Please absolutely no commercial interest here: only a happy user of Preamp Cortese for over 15 years ...
Monday, April 9, 2018
What is your experience for the most liquidity and presence of midrange and emotion, if not an all DHT tube rectified transformer coupled pre-amp ?
I was asked this question:
What is your experience for the most liquidity and presence of midrange and emotion, if not an all DHT tube rectified transformer coupled pre-amp ?
This is a very complex question with a myriad of complex answers, but is very interesting so lets dive in .
I think the key word here is EMOTION, ie the feeling we get that we're connected to the music and the musicians and participating in the joy of the performance.
Its quite different from the "hi-fi" experience which often becomes quite critical and even non-satisfactory sometimes.
To achieve this emotion does take a very good preamp, which I will go into, but primarily it means a synergy of the whole system , which must be very carefully tuned to be above all things REALISTIC.
To get emotion, we must be coerced into thinking we are listening to an actual performance , voices must sound real and personal, our system has to fool us into thinking we are listening to the real thing, or as close as possible.
That doesn't necessarily mean accuracy, although its important. Our perceptions and listening equipment - ears, consciousness are not the same and are not linear, if you have ever seen Fletcher-Munson curves you will see that it makes a mockery of linear flat response 20Hz-20Khz, although it is important to have a standard.
More important than linear frequency response , I think , is dynamics, especially micro-dynamics. This is the source of realism , this is what makes recorded music sound real, when you can hear the whole spectrum.
But don't confuse this with detail, as many do, detail is often just a tilt of the frequency response to brighten the top end , and eventually becomes tiring and un-realistic.
Dynamics are essential, and it is essential that every part of the system can reproduce it, but it will all fail if the final component in the chain- the speaker isn't capable of doing micro and macro dynamics.
I have 4 speaker systems in my factory, they all have strengths and weakness's and I wouldn't call any one of them the "best" - I like all of them and enjoy them all.
There is one speaker though that repeatedly stuns people with its realism and portrayal of "emotion".
Its a high efficiency, (nearly) full range Supravox driver , with field coil magnet, that is used in an open baffle with 15" open baffle bass drivers above and below it , and a RAAL tweeter . Simple 6dB passive crossovers , but a DEQX digital crossover for low bass crossover and some bass room correction.
Seperate tube amps for the Supravox and RAAL, and a SS amp for bass.
The Supravox has dynamics that are astounding . Its not perfectly accurate, but with active operation can be adjusted to be reasonably accurate.
But for realism and "you are there", high efficiency speakers have a real advantage in achieving the dynamic range that is needed, to fool one into thinking "they are there".
Unfortunately, there are many more flawed HE speakers than there are good ones. Some are used full range and have terrible frequency responses that emphasise a particular part of the response and become very tiring to listen to.
People then use "soft" or "warm" SE amps to correct this situation, although it rarely does.
Horns are very efficient, and there are some very good horn systems, although its nearly impossible to remove the coloration of the horn geometry. But the dynamics are there in spades , and for a sense of realism they are remarkable, depending on the level of coloration - some are exceptionally good, many are bad.
Dynamics can be achieved with more conventional moving coil speakers, but it usually means multiple drivers and very powerful amplifiers.
Multiple drivers means multiple crossovers, usually in the worst frequency ranges, and complexity harms dynamics.
Not to say that these systems can't sound very good, they certainly can, but its not easy or inexpensive to build them.
However we do it, we need full scale dynamics from our systems for realism.
We won't get it with "warmth" or "romantics" or tilted frequency responses .
No lets get back to the original question:
What is your experience for the most liquidity and presence of midrange and emotion, if not an all DHT tube rectified transformer coupled pre-amp ?
What does liquidity and presence mean ? The hifi reviewers will come up with all sorts of lovely words, but for me, realism is just fine.
Not warmth , or musical, or syrupy, or all the other descriptions that really describe a lack of dynamics .
There are plenty of old style tube preamps around that sound like this , simply because they don't do dynamics well.
For example , low gain triode stages AC or DC coupled to a cathode follower buffer, no dynamics and boring as hell.
To achieve startling dynamics a tube preamp must have gain , and the more gain, the more dynamic it becomes, up to a point of course, but in virtually every situation, a high gain preamp will sound more realistic.
When I made the first commercially available 300B preamp, it had a 6SN7 triode as a driver tube, to get the gain it needed to be dynamic. Without the 6SN7 it was just another "nice" sounding preamp.
All the DHT preamps I built using 300B, 45, PX4, 101D ,4P1L etc had a 6SN7 driver stage to get the gain needed for a dynamic sound with a wide soundstage and precise imaging.
They also were used with output transformers to limit the gain to manageable levels and provide low output impedance and powerful drive ability. 6 solid state power amps in an active system? No problem!
DHT tubes aren't perfect though, and when combined with high gain designs can be problematic in regards to microphonics and noise.
And although DHT designs can produce perfect frequency response and square waves, I do feel that some dynamics is lost through the direct heater connection of a DHT tube.
So to turn the question around to:
What is your experience for the most REALISM , if not an all DHT tube rectified transformer coupled pre-amp ?
I would say my choice would now be a high gain non-dht 6SN7 design with transformer coupling , or perhaps a 6SN7 driver with a 6N6/6H30 White Follower.
If you have an different interpretation of "liquidity and presence of midrange and emotion" and think it should mean warmth or some other form of coloration then yes , a DHT preamp should suit you fine, at the expense of some micro-dynamics.
Again, it all comes down to the synergy of the entire system, perhaps with a bright HE speaker, a DHT preamp would be the best solution , or if "warmth or romantics" is something you value then again a DHT preamp should suit.
There's really no right or wrong, its a journey to find whatever ultimately helps you enjoy the music.
After 30 years of building preamps and using just about every available triode tube, for me the 6SN7 and its equivalents are still "king" of the preamp tubes. "
quoted from:
http://supratekaudio.blogspot.com/search?updated-max=2018-12-12T16:18:00+08:00&max-results=50