Author Topic: I think my System is virtually, finally finished  (Read 33686 times)

Offline steve

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Re: I think my System is finally finished
« Reply #30 on: August 23, 2020, 09:57:43 AM »
See my sig line ;)

I had to do a double take read. At first I thought you meant neurotic. But I do visit Ed's once a week.



« Last Edit: August 23, 2020, 10:03:06 AM by steve »
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Offline Barry (NJ)

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Re: I think my System is finally finished
« Reply #31 on: August 24, 2020, 01:02:19 PM »
LOL!
Happiness is when your system overcomes your nervosa ;) 
So much media, so little time... My Media Room...

Offline steve

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Re: I think my System is finally finished
« Reply #32 on: August 24, 2020, 09:58:50 PM »
  Done ?? Never done. With your knowledge and building talent you never will be done.  Just saying. There is always that variable that we want to try. Modding inexpensive gear is fun sometimes with good results sometimes not . Hence the chase. Have fun.

charles
 

Upgrading the dac was fun and now really really accurate. Even used 6 inch 6n all copper wires. Can't do much more with the room.
The 11A is perfect; monoblock triode amps, ics are finished, except looks.

I suppose eventually better drivers for the test speakers and some solid 6n speaker wires? Problems are the cost and the
limited frequency range of the best cone materials. I like two way designs, obviously modded the full range driver. Time to
fully enjoy the music.

cheers
steve
« Last Edit: August 24, 2020, 10:28:46 PM by steve »
Steve Sammet (Owner, Electron Eng, SAS Audio Labs, Ret)
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Offline Nick B

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Re: I think my System is finally finished
« Reply #33 on: August 25, 2020, 12:28:13 AM »
  Done ?? Never done. With your knowledge and building talent you never will be done.  Just saying. There is always that variable that we want to try. Modding inexpensive gear is fun sometimes with good results sometimes not . Hence the chase. Have fun.

charles
 

Upgrading the dac was fun and now really really accurate. Even used 6 inch 6n all copper wires. Can't do much more with the room.
The 11A is perfect; monoblock triode amps, ics are finished, except looks.

I suppose eventually better drivers for the test speakers and some solid 6n speaker wires? Problems are the cost and the
limited frequency range of the best cone materials. I like two way designs, obviously modded the full range driver. Time to
fully enjoy the music.

cheers
steve

Steve,
Time indeed to fully enjoy the music. Congratulations on the result  :thumb: I’m very close to having things dialed in, just awaiting a digital coax. It’s amazing what adding some Jupiter caps and Amperex 7308s can do. I’m a fan of 2 ways. Thank goodness for speakers that sound great and that I can easily handle.
Nick
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Audio Envy p cords
Roon, Tidal, Qobuz
PI Audio UberBUSS

Offline steve

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Re: I think my System is finally finished
« Reply #34 on: August 25, 2020, 01:54:14 PM »
i'm a fan of 2-ways, as well.  if crossed over to subwoofers!   :mrgreen:

re: drivers, you should check out accuton.  expensive?  yes.  but quite efficient, and good frequency range - if you're willing to cross over the woofers at 100hz or so, to subwoofers.  israel blume uses an accuton woofer from 100hz-4khz, crossed to an accuton tweeter; the woofer can be crossed as high as 6khz, but going lower allows better driver overlap, while still allowing the accuton woofer to cover the majority of musical info.  this set-up is in his most expensive offerings, which have gotten critical praise from most everyone.  while i've never heard them, i owned a pair of his less-expensive offerings, (the coincident victory's), and i can say w/o reservation that he knows how to design speakers...

doug s.
Upgrading the dac was fun and now really really accurate. Even used 6 inch 6n all copper wires. Can't do much more with the room.
The 11A is perfect; monoblock triode amps, ics are finished, except looks.

