A case for warm (vintage) amplifiers

[AJM1981]

Having a background in producing and working with analytical equipment to hear if everything connects well, I would like to make a case for vintage amplifiers with a warm sound, a total opposite.

I have, over time mostly used analytical-"facing" amplifiers. It was all logic, hearing as much of information possible as I was used to. Until the point I went for old Sansui amplifiers, starting with the AU-101 (which is now in use for a secondary set, with the "magic" is in its loudness contour, not so much in its flat settings) and followed by the au-505 that of itself provides a floor of presence audio wise without any aides. Yes, I know that these amplifiers are totally not anywhere near monitor-quality like. In cases they cut off the razor sharp edges at some frequencies, I totally get the critics that this might be not something to look for, given heavy coloration, horrible measurements etc.

An image of the au101 on top of the au505, found on the net. Not my photo


But.. for multiple reasons I started to like them.

The Sansui AU-505 has this presence as earlier mentioned. A stable floor of bass, nothing that feels compressed, a nice roll-off and a great mid-range quality. When turning on the music is present at the start, turning the volume up is like lifting that presence, instead of just turning up the volume. When I turn on any modern amp, it is like a screen that barely has presence at low volumes (yes, I know.. loudness control is absent on my NAD) and can be too articulating. Something, which I admit, might be pleasant to others. I get why people like that, it is what should be presented.

But when listening to a recording through the au505 it is more theatrical, as sitting a bit away from what is performed on a stage in a theatre. A recording of a Hendrix album presents itself as atmospheric, not one to get lost in by listening to byproducts. It is the tone and the emotion. Not that much the 'sitting in between' the musicians as in a studio where every breath and tiny scratch is audible. Maybe analytical amps work for that as in 'I want to be there with the engineer', i get that.

When watching a film, the soundscape on one of these amps seems much more coherent and the film draws more attention to itself with the soundmixing coming up next. Recently I connected the NAD again, just to compare. But the first thing I noticed was that every added layer of sound drew my attention away as a collage, a knife being sharpened for example (with the most used stock sound for that purpose probably) It should be complimentary to what's on screen, not drawing attention to itself. But it was. It gave the blue print.The Au505 does not have that, the slicing sound is still there, but it does not become the most important thing at that moment. Which is what I personally prefer as a viewer.

The case that I would like to make is that I think it is not only the theatrical sense in music. Also films are being uplifted by the vintage toning. Maybe a bit comparable to why a 24fps frame rate film being properly color graded as well, feels theatrical, compared to a much higher frame rate with much more emphasis on clarity and sharpness.

A case for 'less is more'

Disclaimer : I know there are modern brands that should perhaps offer similar experiences, I know Luxman and others are there in the "vintage times" as well besides Sansui, but I could only write about these two from experience in a well treated room.

Anyone else who is on this bandwagon? : )

 

[JeffS7444]

Those look super-cute: A pair of low-power, capacitor-coupled Class AB amps, with THD ratings in the 0.8% range. I imagine when they were new, they would've sounded pretty transparent, but today, who knows.

 

[DVDdoug]

Other than loudness compensation, I don't know what you're trying to say... "Warm" and "analytical" aren't well defined. You're also using lots of other "poetic" language.

The sound quality of amplifiers (and other electronics) is completely defined by noise, distortion, and frequency response, unless you have a channel imbalance or something like that. Audiophoolery discusses the characteristics of sound quality, including additional characteristics you can get with speed/timing (usually from analog records & tapes) and room acoustics.

Unless you go back the tube days, there's not really a "vintage sound". Good sound (low noise, low distortion, and flat frequency response) have always been "easy" with solid state. Overall, electronics have improved and not all solid state electronics were (or are) "great" but most "hi-fi" electronics was very good. There were some good tube amps too but it wasn't cheap or easy to make a good tube power amp (and it still isn't).

