Author Topic: SENERGY What really is It ??  (Read 9395 times)

Offline rollo

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Re: SENERGY What really is It ??
« Reply #15 on: August 15, 2017, 08:00:50 AM »
   Very informative explanation of the science. Exactly what I look for in a component. Harmonic structure and tonality.  I put this question out there to hear the engineering or scientific reasons for component synergy.
  My subjective synergy combos are just that. You know a tubed pre with SS amp. DCs and tubes and so on. however if I'm choosing a speaker cable should I be aware of the capt ? Inductance, impedance as a guide to select contenders. When matching a Pre to amp output and input impedance of each is important.
  So what I'm looking for is a guide to help select the right stuff to audition.


charles
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Offline Nick B

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Re: SENERGY What really is It ??
« Reply #16 on: August 15, 2017, 08:37:09 AM »
Good posts. More harmonic structure is the missing ingredient  right now. As I've broken in the four receptacles on the Uber, I may plug the dac in soon with that in mind
Nick
Orchard Starkrimson Ultra amp
Supratek Chardonnay preamp
JMR Voce Grande speakers
Border Patrol SEi 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 Nick B

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Re: SENERGY What really is It ??
« Reply #17 on: August 15, 2017, 10:13:03 AM »
hi nick,

in the electrocoompaniet thread, i mentioned the stellar melos ma333r preamp f/s on agon and audiomart; and you said it was too spendy.  but, that's what you need in your system, imo, if you want "more harmonic structure".  you don't have to spend that much.  i saw three melos sha-1's sell recently on ebay, for $325 to $450.  (also one of the best headfone amps ever, according to the headfone freaks.)  this is a simple low-frills unit w/three line inputs.

and, there's one f/a now, w/discolored faceplate; a not uncommon feature of vintage black melos gear:
http://www.ebay.com/itm/253093887794

and another more traditional unit:
http://www.ebay.com/itm/172816881914

yes, i am partial to the melos preamps; mine was fabulous before i upgraded it.  i only had it upgraded because i could!  but, you don't have to get a melos just cuz i like it; there's other preamps out there as well, that garner good reviews.

also, i am curious - you mentioned in the ec thread about wanting to upgrade your speakers, possibly to sp tech.  what speakers do you have now; unless i am missing it, there's none listed in your signature, w/the rest of your stuff.

doug s.
Good posts. More harmonic structure is the missing ingredient  right now. As I've broken in the four receptacles on the Uber, I may plug the dac in soon with that in mind
Nick

Doug,
Can't believe I left the speakers out  :duh They are SP Tech 2.0 upgraded to 2.1 or 3.0 status. Where is that paperwork from 2008 ??? As I've seen your posts since you came on AN,  I'm comfortable trusting your judgment. But getting a Melos is kinda like shooting in the dark for me. It's also a bit difficult to comprehend that I'd be getting the excellent sq that I'm getting now from an older,  unmodded unit.
I'd be a bit more inclined to try a Tortuga LDR  and my Buddy Gary has one. If I'm extra nice, he may bring it from Vegas. At one time, I had thought of getting a McCormack unit, but the upgrade was more than I wanted to spend. I am going to read up more on the EC though as I've always thought favorably of the company.
Nick
Orchard Starkrimson Ultra amp
Supratek Chardonnay preamp
JMR Voce Grande speakers
Border Patrol SEi 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 Nick B

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Re: SENERGY What really is It ??
« Reply #18 on: August 15, 2017, 12:06:39 PM »
Hi Doug,
I believe you're right and a tube buffer may be the way to go for what I'm trying to achieve. I was on the Tortuga site and the cost of the buffer is way more than I want to spend right now. I checked out the Zman ASE and part of the description mentions a reduction in noise..lessening the harsh sound of CDs. Well that's fine, but the Uber already does a great job at lowering the noise floor with all the resultant benefits. But I'm trying to reproduce the harmonic structure of violins, guitars etc. or at least what they should sound like imo. All my components are capable of excellent resolution, so why am I not getting that right now and why would a tube buffer be able to do/create that? None of my audio buddies even use one afaik. I haven't checked out the Kaitlin yet. If any of your units are for sale, send me a pm if you'd like.
As a side note, I plugged in my dacs Voltikus power supply into the P and S polished receptacle. It's a fuller, seemingly more accurate sound. Very nice and an apparent improvement in "harmonic structure", but not there yet. More listening tonight in the later hours
Nick
Orchard Starkrimson Ultra amp
Supratek Chardonnay preamp
JMR Voce Grande speakers
Border Patrol SEi 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 Nick B

