Using Spade connector for speaker cable - Page 2 - AVS Forum | Home Theater Discussions And Reviews
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post #31 of 77 Old 05-04-2019, 03:42 PM
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Originally Posted by MTVhike View Post
Aluminum oxide is what coats anodized aluminum! Not only is it an excellent insulator but extremely hard! Sapphire is aluminum oxide.
Cool, my wife likes sapphires! Next birthday, new set of rims for the Jeep for the wife, tell her they're sapphire, eh?

Seriously, thanks for the information.

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post #32 of 77 Old 05-05-2019, 01:03 AM - Thread Starter
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I really don't worry about the composition of the metal, I think the contact resistance is the important factor. If you crank everything tight, plenty of contact surface, the kind of metal is really not as important. If you have spring loaded ( I include banana connectors) where the contact spot is very small, that's where the problem started.


The test I did was measuring THD with 3.9ohm metal film resistor ( 25 of the 3W 3.9ohm resistors in 5 X 5 array). Those resistor does not have distortion. The fact I see THD increase and inconsistent tells me there is MORE to it than just contact resistance. Increase in THD indicates the resistance has voltage coef ( non linear). Remember the amp has finite output resistance, the output resistance with the load resistance(load resistance + resistance of the cable + contact resistance of banana plug) forms a voltage divider and if any of the resistance change with voltage, you measure increase of THD. You can see this if you write out the voltage divider equation.


This is the same equation I use to proof the speaker cable inductance causes increase THD at the speaker input.


Post 2 onwards:https://www.avsforum.com/forum/173-2...an-cables.html


Post 672 https://www.avsforum.com/forum/173-2...closed-23.html

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post #33 of 77 Old 05-09-2019, 04:40 PM
 
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My eBay spades a noticeably better than the Monoprice banana plugs I was using.
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post #34 of 77 Old 05-09-2019, 05:32 PM - Thread Starter
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Originally Posted by bing! View Post
My eBay spades a noticeably better than the Monoprice banana plugs I was using.
I love ebay express and Amazon. I don't believe is special metal and all that.

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post #35 of 77 Old 05-10-2019, 12:18 PM
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Originally Posted by alan0354 View Post
Take it as a piece of info and do whatever with it. This is scientific as I actually measured with instruments that show quite a bit difference. I am talking about from 0.003% TO 0.0022%, that's a big difference.
Good stuff. Any consistently measurable difference is educational even if it's not audible. I would encourage you to try treating the terminals and spades/bananas with Deoxit Gold (https://www.parts-express.com/caig-k...e-kit--341-203) and then see how they perform in comparison to the prior measurement and relative to each other. I've seen "perfectly clean" connectors work much better after Deoxit Gold -- it would be very interesting to measure the difference (if there is one, I'd be very surprised if not, but you never know).
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post #36 of 77 Old 05-10-2019, 12:34 PM
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Originally Posted by alan0354 View Post
Take it as a piece of info and do whatever with it. This is scientific as I actually measured with instruments that show quite a bit difference. I am talking about from 0.003% TO 0.0022%, that's a big difference.
.0008% points to be exact.

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post #37 of 77 Old 05-10-2019, 12:46 PM
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Originally Posted by m. zillch View Post
.0008% to be exact.


Percentage difference
30.76923%



Difference
0.0008



If you can’t explain it simply, you don’t understand it well enough – Albert Einstein
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post #38 of 77 Old 05-10-2019, 01:23 PM
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Originally Posted by DonH50 View Post
Others have answered pretty much as I would...
Yes, but the far more important question is : Is that a Selmer 19A Balanced in your profile pic?


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post #39 of 77 Old 05-10-2019, 01:32 PM
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Yes, but the far more important question is : Is that a Selmer 19A Balanced in your profile pic?

Sorry, no... Flip Oakes Wild Thing https://flipoakes.com/ I have half a dozen or so horns in various flavors but am not playing much now. It is brass with a silver exterior, probably a good conductor, maybe not as good as my gold-plated flugelhorn.
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post #40 of 77 Old 05-10-2019, 01:45 PM
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Originally Posted by DonH50 View Post
Sorry, no... Flip Oakes Wild Thing https://flipoakes.com/
I know everyone on the thread was curious , but only I had the guts to ask

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Originally Posted by DonH50 View Post
I have half a dozen or so horns in various flavors but am not playing much now.
Same, but only 4 horns, all vintage.

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Originally Posted by DonH50 View Post
It is brass with a silver exterior, probably a good conductor, maybe not as good as my gold-plated flugelhorn.
Well done sir to bring back on topic
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post #41 of 77 Old 05-10-2019, 02:06 PM
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Quote:
Originally Posted by emcdade View Post
I use Rhodium plated Furutech locking bananas and spades.