I suppose eventually better drivers for the test speakers and some solid 6n speaker wires? Problems are the cost and the
limited frequency range of the best cone materials. I like two way designs, obviously modded the full range driver. Time to
fully enjoy the music.

cheers
steve

Hi Doug,

Thanks, but some years ago I decided to exit the midrange crossover frequencies, where the ear is most sensitive, and crossover quite low, in my case around 170hz. By doing so, I don't have the doppler effect while having the advantage of one driver from
low mids to 20khz.

The main problem I am having now is that the typical pots are so touchy and change resistance due to play in the control shaft.
So it looks like 10 or 15 turn pots are in order.

Cheers

steve
« Last Edit: August 25, 2020, 02:11:53 PM by steve »
Steve Sammet (Owner, Electron Eng, SAS Audio Labs, Ret)
SAS "V" 39pf/m 6N copper ICs,
SAS Test Phono Stage
Acutex 320 STR Mov Iron Cart
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Offline Nick B

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Re: I think my System is finally finished
« Reply #35 on: August 25, 2020, 04:25:45 PM »
Doug,
You did say expensive, but these prices surprised me a bit  :shock:
https://www.madisoundspeakerstore.com/accuton/

I have heard of Coincident, but Israel Blume’s name wasn’t familiar to me. An interesting read for me.
http://coincidentspeaker.com/about.htm
Nick

i'm a fan of 2-ways, as well.  if crossed over to subwoofers!   :mrgreen:

re: drivers, you should check out accuton.  expensive?  yes.  but quite efficient, and good frequency range - if you're willing to cross over the woofers at 100hz or so, to subwoofers.  israel blume uses an accuton woofer from 100hz-4khz, crossed to an accuton tweeter; the woofer can be crossed as high as 6khz, but going lower allows better driver overlap, while still allowing the accuton woofer to cover the majority of musical info.  this set-up is in his most expensive offerings, which have gotten critical praise from most everyone.  while i've never heard them, i owned a pair of his less-expensive offerings, (the coincident victory's), and i can say w/o reservation that he knows how to design speakers...

doug s.
Upgrading the dac was fun and now really really accurate. Even used 6 inch 6n all copper wires. Can't do much more with the room.
The 11A is perfect; monoblock triode amps, ics are finished, except looks.

I suppose eventually better drivers for the test speakers and some solid 6n speaker wires? Problems are the cost and the
limited frequency range of the best cone materials. I like two way designs, obviously modded the full range driver. Time to
fully enjoy the music.

cheers
steve
Orchard Starkrimson Ultra amp
Hattor Big preamp
JMR Voce Grande speakers
Holo Cyan2 dac
Holo Red streamer
Hapa Aero digital coax
WyWires Silver cables
TWL Digital American II p cord
Audio Envy p cords
Roon, Tidal, Qobuz
PI Audio UberBUSS

Offline steve

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Re: I think my System is finally finished
« Reply #36 on: August 25, 2020, 05:41:19 PM »
Doug,
You did say expensive, but these prices surprised me a bit  :shock:
https://www.madisoundspeakerstore.com/accuton/

I have heard of Coincident, but Israel Blume’s name wasn’t familiar to me. An interesting read for me.
http://coincidentspeaker.com/about.htm
Nick

i'm a fan of 2-ways, as well.  if crossed over to subwoofers!   :mrgreen:

re: drivers, you should check out accuton.  expensive?  yes.  but quite efficient, and good frequency range - if you're willing to cross over the woofers at 100hz or so, to subwoofers.  israel blume uses an accuton woofer from 100hz-4khz, crossed to an accuton tweeter; the woofer can be crossed as high as 6khz, but going lower allows better driver overlap, while still allowing the accuton woofer to cover the majority of musical info.  this set-up is in his most expensive offerings, which have gotten critical praise from most everyone.  while i've never heard them, i owned a pair of his less-expensive offerings, (the coincident victory's), and i can say w/o reservation that he knows how to design speakers...

doug s.
Upgrading the dac was fun and now really really accurate. Even used 6 inch 6n all copper wires. Can't do much more with the room.
The 11A is perfect; monoblock triode amps, ics are finished, except looks.