BTW - An amplifier doesn't affect soundstage, again unless one channel is louder than the other or if left & right are mixed to mono. Soundstage comes from the recording with some influence from the speakers and room acoustics, and of course from your brain since it's an illusion with the sound actually coming from a pair of speakers.

Floyd Toole says:

Soundstage and imaging is determined by recordings...

...The important localization and soundstage information is the responsibility of the recording engineer, not the loudspeaker.

P.S.
With all of my negativity and skepticism... it's FOR YOUR ENJOYMENT. If you're happy that's the important thing!!!

 

[mhardy6647]

Since I am very lazy (i.e., too lazy to check for myself ) , I will ask @AJM1981--does either of those old-ish Sansui integrated amplifiers have capacitor-coupled outputs? The LF roll-off and other nonlinearities of old, high-ish value electrolytic capacitors is often associated with the warm* sound of some of the earlier solid state amplifiers.

HH Scott 342B solid state stereo receiver class AB power amplifier output section schematic: note the 1000 uF @ 30V electrolytic coupling capacitors.
source: https://audiocircuit.dk/downloads/hhscott/HHScott-342B-rec-sm.pdf
______________
* some of the fringe-ier modern-day fans of vintage hardware imagine a past in which the designers of the early ss equipment were actively striving to retain the "sound signature" of their transformer-coupled, vacuum tube predecessors. However, there's little if any evidence to support that! The use of capacitor coupled outputs was more pragmatically than nostalgically driven, by all indications.

 

[EERecordist]

Having a background in producing and working with analytical equipment to hear if everything connects well, I would like to make a case for vintage amplifiers with a warm sound, a total opposite.

I have, over time mostly used analytical-"facing" amplifiers. It was all logic, hearing as much of information possible as I was used to. Until the point I went for old Sansui amplifiers, starting with the AU-101 (which is now in use for a secondary set, with the "magic" is in its loudness contour, not so much in its flat settings) and followed by the au-505 that of itself provides a floor of presence audio wise without any aides. Yes, I know that these amplifiers are totally not anywhere near monitor-quality like. In cases they cut off the razor sharp edges at some frequencies, I totally get the critics that this might be not something to look for, given heavy coloration, horrible measurements etc.

An image of the au101 on top of the au505, found on the net. Not my photo


But.. for multiple reasons I started to like them.

The Sansui AU-505 has this presence as earlier mentioned. A stable floor of bass, nothing that feels compressed, a nice roll-off and a great mid-range quality. When turning on the music is present at the start, turning the volume up is like lifting that presence, instead of just turning up the volume. When I turn on any modern amp, it is like a screen that barely has presence at low volumes (yes, I know.. loudness control is absent on my NAD) and can be too articulating. Something, which I admit, might be pleasant to others. I get why people like that, it is what should be presented.

But when listening to a recording through the au505 it is more theatrical, as sitting a bit away from what is performed on a stage in a theatre. A recording of a Hendrix album presents itself as atmospheric, not one to get lost in by listening to byproducts. It is the tone and the emotion. Not that much the 'sitting in between' the musicians as in a studio where every breath and tiny scratch is audible. Maybe analytical amps work for that as in 'I want to be there with the engineer', i get that.

When watching a film, the soundscape on one of these amps seems much more coherent and the film draws more attention to itself with the soundmixing coming up next. Recently I connected the NAD again, just to compare. But the first thing I noticed was that every added layer of sound drew my attention away as a collage, a knife being sharpened for example (with the most used stock sound for that purpose probably) It should be complimentary to what's on screen, not drawing attention to itself. But it was. It gave the blue print.The Au505 does not have that, the slicing sound is still there, but it does not become the most important thing at that moment. Which is what I personally prefer as a viewer.

The case that I would like to make is that I think it is not only the theatrical sense in music. Also films are being uplifted by the vintage toning. Maybe a bit comparable to why a 24fps frame rate film being properly color graded as well, feels theatrical, compared to a much higher frame rate with much more emphasis on clarity and sharpness.

