Oh well . It's alive .
Fab .
First impression .
It's similar but different
Usspa 2
More zing and grunge.
More muscle
Less delicate and smooth less airy .
More bass especially upper bass
Better for jazz .rock .
More slow and heavy .which bring out the swing and groove.
3d . Stage ..is there . But I think there is a slight difference in stage size and presentation .will see later
Quite similar to the impression I got from my friend
Input change to 100p that's a good move .more lively
I like it ! Good to have both.
I'll have more in a month or two .
Chiao
Fab .
First impression .
It's similar but different
Usspa 2
More zing and grunge.
More muscle
Less delicate and smooth less airy .
More bass especially upper bass
Better for jazz .rock .
More slow and heavy .which bring out the swing and groove.
3d . Stage ..is there . But I think there is a slight difference in stage size and presentation .will see later
Quite similar to the impression I got from my friend
Input change to 100p that's a good move .more lively
I like it ! Good to have both.
I'll have more in a month or two .
Chiao
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Hi AnthonyA
Thanks for the feedback.
Looking forward to hearing your next review in a month or two🙂
Fab
Thanks for the feedback.
Looking forward to hearing your next review in a month or two🙂
Fab
Lt1963/3015
Wider deeper higher Soundstage. No frills. Smoother sound
Studer 900 more mascular. Hint of pro audio sound. If u use this... Pre burn in 72 hrs before final setting. Sound a touch quieter
200ma per channel
Thanks for sharing the PSU differences with USSPA2. Ensure you have completed the USSPA2 “full” breakin period before your test evaluation.
Fab
Fab
OK! About 200 hours of burn in.
I plug into the more clearer and better system (I got 2 listening areas) to have a listen. I'm familiar with the setup so should be decent review
the initial impressions is correct.
Just additional note.
The depth is clearer with usspa 1
Sound is neater and true with usspa 1 better instrument distance
Width usspa 1 better
If after accuracy clarity smoothness .listen to classical and acoustics alot. Version 1
If after grunt. body and weight, listen to more rock. Audiophile version 2. If room is small this will shine more (3m wide or shorter)
If you ask me which is more special.. Usspa 1 is more hi end, the wall dissappear more in a bigger room
Also.. Lt 1963 is still champion. Sounds better.
Last note.. 18v is slightly better than 15v
I plug into the more clearer and better system (I got 2 listening areas) to have a listen. I'm familiar with the setup so should be decent review
the initial impressions is correct.
Just additional note.
The depth is clearer with usspa 1
Sound is neater and true with usspa 1 better instrument distance
Width usspa 1 better
If after accuracy clarity smoothness .listen to classical and acoustics alot. Version 1
If after grunt. body and weight, listen to more rock. Audiophile version 2. If room is small this will shine more (3m wide or shorter)
If you ask me which is more special.. Usspa 1 is more hi end, the wall dissappear more in a bigger room
Also.. Lt 1963 is still champion. Sounds better.
Last note.. 18v is slightly better than 15v
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Hi AnthonyA
Thanks for sharing. Can you confirm that only the output transistors (with some resistors value changes) are different and the rest is the same for a fair comparison.
Fab
Thanks for sharing. Can you confirm that only the output transistors (with some resistors value changes) are different and the rest is the same for a fair comparison.
Fab
The caps also I had one set of poly and 10uf bypass smd at breakoff so should be fairly similar just some difference in tone, supply is also similar . Solder also similar .
Usspa 1 is more overview we see everything
Usspa 2 is more spotlight you feel into the music more
Does that make sense to you?
Usspa 1 is more overview we see everything
Usspa 2 is more spotlight you feel into the music more
Does that make sense to you?
Hi Anthony,
Nice builds and interesting finds. I've assembled two USSPA v1 and absolutely love them! One of them using a Tortuga Audio LDR3x volume attenuator and another one using AMB's R2R volume and source selector. All using Sigma 22 PSUs. I haven't tried any other PSUs but I was curious about the Studer...
All the best!
Do
Nice builds and interesting finds. I've assembled two USSPA v1 and absolutely love them! One of them using a Tortuga Audio LDR3x volume attenuator and another one using AMB's R2R volume and source selector. All using Sigma 22 PSUs. I haven't tried any other PSUs but I was curious about the Studer...
All the best!
Do
Dominic,
Studer.. I won't recommend the kit.. Not very stable. Sound is ok. Sound wise.. It's not better than LT.
I much prefer your recommendation of Sigma22. That's still worth the effort VS musicality.
Also I'm building walt jung super regulator just to take a look. But ad817 based.. I hate tweaking and going round and round.. Just some surefire method.
Studer.. I won't recommend the kit.. Not very stable. Sound is ok. Sound wise.. It's not better than LT.
I much prefer your recommendation of Sigma22. That's still worth the effort VS musicality.
Also I'm building walt jung super regulator just to take a look. But ad817 based.. I hate tweaking and going round and round.. Just some surefire method.
Build alternatives that works besides the BOM
Our 2 cents.