I suppose eventually better drivers for the test speakers and some solid 6n speaker wires? Problems are the cost and the
limited frequency range of the best cone materials. I like two way designs, obviously modded the full range driver. Time to
fully enjoy the music.

cheers
steve

No problem Nick. Just zip out to your money tree.   :-P


----------

Seriously, I hate to be a downer to anyone, but I checked out some of the midrange and tweeter FR plots and am not a fan
in my two way designs. I doubt I would use them in a three way design either.

Just my opinion.

steve
« Last Edit: August 25, 2020, 06:07:35 PM by steve »
Steve Sammet (Owner, Electron Eng, SAS Audio Labs, Ret)
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Offline toobluvr

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Re: I think my System is finally finished
« Reply #37 on: August 26, 2020, 12:06:27 PM »
.........  while i've never heard them, i owned a pair of his less-expensive offerings, (the coincident victory's), and i can say w/o reservation that he knows how to design speakers...

doug s.

[/quote]

I concur.

Over the years I've owned several pair of Coincident speakers:  Conquest, Visionary Reference, Super Eclipse, Digital Master.
All excellent.
Spkrs: Sunny Cable Tech, Reynaud, Zu, Klipsch, Gallo subs, Wharfedale
TT1: Townshend Rock 3/OL Silver Mk3A
TT2: OL Aurora/OL Encounter Mk3C
Carts: Soundsmith Zephyr,  Music Maker 3, Dynavector xx2-Mk2, Shelter 501
complete: see Sunnydaze system on AC

Offline steve

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Re: I think my System is finally finished
« Reply #38 on: August 26, 2020, 04:49:54 PM »
hi steve,

it was my understanding that crossovers at 100hz and 4khz pretty-much avoid having a x-over in the midrange.

i do have a speaker driver in my oris 150 horn that goes from 150hz to 20khz...

doug s.
Hi Doug,

Thanks, but some years ago I decided to exit the midrange crossover frequencies, where the ear is most sensitive, and crossover quite low, in my case around 170hz. By doing so, I don't have the doppler effect while having the advantage of one driver from
low mids to 20khz.

The main problem I am having now is that the typical pots are so touchy and change resistance due to play in the control shaft.
So it looks like 10 or 15 turn pots are in order.

Cheers

steve

Hi Doug,

That is what some may say, so I attached some data graphs. Notice that the ear is most sensitive between ~800hz to 6khz, with 3.5khz/4khz clearly being the most sensitive frequencies of the ear. 100hz is somewhat ok, I used 170hz and found it was very touchy. How touchy?

150hz +/- is a normal low impedance area of a typical cone type speaker. I had been playing around with 5 feet length of 10 solid 18 gauge wires on one speaker leg, but only 9 parallel wires in the other speaker leg. 10 was too many and 8 was too few in that leg.

And the wire is nothing special, certainly not 4 or 6n. (Maybe that will be my next project but it won't be cheap.)

As mentioned before, I can also make a variable control adjustment to a millionth of an ohm or less range and visitors can perceive the sonic difference. Kinda backs up my parallel wires conclusions above. Could also mention 0,5mm rotation of speakers.

If a speaker is that critical at 170hz, imagine how sensitive the ear is at 4khz.

I like to keep the crossover as simple as possible, minimal slopes, minimal parts, for flat response, dynamics, sound stage, naturalness, which is difficult with the poor quality capacitors in the components and crossovers these days. Whenever I see
sharp resonances, even if out of band, I avoid it.

I have not found a speaker that I like, and I have auditioned plenty, up to $28k, pricey. After all these decades, that is why I designed my own test speakers.

cheers

steve
 
« Last Edit: August 26, 2020, 09:45:16 PM by steve »
Steve Sammet (Owner, Electron Eng, SAS Audio Labs, Ret)
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SAS Test Phono Stage
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Offline steve