A case for 'less is more'

Disclaimer : I know there are modern brands that should perhaps offer similar experiences, I know Luxman and others are there in the "vintage times" as well besides Sansui, but I could only write about these two from experience in a well treated room.

Anyone else who is on this bandwagon? : )

With your background in producing, you would be a good candidate for setting up at home with a good A-D+D-A converter and free Room EQ Wizard software to correlate what you are hearing with measurements. You can add a calibrated microphone to understand what your speakers and room are doing. It will not be equal to an Audio Precision or Klippel, but will probably clearly indicate distortion above the threshold of audibility.

If you want to go deeper, you could set up a digital audio workstation and study what you hear through compressor and equalizer plugins. There are several free DAW software systems and almost all plugins gave a free trial period. A DAW can ingest a piece of music and show you the dynamics at every point. With a DAW and a stereo A-D+D-A, you can capture the input to your integrated amp and bridge across your speaker line with a power-reducing pad, record the input into the DAW, and the output phase reversed into the DAW and analyze the difference at all frequencies to study the high and low frequencies and dynamics. Maybe there will be an AI DAW that can scan and summarize a difference track in words?

In my experience, professional equipment of the transistor age onward is pretty linear if you manage gain staging, even in the days where there were low tens of transformers between the microphone and the master, considering all the round trips through the console, Dolby, tape, and outboard gear. The early digital days were a little rough until anti-aliasing filters were perfected.

I've never recorded through tubes. ASR has measured some tube gear, and it would be fun to run an audio precision through a classic McIntosh tube power amplifier. There are many tube processing plugins one could reverse engineer with RoomEQ Wizard.

 

[Devnull]

I understand the point you're trying to make which leads back to the circle of confusion. Are we trying to hear what the guy on the console was hearing or are we trying to hear what was actually recorded? Think about a tube amp driving an 8 inch speaker with a whizzer cone vs a Benchmark amp driving Revel Salon2s, maybe playing something that was recorded and mixed in the 1950s. Two radically different setups but which actually reproduces the sound that the engineer and artists wanted the listener to hear?

 

[MAB]

I post reviews here on vintage gear - you can go find some of that in my about page.... They typically perform well, transparent in most every aspect. Lots of legends exist, like Yamaha, Marantz, etc. all have certain house sound sound. What I find is this is urban legend. They test with typically flat FR, as their specs back in the day suggested. They typically have really great distortion, often good by contemporary standards. They often have some mains noise, not surprising given readily available test hardware back in the '70s had residuals at or above 0.001% or so, making detection very difficult without exceptional test methods.

It would be nice to see the actual Frequency Response and other measurements of these old Sansui.

 

[AJM1981]

Since I am very lazy (i.e., too lazy to check for myself ) , I will ask @AJM1981--does either of those old-ish Sansui integrated amplifiers have capacitor-coupled outputs? The LF roll-off and other nonlinearities of old, high-ish value electrolytic capacitors is often associated with the warm* sound of some of the earlier solid state amplifiers.

Yes, looked it up. They are both capacitor coupled.

______________
* some of the fringe-ier modern-day fans of vintage hardware imagine a past in which the designers of the early ss equipment were actively striving to retain the "sound signature" of their transformer-coupled, vacuum tube predecessors. However, there's little if any evidence to support that! The use of capacitor coupled outputs was more pragmatically than nostalgically driven, by all indications.

Didnt believe nostalgia was a factor either. I am not even sure if I may call them good amplifiers here. But will stick with them

 

[AJM1981]

With your background in producing, you would be a good candidate for setting up at home with a good A-D+D-A converter and free Room EQ Wizard software to correlate what you are hearing with measurements. You can add a calibrated microphone to understand what your speakers and room are doing. It will not be equal to an Audio Precision or Klippel, but will probably clearly indicate distortion above the threshold of audibility.

