Hopkins' System

hopkins

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One of the pioneers of Jazz, performing in a small club in Long Island in 1965 two years before passing away. How I wish I could have been there, but I was born a year later :(

Liner Notes - Martin Williams

Henry "Red" Allen, Jr., represents the final develop ment of one of the great traditions in American music. The tradition, of course, is that of New Orleans' cornet and trumpet men, It begins with Buddy Bolden, the man who (at least to New Orleans musicians) first played jazz. It includes Freddie Keppard and King Oliver and Tommy Ladnier and Louis Armstrong.

And it includes Red Allen, who had already begun to develop a personal style by the late Twenties, when he was a featured soloist with the Luis Russell orchestra. With Fletcher Henderson in the early Thirties, Allen helped set that archetypal group's classic swing-band style, and his solos were widely imitated by other trumpeters. Meanwhile, he had a separate and long-standing career as leader on his own recording dates. He worked with Benny Goodman. And for a while, Red Allen was a featured soloist, with billing, in Louis Armstrong's orchestra - perhaps the supreme compliment for any trumpeter or any jazzman.

Henry Allen, Jr., now in his late fifties, has not settled into a complacent music which only occasionally recaptures former glories. He does not play "as well" as he ever played, either. In many ways he plays better. His trumpet techniques are so inventive, resourceful and personal that a younger brassman, Don Ellis, recently called him the most avant-garde trumpet player in New York.

If this album were nothing else (and it is a great deal else) it would be a document of how this deceptively casual musician sounds before an audience, something which has never been captured on records before. For the audience here is decidedly Red Allen's kind of audience. The numbers were recorded at the Blue Spruce Inn, a suburban New York restaurant in Roslyn, Long Island. The Inn is not a jazz club, but its customers have been receptive to pianist Teddy Wilson, and Allen's quartet has become something of a fixture there. Before such an audience, Allen is genial and full of a kind of amiable raucousness that titillates his listeners. At least, that is Red Allen on the surface. Under the surface, however, the entertainer is also an artist.

To another professional, Allen's trumpet playing is a frequently astonishing array of bent notes; smeared notes; choked, half-valve notes; rips; glissandos; flutters; growls, and asymmetrical rhythms that somehow come out right. They are delivered by a trumpeter with excellent control over the lowest and the most intimately whispered tones as well as over piercing, high-noted shouts. But the effects are not there for their own sake. They are parts of a sustained musical tissue held together by the force of Allen's personality and his innate gifts as an improviser an aesthetic fact that can be readily appreciated and enjoyed by the squarest head in the house.

 
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hopkins

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Far from perfect, but I like the way the interplay between Ella and Louis' voices are captured.

I sometimes move around my speakers (they are on wheels) to check how different placements affect the sound. There are tradeoffs...

I am now really curious to hear what a new version of the "powerDAC" will bring to the table. Hopefully, I will find out by the end of September.
 
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hopkins

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Very interesting room described in this video (German, with English subtitles) - around 28:00 in the video:


Notice how the reverberation levels in that room can be tweaked from 1.2 seconds to 500 milliseconds. The emphasis is on the balance of the sound, not on achieving extremely low reverberation levels.
 
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PXL_20230912_014308923.MP.jpg

Mingus Big Band performing at the DROM in NYC. Great music, good performance. They were using microphones to amplify the sound, and the sound system was not that great, so that was an unfortunate choice given the small size of the venue.

 
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hopkins

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For those interested in checking out the specs and reading about the inner workings of ECDesigns' new products, manuals have been added to the product pages on their website. For example:


These new products should be available at the end of the month.
 

hopkins

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View attachment 116400

Savion Glover caught in the act. Amazing show.


Savion Glover is an exceptional tap dancer. From an "audio" perspective, it was also interesting to "hear" his dancing. The sound is really unique, unlike any instrument, with a wide range, subtlety and finesse.

The "dialogue" with the drums and percussion was also very interesting.I assume a lot of it was improvised.
 

hopkins

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There was an interesting discussion on another thread about DSP and frequency response (among other "corrections").

I quote Bjorn's comment on the frequency response curve of my speakers - I posted the FR measurement of my speakers a while back on this thread:

"Your frequency response is exactly very much lifeless in regards to the tonality IMO. The response is overall more falling in areas where it should be raising.You lack about 15 dB between 90 Hz to 115 Hz, which is a heck of lot in this important fundamental area. And there's a broad cancellation between 8 kHz and 12 kHz."

I will not deny that the frequency response of my speakers is not perfect, and that my room's acoustics can be improved upon. But the reason I like the sound of my system is precisely because it does not sound "lifeless". So I enjoy music in spite of these acoustical imperfections? How can that be ?

