USSA-5 Build with Review

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poseidonsvoice

poseidonsvoice

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Joined 2004
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Ernst,

I wouldn’t discount the Sigma 22. Understand that it is used in AMB’s own preamp designs and particularly for the input/driver stage of the excellent B24 amplifier that Do has built as well. It’s well designed although better suited for higher currents but under 1A continuous. In addition, the online instructions are excellent.

Other options include:

Jan Didden’s Linear Audio Silent Switcher Mk II (Linear Audio Silent Switcher MkII – diyAudio Store)

AMB’s Sigma 78 and 79 along with their companion CRC boards (The σ78 and σ79 ultra low noise voltage regulators)

LDOVR (http://www.ldovr.com), he participates on the Vendor forum here.

and others...

Other than AMB’s Sigma 22, they are all applications of the Texas Instruments TPS7A series...

Best,
Anand.
 
Last edited:
T

tomtest

Member
Joined 2018
poseidonsvoice said:
Ernst,

I wouldn’t discount the Sigma 22. Understand that it is used in AMB’s own preamp designs and particularly for the input/driver stage of the excellent B24 amplifier that Do has built as well. It’s well designed although better suited for higher currents but under 1A continuous. In addition, the online instructions are excellent.

Other options include:

Jan Didden’s Linear Audio Silent Switcher Mk II (Linear Audio Silent Switcher MkII – diyAudio Store)

AMB’s Sigma 78 and 79 along with their companion CRC boards (The σ78 and σ79 ultra low noise voltage regulators)

LDOVR (http://www.ldovr.com), he participates on the Vendor forum here.

and others...

Other than AMB’s Sigma 22, they are all applications of the Texas Instruments TPS7A series...

Best,
Anand.
Click to expand...

Hi Anand,

I think the Linear Audio Silent Switcher Mk II from Jan Didden is a really interesting device, but I'm afraid it is not strong enough.
“Primary output: Your choice of ±15V, ±12V, ±8V or ±5V at 150ma. Jan has posted some notes detailing how ±18V (at 100ma) and ±24V (at 50ma) are also possible if you add your own resistors. ”

And Fabs suggestion is:
“Power supply requirements (for 2 channels) Well regulated Voltage: +/- 12v to +/- 15vdc (with heatsink shown). Use very good PSU here since PSRR of CFA topology is not that good. Current: >= 1A to be on the safe side. ”

So if I interpret it correctly, we should use a power supply which could deliver more then 500mA for each channel (dual mono).

Greetings,
André
 
maty tinman

maty tinman

Member
Joined 2012
nauscopio.wordpress.com/about/
Other options, with a graph, are the regulators made/sell by Aleksandar (ATL Audio). Two PCB or assembled and tested. From Bulgary (EU).

Modified Sulzer Regulator – assembled and tested | ATL Audio Ltd.

ATL-Hifi Sulzer modified regulator

ATL-Hifi-Sulzer-modified-regulator.jpg


ATL-Hifi Sulzer 15V 375mA OP37 graph

ATL-Hifi-Sulzer-15V-375mA-OP37-graph.jpg


[Big IMG, link] http://maty.galeon.com/WP-imagenes/hard/ATL-Hifi-Sulzer-15V-375mA-OP37-graph.jpg

On the picture below can be seen Regulator’s measured performance with output voltage 15V, 40 Ohm load (375 mA load current)

For the tests was used a 35VA toroidal transformer with two secondary windings; soundcard used – E-MU 0404.

The regulator is offered with the following standard output voltages: 9V, 12V, 15V, 18V, 24V.
Click to expand...
 
Last edited:
T

tomtest

Member
Joined 2018
poseidonsvoice said:
Ernst,

I wouldn’t discount the Sigma 22. Understand that it is used in AMB’s own preamp designs and particularly for the input/driver stage of the excellent B24 amplifier that Do has built as well. It’s well designed although better suited for higher currents but under 1A continuous. In addition, the online instructions are excellent.

Other options include:

Jan Didden’s Linear Audio Silent Switcher Mk II (Linear Audio Silent Switcher MkII – diyAudio Store)

AMB’s Sigma 78 and 79 along with their companion CRC boards (The σ78 and σ79 ultra low noise voltage regulators)

LDOVR (http://www.ldovr.com), he participates on the Vendor forum here.

and others...

Other than AMB’s Sigma 22, they are all applications of the Texas Instruments TPS7A series...

Best,
Anand.
Click to expand...

