The fasterst Sansui amp known to man

[JOMARK911]

Also bare in mind that slew rate's value increases along with amp's power. Greater power , greater slew rate. It has to do with the time in μsecs. So au d11's slew rate and rise time don't quite equate one another. There is a relation between them and one can be derived from the other.

 

[DVNOBLE]

The greatest slew rate belongs to b 2301l b 2302. 350 v/μ sec.

Hello Jomark! I have doubts whether the value of 350v/us reported in 2301/2302 is the internal or external .....
You have the power to raise the b2301/b2302 waveform to 200kHz in order to compare the waveforms?
The test can to 1watt of power not to risk the device.

 

[ConradH]

A new record? 10 year old thread back from the dead! I'm working on a 919 right now that has a mysterious HF distortion problem from some previous service work. IMO, all that was said above concerning high slew rate is right. Beyond a certain point it just introduces stability problems and has no audible benefits. If you want to eliminate TIM (probably not a problem anyway) just limit the incoming signal bandwidth to something reasonable.

I find it very interesting that the service manual for the 919 actually suggests the final installation be checked with an oscilloscope for oscillation. How many customers will do that?

Somebody put a 3-wire line cord on this particular unit. When you have this kind of bandwidth, creating a ground loop is a good way to destroy the thing.

FWIW, you could put a long wire on these amps and use them to broadcast AM radio signals, albeit at a fairly low level. Just plain silly, but I will grant that when everything is working right, they sound very good. Do they sound any different from any other amp of similar power with the same low THD in the audio bandwidth? Probably not, though you'd have to double blind the test to be sure.

One other comment- Sansui seemed to have tried various configurations for tone controls, not all of which are flat when the controls are zeroed. Sometimes surprisingly not flat! If you want flat, use the defeat switch.

 

[DVNOBLE]

Also bare in mind that slew rate's value increases along with amp's power. Greater power , greater slew rate. It has to do with the time in μsecs. So au d11's slew rate and rise time don't quite equate one another. There is a relation between them and one can be derived from the other.

Not always the slew rate increases with power, look at the case of KR-9050 (110v/us) 200Watts and the KR-8050 (200V/US) 120Watts.
The slew rate of "output" depends on the stabilization of the circuit and transistor output. If the circuit does not stabilize the frequency bandwidth has to be limited at the input of the amplifier and consequently the slew rate will fall. I think that was what happened with the KR-9050 it only stabilized at 200watts with a slew rate of 110v/us. I think it was originally designed to 200V/us. This is a curious case in which the top is slower than the downline. Quoting G-22000 and G-33000 The slew rate is the same 170v/us.

The more potent harder to stabilize. It's easy to build a powerful and slow amp, the same way that is easy to build low power and fast. It's like building a car engine: In a powerful engine is difficult to achieve a high speed .... but it is easy to get high speed at low power.

 

[onwardjames]

A new record? 10 year old thread back from the dead! I'm working on a 919 right now that has a mysterious HF distortion problem from some previous service work. IMO, all that was said above concerning high slew rate is right. Beyond a certain point it just introduces stability problems and has no audible benefits. If you want to eliminate TIM (probably not a problem anyway) just limit the incoming signal bandwidth to something reasonable.

I find it very interesting that the service manual for the 919 actually suggests the final installation be checked with an oscilloscope for oscillation. How many customers will do that?

Somebody put a 3-wire line cord on this particular unit. When you have this kind of bandwidth, creating a ground loop is a good way to destroy the thing.

FWIW, you could put a long wire on these amps and use them to broadcast AM radio signals, albeit at a fairly low level. Just plain silly, but I will grant that when everything is working right, they sound very good. Do they sound any different from any other amp of similar power with the same low THD in the audio bandwidth? Probably not, though you'd have to double blind the test to be sure.

One other comment- Sansui seemed to have tried various configurations for tone controls, not all of which are flat when the controls are zeroed. Sometimes surprisingly not flat! If you want flat, use the defeat switch.

point #1 - almost certainly a contendahh!

point #2 - Interesting. Could you elaborate on why a 3 prong plug/ground loop is bad? I'm a non-techie.

 

[JOMARK911]

Yes you can build a powerful amp and fast too. Provided you have a good design , and utilising ultra fast semiconductors, for drivers and output stage. 2301's output devices go as high as 35mhz? I don't remember now. You are right about the 22k and 33k though. This is the case also for 2201, 2301.
2301's slew rate was checked at the rep's service center here in Greece , back in 1987 and it truly refers to external , slew rate , at the speakers terminal. This amp goes as high as 300khz, limited by the factory. If it wasn't stopped it would gone right to am broadcasting.

