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USSA-5 PCB GB
USSA-5 PCB GB
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Old 15th June 2018, 04:19 AM   #1
fab is offline fab  Canada
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Join Date: Mar 2004
Location: Canada
USSA-5 PCB GB
Default USSA-5 PCB GB

PCB (1) will be less than 10$ US each + envelope +shipping (to be confirmed based on quantity). Price will decrease if the numbers of pcb increases.

Please write your name here and the quantity from the latest list in the thread.
1)
...

************ note ************
This group buy was originally part of the following thread but specific posts were moved by an administrator of the forum. See more details about the USSA-5 here:

USSA-5 Build with Review


------------- added information ---------

USSA is a family of 20-25 Wrms (8 ohms) class A amplifiers.

Design philosophy:
- Current feedback type thus almost constant feedback factor amongst all the audio band.
- only 2 stages (also with buffer stage for versions 3 to 5)
- low/medium feedback factor (< 35db)
- medium damping factor (20 to 50 for 8 ohms load at 100 Hz)
- push-pull that allows to switch into class AB if maximum of class A is reached
- THD is dominant 2nd and 3rd harmonics
- Audio grade transistors only and operated in their more linear region
- Soft clipping behaviour
- main target is big soundstage, sound big (not thin) even at lower level, articulated bass, natural tonal balance (not artificially over bright), no extra sibilance and overall smoothness

Pcb features:
- output transistors optimally positioned for better heat distribution on heatsink;
- carefull layout using ground plane, ground return scheme, reduced cross coupling of signals and proper feedback point
- 2oz density copper trace
- 2mm pcb thickness
- gold immersion exposed traces
- pcb compatible with either USSA-3 or USSA-5

Documentation:
detailed manual including pictures at different steps and intermediate testing procedure at different phases of assembly to ensure fully working board at end of assembly.

Test equipment needed:
- 2 x standard multimeters (precision 1mv) ( mandatory)
- intelligent phone/pad sound generator application (optional)
- 8-10 ohms 20W power resistor (optional)

Warnings:
- If you are looking for a high power very bright sound this amp is not for you.
- If you are listening mainly hard rock/metal music at high sound level this amp may not be for you.
- if you want very tight /dry bass ( as opposed to articulated emotional big bass ) than this amp is not for you.
- if you are not ready to manage the heat generated by class A than this amp is not for you.
- the cost of several transistors is relatively expensive.

Group buy conditions:
1) partial manual including BOM is provided after some communications by PM with me showing your real interest in building the amp in a timely manner so you are not a pcb collector- from my estimation roughly only 10% of pcb sold are really used for a real build within one year. Also to verify if this amp is really for you so you do not lose your time and money. Group buy is too much work to lose my time sending pcb with custom papers preparation....
2) once agreed by PM, your name is added on the official list and I send you the partial Manual at your email.
3) you provide your address so I can compute the shipment cost , then total cost
4) you pay me with PayPal as a gift at the address I give you
5) you provide a proof of either Mosfet drivers and Mosfet output to show your good faith to build the amp since they are very costly.
6) once step 5 is done I provide the complete manual including adjustment instructions.
7) once all payments received, I order the pcb form manufacturer.
8) I ship the pcb to your provided address.


Fab

Last edited by fab; 28th July 2018 at 05:08 AM. Reason: Moderator has split the original thread
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Old 15th June 2018, 04:56 AM   #2
Samuel Jayaraj is offline Samuel Jayaraj  India
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1) Samuel Jayaraj, India - 1 set
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Old 15th June 2018, 06:46 AM   #3
jacques antoine is offline jacques antoine  France
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Join Date: Jan 2013
USSA-5 PCB GB
1) Samuel Jayaraj, India - 1 set
2) Jacques Antoine, France - 1 set
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Old 15th June 2018, 07:02 AM   #4
patriz is offline patriz
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Join Date: Apr 2002
1) Samuel Jayaraj, India - 1 set
2) Jacques Antoine, France - 1 set[
3) Patriz 1 set
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Old 15th June 2018, 09:20 AM   #5
nfsgame is offline nfsgame
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Join Date: Nov 2017
Location: Germany
1) Samuel Jayaraj, India - 1 set
2) Jacques Antoine, France - 1 set[
3) Patriz 1 set
4) nfsgame, Germany - 2 sets
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Old 15th June 2018, 10:15 AM   #6
baswamin is offline baswamin  India
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Join Date: Oct 2011
1) Samuel Jayaraj, India - 1 set
2) Jacques Antoine, France - 1 set[
3) Patriz 1 set
4) nfsgame, Germany - 2 sets
5) baswamin, India - 1 set
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Old 15th June 2018, 10:45 AM   #7
thimios is online now thimios  Greece
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Join Date: Aug 2009
Location: Agrinion
1) Samuel Jayaraj, India - 1 set
2) Jacques Antoine, France - 1 set[
3) Patriz 1 set
4) nfsgame, Germany - 2 sets
5) baswamin, India - 1 set
6)Thimios-2 sets(4 pcb)

Last edited by thimios; 15th June 2018 at 10:49 AM.
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Old 15th June 2018, 12:31 PM   #8
ravid is offline ravid  India
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Join Date: Feb 2011
1) Samuel Jayaraj, India - 1 set
2) Jacques Antoine, France - 1 set[
3) Patriz 1 set
4) nfsgame, Germany - 2 sets
5) baswamin, India - 1 set
6)Thimios-2 sets(4 pcb)
7)ravid, India - 3 sets
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Old 15th June 2018, 01:26 PM   #9
baswamin is offline baswamin  India
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Join Date: Oct 2011
Updating mine to 2 sets for another member.
------------------------------------------------------------------
1) Samuel Jayaraj, India - 1 set
2) Jacques Antoine, France - 1 set[
3) Patriz 1 set
4) nfsgame, Germany - 2 sets
5) baswamin, India - 2 sets
6)Thimios-2 sets(4 pcb)
7)ravid, India - 3 sets

Thanks
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Old 15th June 2018, 03:20 PM   #10
BDL is offline BDL  Romania
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Join Date: Aug 2009
Location: Timişoara
USSA-5 PCB GB
1) Samuel Jayaraj, India - 1 set
2) Jacques Antoine, France - 1 set[
3) Patriz 1 set
4) nfsgame, Germany - 2 sets
5) baswamin, India - 2 sets
6)Thimios-2 sets(4 pcb)
7)ravid, India - 3 sets
8) BDL, Romania - 1 set
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