Power amp under development

[Ahmad_tbp]

Hi Quasi & keypunch
thanks for layouts
yeah quasi , for sure ur amp has very hard working times
and it s for sure it ll stand strong ....
u wont believe , it sounds much better than some commercial Marshall amps !
thanks again
Bye

[anatech]

Hi John,
The 2SA970 is the compliment to the 2SC2240. The prices I paid for these is no longer relevant. My source was a Canadian parts supplier that was commercial only. He has closed his doors.

-Chris

[quasi]

Originally posted by BlacK_Chicken
Quasi,

Your proposal of a new layout for to220-fets is very promising....The maximum size, I am able to etch is 100x160mm....

BTW wich version of the schematic (and layouts) is the latest one?

Thanks for info
Black

The new board will be approx 75mm x 90mm. If you send me an email I will send you the latest version of schematics and layouts (larger board).

Cheers
Q

[quasi]

Originally posted by Ahmad_tbp
u wont believe , it sounds much better than some commercial Marshall amps !

I wouldn't say that too loud, especially iin the tube and musical instrument forums....

[TomWaits]

Originally posted by quasi
The new board will be approx 75mm x 90mm.
Cheers
Q

Now that is a small Quasi

Shawn.

[keypunch]

Originally posted by BlacK_Chicken
Quasi,

BTW wich version of the schematic (and layouts) is the latest one?

Thanks for info
Black

Black,

Below I believe are the latest PCB and schematics for the MOSFET version of the quasi amp and related items. It is in your best interests to take the time to read the thread before asking any questions. Many of the questions have already been answered in the thread, and at times different times with some additional insights. I have taken the time to find and collect all of the most related links to your question as it is one of the most often asked questions. Please note I have chosen to link to the posting and not the attachments on purpose so you can find the associated thread discussion before and/or after the related posting:


Table can be used as a guide when trying to determine output configurations for the amp module based only on the IRFP450 (different devices have different power handing abilities and there are many points in the thread that discuss this and how one can calculate with the power handing ability for the device you may choose to use or others have chosen to use), Post #285:

http://www.diyaudio.com/forums/showt...932#post794932


Latest Schematic, Post #1123:

http://www.diyaudio.com/forums/showt...16#post1008216


Latest PCB layout for 3 output pair devices, AKA NMOS350, Post #1034:

http://www.diyaudio.com/forums/showt...722#post996722


Latest PCB tracks for 3 output pair devices, AKA NMOS350, Post #1035:

http://www.diyaudio.com/forums/showt...723#post996723


Latest PCB layout for High Power 5 output pair devices, AKA NMOS500, Post #1036:

http://www.diyaudio.com/forums/showt...725#post996725


Latest PCB tracks for High Power 5 output pair devices, AKA NMOS500, Post #1037:

http://www.diyaudio.com/forums/showt...726#post996726


R9 to be 33r0 or 39r0 difference between latest schematic and latest PCB images, Post #1102:

http://www.diyaudio.com/forums/showt...762#post999762


Current R6 values for different supply rail voltages, Post #1025:

http://www.diyaudio.com/forums/showt...556#post996556


One part of background to R6 (known as R7 on much older schematic) item 2 reply in posting, Post #159:

http://www.diyaudio.com/forums/showt...848#post600848


Bench Setup Guide for module once completed, Post #644:

http://www.diyaudio.com/forums/showt...215#post945215


Schematic very close to current schematic above missing some a couple corrections to current schematic but this one has the currents shown on the schematic that are still valid and correct that may be useful, Post #325:

http://www.diyaudio.com/forums/showt...662#post818662


Slow Turn On Schematic, Post #224:

http://www.diyaudio.com/forums/showt...687#post784687


Slow Turn On PCB layout, Post #217:

http://www.diyaudio.com/forums/showt...781#post783781


Slow Turn On PCB tracks, Post #218:

http://www.diyaudio.com/forums/showt...783#post783783


The DC Detect schematic which is not in the amplifier schematic, but is part of the amplifier PCB modules for the amplifier (except for the first posting of the PCBs), Post #191:

http://www.diyaudio.com/forums/showt...114#post776114


A standalone version of the DC Detect PCB (layout and tracks) used on the amp module board and has two DC Detect circuits on the one PCB, Post #853:

http://www.diyaudio.com/forums/showt...400#post972400

As footnote one can make a standalone version of the DC Detect as a single board with a bit of effort using the base module PCB using a graphics editing program or (I have not tried) actually cutting it out from the printed paper images.


How to mount T8, the TO-92 (cbe) Vbe, to heatsink, Post #321:

http://www.diyaudio.com/forums/showt...468#post800468




There is a BiPolar version of the amplifier as well known as the "Brother of Quasi".

Brother of Quasi

Last posting of the BiPolar version schematic in the MOSFET thread, Post #1149:

http://www.diyaudio.com/forums/showt...87#post1029087

For the BiPolar version please refer to the dedicated thread for the "Brother of Quasi", but to save duplicate questions on things like PSU, slow start, DC Detect, Input stage and perhaps the predriver and related alternate part values you should consult this thread as much of the design and related questions could be duplicates of what has already been well covered on the base design.

I am not sure if the same alternate values for the R6 like resistor in the BiPolar design apply for different PSU rail voltages. You will need to ask quasi that question.


I trust this is not just helpful to Black, but to other current and future builders of the quasi MOSFET amplifier. After I post this I will double check I have all the links matched up with the link description and hope I can validate and do any required corrections before the post time limit for editing a post expires.


Regards,

John L. Males
Willowdale, Ontario
Canada
10 January 2007 18:00 - 20:24
10 January 2007 20:33 Corrected link copy/paste for Post #224
10 January 2007 20:44 Typo correction and new point re R6 like resistor for BiPolar design.
10 January 2007 20:48 Minor spacing correction. Hopefully all links for post are correct now as I have checked all the links in the posting as best can without going crossed eyed.
10 January 2007 20:50 Opps, corrected typo error missed

[Ahmad_tbp]

I wouldn't say that too loud, especially iin the tube and musical instrument forums....

i ll not ... :-"

[quasi]

Here's the mini board. Could be used for multi-channel amplifiers, but also compact stereo units. Has been designed for rails up to +/- 55v (FET dependant).

Not built or tested so please check layout against schematic if you decide to use it before I build one.

As promised PCB is 75mm x 90mm (not including heatsink bracket). Have fun....

Cheers
Q

[zeonrider]

Finally small design !
Which schematic you used, post please .
Regards zeoN_Rider

[zeonrider]

I see you is online now !
Regards zeoN_Rider