DIY - USSA-5 Class A Power amplifier

Wharfedale Diamond 12 Series

manniraj

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Got inspired with so many DIY build threads, so let me also start another one which I built some time back. This is the USSA-5 class A power amplifier from the "fab" member of the diyaudio.com forum. Here is the link to the thread - https://www.diyaudio.com/forums/solid-state/323778-ussa-5-build-review.html. I got the PCB boards along with couple of other forum members I guess in the year 2018 and then the matched lateral mosfets of Exicon. This one uses matched original Toshiba 2SK2013/313 driver stage mosfets. Fab provides an excellent build guide for the members who buy the PCB boards in his group buy.

With so many good reviews and me being a pure Class A guy wanted to go all out and blinked to build a dual mono. Initially in a single chassis used pair of toroidal transformers and pair of Prasi (another member of diyaudio) CRC psu boards with LT4320 regulators and 22000uf 63v CD caps. The psu build was a bomb considering the regulators which are like $12 or so each and then low noise power mosfets 8 of them on each board. Did not expect the cost but worth it considering how the amp plays :)

Was running this amp dual mono in a single chassis but the heat was too much to handle using 300/150/83 perfect metal heat sinks with Nishant cabinet. I have biased it pretty high around 1.3A, so in a single chassis I can cook omelettes easily ;)

Then decided to make pure mono blocs and back to Nishant for the cabinets, with my requirements he came up with a simple design using the same sized heat sinks of perfect metals, Pune. Because of the lockdown and other issues the cabinets build took many months and thanks to Nishant to pursue my patience as I was anyway into other builds. More than a month or so I finally received the mono blocs from Nishant and started to finish the USSA-5. As you guys would have seen that Sadik built my Troels Gravesen TQWT MKii speakers and I was running them with my all time favourite amp Nelson Pass Sony VFET-2 :)

I love my USSA-5 in mono blocs and it makes Troels to sing beautifully paired with my Korg Nutube buffer. Do not ask me for the comparison of USSA-5 to VFET-2 as there is not much of a difference and each has its own flavour, with VFET being very sweet sounding and it will cover the flaws coming from the downstream. But the USSA-5 is brutal anything bad source/preamp it just shows up immediately, so you need to be very careful with USSA-5. But it does make some of the best music that you can ever hear with every musical instrument sounding precisely and lively. I get to hear the deep sound stage, concert like feeling with dead silent and pitch background and what ever superlatives you want to add ;)

I am waiting for my RCORE transformers rated 12v for the speaker protection module as currently using generic EI core which after an hour of playback starts making its own music :p

Enough of the blabbering, here are some of the build pictures which I took and not many pics as I usually build in the night when everyone sleeps and I have a peaceful time.















Thanks for hearing me out.
 

Hiten

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GM
Thats professional work ! Enclosure also well made. Nice system too. Well done.
Regards
 

Beginner_N

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Oct 10, 2014
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Pune
Then decided to make pure mono blocs and back to Nishant for the cabinets, with my requirements he came up with a simple design using the same sized heat sinks of perfect metals, Pune. Because of the lockdown and other issues the cabinets build took many months and thanks to Nishant to pursue my patience as I was anyway into other builds. More than a month or so I finally received the mono blocs from Nishant and started to finish the USSA-5.
Thanks for the patience throughout this build. Really appreciate it. Great part was you never pushed me for delivery.

Now waiting for your other build of VU meter power amplifier

Regards
 

arunkvivek

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Looks lovely and Amazing! Good for us FMs if you continue on the build spree. We can snap them from you if you run short of space.
 

manniraj

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Looks lovely and Amazing! Good for us FMs if you continue on the build spree. We can snap them from you if you run short of space.
Thanks Arun, PM me and you might get a surprise one ;)

Slight correction from my first post, the heat sinks which I used are from Akash metals, Pune and not Perfect metals Bangalore. Thanks to Nishant to procuring these as getting 2-4 pieces is a pain from them.

Thanks

Its really good to see more and more actual DIY threads in DIY section. Its a Beauty Bro.
Thanks Sadik, you are the flag bearer of the DIY :)
 

Bizi05

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Joined
Nov 7, 2016
Messages
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Points
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Location
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Got inspired with so many DIY build threads, so let me also start another one which I built some time back. This is the USSA-5 class A power amplifier from the "fab" member of the diyaudio.com forum. Here is the link to the thread - https://www.diyaudio.com/forums/solid-state/323778-ussa-5-build-review.html. I got the PCB boards along with couple of other forum members I guess in the year 2018 and then the matched lateral mosfets of Exicon. This one uses matched original Toshiba 2SK2013/313 driver stage mosfets. Fab provides an excellent build guide for the members who buy the PCB boards in his group buy.

With so many good reviews and me being a pure Class A guy wanted to go all out and blinked to build a dual mono. Initially in a single chassis used pair of toroidal transformers and pair of Prasi (another member of diyaudio) CRC psu boards with LT4320 regulators and 22000uf 63v CD caps. The psu build was a bomb considering the regulators which are like $12 or so each and then low noise power mosfets 8 of them on each board. Did not expect the cost but worth it considering how the amp plays :)

Was running this amp dual mono in a single chassis but the heat was too much to handle using 300/150/83 perfect metal heat sinks with Nishant cabinet. I have biased it pretty high around 1.3A, so in a single chassis I can cook omelettes easily ;)

Then decided to make pure mono blocs and back to Nishant for the cabinets, with my requirements he came up with a simple design using the same sized heat sinks of perfect metals, Pune. Because of the lockdown and other issues the cabinets build took many months and thanks to Nishant to pursue my patience as I was anyway into other builds. More than a month or so I finally received the mono blocs from Nishant and started to finish the USSA-5. As you guys would have seen that Sadik built my Troels Gravesen TQWT MKii speakers and I was running them with my all time favourite amp Nelson Pass Sony VFET-2 :)

I love my USSA-5 in mono blocs and it makes Troels to sing beautifully paired with my Korg Nutube buffer. Do not ask me for the comparison of USSA-5 to VFET-2 as there is not much of a difference and each has its own flavour, with VFET being very sweet sounding and it will cover the flaws coming from the downstream. But the USSA-5 is brutal anything bad source/preamp it just shows up immediately, so you need to be very careful with USSA-5. But it does make some of the best music that you can ever hear with every musical instrument sounding precisely and lively. I get to hear the deep sound stage, concert like feeling with dead silent and pitch background and what ever superlatives you want to add ;)

I am waiting for my RCORE transformers rated 12v for the speaker protection module as currently using generic EI core which after an hour of playback starts making its own music :p

Enough of the blabbering, here are some of the build pictures which I took and not many pics as I usually build in the night when everyone sleeps and I have a peaceful time.















Thanks for hearing me out.
Nice build. I believe both unit at top left cabinet are Soekris R2R DAC
 
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