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Re: I think my System is finally finished
« Reply #39 on: August 27, 2020, 11:58:58 AM »
hi steve,

while i haven't heard mr blume's implementation of the accuton drivers, i have heard them in other speakers, and they sound damned nice, imo.  and considering my experience i've had w/the coincident victory's, and the almost universal raves from reviewers and customers alike, regarding all his products, i can't imagine a proper implementation of the accuton midrange and tweeter wouldn't be outstanding.  and coincident does it with a 1st order x-over using only one cap and two inductors.  according to mr blume, he can do this due to the synergy of the accuton midrange and tweeter, and that you cannot tell it isn't a single driver.  the accuton midrange is flat to 6khz; i'm sure he would have crossed it over higher if he felt it sounded better.

here's what coincident says about its x-over implementation w/these two drivers:
"As with all Coincident speakers, first order crossovers (which are the purest and preserve phase coherency) are used with only the finest components, matched to within 1%, all hardwired with lead to lead construction (eschewing the use of unnecessary wires or connectors). The signal path contains only one capacitor (Mundorf – The most transparent cap for the purpose) and two inductors (proprietary 10 AWG OFC Litz - one for the midrange and one for the bass). That is it. Elegant simplicity but as Einstein remarked- not too simple. This crossover is the most transparent, unobtrusive in existence. In bypass tests, its presence is virtually undetectable."

don't get me wrong; i think it's great that you're designing your own speakers.  which is why i suggested the accutons.

doug

Don't get me wrong Doug, I really appreciate the suggestions and thoughtfulness. I think I have heard of Accuton, but never
checked them out.

It is just that I am extremely picky when it comes to drivers, and I almost always go with the flattest response. Yes, there are other parameters such as cone material, the ts and Xmax values etc that I also take into account.

Past this point is more for newbies, not at Doug.

For instance, Qts is all important for me when it comes to woofers for my test speaker. An Fs of 20hz with a Qts of .2 is not what I am looking for when I want response to 20hz. I want accurate and tight response even with a tube amp.

Interestingly, two amplifiers can have a damping factor of 10, yet one will "sound" tight bass while the other will have flabby bass.

I went with the old tried and tested big box because it just sounds better than all these new concept types using
the above parameters (Fs 20 and Qts of .2). One of the comments I receive is how in the world did I get such taut and
natural sounding bass (both electric and double bass). Proper speaker design and proper amplifier design.
I realize that many folks do not like large 4.5 cubic foot cabinets. But I find it yields the best bass response. (Even with a 12"
woofer, the Xmas, cone movement, limits the spl of deep bass.)

I don't know which midrange or tweeter is used in a particular design.
But here is the response of a 2" Accuton Cell C51-6-286 2" Ceramic Dome Midrangemidrange driver.

https://www.madisoundspeakerstore.com/approx-2-midrange/accuton-cell-c51-6-286-2-ceramic-dome-midrange/

Below is the FR plot. Using a 1st order, 6db/octave crossover at 4khz is begging for problems. There is
going to be a problem due to the rise above 10khz. My system would easily expose the problem.
A special low pass filter is needed above 10khz or so. But that is more parts which will also influence the purity.
One could also use a 4th order, but again too many parts for me.

Anyway, that is my rant for now.

Cheers and thanks for thinking of me Doug. I do appreciate your thoughtfulness.

steve
« Last Edit: August 27, 2020, 12:25:50 PM by steve »
Steve Sammet (Owner, Electron Eng, SAS Audio Labs, Ret)
SAS "V" 39pf/m 6N copper ICs,
SAS Test Phono Stage
Acutex 320 STR Mov Iron Cart
SAS 11A Perfect Tube Preamp
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2 way Floor Standing Test Speakers

Online _Scotty_

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Re: I think my System is finally finished
« Reply #40 on: August 27, 2020, 02:31:28 PM »
That out of band undamped resonance has been the flaw with all of the drivers I've seen with very stiff cones.
According to distortion plots  I've seen of both the raw drivers and complete speaker systems the out band resonance point has a very large amount of 3rd order harmonic distortion associated with it. Even when this resonant peak is suppressed X dB with a 24db/oct. network the 3rd order distortion can be heard by many people and is very off putting.
 Sidebar, the dynamic life of the music takes a hit every time another component is added to the X over network in my opinion , which why I am proponent 1st order networks even though speakers designed this way usually come with off axis frequency response errors. The music sounds more alive to me and the off axis response errors can be ameliorated by appropriate room treatment.
Obviously YMMV.
Scotty