Gate resistors carbon film
Voltage resistors {4.7 and 10 ohm} mox
Feedback resistor 22 ohm 150 ohm carbon film
Output R 100 resistors carbon
Input filter 220pf. For sanken use 100pf polystyrene or silver mica. Polystyrene works best.
Match your resistors
Result in much more bloom and musical. Similar to tubes more warm and Airy, thicker mids, natural hi if that's your taste.
Original parts more accurate cleaner tone.
Power supply recommended
Lt 1963/3015
Lm723 types
Sigma 22
Havent tried but walt super regulator should be great. Building now.
Use only good quality leaded solder without silver. Soldering temp 330 to 350 deg c, very important with temperature.. Over that it sound bleached out. Under that sound sharp and vague.{we had others made this mistake}. Wait at least 450 hours to see good results. It's how it eventually sounds thats important. We seem many case this turn to crap.
Try to use a bigger heat sink!
Bias it 130ma and higher. More smooth and airy. Max 200 ma so far no issues, everything will sound fuller.
If build more than 1.. If you want something different and more tube like . This is alternative.
Most important have fun
Our 2 cents.
Gate resistors carbon film
Voltage resistors {4.7 and 10 ohm} mox
Feedback resistor 22 ohm 150 ohm carbon film
Output R 100 resistors carbon
Input filter 220pf. For sanken use 100pf polystyrene or silver mica. Polystyrene works best.
Match your resistors
Result in much more bloom and musical. Similar to tubes more warm and Airy, thicker mids, natural hi if that's your taste.
Original parts more accurate cleaner tone.
Power supply recommended
Lt 1963/3015
Lm723 types
Sigma 22
Havent tried but walt super regulator should be great. Building now.
Use only good quality leaded solder without silver. Soldering temp 330 to 350 deg c, very important with temperature.. Over that it sound bleached out. Under that sound sharp and vague.{we had others made this mistake}. Wait at least 450 hours to see good results. It's how it eventually sounds thats important. We seem many case this turn to crap.
Try to use a bigger heat sink!
Bias it 130ma and higher. More smooth and airy. Max 200 ma so far no issues, everything will sound fuller.
If build more than 1.. If you want something different and more tube like . This is alternative.
Most important have fun
Just for fun and for a bit of praticing doing board layouts I've done my (virtual) version of the USSPA... With LDOVR.com LT3045/LT3094 onboard and MELF-resistors - mounted on both sides of the board and with clear PGND-area and SGND-star. Boardsize 76,2cm x 69,2cm 
(no, I won't provide production files...)
(no, I won't provide production files...)
Attachments
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Comparison of 3 types of diy preamp topology
1st 5687 tube
5687 tube preamplifier - YouTube
2nd korg b1
Korg b1 - YouTube
3rd Usspa2
Usspa2 - YouTube
Couple of friends say. Single ended tubes are the best..
Let's compare. What's your take on it
All 3 preamplifier have passed the reviews. Which mean they are all at least good enough.
1st 5687 tube
5687 tube preamplifier - YouTube
2nd korg b1
Korg b1 - YouTube
3rd Usspa2
Usspa2 - YouTube
Couple of friends say. Single ended tubes are the best..
Let's compare. What's your take on it
All 3 preamplifier have passed the reviews. Which mean they are all at least good enough.
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It's system dependant as well.
If the source is sub par.. Korg B1 will sound better, it's also very interesting because controlling the H2 can control Alot of sound character. Example neg 1.h2. Darkest background, deepest stage. It will make a bland system sound better. My buddy made a 2 stage single ended jfet.. Guess what... Very similar basically to korg B1 and B1. To a certain extend it shapes the sound but 1 pick korg B1 for this topology as flexibility to change H2 easily
But if source is good... Usspa is better, As it doesn't really impart a much of a color of its own. Highest bandwidth dymanic range. It's the least boring to listen to in the long run. And it have a wow.. I never hear this detail in the recording factor. It's like bareback horse riding you feel everything, it throws the hugest image which is a plus for me
Both is better for me than tubes only. The advantage is the triode character.. Which is only good for softening up a stiff sounding system..I get bored and won't last long in rotation
If the source is sub par.. Korg B1 will sound better, it's also very interesting because controlling the H2 can control Alot of sound character. Example neg 1.h2. Darkest background, deepest stage. It will make a bland system sound better. My buddy made a 2 stage single ended jfet.. Guess what... Very similar basically to korg B1 and B1. To a certain extend it shapes the sound but 1 pick korg B1 for this topology as flexibility to change H2 easily
But if source is good... Usspa is better, As it doesn't really impart a much of a color of its own. Highest bandwidth dymanic range. It's the least boring to listen to in the long run. And it have a wow.. I never hear this detail in the recording factor. It's like bareback horse riding you feel everything, it throws the hugest image which is a plus for me
Both is better for me than tubes only. The advantage is the triode character.. Which is only good for softening up a stiff sounding system..I get bored and won't last long in rotation
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