USSPA Build thread

fab

Member
Joined 2004
Paid Member
Group buy ended

Group buy is now finished and I have ordered the stereo pcbs.

Price description ($CAD):
Stereo pcb: 8$
Packaging: 1$
Shipment : depending of address and option

Payment by PayPal.
Please contact me by message and provide your home address so I can calculate shipment price. Provide also your personal email so I can send you the complete manual after payment.

Thank
Fab
 

fab

Member
Joined 2004
Paid Member
Hi
For the complete manual you need to buy the pcb as stated previously because it is a build manual ;)
There is enough information provided with the schematics including parts and value from this thread that you should know what to expect. If you have other specific questions then you can simply ask in this thread. It is a straightforward easy build :)

Fab
 
Hi
For the complete manual you need to buy the pcb as stated previously because it is a build manual ;)
There is enough information provided with the schematics including parts and value from this thread that you should know what to expect. If you have other specific questions then you can simply ask in this thread. It is a straightforward easy build :)

Fab

Yes thanks. The reason for the manual is I need to know regarding transistors matching criteria and options for the transistors if I could look for common type instead of the obsolete one.
 

fab

Member
Joined 2004
Paid Member
Hi
Input jfet can only be LSK/LSJ equivalent instead of 2SK/2SJ because Linear Sytems still produce parts. For USSPA1 there is no equivalent for obsolete mosfet but some members here still have them.
For USSPA2 the output bjt is still in current production so no issue here.
See below manual extract for active parts recommended matching.

Fab
 

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Hi.

Like to report usspa sound is reaching close to its optimal phase of break in.

The 3 dimensional aspects is stellar. Best one tried it throws out a huge stage with very rounded notes. Very musical, detailed and textured , like a very very expensive tube line stage i compared but i like this one better.my buddies all shocked to hear any kind of rock music with immensed 3 dimensional. Which some of you know its very very difficult to achieve even with very expensive preamplifier. Not much people likes rock in high end..it shows the worst of the system because its not easy to get it right . Best of all doesn't cost a bomb to build.

Its just so good that the other stuffs i have and spent much more sounded compressed and like mp3.. And digital.

I feel not much urge to try another design and will proceed to a balanced preamp with Darlington. And yes 2 usspa preamp for me. Thats how happy i am with the preamplifier

Thank you very much Fab for your designs and sharing such a wonderful preamplifier.
 

fab

Member
Joined 2004
Paid Member
You are welcome AnthonyA :)
This is quite a nice review of the USSPA. This is an excellent summary and I share your impressions since I listen to many kinds of music but more often to progressive rock music so it is usually difficult to get a realistic sound for that type of music...but it is fine with the USSPA.

I am expecting the USSPA new lot in about one week and I ordered a few extra boards in case ....;)

Fab
 
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Not to mention,

This preamplifier also checks the boxes on linearity.

The image just sizes linearly with volume. It mean it's a high quality design. And I have no problem to use it as a reference preamplifier.

Based on that.. I personally conclude Fab really knows his stuff and I personally rate him amongst the top designers. Thank you once again.
 
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Nice review, thanks for sharing Anthony!

Fab gets rave reviews from various experienced DIYer on various fora for all his designs... too many positive just to be a coincidence indeed :)

As of me, mmm, I look forward to his hopefully on the coming Class A/B developments, for sure a good match to this preamp or the Korg B1 hopefully

Claude
 
Hi Claude, glad to share. I'm very thankful for pinnocchio as well for sharing and it really helps me a lot in picking what I need. His reviews is both accurate and fun to read, at least to me.

I'm trying fab's class ab amp called fssa. Pinnocchio already tried it and he mentioned it's a good amplifier. Again can be capacitor free coupling like usspa. That is a huge huge advantage.

I'll let you know how that turns out.