandyhooker) City (?) Arizona USA
2+P Nicola City (?) Vincenza Italy
2+P Sparkey (?) Melbourne Australia
2+P Chalkandtalk (?) City (?) NW England UK
4+P Woody1911a1 Marblehead , Ma USA

cheers Woody
  Reply With Quote
Old 9th July 2011, 02:25 AM   #109
AKSA is offline AKSA  Australia
diyAudio Member
 
Join Date: Sep 2001
Location: Melbourne, Australia
You're in, Woody. Now at 54 boards and building!

2+P JoMo Adelaide SA Australia
2+P Ian Finch Coffs Harbour NSW Australia
2+P Gennaji Hyderabad India
2 Ken Lewis LA USA
2 Ron Russell Kent UK
2+P John Kenny Dublin Ireland
2+P Francis Morrin Dublin Ireland
2+P Vitalica Bucharest Romania
2+P Erik Deinum Groningen Netherlands
2+P Keith Correa ? India
2 Igor Polyakov California (city?) USA
2 Steve (aka SRH) Whangarei New Zealand
2+P George (aka JKC) Calgary Canada
2+P Anthony Mills Gold Coast Australia
2+P Dinesh (aka Chlorofille) Christchurch New Zealand
2+P Colin S. (?) (city?) NSW Australia
2 Chris Powell Sydney Australia
2+P Danny (?) Lierde Belgium
2 Sonnya (?) City (?) Denmark
4+P Jozua Cape Town South Africa
2 JT (? aka Sandyhooker) City (?) Arizona USA
2+P Nicola City (?) Vincenza Italy
2+P Sparkey (Brian ?) Melbourne Australia
2+P Chalkandtalk (?) City (?) NW England UK
4+P Woody1911a1 (?) Marblehead , MA USA


Thanks for the support, this is going very well......

Cheers,

Hugh
__________________
Aspen Amplifiers P/L (Australia)
www.aksaonline.com
  Reply With Quote
Old 9th July 2011, 05:23 PM   #110
JKC is offline JKC  Canada
diyAudio Member
 
Join Date: Jun 2011
Location: Calgary
Hugh

As I said before those values can be changed. I think that the best compromise will be to use two big capacitors just after the bridge in the range 6800uF to 10000uF and another pair of smaller capacitors 3300uF to 4700uF directly on the boards. In this case length of the wires you ran from power supply to the amp will be not that critical. If you need to get low ripple voltage on the rails you will need quite big caps. In this case at 50W into 8ohm impedance will produce 3.5A peak current. With four 8200uF you looking at ripple voltage around 0.76Vpp at peak current. In reality it will be little smaller than that because of those series resistors between caps (those resistors should be an inductive wire-wound type for the best filtration). However, if you are looking for the worst case scenario let say 100W into 4ohm impedance load then your ripple voltage on the rails will double to 1.5Vpp at peak current of 7A which is quite high. Because of non-linearity of the speakers you should be expecting that kind of situation on a transient basis.

Regards
George
  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
Aspen Headphone Amp AKSA AKSA 1129 2nd June 2011 05:48 AM
Aspen Maya Vegking AKSA 7 17th May 2011 05:02 AM
DIYaudio to become new Aspen Forum AKSA AKSA 13 2nd May 2011 07:04 AM
Sachiko/aspen slab rmcelroy Full Range 0 9th March 2011 06:34 PM
Aspen HAKSA Group Buy AKSA AKSA 74 16th November 2010 05:17 AM


New To Site? Need Help?

All times are GMT. The time now is 05:38 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