Author Topic: A Problem With Solid State Devices  (Read 488 times)

Offline steve

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A Problem With Solid State Devices
« on: September 28, 2022, 02:53:32 PM »
Even with a 1N914/4148 high frequency type diode with only 1pf of capacitance, when reversed biased
the solid state device bleeds musical information through. A vacuum tube won't.
The bleed thru is not evenly across the band but frequency sensitive.

So can one actually ever achieve linear operation of a solid state component in an analog component?
Not much chance.

Tubes rule.

steve
« Last Edit: October 09, 2022, 03:31:43 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 Perfect Tube Preamp
SAS 25 W Reference Triode/UL Monoblocks
2 way Floor standing Test Speakers

Offline Nick B

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Re: A Solid State Device Problem.
« Reply #1 on: September 28, 2022, 07:37:30 PM »
Iíll agree with your tubes rule statement. Am running a tube preamp and the sound is captivating.
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: A Solid State Device Problem.
« Reply #2 on: September 29, 2022, 01:12:43 PM »
Iíll agree with your tubes rule statement. Am running a tube preamp and the sound is captivating.

I found out the problem by accident Nick, or I might not have believed it myself.
I have never heard anyone ever discuss solid state in this realm before.

The specs on the diode in no way gives a hint that bleed through is possible.
Only 1 micro micro farad of capacitance is next to zero. Yet the 1n4148 influences the
musical quality. Simply amazing.

There is a lot of science that is never discovered/tested, let alone discussed.

In one of my test designs, it took 5 reversed biased 1n4148 diodes in series to totally
block out the bleed through. Of course it depends upon the surrounding impedances (Z).

Cheers

steve
« Last Edit: September 29, 2022, 09:09:14 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 Perfect Tube Preamp
SAS 25 W Reference Triode/UL Monoblocks
2 way Floor standing Test Speakers

Offline Nick B

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Re: A Solid State Device Problem.
« Reply #3 on: September 29, 2022, 07:43:32 PM »
Iíll agree with your tubes rule statement. Am running a tube preamp and the sound is captivating.

I found out the problem by accident Nick, or I might not have believed it myself.
I have never heard anyone ever discuss solid state in this realm before.

I have worked with not only small signal diodes, but transistors, FETs as well.
There is a lot of science that is never discovered/tested, let alone discussed.

In one of my test designs, it took 5 reversed biased 1n4148 diodes in series to totally
block out the bleed through. Of course it depends upon the surrounding impedances (Z).

Cheers

steve

Thanks, Steve. :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: A Solid State Device Problem.
« Reply #4 on: October 02, 2022, 04:01:24 PM »
Thought a little bit more and a couple of reasons why.

1. Being a total solid, unlike a tube with a vacuum as an insolator, there is leakage current
through the junctions. Bipolars have what I would call high leakage currents.
Even capacitors from electrolytics to polys have leakage current.

2. Junction capacitance in transistors can cause problems. A 2 amp hexfet has variable capacitance
up to 25 volts from drain to source etc. At low voltages, the drain to gate capacitance was measured
over 1000pf. That is a .001uf capacitor.

The Miller effect is calculated as gain times drain to gate capacitance. If the gain were 10, the Miller
capacitance could 10,000pf, or .01uf capacitor. Some designers use only a .1uf capacitor for coupling.

Of course small signal transistors should have much less capacitance, but it does not take much
to "transfer" a signal from input to output.

Anyway, another example of science that is never considered.

cheers

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 Perfect Tube Preamp
SAS 25 W Reference Triode/UL Monoblocks
2 way Floor standing Test Speakers

Offline Folsom

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Re: A Solid State Device Problem.
« Reply #5 on: October 02, 2022, 10:19:27 PM »
Now this is a topic I can approve of!

I can tell you that I'm an absolute nut job over picking diodes for rectification. Should I move to tube rectifiers?

Offline steve

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Re: A Solid State Device Problem.
« Reply #6 on: October 03, 2022, 01:22:23 PM »
Now this is a topic I can approve of!

I can tell you that I'm an absolute nut job over picking diodes for rectification. Should I move to tube rectifiers?

It depends upon your goal. If one is attempting to synergize a component as best as one can to one's
system, limiting the number and quality of the filter stages will allow the rectifier, transformer, power cord,
part's quality etc to affect the sound quality to some extent.

