u-sound
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yes....then again the 520 wont stop you thinking about the 725
Soulution 711
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Design Audio Video
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- Jul 6, 2013
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Yes the 725 is a definite upgrade over the 520. The picture of the back of that amp is a 710 not a 711
Design Audio Video
New member
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- Jul 6, 2013
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- Thread Author
- #64
From TAS review of 725, 711 and 701.
Is Soulution still advocating a high-speed, high-feedback approach to circuit design in amps and preamps? Or have you changed or improved upon your approach?
The audio sections of the 701/711 power amplifirs and the 725 preamplifir haven’t been changed. Their specifiations are still exactly the same as those of the older models. However, because of the large improvement in the “quality” of the supply voltages, the circuits are now better able to reveal their full potential.
Both the new and the old power amplifirs work with close to zero (0.1dB) global negative feedback (where we have just 1MHz of bandwidth of work with), but we use a lot of negative feedback in the local loops (where bandwidth goes up to 200MHz). The speed of the feedback loop is absolutely key for best sonic results.
In our original 700/710 amplifirs, voltage flctuations in the power supply to the power transistors of the output stage were compensated for by the global negative feedback loop. This worked quite effectively, although the feedback loop had to intervene more actively the higher the flctuations were. The 1MHz bandwidth of the global-feedback loop, usually considered very high compared to the audio bandwidth of 20kHz, turned out to be way too low not to have any sonic impact. This was exactly why we applied very little negative feedback in the global loop, although it also implied that every deviation that got corrected by this loop would have a sonic impact. By improving the performance of the power supplies in the 701/711 (and effectively eliminating voltage flctuations to the power transistors), we actually made the global feedback loop more or less redundant.
Is Soulution still advocating a high-speed, high-feedback approach to circuit design in amps and preamps? Or have you changed or improved upon your approach?
The audio sections of the 701/711 power amplifirs and the 725 preamplifir haven’t been changed. Their specifiations are still exactly the same as those of the older models. However, because of the large improvement in the “quality” of the supply voltages, the circuits are now better able to reveal their full potential.
Both the new and the old power amplifirs work with close to zero (0.1dB) global negative feedback (where we have just 1MHz of bandwidth of work with), but we use a lot of negative feedback in the local loops (where bandwidth goes up to 200MHz). The speed of the feedback loop is absolutely key for best sonic results.
In our original 700/710 amplifirs, voltage flctuations in the power supply to the power transistors of the output stage were compensated for by the global negative feedback loop. This worked quite effectively, although the feedback loop had to intervene more actively the higher the flctuations were. The 1MHz bandwidth of the global-feedback loop, usually considered very high compared to the audio bandwidth of 20kHz, turned out to be way too low not to have any sonic impact. This was exactly why we applied very little negative feedback in the global loop, although it also implied that every deviation that got corrected by this loop would have a sonic impact. By improving the performance of the power supplies in the 701/711 (and effectively eliminating voltage flctuations to the power transistors), we actually made the global feedback loop more or less redundant.
FlexibleAudio
Member
Good post; timely too. I have been contemplating the merits of upgrading my 721.
FlexibleAudio
Member
Yes Kev, I am making a snail look fast.
Odyssey
Member
Paul, when do you plan on doing the Torus Wall Mount install?
FlexibleAudio
Member
Le Roy, I have been out west skiing but I think it hit my dock in Elgin last week (it was supposed to). I will check when I go into the office Monday. I will get going in the next couple of weeks but again am not in a hurry because I am still lining up my vinyl as the next priority.
Paul,
It's been fun to watch your amazing audio journey. I guess my signature line is under construction too. I'm mostly swapping gear but it's really neat to see you methodically build your system from scratch.
Best,
Ken
FlexibleAudio
Member
Thanks Ken....just make sure you don't try to set your watch by my rate of progress; you will be late for work.:lol:
Paul,
LOL, but you'll get it right the first time. I actually got the idea to go for my Soulution 501's from watching you build your system, so I owe you a big thank you because they sound absolutely wonderful. They are lightning fast, have huge dynamics and amazing timbral purity. I can't wait to add a 520 in the signal chain and hear what that does.
Ken
LOL, but you'll get it right the first time. I actually got the idea to go for my Soulution 501's from watching you build your system, so I owe you a big thank you because they sound absolutely wonderful. They are lightning fast, have huge dynamics and amazing timbral purity. I can't wait to add a 520 in the signal chain and hear what that does.
Ken
MDP
Behavior Moderator (be nice police!)
Ken, you should hear how good your amps are on the D3's :exciting:
FlexibleAudio
Member
They are indeed remarkable.....all the goodness of tubes with speed, bass and control of SS. At night if you close your eyes they glow too!!
:lol:
- Thread Author
- #76
Some new pics and technical info.
711 uses 8 Sanken 2SC3519 and 8 2SA1386 bipolar output transistors pr side, each deliver up to 15A each.