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Re: SENERGY What really is It ??
« Reply #19 on: August 15, 2017, 01:06:05 PM »
Ok, Doug. Thanks for the "sound" advice:thumb:
Nick

nick, the kailin mu-1 and the z-man have both been out of production for a long time; good luck finding one used.  mine are keepers; i find them useful in 2nd systems, and sometimes even w/a tubed preamp, in front of particularly dry sounding gear.

i am a firm believer in tubed preamps; they seem to me to provide that "je ne sais quoi" to a system that makes it sound more like real music instead of a recording.  (at least tube preamps that i like anyway!  :D)

a tube buffer (like the yaqin) is an inexpensive way to see what you think.  w/the particular yaqin i linked, i'd recommend some quality nos tubes; you still won't be out a ton of cash, and could always recoup most of the investment if it's not your cuppa.  and, i'd ask that seller if he would consider including the tubes he used in it - he obviously has other tubes or the ones he's including w/it would not be "unused"   8)

doug s.

Hi Doug,
I believe you're right and a tube buffer may be the way to go for what I'm trying to achieve. I was on the Tortuga site and the cost of the buffer is way more than I want to spend right now. I checked out the Zman ASE and part of the description mentions a reduction in noise..lessening the harsh sound of CDs. Well that's fine, but the Uber already does a great job at lowering the noise floor with all the resultant benefits. But I'm trying to reproduce the harmonic structure of violins, guitars etc. or at least what they should sound like imo. All my components are capable of excellent resolution, so why am I not getting that right now and why would a tube buffer be able to do/create that? None of my audio buddies even use one afaik. I haven't checked out the Kaitlin yet. If any of your units are for sale, send me a pm if you'd like.
As a side note, I plugged in my dacs Voltikus power supply into the P and S polished receptacle. It's a fuller, seemingly more accurate sound. Very nice and an apparent improvement in "harmonic structure", but not there yet. More listening tonight in the later hours
Nick
Orchard Starkrimson Ultra amp
Supratek Chardonnay preamp
JMR Voce Grande speakers
Border Patrol SEi 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 topround

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Re: SENERGY What really is It ??
« Reply #20 on: August 15, 2017, 02:03:24 PM »
I agree
a good tubed preamp would work wonders, the amp you have is very good I had a DNA 0.5 deluxe and loved it.
Also those speakers might be a little problem, I had the 2.0 for a while and while they play loud very cleanly they do not impart any great amount of love.
They are very neutral and fast, they really benefit from tubes, not trying to knock them just being honest in their sonic signature.

Tmazz has Nola Boxers. you might LOVE those, very musical speakers.

what is your budget for a preamp?
System consists of an amp a preamp, 2 speakers a turntable and a phono preamp, Also some cables and power cords and a really cheap cd player.

Offline steve

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Re: SENERGY What really is It ??
« Reply #21 on: August 15, 2017, 04:05:34 PM »
Things are a little more complicated than what might appear. There are several other factors to consider, this is not exhaustive. For general consumption.

Quote
and yes, impedance matching between pre and amp is important, as i mentioned. 

Not so much as one normally thinks. RCA Radiotron Designers Handbook suggests a 5:1 ratio, amp input Z to preamplifier output Z. I suggest, as you have heard, 10:1 to be safe. But that is normally calculated at midband. What is really important is across the entire audio band.

My Preamplifiers are approximately 1.9k output Z, and works fine to 20k amp input Z. So a buffer stage is not necessary. Why not? What is the scoop.

1) Let's examine high frequency first. Example: we have an IC capacitance of 100pf and amplifier input capacitance of 50pf, so 150pf in parallel with the 100k input resistor (100k input Z at 1khz).

The reactance of 150pf at 20khz is ~53k ohms. So at 20khz, we actually have 100k ohm in paralleled with 53k ohms of capacitive reactance (called "I").

However, the preamplifier output Z is in parallel with "I" and 100K resistor, so not that bad. With 1.9k output Z, the high frequency response exceeds half a mhz (550khz) before -3db. 