Here's the matching AC receptacle:

https://www.amazon.com/Furutech-Ulti...1YK3TFSK8WPV4D

In the audiophile world, ignorance truly is bliss. Save your money.
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post #42 of 77 Old 05-10-2019, 03:31 PM
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Originally Posted by Out-Of-Phase View Post
But wouldn't the nano crystals destabilize the magnetic coupling flux or more specifically the (possible) Henway?

In A/V reproduction accuracy, there IS no concept of "accounting for personal taste/preference". As art consumers we don't "pick" the level of bass, nor the tint/brightness of a scene's sky, any more than we pick the ending of a novel or Mona Lisa's type of smile. "High fidelity" means "high truthfulness", faithful to the original artist's intent: an unmodified, neutral, accurate copy of the original master, ideally being exact and with no discernable alterations, aka "transparency".

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post #43 of 77 Old 05-10-2019, 05:09 PM - Thread Starter
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I want to show another case of how critical the connector is. This test is for power amp stability test. I connect different values of capacitors directly to the output of the amp to test for stability. As shown in the picture, I put capacitors onto a banana plugs, 3,300pF, 6,600pF, 9,900pF, 22,000pF and 0.1uF. I test the stability of the amp by plugging directly onto the output connector of the amp for testing whether the amp can be stable under the capacitor load.

This test doesn't necessary to have a large output signal, so there is not necessary to have high current going through the connector to create hot spot. You would think this is ok for the application.......WRONG. I have to constantly ply the spring of the connectors out to get a tighter fit, I have to jiggle the connector to test. I can see if I don't press the banana connector tight, the amp can falsely look stable, but when I push it tight, it started oscillates. That little extra resistance can make a day and night difference at the output of the amp.

On the side note, there goes to tell you those so called experts and so called EE doesn't guaranty they know what they are talking. You look at those service manual from amp companies like Marantz and others, they do test for stability. The problem is when you read their test procedures, they use a speaker cable to connect the capacitor to the amp for testing. They test to like 1uF or more and claim it's stable. That is completely WRONG. That's why amplifier oscillation or instability is so common. Not only they put the capacitor at the other end of the cable, they put a 8ohm resistor in parallel with the capacitor to simulate the speaker load. This doesn't work for stability test.

That's the reason a lot of amps are NOT stable with the knitted cables when instead of using a single 12 gauge or 10gauge for speaker cable, they use many small cables like 18 or even 20 gauge cables and knit them together to decrease the inductance. Problem with this closed coupled type of speaker cables is the capacitance is very high, it can be over 6000pF. A lot of so called big name brand power amps will oscillate using this kind of cable. You need to test amps with capacitors directly connect to the output of the amp.

Also, it's important NOT to have an 8ohm resistor parallel with the capacitor as in real life, at the frequency of instability, speakers are very high impedance ( it's an inductor!!) and is out of the picture.

As an example, the Nakamichi PA-7 designed by famous Nelson Pass, it's the improved version of his famous Threshold S-300 power amp.........Sang like a canary with only 1500pF capacitor directly across the output of the amp......only 1500pF and oscillate like crazy. I tested all my amps to 33,000pF. The PA-7 is NOT stable with my custom knitted cable. I had to turn it on and off to get it stable one time to use it. This is because the capacitance of the speaker cable is connected directly to the output of the amp, not through a 12 gauge cable. The little contact resistance created by the hot spot of the banana connector in my test will give a false result. I have to push it hard. I get different values of capacitance by plugging multiple capacitors combination to cover the full range of capacitance. Amps can be stable with 50,000pF and 100,000pF, but that does not guaranty it will be stable at 75,000pF. This is electronics for you, this can be explain in Bode Plot or Nyquist stability theory in electronics.



But of cause, I don't have an EE degree, what do I know.




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Not hooked up: Nakamichi Stasis PA-7 power amp, Velodyne VA1210 sub, Kef Reference Series center, Kef Bookshelf speaker, Monitor Audio bookshelf speaker, Infinity rear speakers. Acurus 3X200W amp.

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post #44 of 77 Old 05-10-2019, 05:24 PM
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Thanks I may pick one of those up.
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post #45 of 77 Old 05-10-2019, 06:32 PM
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Originally Posted by m. zillch View Post
But wouldn't the nano crystals destabilize the magnetic coupling flux or more specifically the (possible) Henway?
This is a question for Paul McGowan.

