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USSA-5 PCB GB

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M

meanie

Member
Joined 2018
Hi Fab,

I hope to buy the correct pcb version that uses transistor output, as i already has the Mosfet version.

meanie - 2 pcs (BJT)
Vunce - 2 pcs (BJT 5.1)
Brianco - 2 pcs (any colour)
boba1000 - 2 pcs
FAA - 2 pcs
Funke - 2 pcs
gary s - 2 pcs (any colour)

Running Total = 14 pcs.


Thanks
 
fab

fab

Member
Joined 2004
fabaudio.online
Paid Member
Hi Meanie
The original version 5.0 and the new one 5.1 use the same pcb version. In fact the bjt driver has the same pin out and only resistors value are changed. If you look at my board it is latest current version of the pcb. For clarification the change Between versions 5 and 5.1 is the driver type (since these mosfet drivers are hard to find and require matching) but not the output transistors. Doing a bjt output would be another USSA-x and the actual pcb would not fit because lateral mosfet has a different pin out than darlington bjt. Could be interesting project like the difference between USSA1 and USSA-B I did in the past...:rolleyes:

The version 5.1 board with bjt drivers:
USSA-5 Build with Review

Fab
 
Last edited:
fab

fab

Member
Joined 2004
fabaudio.online
Paid Member
Glad you still want to try it Meanie :) I need someone to compare sound between USSA5 and USSA5.1.
Since I normally order a few more pcb than requested then I could spare one pcb to try to build a complete bjt version (except the jfet current sources)....:rolleyes:
I would need to reverse the output pins though and Temperature compensation is more challenging with that topology using bjt but I succeeded with USSA-B...

Fab
 
fab

fab

Member
Joined 2004
fabaudio.online
Paid Member
Just a reminder to read 1st post. Again, if you do not intend for sure to build the amp within one year then please do not register here to buy pcb. I am not a pcb seller and I do want to waste my time for that. Time is precious for everybody:D I only want to share my amp with others :)

Thanks for your understanding.
Fab
 
G

gary s

Member
Joined 2002
A question to any member who has done a previous build on the pcb. Has anyone a preferred type for input capacitor C2 (4.7uF) or indeed listened to different types at this position.

fab, has indicated to me that one should use a good quality cap here. Probably not room on the board for many of the "exotic" type caps, but could be mounted off board. Very interested in any opinions here.
 
B

boba1000

Member
Joined 2005
Pieces of the puzzle

All my transistor are ordered. The profusion outputs are already here. Just waiting for the circuit boards and final assembly instructions. Can't wait!! I am working on a Pass f6 at the moment. Working on the case for this project. I wonder which will sound better with Edgarhorns speakers I built years ago or the Zu audio dirty weekend omen speakers that I just ordered.
 
ggetzoff

ggetzoff

Member
Joined 2004
gary s said:
A question to any member who has done a previous build on the pcb. Has anyone a preferred type for input capacitor C2 (4.7uF) or indeed listened to different types at this position.

fab, has indicated to me that one should use a good quality cap here. Probably not room on the board for many of the "exotic" type caps, but could be mounted off board. Very interested in any opinions here.
Click to expand...

Gary,

As you can see my build uses the Sonicap Gen I, a large “boutique” cap. There’s plenty of room on the pad for medium sized film caps. All kinds of options with that kind of room. The CDE940 (5984-940C6W4P7K-F) or 936 series caps compete equally with overpriced boutiques and Mouser carries them.

Cheers,

Greg
 
Z

zman01

Member
Joined 2011
boba1000 said:
All my transistor are ordered. The profusion outputs are already here. Just waiting for the circuit boards and final assembly instructions. Can't wait!! I am working on a Pass f6 at the moment. Working on the case for this project. I wonder which will sound better with Edgarhorns speakers I built years ago or the Zu audio dirty weekend omen speakers that I just ordered.
Click to expand...

boba1000,

Good to know that you're making progress on the project.

Do you have the case and toroidal transformers already ordered? What power supply are you planning to use?
 
fab

fab

Member
Joined 2004
fabaudio.online
Paid Member
Confirmation of your order please

I will be ordering shortly, please confirm again your commitment to buy a pair of pcbs and also to build the amp within less than one year.

meanie - 2 pcs (BJT)
Vunce - 2 pcs (BJT 5.1)
Brianco - 2 pcs (any colour)
boba1000 - 2 pcs
FAA - 2 pcs
Funke - 2 pcs
gary s - 2 pcs (Toshiba mosfet drivers) (any colour)

Running Total = 14 pcs.

Thanks
Fab
 
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