Believe it or not, the major limit on high frequency response is the volume control to tube grid input capacitance (including Miller effect). Not only that, the minimum frequency response (FR) occurs at mid resistance setting of the volume control. Using a 100k volume pot limits the HF more than a 50k or 25k pot.

2) Let's examine the low frequency response. Pretty easy as a coupling capacitor and following grid resistor. Here is some data.
Frequency 10hz. Grid resistor 100k ohms.

Coupling Capacitor          -db

1uf                                 .114
.82                                 .162
.68                                 .235
.47                                 .47
.33                                 .883
.22                                1.76
.1                                  5.5 db

With 50k grid resistor.

1uf                                 .38db
.1                                 10.

That is just one stage coupling. With multiple stages, dbs add. By the way, the 1uf coupling capacitor, - 0.116db at 10hz may seem small enough to not be perceived, but when additional stages and/or the OPT are considered, don't be so sure. By the way, bloated bass in tube amps is not so much damping factor, but more likely a power supply design problem.

Quote
my first foray into a tube preamp was the arc sp-9mkll.  in a word - it totally sucked.  it was worse than the adcom gfp-1a i was using at the time.  reading this thread, and seeing that tmazz uses an sp-9 in his system made me go and read a lot of articles on it, and what folks thought, good and/or bad.  one thing i gleaned was that the sp9 wants to see an amp w/minimum 60k ohm input impedance.  i knew nothing about that back then.  the amp i was using at the time has an input impedance of 22k ohms.  maybe that was why everything sounded like it had molasses poured over it; the sound was so thick, heavy and lifeless.

With a smaller 22k ohms, the sound should have been thinner than using 60k ohms minimum, not heavier. This leaves several possibilities.
One, the room is quite bass resonant.
Two, the speakers are not correctly matched for the venue,
Three, the speakers are bass heavy to begin with, due to either their venue or electronic components they used
Four, the other electronic components in your system are not designed properly, thus bass heavy

The proper way I have found is to design the electronics first, since the preamplifier and amplifier can be listening tested for accuracy. After that, then I worked teeter/totter with speaker/venue.

Quote
even so, i wonder, as the sp-9 mkll's output impedance is 250 ohms, and the standard rule of thumb is the amp's input impedance should be at least 10 times greater.  and tho arc recommends 60k ohm amp input, it also says "min 20k ohms".  but, in any event, preamp-amp impedance matching is definitely something to consider.

Although the rule of thumb 10:1 is good, as shown above, the real culprit is the output capacitor size and quality, and also the power supply, which I did not address.
 
There are some weird "rules of thumb", such as concerning the -3db point, way out of line.

Cheers

Steve

« Last Edit: August 15, 2017, 04:25:50 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
SAS 25 W Ref Triode/UL Monoblocks
2 way Floor Standing Test Speakers

Offline steve

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Re: SENERGY What really is It ??
« Reply #22 on: August 15, 2017, 06:06:29 PM »
steve, it could simply be that i think the sp-9 sucks!   :D  i was just trying to figure out a possible reason, as i know others are fond of it.  looking at the sp-9's specs, i suspect it's less likely any impedance mismatch, and more likely that i just don't like that preamp.

regarding the speakers and venue, i seriously doubt either was an issue.  the room was quite huge - ~20x40, w/ceiling vaulted to a 2nd story balcony along the 40' length.  and, tho i don't know the design specifics, i do know, just from my ears, that items 3 & 4 also don't apply.  nothing at all bass heavy was going on.  (and it wasn't bass heavy w/the sp-9 either - just dull lifeless sound.)  speakers were on the short wall, about 4' from the back wall.  there were some short walls in the room splitting it up, but it was basically one big open space.  speakers were thiel 3.5's, (flat to 20hz w/factory eq), amp was original series adcom gfa555 (smooth faceplate w/rack handles.)  the adcom gfp-1a was adequate, the sp-9 was not.  if anything the preamp should have been a good match, due to the sonic characteristics that have been attributed to the speakers and the amp. (at least according to the audio press.)  next preamp was an arcam delta 110 preamp; it was most excellent.  (a bud of mine still uses one; bought after he heard mine.)  that was followed by the electrocompaniet ec-1a; even better.  it was several years later before i tried another tube preamp; the melos ma333r completely thrashed the rogue magnum 99 and the cary spl98 that i was auditioning.  at that point, i stopped investigating preamps; the melos was that good.  (different venue, by then, and various speakers were now being actively crossed over to subs.)  i was really wanting to like the cary because it looked so nice, but it was not to be..

doug s.

Thanks for the info Doug. I hope you did not think I was simply addressing you, but for the audience in general. Your info was quite helpful, good logical way to address the problem. I too would estimate the SP9 was the culprit.

I find that components in general can be syrupy, "lifeless sound" and yet not overly bass because of undersized ufd while terminated improperly. The Orange Drop 716 copper lead polypropylene capacitors are known for this characteristic. Other brands as well.

I have mentioned that I am adjusting an ~ 9k ohm resistor by 0,05 ohms or less. That is one part in ~200,000. That is incredibly touchy. Adjust 0,05 ohms too much, and too much bass. Same the opposite. My work has demonstrated just how tough it is to get a system right.

Aside from our conversation, who knows what associated electronics or speakers are part of the manufacturer's test system. If their associated components are not accurate/natural, that has to be considered. Now back to our conversation.

There are a very few manufacturers who can design a great preamplifier. Glad the Melos worked out great.

One other thing. It has become apparent to me that the future will be those whose company can become "vertical" in nature. By that I mean that all the components, phono, preamp, amp, speakers are all designed together almost as one piece so to speak. I use separate components simply because it takes separate power supplies to optimize each stage of electronics.

I find the "audio press" to be questionable at best ever since, when I opened for business, one reviewer literally hammered my 10A and shipped it back to me destroyed because I would not sell it to them for $300.00. They, and friends, have attempted to destroy me several more times over the years.

Cheers

Steve
« Last Edit: August 15, 2017, 06:10:14 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 topround

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Re: SENERGY What really is It ??
« Reply #23 on: August 15, 2017, 06:21:19 PM »
I've never owned an SP9 but aren't they sort of known for a warmish vintage tone?
I think the magic started to happen at the SP10
System consists of an amp a preamp, 2 speakers a turntable and a phono preamp, Also some cables and power cords and a really cheap cd player.

Offline steve

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Re: SENERGY What really is It ??
« Reply #24 on: August 15, 2017, 08:32:04 PM »
Doug, you and anyone else are always welcome to visit if you get to central Illinois and see how my experiments are coming along. Just give me a shout/email before hand so I can warm the system up.

Getting ready for the eclipse. Tomorrow morning a shipment of special approved glasses is coming into town. This after every single pair has been sold a week ago. None to be had. Neighboring Peoria museum had 1000 pairs come in this morning, but by 1 pm were sold out. See if I can get some tomorrow, get in line early and hope the proper ISO is printed on them.

Cheers
Steve


steve, no problem - there's plenty here for everyone.  as i can't design equipment, i can only read what others say, and then use my best judgement as to what i might want to try, and then trust my ears.  you go into details as to why the sp9 may sound the way it does; could be; i have no way of knowing that.  those more technically inclined, that own this gear, might want to consider parts upgrades.   8)  me, personally, i am good at parts swapping, but someone needs to tell me what parts to swap!   :rofl:  i still have a wintage art di/o dac that i modded, and it's still competitive w/dacs costing a wee bit more...

everything i've read about what you have said over the years, and about what others have said about sas gear leads me to believe i'd enjoy sas products, tho i have never sampled...

there's something to be said about a mfr making gear that fits well with its other gear.  especially if people like the sonic signature of that mfr.  i know i'd love to hear the powered kef ls50 monitors, as i own a pair of the passives, and they are simply astounding, considering their size and cost.  and for me, personally, especially when it comes to speakers, i now believe that, even w/multi-driver speakers, separate amplification and active x-overs for each driver will give far more accuracy than will passive x-overs, even if the speakers are not by themselves, active.

doug s.
steve, it could simply be that i think the sp-9 sucks!   :D  i was just trying to figure out a possible reason, as i know others are fond of it.  looking at the sp-9's specs, i suspect it's less likely any impedance mismatch, and more likely that i just don't like that preamp.