If you want to go deeper, you could set up a digital audio workstation and study what you hear through compressor and equalizer plugins. There are several free DAW software systems and almost all plugins gave a free trial period. A DAW can ingest a piece of music and show you the dynamics at every point. With a DAW and a stereo A-D+D-A, you can capture the input to your integrated amp and bridge across your speaker line with a power-reducing pad, record the input into the DAW, and the output phase reversed into the DAW and analyze the difference at all frequencies to study the high and low frequencies and dynamics. Maybe there will be an AI DAW that can scan and summarize a difference track in words?

In my experience, professional equipment of the transistor age onward is pretty linear if you manage gain staging, even in the days where there were low tens of transformers between the microphone and the master, considering all the round trips through the console, Dolby, tape, and outboard gear. The early digital days were a little rough until anti-aliasing filters were perfected.

I've never recorded through tubes. ASR has measured some tube gear, and it would be fun to run an audio precision through a classic McIntosh tube power amplifier. There are many tube processing plugins one could reverse engineer with RoomEQ Wizard.

There are people here who are experts in this scientific side of audio and gear analysis who I respect for their meaningful contributions over a romanticized user experience like the one I posted. It would be fun to go into, but measuring gear would be new terrain for me.

The thing with valves and "valve-voicing" is when an electric guitar is recorded through a valve amp, having a valve amp for amplification in reproduction I would assume it would double the "smear" So, in that sense it is a bit of a question and would say that modern built and calibrated amps of any signature do it far better from a professional point of view. And there are probably plenty of other arguments in why the NAD amplifier would be preferable to demo something at home to a customer over the Sansuis. But I would argue that the illusion the Sansuis give through their voicing is one I would prefer for every day use as a consumer.

 

[DanielT]

I got curious and found this:

Zoomed in:

Sansui AU-505 Amplifier 1973 : Sansui Electric Company, Ltd. : Free Download, Borrow, and Streaming : Internet Archive

Sansui AU-505 Solid State Integrated Amplifier, Sansui Electric Co., Ltd., Tokyo, Japan, 1973.

archive.org

 

[AJM1981]

I got curious and found this:
View attachment 483611View attachment 483612

Zoomed in:
View attachment 483613

Sansui AU-505 Amplifier 1973 : Sansui Electric Company, Ltd. : Free Download, Borrow, and Streaming : Internet Archive

Sansui AU-505 Solid State Integrated Amplifier, Sansui Electric Co., Ltd., Tokyo, Japan, 1973.

archive.org

Will save these! Thanks : )

 

[DanielT]

Will save these! Thanks : )

Sansui AU-505 operating around 10 watts seems to be quite optimal, so (high) efficient speakers make sense to have.
Also, from what I see, AU-505 is spec'd to handle 4 Ohm speakers. That's good because with that it shouldn't be so load sensitive.
All this assuming that it performs as new regarding the given spec/data.

By the way, what kind of speakers do you have?

 

[mhardy6647]

Yes, looked it up. They are both capacitor coupled.


Didnt believe nostalgia was a factor either. I am not even sure if I may call them good amplifiers here. But will stick with them

There's an HH Scott 260 here (the kit-built morph, LK-60), so I am not pointing any fingers.



Relatively few Sansui pieces here -- not because I don't like some of them, but the ones I really like are too hard to find or to expensive for me to pick up just to have sitting on a shelf.

 

[jmdesignz2]

If we are talking about pre 1990ish, My case for warm vintage amplifiers is a very large plastic bin that gets taken out twice a week

 

[RexrothPigeon]

But I would argue that the illusion the Sansuis give through their voicing is one I would prefer for every day use as a consumer.

You don't have to make arguments for your personal preference. Nobody here has any problem with you liking what you like, even if what you like measures terribly.