I was looking for absolute accuracy and naturalness. I used enough and quality filter stages to
eliminate the rectifier, transformer, power cord etc from the equation. I also used separate
transformers/supplies for each stage of my system.

cheers

steve
« Last Edit: October 03, 2022, 01:23:59 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 Perfect Tube Preamp
SAS 25 W Reference Triode/UL Monoblocks
2 way Floor standing Test Speakers

Offline Folsom

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Re: A Solid State Device Problem.
« Reply #7 on: October 03, 2022, 03:47:01 PM »
I've never found anything immune to a power cable unless maybe it has no safety ground, then it might be close.

Do you use large chokes in your devices? I've never had the chance to hear SAS in person.

Offline steve

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Re: A Solid State Device Problem.
« Reply #8 on: October 03, 2022, 07:10:07 PM »
I've never found anything immune to a power cable unless maybe it has no safety ground, then it might be close.

Do you use large chokes in your devices? I've never had the chance to hear SAS in person.

Good questions for the general public as well.

The power cord pin 1, safety ground, is the main culprit when using two components, say preamp and
amplifier together in a system.

I found my old block schematic I hope makes it simple.

Red inside each component box is signal ground for both, or more channels.

Each ic cable has inside and a shield. Signal return is via the shield of each channel, and some mixing
between the channels along the way.

Notice the pin 1 ground wire of power cords are connected via the outlet and to the signal grounds of each
component.

(Actual ground means nothing, just the fact that both pin 1s of the power cords are connected at the
outlet.)

Each center conductor is exclusive in its channel musical signal. Return, however, has three conductors, shield,
shield, and pin 1 ground wire. The ratio of signal current is frequency dependent upon the DC resistance,
inductance and maybe capacitance of each return path.


As far as chokes/inductors, chokes are used in single ended circuits such as SETs, Preamplifiers,
and Phono stages etc. Due to their enhanced ability to reduce hum. In push pull circuits the
120hz ripple is basically cancelled.

The disadvantage of chokes is that when connected to a power supply filtering setup, there are three
reactive circuits together next to the signal tube, capacitor, inductive, capacitor. (With inductive input, we
have inductor, capacitor and is a little better, but not much.)

Cap C1/inductive/cap C2 is especially complex
and a non linear problem. (I know, a basic few say "passive" caps and inductors are linear. But the
results of use demonstrate they are not. Any sonic difference cause by said "passive" parts is a form of
distortion.)

The inductive reactance of a choke is calculated as:  2pi X F x L
where F is frequency
L is inductance
pi -3.1416
x is times

Notice the inductive reactance is frequency sensitive. The isolation between the two capacitors C1 and C2
is via the choke's inductive reactance. So that schematic showing C1 and C2 looks nice, but is far from
true. C1 and C2 are not really just C1 and C2.

Now add the DC resistance of the choke's wire, which is constant over the audio band, and we
have something even more nonlinear as shown by the photo below.

If we use a straight non inductive resistor, essentially has the same resistance over the entire audio band,
the isolation of C1 from C2 is constant over the entire audio band.

I use no chokes in any of my electronic components. The speakers, I use 2 very low resistance chokes in the
crossover for a quasi second order configuration.

Hope this helps all.

steve
« Last Edit: October 03, 2022, 07:40:52 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 Perfect Tube Preamp
SAS 25 W Reference Triode/UL Monoblocks
2 way Floor standing Test Speakers

Offline Folsom

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Re: A Solid State Device Problem.
« Reply #9 on: October 03, 2022, 11:19:56 PM »
I'm hoping to pick up subtle information from you that is useful - especially now that you're retired. But all I got (that I didn't know) was you like CRC over CLC's in your tube gear. I just checked and one of my all time favorite diodes has 20pf, which is high based on what you say - funny though how others don't even list theirs.

It is not necessary to turn the thread into a public ed thing; people will ask when they want to know something.

When you use the word natural I get pretty curious. Most people I know that gravitate towards that as being something particular like Lamm gear.

Offline steve

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Re: A Solid State Device Problem.
« Reply #10 on: October 04, 2022, 01:25:14 PM »
I'm hoping to pick up subtle information from you that is useful - especially now that you're retired. But all I got (that I didn't know) was you like CRC over CLC's in your tube gear. I just checked and one of my all time favorite diodes has 20pf, which is high based on what you say - funny though how others don't even list theirs.

It is not necessary to turn the thread into a public ed thing; people will ask when they want to know something.

When you use the word natural I get pretty curious. Most people I know that gravitate towards that as being something particular like Lamm gear.

For the public.

Seems most all have the impression that all knowledge is contained in the College classroom and
textbooks. Collge/books give us basic information and tools in which to work. We still have
R&D in science and industry to learn using those tools.

Interestingly, in the past 15 years, some still considered MP3 to be equal to redbook.
 