regarding the speakers and venue, i seriously doubt either was an issue.  the room was quite huge - ~20x40, w/ceiling vaulted to a 2nd story balcony along the 40' length.  and, tho i don't know the design specifics, i do know, just from my ears, that items 3 & 4 also don't apply.  nothing at all bass heavy was going on.  (and it wasn't bass heavy w/the sp-9 either - just dull lifeless sound.)  speakers were on the short wall, about 4' from the back wall.  there were some short walls in the room splitting it up, but it was basically one big open space.  speakers were thiel 3.5's, (flat to 20hz w/factory eq), amp was original series adcom gfa555 (smooth faceplate w/rack handles.)  the adcom gfp-1a was adequate, the sp-9 was not.  if anything the preamp should have been a good match, due to the sonic characteristics that have been attributed to the speakers and the amp. (at least according to the audio press.)  next preamp was an arcam delta 110 preamp; it was most excellent.  (a bud of mine still uses one; bought after he heard mine.)  that was followed by the electrocompaniet ec-1a; even better.  it was several years later before i tried another tube preamp; the melos ma333r completely thrashed the rogue magnum 99 and the cary spl98 that i was auditioning.  at that point, i stopped investigating preamps; the melos was that good.  (different venue, by then, and various speakers were now being actively crossed over to subs.)  i was really wanting to like the cary because it looked so nice, but it was not to be..

doug s.

Thanks for the info Doug. I hope you did not think I was simply addressing you, but for the audience in general. Your info was quite helpful, good logical way to address the problem. I too would estimate the SP9 was the culprit.

I find that components in general can be syrupy, "lifeless sound" and yet not overly bass because of undersized ufd while terminated improperly. The Orange Drop 716 copper lead polypropylene capacitors are known for this characteristic. Other brands as well.

I have mentioned that I am adjusting an ~ 9k ohm resistor by 0,05 ohms or less. That is one part in ~200,000. That is incredibly touchy. Adjust 0,05 ohms too much, and too much bass. Same the opposite. My work has demonstrated just how tough it is to get a system right.

Aside from our conversation, who knows what associated electronics or speakers are part of the manufacturer's test system. If their associated components are not accurate/natural, that has to be considered. Now back to our conversation.

There are a very few manufacturers who can design a great preamplifier. Glad the Melos worked out great.

One other thing. It has become apparent to me that the future will be those whose company can become "vertical" in nature. By that I mean that all the components, phono, preamp, amp, speakers are all designed together almost as one piece so to speak. I use separate components simply because it takes separate power supplies to optimize each stage of electronics.

I find the "audio press" to be questionable at best ever since, when I opened for business, one reviewer literally hammered my 10A and shipped it back to me destroyed because I would not sell it to them for $300.00. They, and friends, have attempted to destroy me several more times over the years.

Cheers

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 tmazz

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Re: SENERGY What really is It ??
« Reply #25 on: August 15, 2017, 09:34:24 PM »
steve, it could simply be that i think the sp-9 sucks!   :D  i was just trying to figure out a possible reason, as i know others are fond of it.  looking at the sp-9's specs, i suspect it's less likely any impedance mismatch, and more likely that i just don't like that preamp.

regarding the speakers and venue, i seriously doubt either was an issue.  the room was quite huge - ~20x40, w/ceiling vaulted to a 2nd story balcony along the 40' length.  and, tho i don't know the design specifics, i do know, just from my ears, that items 3 & 4 also don't apply.  nothing at all bass heavy was going on.  (and it wasn't bass heavy w/the sp-9 either - just dull lifeless sound.)  speakers were on the short wall, about 4' from the back wall.  there were some short walls in the room splitting it up, but it was basically one big open space.  speakers were thiel 3.5's, (flat to 20hz w/factory eq), amp was original series adcom gfa555 (smooth faceplate w/rack handles.)  the adcom gfp-1a was adequate, the sp-9 was not.  if anything the preamp should have been a good match, due to the sonic characteristics that have been attributed to the speakers and the amp. (at least according to the audio press.)  next preamp was an arcam delta 110 preamp; it was most excellent.  (a bud of mine still uses one; bought after he heard mine.)  that was followed by the electrocompaniet ec-1a; even better.  it was several years later before i tried another tube preamp; the melos ma333r completely thrashed the rogue magnum 99 and the cary spl98 that i was auditioning.  at that point, i stopped investigating preamps; the melos was that good.  (different venue, by then, and various speakers were now being actively crossed over to subs.)  i was really wanting to like the cary because it looked so nice, but it was not to be..

doug s.