 

[DanielT]

A little OT but I hope it's okay with you @AJM1981 that I bring this up in your thread:

I have said this before but I have not yet seen many examples of good speakers that have a high, let's say at least 91-92 dB sensitivity that is amp friendly, does not expose the amplifier to a tough load. The counterargument is -and it is a reasonable one - that good modern amplifiers with a lot of power are not that expensive these days so it does not matter much if the speakers do not have high sensitivity. I buy that argument BUT I think that speaker manufacturers are missing out on a potential customer group. There are those who still have low powered amplifiers. Think of all these SET amps for example.
I do not know how big this potential customer group is but if I were a speaker manufacturer I would have investigated the market potential.

An example of the type of speaker I'm talking about. HECO Aurora 1000 which is measured to have 91 dB sensitivity and look how pleased this tube dude is with them:

Wow! OMG! How do you express intense like without being over-dramatic?

I am glad I've lasted to 73 years old. I've blissed listening to music over the last 50 years through live performances and with a large variety of hi-end and hi-end adjacent gear. Although memories can deceive us, my current rig is the culmination of a fabulous journey. Perhaps my hearing has...

www.audiosciencereview.com

In addition to their relatively high sensitivity, it doesn't hurt that they are good speakers/measure well:

HECO Aurora 1000 Floorstanding Loudspeaker Review

The German made Heco Aurora 1000 floor-standing speakers ($799/ea) were put through the wringer with our in depth measurement testing and yielded surprising results. Are these the speakers to get?

www.audioholics.com

 

[AJM1981]

Sansui AU-505 operating around 10 watts seems to be quite optimal, so (high) efficient speakers make sense to have.
Also, from what I see, AU-505 is spec'd to handle 4 Ohm speakers. That's good because with that it shouldn't be so load sensitive.
All this assuming that it performs as new regarding the given spec/data.

By the way, what kind of speakers do you have?

A pair of Wharfedale evo 4.2 to the Sansui Au505 and the Denton 85th to the au101.

I don't know how you view it. What I think is that the shift in preference of signatures was a shift in which the prototype of the CD in the mid 70s and the CD moved the production industy and the market to a level in which it all was dragged more towards transparancy, cleaner recordings, overpolished production. Less Hendrix, less The Doors, less sloppier sounding synthesizers with "ugly' byproducts,.. more clean pop, rock and jazz, new wave. The age of clear and smooth of which "content creators" went along with the flow. Followed by an audience / a market for refinements, being able to hear the finest fingerstrokes on an accoustic guitar in the age of 'unplugged' (I remember the Clapton recording live was a big deal for people being obsessed with the byproducts and kind of re-blew life into singer songwriter later on) The more articulated and refined synthesizers even much later. Still driven by the CD and digital media The consumer being dragged into a detail-obsession, "hearing the blue print". This is offcourse a heavy oversimplifcation, I am aware of that.

In the older days revealing the recording was not that much of a wish. From tape to vinyl was seen as a loss they had to deal with as producers spoke about it, Reel to Reel for consumers was a thing, but a niche. There was no overobsession with the finest details as those kind of details were questionable. The "better" an amp, the more an illusion it gave of a slightly better room to theater experience. There are some jazz recordings of Ellington that start with really bright bursts of brass chords, that makes someone run to the volume button on an amp that measures perfectly (after realizing that the rest of the music is at a lower gain level) And that is even after modern remastering. Amps like the Sansuis mentioned and their signatures even make those bursts of chords pleasant to listen to.

It might be also wrong to call it a philosophy of the age, things were just as they were. But in retrospective, the thing with the warm voicing feels a bit like the deal with scanlines for classic game consoles. As in, yes.. without scanlines there is a crispier pixelated image. But the masking with scanlines was a feature that served a purpose as well in color blending and a smoother image. Probably not the best of analogies, but a fair try

 

[DanielT]

A pair of Wharfedale evo 4.2 to the Sansui Au505 and the Denton 85th to the au101.