That gives an absolute max output current of 120A.
711 is fast, slew rate rise time is 170V and fall time is 200V.
Damping factor in 8 ohm at 1kHz is around 5600 (halves in lower impedances) = a lot of local feedback is used.
Compared to D'Agostino Momentum Stereo:
It uses 6 Sanken 2SC6145A and 6 2SA2223A bipolar output transistors pr side, each deliver up to 15A each.
Max output is 90A.
Slew rate is slower at 80V, but it's fast compared to many other brands.
Damping factor is 53 because of only 5dB local feedback.
711 uses 8 Sanken 2SC3519 and 8 2SA1386 bipolar output transistors pr side, each deliver up to 15A each.
That gives an absolute max output current of 120A.
711 is fast, slew rate rise time is 170V and fall time is 200V.
Damping factor in 8 ohm at 1kHz is around 5600 (halves in lower impedances) = a lot of local feedback is used.
Compared to D'Agostino Momentum Stereo:
It uses 6 Sanken 2SC6145A and 6 2SA2223A bipolar output transistors pr side, each deliver up to 15A each.
Max output is 90A.
Slew rate is slower at 80V, but it's fast compared to many other brands.
Damping factor is 53 because of only 5dB local feedback.
the professor
Well-known member
Interesting comparison.
Thanks
Thanks
- Thread Author
- #78
Compared to two more:
Tidal Impulse Stereo:
It uses 4 Sanken 2SC2921 and 4 2SA1215 bipolar output transistors pr side, each deliver up to 15A each.
Max output is 60A.
Slew rate is 60V and damping factor is 400.
Wells Audio Innamorata Signature:
It uses 4 Toshiba 2SC5200 and 4 Toshiba 2SA1943 bipolar output transistors pr side, each deliver up to 15A each.
Max output is 60A.
Slew rate is ?, but damping factor is 200.
Tidal Impulse Stereo:
It uses 4 Sanken 2SC2921 and 4 2SA1215 bipolar output transistors pr side, each deliver up to 15A each.
Max output is 60A.
Slew rate is 60V and damping factor is 400.
Wells Audio Innamorata Signature:
It uses 4 Toshiba 2SC5200 and 4 Toshiba 2SA1943 bipolar output transistors pr side, each deliver up to 15A each.
Max output is 60A.
Slew rate is ?, but damping factor is 200.
- Thread Author
- #79
Compared to Accuphase:
A-70:
It uses 10 2SK3497 and 10 2SJ318 Mosfet output transistors pr side, each deliver continuous up to 10A each.
But unlike bipolar mosfet like heat. They can be used up to 150 degrees - if under it the mosfets can deliver up to 20A peak and 30A pulse power each.
Slew rate is ?, but damping factor is 800 means a lot of global feedback is used.
M-6000:
It uses 8 2SK3497 and 8 2SJ318 Mosfet output transistors pr side, each deliver continuous up to 10A each.
Slew rate is fast - rise time is 100V and fall time is 150V.
Residual noise which is not normal S/N specs on M-6000 is phenomenal -119,5dB.
On the older Soulution 710 not so good - unbalanced/balanced -113/-102dB.
A-70:
It uses 10 2SK3497 and 10 2SJ318 Mosfet output transistors pr side, each deliver continuous up to 10A each.
But unlike bipolar mosfet like heat. They can be used up to 150 degrees - if under it the mosfets can deliver up to 20A peak and 30A pulse power each.
Slew rate is ?, but damping factor is 800 means a lot of global feedback is used.
M-6000:
It uses 8 2SK3497 and 8 2SJ318 Mosfet output transistors pr side, each deliver continuous up to 10A each.
Slew rate is fast - rise time is 100V and fall time is 150V.
Residual noise which is not normal S/N specs on M-6000 is phenomenal -119,5dB.
On the older Soulution 710 not so good - unbalanced/balanced -113/-102dB.
FlexibleAudio
Member
I believe these are the ratings for the 710. The SMPS in the 711 significantly improved the noise floor. The web site failed to update this stat in the ratings spec on the site but added the following:
"Noisefloor reduced by SMPS Technologie
The noisefloor measurement of the 710 stereo*amplifier clearly shows the in*fluence of the big toroidal trans*formers. Despite massive shielding of these trans*formers thte magnetic fields could cound induce noise arte*facts with amplitudes of -100dBr compared to the music signal. This is "state of the art" although it would be better to not have any noise artefacts at all. With our new SMPS based power supply we could significantly reduce this impact. The noise*floor measurements shows as well that the SMPS modules do not emmit any residual noise. A clear improvement!"
Noisefloor for 710 Stereoamplifier
Noisefloor for 711 Stereoamplifier
The 701 noise floor is claimed to be -160 db; the 711 is not not too far behind that (cross talk aside).