I think that the unique "minimalistic" approach of the system brings things to the table that "transpire" in spite of the "predictable" deficiencies in frequency response.

I am happy with the results, that's what counts.

Now for the next step of the journey, the new powerDAC-SX from ECDesigns is going to offer improved performance. Hopefully I will be able to try it soon, and go were no audiophile has ever been before :)
 
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hopkins

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This new DAC/Amplifier brings digital to a whole new level. It produces, from a simple raspberryPi, a firework of sounds for the ears. Simply incredible. I'll post better quality videos that hopefully will give a sense of what I am hearing, as well as more details of my impressions, with perhaps some explanations as to how they have accomplished this (though the technical aspects can also be found on their website).
 

hopkins

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This new powerDAC-SX, which I have had the opportunity to listen to for a week now, is a fantastic product. The overall feeling when listening is one of less distorsion, and this impacts all aspects of the sound. The paradox is that it is very difficult to convey in words. I wish recordings could fully capture the sound, but they simply don't, and speakers/rooms have their own limitations. I will try to make some recordings (and publish the wav files) comparing the sound of this new model to the sound of the previous model.i will also try to setup a comparison with a more traditional system composed of separate components (DAC + preamp + amp).

In the meantime I will be happy to answer any questions.
 
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hopkins

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Here is a picture of the back of this "amplifier":

PXL_20231013_160216128.jpg

- power input
- digital toslink input
- speaker outputs

It functions as an "attenuator". From what I understand, the output analog signal is produced directly by a regulated power supply that goes through a number of parallel resistors. Each bit from the digital signal work as a "gate" that opens or close the current's flow to each resistance. Each bit position corresponds to a resistance of different value. The current coming out of these different resistance forms the output signal. So there is no traditional "amplification" but rather an "attenuation" determined by each digital sample.

Volume settings control how much power is supplied to these circuits, in combination with some bit-switching (effectively lossless).

So there is no traditional "amplification" or "preamplification". What you hear is essentially a power signal going through a resistance...

How this works is described in more detail (and certainly more accurately) in their documentation: https://www.ecdesigns.nl/info/powerdac-sx

The previous model (S) worked on basically the same principles. This new model (SX) improves the performance by reducing noise and increasing the accuracy of converter (bit switching). It also offers more output power.

Next I'll mention some aspects of the digital signal processing and "source immunity" which has also improved...
 
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hopkins

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I changed the title of my thread as I thought the previous one was giving too much focus to the speakers (open baffle). I love these speakers, and will continue to "tweak" them and try to improve them, but I do plan on exploring other speakers as well, perhaps of a smaller scale, that can provide a similar "experience". The added power available in this new amp offers more opportunities to try out a variety of speakers. I also hope some people will provide their feedback if they decide to try it out.
 
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hopkins

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Sep 10, 2022
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One aspect which ECDesigns has been working on for quite some time is (digital) "source immunity", a subject that probably interests many audiophiles.

They claimed to have achieved this "source immunity" with their previous system, and I agreed at the time. I only changed my mind about this recently, as I decided to test again their minimalistic WAV file player (UPL) as a source with the powerDAC-S (so, previous model).

This UPL player uses a microprocessor (STM32 family) which they programmed to read wav files from a USB storage and outputs a digital optical signal. The operating system is minimalistic (no bloated Linux OS) and the code to read files and send the audio as well. It has no network connection or control screen. Music playback is controlled through a serial connection to another computer.

About 3 months ago, I decided to test the use of the UPL again. With my speakers now properly setup in my new apartment, and some room treatment, the difference with a network player (raspberryPi) were now more obvious.

I asked ECD to check for themselves, and they agreed with my conclusions. ECDesigns then figured out that one piece of circuitry that had been included in the last version of the UPL (and in the U192ETL, for those familiar with their previous product line) made the difference. This circuit limits the bandwidth of the signal being transmitted to the DAC to 192khz. This bandwidth limiter had not been included in the powerDAC products. They added it back to the new products (SX, RX...) with some improvements.

Not knowing when these new products would be released, I decided to continue using this UPL as a source, in spite of its "ergonomic" limitations.

I was eager to check the "source immunity" of the new SX model when I received it. From the get-go, it was obvious that there was no longer any difference between my basic network player (raspberryPi running MPD) and the very low noise UPL. I also confirmed this with numerous back and forths between the two. Both digital sources provided the same glorious sound! I now no longer use this UPL, and rely on a simple raspberryPi to play all my music. This simplifies things, and source optimization is something that has now become irrelevant to me, as it should.

The techniques they use to obtain this source immunity are complex and rely on multiple features. The devil is in the detail, as always.

I am eager to find out whether others will reach the same conclusions.
 
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