Offline steve

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Re: I think my System is finally finished
« Reply #41 on: August 27, 2020, 10:32:41 PM »
That out of band undamped resonance has been the flaw with all of the drivers I've seen with very stiff cones.
According to distortion plots  I've seen of both the raw drivers and complete speaker systems the out band resonance point has a very large amount of 3rd order harmonic distortion associated with it. Even when this resonant peak is suppressed X dB with a 24db/oct. network the 3rd order distortion can be heard by many people and is very off putting.
 Sidebar, the dynamic life of the music takes a hit every time another component is added to the X over network in my opinion , which why I am proponent 1st order networks even though speakers designed this way usually come with off axis frequency response errors. The music sounds more alive to me and the off axis response errors can be ameliorated by appropriate room treatment.
Obviously YMMV.
Scotty

I agree Scotty. Resonances in, above, below the audio band cause all sorts of problems. Thanks for posting this
valuable information.

On a side note, I try very hard to keep my strings clean, keep the shovel in the shed. However, as a fool, at midnight,
I checked a link in this string, and had to get the shovel out and the hip boots on. It got pretty deep.

cheers
steve
« Last Edit: August 28, 2020, 02:38:26 PM by steve »
Steve Sammet (Owner, Electron Eng, SAS Audio Labs, Ret)
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Offline steve

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Re: I think my System is finally finished
« Reply #42 on: August 28, 2020, 02:36:07 PM »
hi steve,

i suspect this is the midwoofer that coincident uses in its top speakers:
https://www.madisoundspeakerstore.com/approx-6-midrange/accuton-c173-6-090-6.5-ceramic-cone-midrange/
its fs is 57hz, and it's crossed over to subwoofers at 100hz in the coincidents; it's not the fs of 581hz like the one you linked.  and no large frequency peak at higher frequencies like the one you linked.

and the point scotty made re: distortion, the midrange driver i linked has ~1.5% 2nd order distortion between 5-6khz, (no 3rd order to speak of); accuton says this about it:
"Anti-resonant cutout fills in the ceramic dome provide for damping of the 6 kHz dome resonance."

and this is the tweeter:
https://www.madisoundspeakerstore.com/hard-dome-tweeter/accuton-c30-6-024-1.2-ceramic-dome-tweeter-neodymium-magnet/

and, its 1st order crossover implementation is minimal - 1 cap and 1 inductor on the mid/tweet. and 1 inductor on the mid/subwoofers.

coincident may have some custom work done for its drivers by accuton, but as-is, the driver's frequency plots seem to indicate they could blend well, with appropriate cabinetry and crossover design.  and that audio nerd arthur salvatore, who has interesting things to say about all things audio, [http://www.high-endaudio.com/], thinks the top coincident model is the best speaker period, regardless of price.  personally, i'd love to hear these speakers.  there's a pair of the next model down - same drivers, but one box - f/s used at a great price, and i'm sorely tempted.  too bad i'm on furlough at present.  or maybe, it's a good thing!  ;)

doug s.

Don't get me wrong Doug, I really appreciate the suggestions and thoughtfulness. I think I have heard of Accuton, but never
checked them out.

It is just that I am extremely picky when it comes to drivers, and I almost always go with the flattest response. Yes, there are other parameters such as cone material, the ts and Xmax values etc that I also take into account.

Past this point is more for newbies, not at Doug.

For instance, Qts is all important for me when it comes to woofers for my test speaker. An Fs of 20hz with a Qts of .2 is not what I am looking for when I want response to 20hz. I want accurate and tight response even with a tube amp.

Interestingly, two amplifiers can have a damping factor of 10, yet one will "sound" tight bass while the other will have flabby bass.