 

[vigman]

Ok all this being said… who has a tweeter that can go to 50KHZ FLAT let alone what these amps can do, seems like a 1000 hp engine with small pep boy's tires on it… make a lot of noise N smoke but can't get the HP to the ground ( or speaker in this case )…
Not to mention the bandwidth limiting of the input source. What album ( or digital recording ) has USEFUL information @ 30khz ?

 

[ConradH]

Expanding on the line cord issue, If something else in the system has a 3-wire cord, you can get competing ground paths, IOW, a ground loop. Usually this just affects hum levels, but when you have very high bandwidth components you can also get high frequency oscillation. I think the service manual has a caution about making any extra ground connections between components, though I don't remember at this point. Reading between the lines, they knew full well the amps were prone to oscillation if not hooked up properly. Hey, if you're a bat wanting a sound system for your cave, these are the amps to have!

 

[JOMARK911]

Ok all this being said… who has a tweeter that can go to 50KHZ FLAT let alone what these amps can do, seems like a 1000 hp engine with small pep boy's tires on it… make a lot of noise N smoke but can't get the HP to the ground ( or speaker in this case )…
Not to mention the bandwidth limiting of the input source. What album ( or digital recording ) has USEFUL information @ 30khz ?

You should sony's super tweeters, at ssm9ed. UP to 100khz.
Tanoy's also. SEAS tweeters also go up to 50 kHz. And there are more.
Usefull or not , the information is there and called upper harmonics. What's the , drums , metal plates called? fucibals? and so on.
The point though is not the content in the albums , analog or digital. There are quite a few mc cartriges that go to 100khz. Super audio as a media does it too.
The point in all this is high speed amplifiers.Apart from dynamics and other stuff , the faster the amp the more natural reproduction we get. THat is of course if the speakers can keep up. Most of the time they don't . But there are some that they do. And they do it nice.

 

[DVNOBLE]

Ok all this being said… who has a tweeter that can go to 50KHZ FLAT let alone what these amps can do, seems like a 1000 hp engine with small pep boy's tires on it… make a lot of noise N smoke but can't get the HP to the ground ( or speaker in this case )…
Not to mention the bandwidth limiting of the input source. What album ( or digital recording ) has USEFUL information @ 30khz ?

In a presentation of live orchestra without amplification the harmonics reach over 100kHz, when it is recorded and played back is limited to 22kHz band in general, this time is lost naturalness of music.
I think that is why all audiophiles worldwide are never satisfied with their systems, do not understand what is missing are the harmonics.

I hope the recording studios take this into consideration and start recording all harmonics with good microphones to 96khz in the future.

I believe HI-FI in the future will be set to "0 Hz to 96khz" at least.

Speakers and amplifiers superfast cited already have.
I cite the example of good speakers that reaches 100kHz.:
http://www.monitoraudio.co.uk/products/platinum/pl300/

I would like to show you how an amplifier with low slew rate can distort the signal within the audible range.

First picture = 20khz frequency
Second picture = Amplifier High slew rate
Third picture = Amplifier low slew rate

 

[JOMARK911]

OK live all that aside and give me your amp. Is it a BA 3000?

Did I tell you guys I'm after a BA 3000 ?, FOR START.
Then make them two. In bridge mode.

 

[vigman]

DV
I agree with all your points...
Sitting on the scoring stage @ MGM listening to a live session.
THEN
Going into the control room and hearing the playback.. something was missing.
Not THAT much... but something.

That being said, the test equipment.. microphones, processing equipment, recorders.. EVERYTHING was limited for the most part to a 20-20 khz bandwidth and the GOOD STUFF was a 10~30khz world..

Yes a fast amp is better then a slow one.

BTW what amp did you use for your example of a " not so good amp "?

 

[ConradH]

... I would like to show you how an amplifier with low slew rate can distort the signal within the audible range.

First picture = 20khz frequency
Second picture = Amplifier High slew rate
Third picture = Amplifier low slew rate

Sorry, but you've showed me a signal far in excess of the audible range. Band limit the input to 20 kHz and the amplifier slew rate won't matter, assuming it's fast enough to pass 20 kHz. I don't believe that the presence or absence of ultrasonic signals has any effect on musical signals, regardless of studies that suggest they're detectable. Most of us aren't in our 20s anymore, so it's even less of an issue.