Hi Anand,

I think the Linear Audio Silent Switcher Mk II from Jan Didden is a really interesting device, but I'm afraid it is not strong enough.
“Primary output: Your choice of ±15V, ±12V, ±8V or ±5V at 150ma. Jan has posted some notes detailing how ±18V (at 100ma) and ±24V (at 50ma) are also possible if you add your own resistors. ”

And Fabs suggestion is:
“Power supply requirements (for 2 channels) Well regulated Voltage: +/- 12v to +/- 15vdc (with heatsink shown). Use very good PSU here since PSRR of CFA topology is not that good. Current: >= 1A to be on the safe side. ”

So if I interpret it correctly, we should use a power supply which could deliver more then 500mA for each channel (dual mono).

Greetings,
André
 
Project16

Project16

Member
Joined 2012
Hi everybody

I will take some pictures of two power supply that I will try on the USSPA soon, I also drew my layout of the UltraBib by Salas.

If you feel like it, here are some tracks to get the most out of the USSA-5. :D
More seriously I found some music tracks that I had created a few years ago on FL Studio, it's special but listenable I think.
Project16's profile on Clyp


;)
 

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poseidonsvoice

poseidonsvoice

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Joined 2004
audiocircle.com/gallery/index.php?cat=48485
Paid Member
tomtest said:
Hi Anand,

I think the Linear Audio Silent Switcher Mk II from Jan Didden is a really interesting device, but I'm afraid it is not strong enough.
“Primary output: Your choice of ±15V, ±12V, ±8V or ±5V at 150ma. Jan has posted some notes detailing how ±18V (at 100ma) and ±24V (at 50ma) are also possible if you add your own resistors. ”

And Fabs suggestion is:
“Power supply requirements (for 2 channels) Well regulated Voltage: +/- 12v to +/- 15vdc (with heatsink shown). Use very good PSU here since PSRR of CFA topology is not that good. Current: >= 1A to be on the safe side. ”

So if I interpret it correctly, we should use a power supply which could deliver more then 500mA for each channel (dual mono).

Greetings,
André
Click to expand...

Andre,

Thanks. I guess the one question to Fab really is what the actual current draw of the USSPA circuit really is? It's understood that most CFA circuits have poorer PSSR than VFA circuits. It seems his advice is a suggestion, but the actual current draw seems to be an unknown? :goodbad:

That being said, there seems to be loads of options on the market for the diy'er. I particularly like XRK's simple cap-mx design as it is measured and documented.

Have fun!

Best,
Anand.
 
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Project16

Project16

Member
Joined 2012
Initially I made this layout based on the RJM regulator shunt for the Kuartlotron with pre-regulator TL431 but I will try it in 12V dual mono version on the USSPA.
A power supply of type regulator series with pre-regulator is also in manufacture that I will try also on the USSPA.
I will inform you soon about my tests.


;)
 

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fab

fab

Member
Joined 2004
fabaudio.online
Paid Member
USSPA PSU

poseidonsvoice said:
Andre,

Thanks. I guess the one question to Fab really is what the actual current draw of the USSPA circuit really is? It's understood that most CFA circuits have poorer PSSR than VFA circuits. It seems his advice is a suggestion, but the actual current draw seems to be an unknown? :goodbad:
.....

Best,
Anand.
Click to expand...
Hi Anand and all
The current consumption is the output bias and input stage current. Input stage current is low compared to output stage. The schematics states 50-60ma output bias minimum for USSPA1 for one channel but can be set higher if desired.
I simply put 1A max psu since it is easy obtain and you can operate in the best operation current for even better performance of the psu. You can also go lower current for psu if the performance is really good.

Fab
 
poseidonsvoice

poseidonsvoice

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Fab,

Thanks for clarifying.

If you look at this link (The SilentSwitcher | Linear Audio NL) and scroll to the bottom, the performance of the Silent Switcher is revealed. Perhaps in a future iteration, Jan will design in more current capabilities at +/- 15V dc. That being said, Jan does say:

The current limits (150mA at the +/-15V and 0.5A at the 6/5/3.3V simultaneously) are such that they can be used with a standard 5V/2.1A USB charger. However, if you use for instance batteries or a wallwart delivering 9V at 2A, the available output currents are doubled.
Click to expand...

Instruction manual: https://linearaudio.nl/sites/linearaudio.net/files/customizing user guide r2.pdf

Best,
Anand.
 
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poseidonsvoice

poseidonsvoice

Member
Joined 2004
audiocircle.com/gallery/index.php?cat=48485
Paid Member
ClaudeG said:
Nice build Fab... As ever dare I say

What volume controller (I believe to see a ladder potentiometer, but what about Muses chip or LDR or else?) and source selection would you consider worthy to your pre-amp module?

Keep on rolling and enjoy music

Claude
Click to expand...

That looks like a Khozmo to my eyes...

Best,
Anand.
 
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