I went with the old tried and tested big box because it just sounds better than all these new concept types using
the above parameters (Fs 20 and Qts of .2). One of the comments I receive is how in the world did I get such taut and
natural sounding bass (both electric and double bass). Proper speaker design and proper amplifier design.
I realize that many folks do not like large 4.5 cubic foot cabinets. But I find it yields the best bass response. (Even with a 12"
woofer, the Xmas, cone movement, limits the spl of deep bass.)

I don't know which midrange or tweeter is used in a particular design.
But here is the response of a 2" Accuton Cell C51-6-286 2" Ceramic Dome Midrangemidrange driver.

https://www.madisoundspeakerstore.com/approx-2-midrange/accuton-cell-c51-6-286-2-ceramic-dome-midrange/

Below is the FR plot. Using a 1st order, 6db/octave crossover at 4khz is begging for problems. There is
going to be a problem due to the rise above 10khz. My system would easily expose the problem.
A special low pass filter is needed above 10khz or so. But that is more parts which will also influence the purity.
One could also use a 4th order, but again too many parts for me.

Anyway, that is my rant for now.

Cheers and thanks for thinking of me Doug. I do appreciate your thoughtfulness.

steve

Hi Doug,

Yes, he picked some of the better drivers which is good. There are still some questions I would ask myself though.

The tweeter looks pretty good, although I would like to check out the off axis response. Does it beam? I take it he minimized that
effect. If I had a choice, and gobs of money etc I would go for the Heils air motion transformers, maybe even the ionized helium, requiring tanks. Nah, the tanks are too much bother.
But so far so good.

The midrange is another matter between 2-4khz, within the most sensitive portion of the ear. I still don't like the 5khz and above
either as there is not a gentle, linear downward slope from 1.8khz to 8khz. That 5db "roughness in response" is going to show an unevenness when combined with the tweeters overlaping response. The worst part is the dip covers a whole octave, well above
the 1/3 octave width Rane claims is the minimum width necessary for being perceivable. Less than 1/3 octave is generally not perceivable.

Forgot to mention DB spikes and dips are directly added. For instance, if we have a spike of 5db, then the overlap will show the
5db spike. If we have a dip of 5db, then the overlap will dip 5db.

Not to worry Doug, I have had the same problem whenever I look at any 3 way design. Overlapping always occurs, worse with lower order crossover designs. That is why I went with a two way design, just one overlap to deal with, and at a much lower frequency.

Cheers

steve
« Last Edit: August 29, 2020, 05:59:06 PM by steve »
Steve Sammet (Owner, Electron Eng, SAS Audio Labs, Ret)
SAS "V" 39pf/m 6N copper ICs,
SAS Test Phono Stage
Acutex 320 STR Mov Iron Cart
SAS 11A Perfect Tube Preamp
SAS 25 W Ref Triode/UL Monoblocks
2 way Floor Standing Test Speakers

Offline steve

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Re: I think my System is finally finished
« Reply #43 on: September 12, 2020, 07:34:40 PM »
Well, I made two more adjustments to the system. I went back to ten 18 gauge wires on both legs of my speaker cables.
This necessitated the lessening of the inductance by ~1 inch of one turn. These adjustments affect mainly the
upper bass/lower midrange output, which affects the perception across the entire audio band.

Going to check over many selections to see if any other touch ups might be necessary.

This is one minute adjustment, yet still made a positive sonic difference in the "lab".

cheers

steve
« Last Edit: September 12, 2020, 07:40:18 PM by steve »
Steve Sammet (Owner, Electron Eng, SAS Audio Labs, Ret)
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SAS 11A Perfect Tube Preamp
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Offline steve

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Re: I think my System is finally finished
« Reply #44 on: September 13, 2020, 06:17:35 PM »
Could be good, but I am not everyone. I use specs, but even more, sophisticated/proprietary listening tests, that no one else uses. I have also "worked" with some exemplary individuals if I may.

Jneutron and I communicated and posted together some years ago. Jneutron worked at FermiLab, then Cern when they were designing and building it, last I heard J is at Brookhaven National Laboratory. He has "professored" other scientists in the classroom, and been an audiophile/music lover for some two decades now.

Decades ago, when fussing over parts quality, I spent some time conversing with Jenalabs. Michael worked as a sub-contractor on the probes that ventured outside our solar system and Jennifer worked on some "minor" government research projects. They gave me clues which parts were the most accurate, thus saving me valuable time.
By the way, I personally checked out their suggestions for myself.

I ran the lab in college, then my own lab for some decades. I have had students and professors consult me, not often, concerning audio projects etc.

One of the flags I look for when checking out a speaker is what electronic components are used to evaluate said speaker design. Using DHT is yesterdays news, and indicates what their "reference" is. DHTs have inherent limitations/flaws that limit the musical quality. Everything follows laws, whether it is room acoustics, parts quality, the design, or listening tests, in otherwards true Physics, not personal theories.

One of the major barriers that is occurring is that NOS tubes are fleeting, prices are rising; so the challenge is to produce a component that is superior without them. It Can be done.

That is where the 10A and 11A preamplifiers come in. Both preamplifiers are designed around new production tubes.
Both models consistently beat the competition, which use expensive NOS tubes, regardless of price.

That is why you won't find a used 11A for sale. The question is, who will continue the legacy when I am gone?

Sorry for the rant but my string has the goal of informing what is possible in audio vs what others are preaching dooms day with newly manufactured tubes.

I like the Heils, but the crossover point dictates a three way system imo. I would not use one with a xover at 800hz or lower as one would have to address Mr. Doppler, which degrades the sound. I would also not like one higher, say 1.6-2khz either.

I hope you can see my goal more clearly, I have been in uncharted territory for well over 20 years.

cheers

steve



 

re: the accutons; well, while not having heard mr blume's top creations, all i can say is i've never heard anyone who has, say anything less than they're one of the best speakers they've ever heard.

interesting you should mention the heil amt's.  their largest driver - 6" tall -  is rated 800hz to 20khz and 96db efficient.  i've always wondered how a stack (8, 9 or 12 drivers per side) would sound.  retail for 24 of them would be $4800 - not chump change, but within the realm of affordability.  ( and if you wanted to buy 24, i suspect the mfr might provide a bit of a price break.)  i wonder how low you could cross them, if running that many.  12 drivers would be something like ~106-107db efficient; i bet you could cross them over quite a bit lower and be successful, w/eq...

best,

doug s.

Hi Doug,

Yes, he picked some of the better drivers which is good. There are still some questions I would ask myself though.

The tweeter looks pretty good, although I would like to check out the off axis response. Does it beam? I take it he minimized that
effect. If I had a choice, and gobs of money etc I would go for the Heils air motion transformers, maybe even the ionized helium, requiring tanks. Nah, the tanks are too much bother.
But so far so good.

The midrange is another matter between 2-4khz, within the most sensitive portion of the ear. I still don't like the 5khz and above
either as there is not a gentle, linear downward slope from 1.8khz to 8khz. That 5db "roughness in response" is going to show an unevenness when combined with the tweeters overlaping response. The worst part is the dip covers a whole octave, well above
the 1/3 octave width Rane claims is the minimum width necessary for being perceivable. Less than 1/3 octave is generally not perceivable.

Forgot to mention DB spikes and dips are directly added. For instance, if we have a spike of 5db, then the overlap will show the
5db spike. If we have a dip of 5db, then the overlap will dip 5db.

Not to worry Doug, I have had the same problem whenever I look at any 3 way design. Overlapping always occurs, worse with lower order crossover designs. That is why I went with a two way design, just one overlap to deal with, and at a much lower frequency.

Cheers

steve
« Last Edit: December 28, 2020, 02:14:45 PM by steve »
Steve Sammet (Owner, Electron Eng, SAS Audio Labs, Ret)
SAS "V" 39pf/m 6N copper ICs,
SAS Test Phono Stage
Acutex 320 STR Mov Iron Cart
SAS 11A Perfect Tube Preamp
SAS 25 W Ref Triode/UL Monoblocks
2 way Floor Standing Test Speakers