 

[JOMARK911]

Man , I was thinking exactly the same. Till one day a semi deaf guy from the lab , came in to watch the tests we were running on a pair of speakers .
We were changing slopes and curves on the tweeters .
As funny it might be this to you " he firstly pointed us to the correct direction of a shallow slope , instead of a steep one. He cleared it as having duration over time , while the other one faded very fast" .
So even "deaf" people have a way of perceiving high frequencies.
That was for , most of us aren't in their 20's.
I can clearly hear up to 18khz , while I used to climb up to 26 , when in my mid 30's. That tested with a freq gen and headphones proved their ability to climb that high.
Uper scale of freqs is detectable , by ear , not on all of us , but on some. So , we have a predicament here.

 

[DVNOBLE]

Sorry, but you've showed me a signal far in excess of the audible range. Band limit the input to 20 kHz and the amplifier slew rate won't matter, assuming it's fast enough to pass 20 kHz. I don't believe that the presence or absence of ultrasonic signals has any effect on musical signals, regardless of studies that suggest they're detectable. Most of us aren't in our 20s anymore, so it's even less of an issue.

Friend our hearing is much more complex than we imagine. We did not hear above 20khz, that's a fact! But you have to take into considração is that frequencies above 20kHz add up and subtract the frequencies below 20kHz. What we hear in an orchestra live performance (without amplification) is the product of fundamental + harmonics. It is for this reason that pleases us greatly.
When we hear a recording of it at home does not sound like there are not present because the harmonics above 11kHz (22kHz sampling).
So hopefully in the future record companies adopt the 96khz band, good microphones capable of filling the spectro, so we can have greater satisfaction in domestic auditions.

 

[vigman]

DV… I agree with your " concept " but until this change is made I don't see that I will be paying the bajillion dollars to get a possible 5% improvement in my audio system…

Maybe this is part of the DRAW on tube gear since it manufactures harmonic's, and no so strident as solid state..

PLUS I USED to enjoy getting the score of a motion picture done on a REAL scoring stage with REAL musicians and listening to that.. NOW you have a " scoring session in a box " with all sorts of " PLUG IN's " that just sounds HORRIBLE….

In short I'm fine with my 4333's & my Sansui gear ( well once I finish my BA-3K ) which will replace my Pioneer Elite 7.1 system.

 

[DVNOBLE]

DV
I agree with all your points...
Sitting on the scoring stage @ MGM listening to a live session.
THEN
Going into the control room and hearing the playback.. something was missing.
Not THAT much... but something.

That being said, the test equipment.. microphones, processing equipment, recorders.. EVERYTHING was limited for the most part to a 20-20 khz bandwidth and the GOOD STUFF was a 10~30khz world..

Yes a fast amp is better then a slow one.

BTW what amp did you use for your example of a " not so good amp "?

Thanks for the consideration.

Contributed a lot in the topic discussed.

It is because of harmonics that an amplifier high slew rate is important, I believe the minimum is 80v/us.

The amplifier used in that example is an Audio Access, it should have a slew rate of 10v/us by my calculations.

 

[DVNOBLE]

DV… I agree with your " concept " but until this change is made I don't see that I will be paying the bajillion dollars to get a possible 5% improvement in my audio system…

Maybe this is part of the DRAW on tube gear since it manufactures harmonic's, and no so strident as solid state..

PLUS I USED to enjoy getting the score of a motion picture done on a REAL scoring stage with REAL musicians and listening to that.. NOW you have a " scoring session in a box " with all sorts of " PLUG IN's " that just sounds HORRIBLE….

In short I'm fine with my 4333's & my Sansui gear ( well once I finish my BA-3K ) which will replace my Pioneer Elite 7.1 system.

It's not about having 5% improvement in audio quality. It's the difference between having or not naturalness reproduction.. It's the chance to get a possible scenario closer to live performance. It is necessary to reduce the large difference in bandwidth between a live performance and a play at home. After all we all want our stereo play as a live presentation. Is not it?

Do not spend much money, I am not talking about HI-HI-END, I'd say with a AU-919 amplifier, one 196khz dac, a good pair of speakers ex: PL-300 is already great, the rest is just expect the music industry to capture all the spectro 96khz.
Do not just have the track sampling 96khz! The recording must be done with microphones that capture up to 96khz spectro be filled correctly.

 

[Vintagear]

Baby bump...not as big as the first 10 year bump!

This was a very interesting thread. Thanks to all for the info provided.

 

[Hyperion]

Baby bump...not as big as the first 10 year bump!

This was a very interesting thread. Thanks to all for the info provided.

Indeed, and interesting for me to note my strong preference for 3 of the most mentioned amplifiers - AU-D11 II, AU-919, and B-2102. :yes: