Author Topic: I think my System is almost finally finished  (Read 12691 times)

Offline rollo

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Re: I think my System is finally finished
« Reply #90 on: March 09, 2022, 01:18:37 PM »
  Steve Youtube has better sonics ?? That is very interesting to hear that.

charles
contact me  at rollo14@verizon.net or visit us on Facebook
Lamm Industries - Aqua Acoustic, Formula & La Scala DAC- INNUOS  - Rethm - Kuzma - QLN - Audio Hungary Qualiton - Fritz speakers -Gigawatt -Vinnie Rossi,TWL, Swiss Cables, Merason DAC.

Offline steve

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Re: I think my System is finally finished
« Reply #91 on: March 09, 2022, 08:15:08 PM »
I think I can answer Nick's, Don's, and Charles's comments and questions in this post.

A few things most already know. But some do not.

1. It has a DAC chip.

2. It  has a following analog chip for gain of about 2, or 6db.

3. The analog chip has no markings/labels.

4. There is no re clocking in this little dac, thus a good usb cable is necessary. (The supra usb cable turned out to be great.)

5. The DAC chip includes both digital and analog circuitry with two power inputs, one for digital and the other for the analog sections. I have no idea of how many transistors are incorporated in the analog section of the chip. We also have X number of solid state resistors and capacitors (silicon types) within the analog section.

Fortunately, Schiit did a wonderful job with the digital part or I would not have gotten the resultant superior quality of my upgrade. However, the analog section is a quite different matter. But then for the $99.00 price point set, what should one expect, not faulting the company at all; they wanted to reach a certain market. Nothing wrong with that.

There is nothing to be done with the analog section of the DAC chip. I have not spent a ton of time on this DAC, no schematic. So I have left the analog chip connected.

One of the faults I often see in players/dacs is the power supply simply using electrolytic capacitors and typical solid state voltage regulators. Both degrade the sound. However, using poly caps takes a huge amount of room. I used a 17" by 10" by 3" chassis for all the parts in my upgrade. I used a variety from my parts bin from yesteryear. Is it possible to improve further? I don't see how, but I need to investigate not assume for that possible ounce.

Maybe I will tweak a little more on the DAC if I can get a schematic. But right now I don't see why.

---------

Charles, I rewrote the last paragraph of my last post to be clearer. What I am saying is that even though I mainly use Youtube premium (many more selections), the sound is more natural, transparent, dynamic etc etc than any other audio system I have ever auditioned over the decades, and those systems used redbook/high rez, or turntable and cost xxxx. (I can use redbook or high rez, even turntable as well, but you tube has so many more selections.)

What I found, as a result of my decades of research is how far off my initial designs were 40 years ago (and other stereo designs to this day) are from accurate. I iinitially fell into the same trap as others, that solving a few
equations is enough, but it is far from true.

Another major factor is the distorted history of ancient designs becoming so propagated, as to become "law".
The problem is one never sees and understands the inherent flaws of those ancient designs. How many times
has one seen the inherent flaws of any design posted? The next question becomes how does one overcome
decades of misinformation by those ignorant of all the science required, yeet claiming expertise. Of course, there
are obvious conflicts of interest with advertisers.

I have mentioned that solving a few equations won't produce an accurate/truly natural sounding component..
The paradigm of what is considered "superior" sound quality was based on just a few equations and lack of
understanding of designs across the decades,d with little understanding of the science.

-------

Here is another question I have. If the older electronic designs/systems are so good, then why are small speaker enclosures being pushed with high power SS amps, instead of sticking with large speaker enclosures? (My large enclosures are only 11" wide.) Is space the only answer?

I hope this has helped in understanding.

Cheers

steve

« Last Edit: July 28, 2022, 10:05:04 PM by steve »
Steve Sammet (Owner, Designer, Electron Eng, SAS Audio Labs, Ret)
SAS "V" 39pf/m 6N copper ICs,
SAS Test Phono Stage
Accutex 320 iii STR Mov Iron Cart
SAS 11A Ref Tube Preamp
SAS 25 W Reference Triode/UL Monoblocks
2 way Floor standing Test Speaker

Offline rollo

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Re: I think my System is finally finished
« Reply #92 on: March 10, 2022, 12:13:30 PM »
  Always a pleasure learning from you.
charles
contact me  at rollo14@verizon.net or visit us on Facebook
Lamm Industries - Aqua Acoustic, Formula & La Scala DAC- INNUOS  - Rethm - Kuzma - QLN - Audio Hungary Qualiton - Fritz speakers -Gigawatt -Vinnie Rossi,TWL, Swiss Cables, Merason DAC.

Offline steve

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Re: I think my System is finally finished
« Reply #93 on: April 06, 2022, 07:23:12 PM »
Thanks Charles. I try to pass important information on, as long as it does not reveal classified company secrets. (I learned that from all the politicians and company execs over the decades.)

I have found that as I improve the system using redbook, hi rez, tidal, that YouTube premium also improves. Got to
give the public some selections that the public can test, adjust, and hopefully help their systems.

Yes, there can be "touch ups" when switching to YT P, but there are so many selections that the others just don't have available but the public loves to listen to. I am hoping that the public sees what is possible in the lab and that stereo improvement is still possible in this day and age.

By the way, my preamplifier and monoblock amplifier design were manufactured in the real world,
and did not use NOS tubes, just modern tubes. The speaker was too cumbersome to move around
or test at other venues.

Anyone wish to come by for an audition, just give a shout.

cheers and thanks again.

steve
« Last Edit: July 28, 2022, 10:11:18 PM by steve »
Steve Sammet (Owner, Designer, Electron Eng, SAS Audio Labs, Ret)
SAS "V" 39pf/m 6N copper ICs,
SAS Test Phono Stage
Accutex 320 iii STR Mov Iron Cart
SAS 11A Ref Tube Preamp
SAS 25 W Reference Triode/UL Monoblocks
2 way Floor standing Test Speaker

Offline steve

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Re: I think my System is finally finished
« Reply #94 on: April 28, 2022, 12:13:05 PM »
A tidbit (for diyers) on your audio quest is the elimination of electrolytic capacitors as decoupling capacitors. Decoupling
capacitors are capacitors that connect to the plate resistor (or collector/drain resistor in solid state
devices) and ground.

In the schematic below, the C1 capacitor connected between RL plate resistor and ground. Decoupling capacitors are
in nearly every stage of the source, preamp, and amplifier.

Even one electrolytic capacitor in your system will cause loss of audio quality, the realism, naturalness of the music.
If all the electrolytic decoupling capacitors were eliminated, that last one makes the most difference. As one adds more electrolytic decoupling capacitors, the effect is less but still perceived. A typical audio system could have up to a dozen or more. That is a lot of degradation to the musical quality.

Unfortunately, electrolytics are generally necessary in the main high voltage power supply for output stages due to the high capacitance (ufd) needed; especially in solid stage amps.

The one obvious hang up is a polypropylene cap's physical size.

But if realism, naturalness is your goal, ridding of electrolytic decoupling capacitors is a positive.

cheers

steve


« Last Edit: July 01, 2022, 01:10:23 PM by steve »
Steve Sammet (Owner, Designer, Electron Eng, SAS Audio Labs, Ret)
SAS "V" 39pf/m 6N copper ICs,
SAS Test Phono Stage
Accutex 320 iii STR Mov Iron Cart
SAS 11A Ref Tube Preamp
SAS 25 W Reference Triode/UL Monoblocks
2 way Floor standing Test Speaker

Offline steve

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Re: I think my System is finally finished
« Reply #95 on: June 30, 2022, 09:42:31 AM »
Doing a little cleaning out my favorites, I found this string from AC forum.

https://www.audiocircle.com/index.php?topic=114637.0

I found a tiny tweak in the up graded DAC's power supply, just a little cleaner in the upper bass, lower midrange.

I know, I know, I performed a tweak. Well, all I can say is that it was extremely minor.

cheers

steve
« Last Edit: June 30, 2022, 09:44:33 AM by steve »
Steve Sammet (Owner, Designer, Electron Eng, SAS Audio Labs, Ret)
SAS "V" 39pf/m 6N copper ICs,
SAS Test Phono Stage
Accutex 320 iii STR Mov Iron Cart
SAS 11A Ref Tube Preamp
SAS 25 W Reference Triode/UL Monoblocks
2 way Floor standing Test Speaker

Offline Nick B

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Re: I think my System is finally finished
« Reply #96 on: June 30, 2022, 04:24:15 PM »
Doing a little cleaning out my favorites, I found this string from AC forum.

https://www.audiocircle.com/index.php?topic=114637.0

I found a tiny tweak in the up graded DAC's power supply, just a little cleaner in the upper bass, lower midrange.

I know, I know, I performed a tweak. Well, all I can say is that it was extremely minor.

cheers

steve

Hi Steve,

Audiophiles  donít forget great products. I imagine you occasionally get in an 11a or a 10a to replace caps or do some other maintenance. As to your dac, Iím assuming you are still using the Schiit Modi 2?
Van Alstine SET 120 Control Amp
Supratek Chardonnay preamp
Fritz Carrera 7 BE speakers
Border Patrol SEi dac
iFi Zen Stream & Mojo Audio lps
Wywires Silver cables & Audio Envy power cords
Roon, Tidal, Qobuz
PI Audio UberBUSS

Offline steve

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Re: I think my System is almost finally finished
« Reply #97 on: July 01, 2022, 12:56:27 PM »
Doing a little cleaning out my favorites, I found this string from AC forum.

https://www.audiocircle.com/index.php?topic=114637.0

I found a tiny tweak in the up graded DAC's power supply, just a little cleaner in the upper bass, lower midrange.

I know, I know, I performed a tweak. Well, all I can say is that it was extremely minor.

cheers

steve

Hi Steve,

Audiophiles  donít forget great products. I imagine you occasionally get in an 11a or a 10a to replace caps or do some other maintenance. As to your dac, Iím assuming you are still using the Schiit Modi 2?

Hi Nick,

To answer your last question first, yes I am still using the hugely upgrade Modi 2. I adjusted the
power supply uf total just a hair as well as the voltage rating for one cap. What is sometimes irking
is that the shape and voltage rating of a cap affects the sonics. Of course higher voltage rating,
more conductor area, more resistance involved.

I have 16 smaller poly caps in parallel in the power supply for the analog chip gain stage. For
another tweak, I could change the other analog supply, with 5 caps, and go with a bunch of smaller
and see what happens.

I just can't stop tinkering for that final gram of improvement, and I thought I could go no farther when I
started this string. The title of this string makes me a hypocrite, so I changed the title to almost finally
finished.

Concerning your first comment, actually no 10As have come for at least a decade or more. The last one I
recall working on had the gold plating of a tube socket filament pin separate, causing an intermittent tube
filament from heating.

I have had two 11As that needed repair a very long time ago. The first was on the initial tour
(~17 years ago?), when a Mills military grade resistor became noisy. The second 11A, in Europe,
an intermittent audio output relay (in parallel) that sometimes refused to open after 45 seconds.

I have tinkered around, on my own 11A, with switching the initial electrolytic capacitor to poly, so it will
last forever (except for lightning strike). This does not affect the sonics because I use a hefty 5 filter
stages after it. I attribute the longevity for two reasons.

1. The caps have very little surge and repetitive peak currents; far far below max rated. Just a few ma.
(milliamps).

2. The operational temperature is just a few degrees F above room temp. I believe the general rule of
thumb is that for every 20 degrees F below max rated temperature by the manufacturer, one can double
the hours of useful life. By the way, the hours rating by manufacturer is at both maximum temperature and
maximum ripple current. Peak current is also minimal.

Just calculating by temperature, I arrived at 90,000 hours. Since the ripple current in the 10A/11A is just
a few ma., the life should be much higher.

One customer, I replaced a couple of resistors to Vishay naked Bulk foil after I tested them in my 11A.
I think they are a little bit better than the originals. No one else has contacted me for the Vishays.

If I have missed something, please correct me, but I don't think so.

Cheers and happy 4th Nick and Gents.

steve


« Last Edit: July 28, 2022, 10:20:38 PM by steve »
Steve Sammet (Owner, Designer, Electron Eng, SAS Audio Labs, Ret)
SAS "V" 39pf/m 6N copper ICs,
SAS Test Phono Stage
Accutex 320 iii STR Mov Iron Cart
SAS 11A Ref Tube Preamp
SAS 25 W Reference Triode/UL Monoblocks
2 way Floor standing Test Speaker

Offline Nick B

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Re: I think my System is almost finally finished
« Reply #98 on: July 01, 2022, 10:29:50 PM »
Doing a little cleaning out my favorites, I found this string from AC forum.

https://www.audiocircle.com/index.php?topic=114637.0

I found a tiny tweak in the up graded DAC's power supply, just a little cleaner in the upper bass, lower midrange.

I know, I know, I performed a tweak. Well, all I can say is that it was extremely minor.

cheers

steve

Hi Steve,

Audiophiles  donít forget great products. I imagine you occasionally get in an 11a or a 10a to replace caps or do some other maintenance. As to your dac, Iím assuming you are still using the Schiit Modi 2?

Hi Nick,

To answer your last question first, yes I am still using it. I adjusted the power supply uf total just a hair
as well as the voltage rating for one cap. What is sometimes irking is that the shape and voltage rating
of a cap affects the sonics. Of course higher voltage rating, more conductor area, more resistance involved.

I have 16 smaller poly caps in parallel in the power supply for the analog chip gain stage. For
another tweak, I could change the other analog supply, with 5 caps, and go with a bunch of smaller
and see what happens.

I just can't stop tinkering for that final gram of improvement, and I thought I could go no farther when I
started this string. The title of this string makes me a hypocrite. I will change the title to almost finally finished.

Concerning your first comment, actually no 10As have come for a decade or more. The last one I recall
working on had the gold plating of a tube socket filament pin separate, causing an intermittent tube
filament heating.

I have had two 11As that needed repair. The first was on the initial tour (~17 years ago?), when a Mills military
grade resistor became noisy. The second 11A, in Europe, an intermittent audio output relay (in parallel) that
sometimes refused to open after 45 seconds, thus the output remained shorted to ground. I believe that was
a decade, give or take, ago.?

I have tinkered around, on my own 11A, with switching the initial electrolytic capacitor to poly, so it will
last forever. This does not affect the sonics because I use a hefty 5 filter stages after it. I checked the
caps in the drawer, and in use, and after 20 years they are still measuring near perfect. I can only
attribute such to two reasons.

1. The caps have very little surge and repetitive peak currents; far far below max rated. Just a few ma.

2. The operational temperature is just a few degrees F above room temp. I believe the general rule of
thumb is that for every 20 degrees F below max rated temperature by the manufacturer, one can double
the hours of useful life. The hours rating by manufacturer is at max temperature and ripple current.

Just calculating by temperature, I arrived at 90,000 hours. Since the ripple current in the 10A/11A is just
a few ma., the life should be much higher.

One customer, I replaced a couple of resistors to Vishay naked Bulk foil after I tested them in my 11A.
I think they are a little bit better than originals. No one else has contacted me for the Vishays.

If I have missed something, please correct me, but I don't think so.

Cheers and happy 4th Nick and Gents.

steve


Hi Steve,

Glad that Modi is sounding excellent. I remember when Jeff at Sonic Craft on AC was raving about the performance of a Bifrost after some mods. Iím surprised you didnít have a number of customers asking you to make changes over the years.  We all get curious over time if a piece of equipment can be made to sound better. I am also curious if a 10a unit can be brought up to the specs of an 11a and has anyone requested that.

As to the yearning to keep tinkering and improving, thatís what this hobby is all about!  :thumb:
Van Alstine SET 120 Control Amp
Supratek Chardonnay preamp
Fritz Carrera 7 BE speakers
Border Patrol SEi dac
iFi Zen Stream & Mojo Audio lps
Wywires Silver cables & Audio Envy power cords
Roon, Tidal, Qobuz
PI Audio UberBUSS

Offline steve

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Re: I think my System is almost finally finished
« Reply #99 on: July 02, 2022, 08:56:36 PM »
Doing a little cleaning out my favorites, I found this string from AC forum.

https://www.audiocircle.com/index.php?topic=114637.0

I found a tiny tweak in the up graded DAC's power supply, just a little cleaner in the upper bass, lower midrange.

I know, I know, I performed a tweak. Well, all I can say is that it was extremely minor.

cheers

steve

Hi Steve,

Audiophiles  donít forget great products. I imagine you occasionally get in an 11a or a 10a to replace caps or do some other maintenance. As to your dac, Iím assuming you are still using the Schiit Modi 2?

Hi Nick,

To answer your last question first, yes I am still using it. I adjusted the power supply uf total just a hair
as well as the voltage rating for one cap. What is sometimes irking is that the shape and voltage rating
of a cap affects the sonics. Of course higher voltage rating, more conductor area, more resistance involved.

I have 16 smaller poly caps in parallel in the power supply for the analog chip gain stage. For
another tweak, I could change the other analog supply, with 5 caps, and go with a bunch of smaller
and see what happens.

I just can't stop tinkering for that final gram of improvement, and I thought I could go no farther when I
started this string. The title of this string makes me a hypocrite. I will change the title to almost finally finished.

Concerning your first comment, actually no 10As have come for a decade or more. The last one I recall
working on had the gold plating of a tube socket filament pin separate, causing an intermittent tube
filament heating.

I have had two 11As that needed repair. The first was on the initial tour (~17 years ago?), when a Mills military
grade resistor became noisy. The second 11A, in Europe, an intermittent audio output relay (in parallel) that
sometimes refused to open after 45 seconds, thus the output remained shorted to ground. I believe that was
a decade, give or take, ago.?

I have tinkered around, on my own 11A, with switching the initial electrolytic capacitor to poly, so it will
last forever. This does not affect the sonics because I use a hefty 5 filter stages after it. I checked the
caps in the drawer, and in use, and after 20 years they are still measuring near perfect. I can only
attribute such to two reasons.

1. The caps have very little surge and repetitive peak currents; far far below max rated. Just a few ma.

2. The operational temperature is just a few degrees F above room temp. I believe the general rule of
thumb is that for every 20 degrees F below max rated temperature by the manufacturer, one can double
the hours of useful life. The hours rating by manufacturer is at max temperature and ripple current.

Just calculating by temperature, I arrived at 90,000 hours. Since the ripple current in the 10A/11A is just
a few ma., the life should be much higher.

One customer, I replaced a couple of resistors to Vishay naked Bulk foil after I tested them in my 11A.
I think they are a little bit better than originals. No one else has contacted me for the Vishays.

If I have missed something, please correct me, but I don't think so.

Cheers and happy 4th Nick and Gents.

steve


Hi Steve,

Glad that Modi is sounding excellent. I remember when Jeff at Sonic Craft on AC was raving about the performance of a Bifrost after some mods. Iím surprised you didnít have a number of customers asking you to make changes over the years.  We all get curious over time if a piece of equipment can be made to sound better. I am also curious if a 10a unit can be brought up to the specs of an 11a and has anyone requested that.

As to the yearning to keep tinkering and improving, thatís what this hobby is all about!  :thumb:

Hi Nick,

Well, I suppose a tiny tweak is not too bad.

It took some major upgrading but the results were worth while, and cost was reasonable. I had the vast
majority of parts in the stock bin. In its stock form, the Modi 2 was quite poor. Fortunately, the problems
were in the analog sections.

I posted 'wanted to purchase Modi 2s' on several forums but not one response, so evidently no one
has one,,, or has one for sale???

No way to upgrade the 10A to the 11A; needs a completely different board.

I have been retired for some 10 years, and would not mind selling my designs, including the amps,
phono stage. I, of course, would teach them the advanced science necessary for their
understanding/knowledge. There is much more involved than one thinks, or as mentioned many
times, a few equations. And the antique designs bantied about will never get one there.

Cheers and great 4th.

steve
« Last Edit: July 28, 2022, 10:28:00 PM by steve »
Steve Sammet (Owner, Designer, Electron Eng, SAS Audio Labs, Ret)
SAS "V" 39pf/m 6N copper ICs,
SAS Test Phono Stage
Accutex 320 iii STR Mov Iron Cart
SAS 11A Ref Tube Preamp
SAS 25 W Reference Triode/UL Monoblocks
2 way Floor standing Test Speaker

Offline Nick B

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  • Posts: 3526
Re: I think my System is almost finally finished
« Reply #100 on: July 02, 2022, 11:06:01 PM »
Doing a little cleaning out my favorites, I found this string from AC forum.

https://www.audiocircle.com/index.php?topic=114637.0

I found a tiny tweak in the up graded DAC's power supply, just a little cleaner in the upper bass, lower midrange.

I know, I know, I performed a tweak. Well, all I can say is that it was extremely minor.

cheers

steve

Hi Steve,

Audiophiles  donít forget great products. I imagine you occasionally get in an 11a or a 10a to replace caps or do some other maintenance. As to your dac, Iím assuming you are still using the Schiit Modi 2?

Hi Nick,

To answer your last question first, yes I am still using it. I adjusted the power supply uf total just a hair
as well as the voltage rating for one cap. What is sometimes irking is that the shape and voltage rating
of a cap affects the sonics. Of course higher voltage rating, more conductor area, more resistance involved.

I have 16 smaller poly caps in parallel in the power supply for the analog chip gain stage. For
another tweak, I could change the other analog supply, with 5 caps, and go with a bunch of smaller
and see what happens.

I just can't stop tinkering for that final gram of improvement, and I thought I could go no farther when I
started this string. The title of this string makes me a hypocrite. I will change the title to almost finally finished.

Concerning your first comment, actually no 10As have come for a decade or more. The last one I recall
working on had the gold plating of a tube socket filament pin separate, causing an intermittent tube
filament heating.

I have had two 11As that needed repair. The first was on the initial tour (~17 years ago?), when a Mills military
grade resistor became noisy. The second 11A, in Europe, an intermittent audio output relay (in parallel) that
sometimes refused to open after 45 seconds, thus the output remained shorted to ground. I believe that was
a decade, give or take, ago.?

I have tinkered around, on my own 11A, with switching the initial electrolytic capacitor to poly, so it will
last forever. This does not affect the sonics because I use a hefty 5 filter stages after it. I checked the
caps in the drawer, and in use, and after 20 years they are still measuring near perfect. I can only
attribute such to two reasons.

1. The caps have very little surge and repetitive peak currents; far far below max rated. Just a few ma.

2. The operational temperature is just a few degrees F above room temp. I believe the general rule of
thumb is that for every 20 degrees F below max rated temperature by the manufacturer, one can double
the hours of useful life. The hours rating by manufacturer is at max temperature and ripple current.

Just calculating by temperature, I arrived at 90,000 hours. Since the ripple current in the 10A/11A is just
a few ma., the life should be much higher.

One customer, I replaced a couple of resistors to Vishay naked Bulk foil after I tested them in my 11A.
I think they are a little bit better than originals. No one else has contacted me for the Vishays.

If I have missed something, please correct me, but I don't think so.

Cheers and happy 4th Nick and Gents.

steve


Hi Steve,

Glad that Modi is sounding excellent. I remember when Jeff at Sonic Craft on AC was raving about the performance of a Bifrost after some mods. Iím surprised you didnít have a number of customers asking you to make changes over the years.  We all get curious over time if a piece of equipment can be made to sound better. I am also curious if a 10a unit can be brought up to the specs of an 11a and has anyone requested that.

As to the yearning to keep tinkering and improving, thatís what this hobby is all about!  :thumb:

Hi Nick,

Well, I suppose a tiny tweak is not too bad.

It took some major upgrading but Modi 2 is worth it. I had the vast majority of parts in the stock bin.
I posted 'wanted to purchase Modi 2s' on several forums but not one response, so evidently no one
has one,,, or for sale???

No way to upgrade the 10A to the 11A. Needs a completely different board.

I would not mind selling my designs, including the amps, phono stage, athough one can build the different
models from my schematics, board, parts etc. I, of course, would teach them the advanced science
necessary for their understanding/knowledge. There is much more involved than one thinks, or as
mentioned many times, a few equations.

Cheers and great 4th.

steve

Hi Steve.

Thanks for answering the questions about the preamps to satisfy my curiosity. You did an amazing job with that Modi 2 and liked it better than my border patrol dac. I had Gary Dews install the Jupiter beeswax caps and I sure like the sound. But I think in-spite of that, your Modi would still likely perform a bit better. I do like the border patrol a lot because of its engaging and natural presentationÖ.  My Supratek Chardonnay preamp resolves so beautifully and Iím very pleased it brings out the best in the border patrol.
Van Alstine SET 120 Control Amp
Supratek Chardonnay preamp
Fritz Carrera 7 BE speakers
Border Patrol SEi dac
iFi Zen Stream & Mojo Audio lps
Wywires Silver cables & Audio Envy power cords
Roon, Tidal, Qobuz
PI Audio UberBUSS

Offline steve

  • Audiologist
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  • Posts: 1040
Re: I think my System is almost finally finished
« Reply #101 on: July 03, 2022, 06:28:59 PM »
Doing a little cleaning out my favorites, I found this string from AC forum.

https://www.audiocircle.com/index.php?topic=114637.0

I found a tiny tweak in the up graded DAC's power supply, just a little cleaner in the upper bass, lower midrange.

I know, I know, I performed a tweak. Well, all I can say is that it was extremely minor.

cheers

steve

Hi Steve,

Audiophiles  donít forget great products. I imagine you occasionally get in an 11a or a 10a to replace caps or do some other maintenance. As to your dac, Iím assuming you are still using the Schiit Modi 2?

Hi Nick,

To answer your last question first, yes I am still using it. I adjusted the power supply uf total just a hair
as well as the voltage rating for one cap. What is sometimes irking is that the shape and voltage rating
of a cap affects the sonics. Of course higher voltage rating, more conductor area, more resistance involved.

I have 16 smaller poly caps in parallel in the power supply for the analog chip gain stage. For
another tweak, I could change the other analog supply, with 5 caps, and go with a bunch of smaller
and see what happens.

I just can't stop tinkering for that final gram of improvement, and I thought I could go no farther when I
started this string. The title of this string makes me a hypocrite. I will change the title to almost finally finished.

Concerning your first comment, actually no 10As have come for a decade or more. The last one I recall
working on had the gold plating of a tube socket filament pin separate, causing an intermittent tube
filament heating.

I have had two 11As that needed repair. The first was on the initial tour (~17 years ago?), when a Mills military
grade resistor became noisy. The second 11A, in Europe, an intermittent audio output relay (in parallel) that
sometimes refused to open after 45 seconds, thus the output remained shorted to ground. I believe that was
a decade, give or take, ago.?

I have tinkered around, on my own 11A, with switching the initial electrolytic capacitor to poly, so it will
last forever. This does not affect the sonics because I use a hefty 5 filter stages after it. I checked the
caps in the drawer, and in use, and after 20 years they are still measuring near perfect. I can only
attribute such to two reasons.

1. The caps have very little surge and repetitive peak currents; far far below max rated. Just a few ma.

2. The operational temperature is just a few degrees F above room temp. I believe the general rule of
thumb is that for every 20 degrees F below max rated temperature by the manufacturer, one can double
the hours of useful life. The hours rating by manufacturer is at max temperature and ripple current.

Just calculating by temperature, I arrived at 90,000 hours. Since the ripple current in the 10A/11A is just
a few ma., the life should be much higher.

One customer, I replaced a couple of resistors to Vishay naked Bulk foil after I tested them in my 11A.
I think they are a little bit better than originals. No one else has contacted me for the Vishays.

If I have missed something, please correct me, but I don't think so.

Cheers and happy 4th Nick and Gents.

steve


Hi Steve,

Glad that Modi is sounding excellent. I remember when Jeff at Sonic Craft on AC was raving about the performance of a Bifrost after some mods. Iím surprised you didnít have a number of customers asking you to make changes over the years.  We all get curious over time if a piece of equipment can be made to sound better. I am also curious if a 10a unit can be brought up to the specs of an 11a and has anyone requested that.

As to the yearning to keep tinkering and improving, thatís what this hobby is all about!  :thumb:

Hi Nick,

Well, I suppose a tiny tweak is not too bad.

It took some major upgrading but Modi 2 is worth it. I had the vast majority of parts in the stock bin.
I posted 'wanted to purchase Modi 2s' on several forums but not one response, so evidently no one
has one,,, or for sale???

No way to upgrade the 10A to the 11A. Needs a completely different board.

I would not mind selling my designs, including the amps, phono stage, athough one can build the different
models from my schematics, board, parts etc. I, of course, would teach them the advanced science
necessary for their understanding/knowledge. There is much more involved than one thinks, or as
mentioned many times, a few equations.

Cheers and great 4th.

steve

Hi Steve.

