The high slew rate design that time forgot?

ingenieus · 09:42 PM

I found this design in an old magazine. It is by Yuri Ezhkov and was published in Electronics World of September 1999 under the title "Fast Audio Power." The circuit diagram is attached to this post. If there is any interest I can post the other two pages.

The design is quite complicated. I have to admit that I have yet to get my mind into high gear to figure it all out.

The specifications given includes output power is 90W into 4 ohm with a slew rate better than 50V/us. Although the author gives some detail of construction in the text, there was no PCB design.

I don't know if any of the ideas presented went any further. The design uses a bewildering number of different transistors. The author does give alternative type numbers for most of them, but it does not help much as they are not familiar to me. What makes it worse is that I do not have a SPICE model for even one of them. Simulating this design will therefore be quite undertaking.

kaos · 13th September 2011, 10:01 PM

50 V/uS isn’t that fast. Don’t care for some of the design choices either.

jcx · 13th September 2011, 10:10 PM

Self, Cordell both manage better SR in their audio amp design books

Bonsai · 14th September 2011, 05:57 AM

This is not a SOTA design.

I'd skip it and take the advice above on Cordell and Self. For more practical and closer to home examples, see OStripper's work on this forum (at the top of the page). This will deliver high slew rates, ultra low distortion in a very practical and down to earth design and uses many of Self and Cordell's techniques.

wahab · 14th September 2011, 10:28 AM

50V/uS is a good value..
Higher slew rate will inherently reduce stability in any classical design,
be it the ubiquitous single differential based topology ala blameless ,
or more refined symetrical differential siblings..

Bonsai · 14th September 2011, 10:35 AM

Yes, agree Wahab, there are some nice fully balanced designs ot there as well ;-D

BTW, its perfectly possible to get 100V/uS and still be stable on an FBS design.

homemodder · 14th September 2011, 10:48 AM

For a trully high slew rate design try the Stochino amp. 300Vus, is fast enough I should think.

BTW the Stochino sounds terrific, about the best sounding DIY design I have seen published and built but be aware its not newby builder material.

wahab · 14th September 2011, 10:54 AM

Hi, Bonsai , that s quite right, but with some limitations.
The usual LR output circuit almost invariably save the day with most
designs that are instable as soon as some capacitive loading is added,
and it will be more than mandatory in those so called high slew rate designs,
partly reducing the expected SR...

As for full symetrical circuits , unfortunately they dont work as easily
as the single differentials , but they have the advantage of better stabilty
as well as symetrical slewing.

ingenieus · 14th September 2011, 12:07 PM

Thanks for all of the input, guys. To advance the state of the art, we have to keep looking at all the alternatives out there.

The Blameless design is certainly the one to go for if you want something that will work, and work well. I have one on the back burner at the moment.

I will look at the Stochino design. Is this the definitive version?

homemodder · 14th September 2011, 12:22 PM

Yes, be sure to upgrade the output mosfets, those are not really capable for the power rating of that amp. When pushed hard into 4 ohm loads those will go up in smoke.
Youll need a very good pcb design too, if you dont get it right, those mosfets will go up in smoke too.

BTW, ingenious where you from??

14th September 2011, 05:57 AM	#4
Bonsai diyAudio Member Join Date: Aug 2006 Location: Taipei, Taiwan	This is not a SOTA design. I'd skip it and take the advice above on Cordell and Self. For more practical and closer to home examples, see OStripper's work on this forum (at the top of the page). This will deliver high slew rates, ultra low distortion in a very practical and down to earth design and uses many of Self and Cordell's techniques. __________________ bonsai http://www.hifisonix.com/

14th September 2011, 10:35 AM	#6
Bonsai diyAudio Member Join Date: Aug 2006 Location: Taipei, Taiwan	Yes, agree Wahab, there are some nice fully balanced designs ot there as well ;-D BTW, its perfectly possible to get 100V/uS and still be stable on an FBS design. __________________ bonsai http://www.hifisonix.com/

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Slew rate calculations - how much do I need?	peranders	Solid State	232	20th November 2011 06:02 PM
IcePower slew rate	Rikard Nilsson	Class D	24	29th April 2009 04:39 AM
slew rate adjustment...	chipmonster	Parts	7	25th January 2008 10:01 AM
Tube rise time and slew rate	gain-wire	Tubes / Valves	11	26th October 2007 02:11 AM
Slew rate value	Luke123	Chip Amps	5	7th April 2005 12:30 AM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read


	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

13th September 2011, 10:01 PM	#2
kaos diyAudio Member Join Date: Dec 2005 Location: Los Angeles	50 V/uS isn’t that fast. Don’t care for some of the design choices either.

13th September 2011, 10:10 PM	#3
jcx diyAudio Member Join Date: Feb 2003 Location: ..	Self, Cordell both manage better SR in their audio amp design books

14th September 2011, 10:28 AM	#5
wahab diyAudio Member Join Date: Nov 2009 Location: algeria/france	50V/uS is a good value.. Higher slew rate will inherently reduce stability in any classical design, be it the ubiquitous single differential based topology ala blameless , or more refined symetrical differential siblings..

14th September 2011, 10:48 AM	#7
homemodder diyAudio Member Join Date: May 2006	For a trully high slew rate design try the Stochino amp. 300Vus, is fast enough I should think. BTW the Stochino sounds terrific, about the best sounding DIY design I have seen published and built but be aware its not newby builder material.

14th September 2011, 10:54 AM	#8
wahab diyAudio Member Join Date: Nov 2009 Location: algeria/france	Hi, Bonsai , that s quite right, but with some limitations. The usual LR output circuit almost invariably save the day with most designs that are instable as soon as some capacitive loading is added, and it will be more than mandatory in those so called high slew rate designs, partly reducing the expected SR... As for full symetrical circuits , unfortunately they dont work as easily as the single differentials , but they have the advantage of better stabilty as well as symetrical slewing.

14th September 2011, 12:07 PM	#9
ingenieus diyAudio Member Join Date: Apr 2011	Thanks for all of the input, guys. To advance the state of the art, we have to keep looking at all the alternatives out there. The Blameless design is certainly the one to go for if you want something that will work, and work well. I have one on the back burner at the moment. I will look at the Stochino design. Is this the definitive version?

14th September 2011, 12:22 PM	#10
homemodder diyAudio Member Join Date: May 2006	Yes, be sure to upgrade the output mosfets, those are not really capable for the power rating of that amp. When pushed hard into 4 ohm loads those will go up in smoke. Youll need a very good pcb design too, if you dont get it right, those mosfets will go up in smoke too. BTW, ingenious where you from??

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)