I don't know how you view it. What I think is that the shift in preference of signatures was a shift in which the prototype of the CD in the mid 70s and the CD moved the production industy and the market to a level in which it all was dragged more towards transparancy, cleaner recordings, overpolished production. Less Hendrix, less The Doors, less sloppier sounding synthesizers with "ugly' byproducts,.. more clean pop, rock and jazz, new wave. The age of clear and smooth of which "content creators" went along with the flow. Followed by an audience / a market for refinements, being able to hear the finest fingerstrokes on an accoustic guitar in the age of 'unplugged' (I remember the Clapton recording live was a big deal for people being obsessed with the byproducts and kind of re-blew life into singer songwriter later on) The more articulated and refined synthesizers even much later. Still driven by the CD and digital media The consumer being dragged into a detail-obsession, "hearing the blue print". This is offcourse a heavy oversimplifcation, I am aware of that.

In the older days revealing the recording was not that much of a wish. From tape to vinyl was seen as a loss they had to deal with as producers spoke about it, Reel to Reel for consumers was a thing, but a niche. There was no overobsession with the finest details as those kind of details were questionable. The "better" an amp, the more an illusion it gave of a slightly better room to theater experience. There are some jazz recordings of Ellington that start with really bright bursts of brass chords, that makes someone run to the volume button on an amp that measures perfectly (after realizing that the rest of the music is at a lower gain level) And that is even after modern remastering. Amps like the Sansuis mentioned and their signatures even make those bursts of chords pleasant to listen to.

It might be also wrong to call it a philosophy of the age, things were just as they were. But in retrospective, the thing with the warm voicing feels a bit like the deal with scanlines for classic game consoles. As in, yes.. without scanlines there is a crispier pixelated image. But the masking with scanlines was a feature that served a purpose as well in color blending and a smoother image. Probably not the best of analogies, but a fair try

Aha. Nice speakers. From what I can see the manufacturer's stated sensitivity is 88 dB. Let's say that's true (manufacturers have a penchant for exaggerations). With then 10-15 amp watts. Then it mostly depends on how high the volume you play and whether you play with very dynamic music or not.
"Normal" dynamic jazz, blues, pop, rock recordings at a "normal" let's say 65 dB listening volume are fine. Or at least they would have been for me under those conditions.
(I would have added a subwoofer, but that's another matter)

Recording technology and how it has developed and philosophy around recordings. Commercial aspects (loudness war for example) also have to be weighed in. There is a lot to be said about it. Here is an AI summary of a number of threads, from different forums, regarding the question of:
The best recording of Kind of Blue:

I leave aside how right or wrong it is regarding what is being said regarding the AI compilation (a topic for a new thread here on ASR?). I'm just stating that discussions exist.

Even modern recordings. For example this superbly good album (the music not the recording). Steven Wilson later fixed the recording though:

They have murdered "Tears for Fears" ... digitally!

Check this out: https://magicvinyldigital.net/2022/03/04/tears-for-fears-the-tipping-point-review-lp-cd-qobuz-tidal-amazon-atmos-blu-ray-audio/ ALL the existing digital formats are screwed! The compression, the clipping! Quoting my buddy Danny: "The sound engineers should be shot. Out of a...

www.audiosciencereview.com

 

[mhardy6647]

Those look super-cute: A pair of low-power, capacitor-coupled Class AB amps, with THD ratings in the 0.8% range. I imagine when they were new, they would've sounded pretty transparent, but today, who knows.

Borderline. The early ss amps... were not great. These aren't real early ones, but not really hifi. These at least probably don't have any germanium transistors to worry about.

 

[JeffS7444]

Borderline. The early ss amps... were not great. These aren't real early ones, but not really hifi. These at least probably don't have any germanium transistors to worry about.

But they're awfully cute, and look like they'd be a breeze to service.

Early SS: My dad's old Scott Stereomaster 388B sounded alright, though the FM never worked. Pretty sure he blew out the FET front-end at least twice, then simply gave up (maybe he shouldn't have hooked it up to the outdoor yagi antenna). Made me appreciate why McIntosh continued to use nuvistor tubes for their tuner front ends well into the SS era.