Thanks for answering the questions about the preamps to satisfy my curiosity. You did an amazing job with that Modi 2 and liked it better than my border patrol dac. I had Gary Dews install the Jupiter beeswax caps and I sure like the sound. But I think in-spite of that, your Modi would still likely perform a bit better. I do like the border patrol a lot because of its engaging and natural presentationÖ.  My Supratek Chardonnay preamp resolves so beautifully and Iím very pleased it brings out the best in the border patrol.

Hi Nick,

The Border Patrol that I tested is pretty darn good. No slouch that is for sure.
I remember I preferred the SS rectification with the box physically warmed up to be its most accurate,
natural.

For my system, I have the upgraded Modi 2 switched to "E", 24/192. I have improved the sound since it
was compared to the $4500 Lampizator and Border Patrol. Too bad music lovers live so far away.

I have come to the general conclusion that the main difference between DACs is in the analog sections.

This includes:

1. the digital to analog chip, analog section power source  (The digital section has a separate power source.)

2. the external analog gain stage of ~2 (6db). (Whether SS or tube, why have it and its associated parts.)

3. the power supply to the external gain stage

Great 4th, and to honor.

https://www.youtube.com/watch?v=Omd9_FJnerY

steve
« Last Edit: July 28, 2022, 10:32:36 PM by steve »
Steve Sammet (Owner, Designer, Electron Eng, SAS Audio Labs, Ret)
SAS "V" 39pf/m 6N copper ICs,
SAS Test Phono Stage
Accutex 320 iii STR Mov Iron Cart
SAS 11A Ref Tube Preamp
SAS 25 W Reference Triode/UL Monoblocks
2 way Floor standing Test Speaker

Offline Nick B

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  • Posts: 3526
Re: I think my System is almost finally finished
« Reply #102 on: July 03, 2022, 09:44:47 PM »
Thank you Steve. That is a very moving Fourth of July tribute.
https://youtu.be/Omd9_FJnerY
Van Alstine SET 120 Control Amp
Supratek Chardonnay preamp
Fritz Carrera 7 BE speakers
Border Patrol SEi dac
iFi Zen Stream & Mojo Audio lps
Wywires Silver cables & Audio Envy power cords
Roon, Tidal, Qobuz
PI Audio UberBUSS

Offline steve

  • Audiologist
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  • Posts: 1040
Re: I think my System is almost finally finished
« Reply #103 on: July 21, 2022, 07:09:48 AM »
Another tidbit is to lose the inductor if one can, especially when next to the decoupling capacitor.
Why? Because there is another filter capacitor on the other side of the inductor.

With the inductor in said circuit, that decoupling capacitor is not what you think it is.

The reactance of the inductor,  is determined by   XL = 2pi times F times L.

2pi is 6.28
F is frequency
L is inductance in henries

As one can see, as the frequency increases, the inductance increases.
The result is the isolation between the before and after filter capacitors varies with frequency.

One has two reactive filter capacitors with a reactive inductor/choke in between. When reactive
parts mix, nothing remains the same. It gets really messy.

However, a good power resistor provides constant isolation regardless of audio frequency.
(Better to have non inductive resistor to behave better at high frequencies.)

If that were not bad enough, it gets worse. The inductor has dc winding resistance. Below is
a circuit/photo showing how the inductive reactance and dc resistance deviate the frequency
response of a simple inductive/resistor circuit.

Instead of a straight diagonal line, it is curved. So the isolation between filter capacitors is
also curved vs frequency.

Simply put, the combination of inductance and dc resistance is not good.
(Unfortunately, SET amps need the inductors to minimize hum while keeping voltage losses to
a minimum. PP type amplifiers have rejection properties inherent to minimize hum.)

Any change in musical information is defined as distortion.

If possible, as a test, bypass the inductor with a power resistor equal to the
winding resistance, to keep the DC voltage constant and isolation between capacitors
constant vs frequency. (Hopefully the hum will be within limits.)

Cheers

steve

ps. I have edited several previous posts for clarity and more info.
 
« Last Edit: July 28, 2022, 10:33:34 PM by steve »
Steve Sammet (Owner, Designer, Electron Eng, SAS Audio Labs, Ret)
SAS "V" 39pf/m 6N copper ICs,
SAS Test Phono Stage
Accutex 320 iii STR Mov Iron Cart
SAS 11A Ref Tube Preamp
SAS 25 W Reference Triode/UL Monoblocks
2 way Floor standing Test Speaker