I also have never seen any info on diodes and bleed through etc posted. In solid state designs, I have
seen small diodes used many times in the signal circuitry. In tube circuits sometimes as well.

All devices have leakage current when reversed biased (shut off).
That presents a finite resistance into the circuit, thus signal bleed through.

Let's check your example of 20pf at 20khz. The capacitive reactance is some 398,000 ohms. At 5khz it is
1.59 meg ohms. Depends upon the impedance of the circuit the diode is installed.


Yes, I clearly prefer CRC over CLC due to the improved, natural sound, which science says should be. Nice
when subjective and objective agree (unless poor parts quality). I would at least attempt to keep the choke
as far away as possible, say 4 to 5 filter stages away from the signal path. I do not like chokes/inductors in
any part of the signal path, such as grid chokes, plate chokes etc.

Back when solid state was born, we had pie in the sky engineers who claimed that since "harmonic distortion"
was lower, the sound was "more accurate", thus "neutral". Since when was there only one form of distortion?

1960 or earlier RCA Radiotron Designers Handbook lists at least 8 forms of distortion, and I have one or two
more myself.

How many times, over the decades, did we hear those above phrases about ss being better. Unfortunately,
some/many audio definitions have been butchered and now folklore.

Webster's and other dictionaries all state that neutral means no favoritism, no artificial manipulation, nothing is
changed. I personally like the music to sound natural, accurate, neutral, like the live event.

Audio components are all over the spectrum, lean, full, and everything in between. I think an important
question is how much masking is occurring, whether lean or too full sounding.

If one is traveling through the central Illinois area, I would love to have you stop by for a listen.
Please give me a couple of days notice.

cheers

steve
« Last Edit: October 05, 2022, 08:30:41 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 Perfect Tube Preamp
SAS 25 W Reference Triode/UL Monoblocks
2 way Floor standing Test Speakers

Offline Folsom

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Re: A Solid State Device Problem.
« Reply #11 on: October 05, 2022, 11:59:09 PM »
What's your favorite signal coupling cap, Steve?

Offline steve

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Re: A Solid State Device Problem.
« Reply #12 on: October 06, 2022, 03:31:36 PM »
What's your favorite signal coupling cap, Steve?

The infinicap, "aluminum/silver" color, values I use. Haven't found any other cap that matches for
true accuracy across the audio spectrum. And at a great price.

Have to special order minimum number per value, thousands of dollars last time I checked some
years ago.

cheers

steve
« Last Edit: October 06, 2022, 04:23:32 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 Perfect Tube Preamp
SAS 25 W Reference Triode/UL Monoblocks
2 way Floor standing Test Speakers

Offline Folsom

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Re: A Solid State Device Problem.
« Reply #13 on: October 08, 2022, 01:39:47 PM »
They now have the Dynicap or something like that you can order in lower quantities from Parts Connexion.

Offline steve

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Re: A Solid State Device Problem.
« Reply #14 on: October 08, 2022, 06:25:20 PM »
They now have the Dynicap or something like that you can order in lower quantities from Parts Connexion.

Unfortunately, the dynamicaps are Not even close to the high quality Infinicap they replaced. But then marketing determines what is sold and what is not.
 
For the public.

TRT simply followed the competition because the public followed the erroneous capacitor testing
comparison articles, and other individuals who supposively tested on their own, both incorrectly,
which pushed the poor quality caps as superior. I am sure there is a little shilling involved as well.

Another reason is those big time marketers of the small SET amps. (Those tubes make big bucks.)
However, when one pushes the amps into clipping, the coupling capacitor goes through abnormalities,
distorting the music/signal. What to do? The smaller the coupling capacitor, the smaller the abnormality.

Unfortunately, a natural/accurate capacitor will sound thin under those conditions. The "solution" is
manipulate the smaller capacitor to sound overly full. However, one should not design any component
with the wrong size part to begin with as it negatively influences the sound.

Now one has to pay through the nose (hundreds or thousands) for natural/accurate capacitors
(assuming they sound accurate/nartural) when the infini sold for only 20 bucks at the time.

It is let's make a buck time with capacitors now.

Solid state is no better. Those huge, gigantic electrolytic capacitors with high DA, ESR, and Inductance problems,
as well as one supply for multiple stages, instead of an individual supply for each stage.

Anyone surprised at the downturn in high end audio?

cheers

steve
« Last Edit: October 08, 2022, 06:32:42 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 Perfect Tube Preamp
SAS 25 W Reference Triode/UL Monoblocks
2 way Floor standing Test Speakers