Wow, I find that interesting. I have had an SP-9 Mk1 since 1988 and never found it to be anything near lifeless.  And as a matter of fact I got the SP-9 not long after I replaced my Dahlquist DQ-10s with a pair of Theil 3.5s. The CJ Premier 2 that sounded so nice with the DQ-10s did not mate well with the Thiels, so out it went. I have compared the SP-9 with many preamps over the years and while so were somewhat better, I never felt the amount of SQ increased justified the $s I would have needed to spend to get it.The SP-9 has been used to drive a Moscode 600, a Classe Twenty Five, an ARC VT-200 an ARC D-130 and currently a pair of Quicksilver Mid Monos. In addition to the Thiel 3.5s it was used with Thiel CS-6s and now Nola Boxers. Throughout all of these combination I have always felt it performed like a champ.

I'm just curious, did you ever swap out the tubes while you had it? Perhaps and under-performing tube may have caused the sound you didn't like (of a bad passive part somewhere in the unit.

Or perhaps I just like it and you just don't. And that is a matter of personal opinion, which means neither is right or wrong, and that's perfectly OK.

I have often wondered if differences in personal taste might in some part  be driven by differences in the frequency response of our own ears, as opposed to those of other audiophiles. In reality what we hear out of our systems is a combination of the sound put out by the system and our own ears sensitivity to sound as a function of frequency. Could it be that we all have the same idea of what is good sound and our personal preferences are simply a way of finding equipment that is more compatible with the response of our own ears? Hmmmm.... but that is a topic for another discussion.
Remember, it's all about the music........

• Nola Boxers
• Sunfire True SW Super Jr (2)
• McIntosh MC 275
• ARC SP-9
• VPI HW-19 Mk IV/SDS/SME IV/Soundsmith Carmen Mk II ES
• Pro-Ject Pre Box S2 DAC/Rasp Pi Roon Endpoint
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Offline _Scotty_

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Re: SENERGY What really is It ??
« Reply #26 on: August 16, 2017, 01:57:43 PM »
While the amount of distortion a piece of gear has seldom tells the whole story, the SP 9 couldn't be described as having a low distortion circuit design as it does no better than 0.1 THD and by 10kHz this has deteriorated to 0.25THD. Looking at the specifications I initially thought it was a non-negative feedback design which is not the case.
 The ARC SP3A measured better than 0.005 THD using an all tube design with 12AX7s. I don't think there is any reason that circuit with 6DJ8s in it should intrinsically have as much distortion as the SP 9 has.
Scotty

Offline steve

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Re: SENERGY What really is It ??
« Reply #27 on: August 16, 2017, 02:22:33 PM »
While the amount of distortion a piece of gear has seldom tells the whole story, the SP 9 couldn't be described as having a low distortion circuit design as it does no better than 0.1 THD and by 10kHz this has deteriorated to 0.25THD. Looking at the specifications I initially thought it was a non-negative feedback design which is not the case.
 The ARC SP3A measured better than 0.005 THD using an all tube design with 12AX7s. I don't think there is any reason that circuit with 6DJ8s in it should intrinsically have as much distortion as the SP 9 has.
Scotty

With the JJs or new Telefunkens no way. I listed the 11A as 0,015%, had trouble measuring lower, and wanted a cushion due to possible tube variations.

I agree as parts quality and design makes a difference.

Cheers

Steve
« Last Edit: August 16, 2017, 02:24:27 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: SENERGY What really is It ??
« Reply #28 on: August 16, 2017, 09:27:30 PM »
While the amount of distortion a piece of gear has seldom tells the whole story, the SP 9 couldn't be described as having a low distortion circuit design as it does no better than 0.1 THD and by 10kHz this has deteriorated to 0.25THD. Looking at the specifications I initially thought it was a non-negative feedback design which is not the case.
 The ARC SP3A measured better than 0.005 THD using an all tube design with 12AX7s. I don't think there is any reason that circuit with 6DJ8s in it should intrinsically have as much distortion as the SP 9 has.
Scotty

With the JJs or new Telefunkens no way. I listed the 11A as 0,015%, had trouble measuring lower, and wanted a cushion due to possible tube variations.

I agree as parts quality and design makes a difference.

Cheers

Steve

Meant to say Scott, that with the JJs or new Telefunkens, that the distortion was way below 0,1%. I used my preamp as an example, which agrees with your assessment.

Cheers
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