In the audiophile world, ignorance truly is bliss. Save your money.
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post #46 of 77 Old 05-10-2019, 07:05 PM
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Originally Posted by Out-Of-Phase View Post
Go big or go home:
https://www.amazon.com/FURUTECH-GTX-...s&sr=1-3-spell

Ths monoblock topology provides better separation so there is less component to component contamination, you see.
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post #47 of 77 Old 05-10-2019, 07:10 PM
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This is a question for Paul McGowan.
I wonder if he encircles his AC outlets with a green magic marker since on CDs he found that, direct quote: "I really found that it worked":

Screen cap taken from this source, at about 2m28s in:
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post #48 of 77 Old 05-10-2019, 07:21 PM - Thread Starter
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Don't joke and sarcastic about different metal and all. I personally don't believe this either, BUT you never know. There are a lot of things cannot be explained. This is power amp and work on what we EE called LARGE SIGNAL CIRCUITS. It is very different from normal small signal circuits that is so so much easier to work on. You can use computer simulation to simulate small signal circuits and get precise results. When I was working on small signal RF circuits, Microwave Office can simulate and plot out Smiths charts that show exactly how the real circuit plots looked like. I was amazed how close the real circuit behaves like the simulation. Large signal is a totally different animal. Ask Don50, he must have a lot of experience on this. I ran simulation on the power amp, it's NOTHING......I repeat, NOTHING like the behavior of the real circuit. You literally shooting blind and rely on experience and instinct and knowledge to work on power amp.

How do you explain the observation I posted in this thread, how much contact resistance we are talking about? why just a little more contact resistance stop the oscillation? You won't find this in the book. I've seen enough of the so called EXPERTS screwed up on the amps. Being sarcastic on things only show how little one knows.
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post #49 of 77 Old 05-10-2019, 07:59 PM
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Originally Posted by alan0354 View Post
I want to show another case of how critical the connector is. This test is for power amp stability test. I connect different values of capacitors directly to the output of the amp to test for stability. As shown in the picture, I put capacitors onto a banana plugs, 3,300pF, 6,600pF, 9,900pF, 22,000pF and 0.1uF. I test the stability of the amp by plugging directly onto the output connector of the amp for testing whether the amp can be stable under the capacitor load.

This test doesn't necessary to have a large output signal, so there is not necessary to have high current going through the connector to create hot spot. You would think this is ok for the application.......WRONG. I have to constantly ply the spring of the connectors out to get a tighter fit, I have to jiggle the connector to test. I can see if I don't press the banana connector tight, the amp can falsely look stable, but when I push it tight, it started oscillates. That little extra resistance can make a day and night difference at the output of the amp.

On the side note, there goes to tell you those so called experts and so called EE doesn't guaranty they know what they are talking. You look at those service manual from amp companies like Marantz and others, they do test for stability. The problem is when you read their test procedures, they use a speaker cable to connect the capacitor to the amp for testing. They test to like 1uF or more and claim it's stable. That is completely WRONG. That's why amplifier oscillation or instability is so common. Not only they put the capacitor at the other end of the cable, they put a 8ohm resistor in parallel with the capacitor to simulate the speaker load. This doesn't work for stability test.

That's the reason a lot of amps are NOT stable with the knitted cables when instead of using a single 12 gauge or 10gauge for speaker cable, they use many small cables like 18 or even 20 gauge cables and knit them together to decrease the inductance. Problem with this closed coupled type of speaker cables is the capacitance is very high, it can be over 6000pF. A lot of so called big name brand power amps will oscillate using this kind of cable. You need to test amps with capacitors directly connect to the output of the amp.

Also, it's important NOT to have an 8ohm resistor parallel with the capacitor as in real life, at the frequency of instability, speakers are very high impedance ( it's an inductor!!) and is out of the picture.

As an example, the Nakamichi PA-7 designed by famous Nelson Pass, it's the improved version of his famous Threshold S-300 power amp.........Sang like a canary with only 1500pF capacitor directly across the output of the amp......only 1500pF and oscillate like crazy. I tested all my amps to 33,000pF. The PA-7 is NOT stable with my custom knitted cable. I had to turn it on and off to get it stable one time to use it. This is because the capacitance of the speaker cable is connected directly to the output of the amp, not through a 12 gauge cable. The little contact resistance created by the hot spot of the banana connector in my test will give a false result. I have to push it hard. I get different values of capacitance by plugging multiple capacitors combination to cover the full range of capacitance. Amps can be stable with 50,000pF and 100,000pF, but that does not guaranty it will be stable at 75,000pF. This is electronics for you, this can be explain in Bode Plot or Nyquist stability theory in electronics.



But of cause, I don't have an EE degree, what do I know.




Haven't really been following this but interesting.

There are specialized models for high-power circuit simulation that model things like quasi-saturation and self-heating effects. Standard G-P is not sufficient; VBIC-xx (don't remember which version) added them. I'm not really up on the latest CMOS models since for the past few years I've been working at a higher level. A few flavors of BSIM (an empirical model) and another one I've forgotten did a reasonable job. I don't really "do" high-power but the problem is the same with deep submicron devices since the active area is so tiny. My problem was usually that parasitics start dominating and they are not always well-modeled for small devices and with so many metal layers and such.

Be careful doing that test with a tube amplifier; the output transformer can be damaged.

Root locus plots are always fun.

The PowerCube is a commercial version: https://www.audiograph.se/

Really good capacitors like you might use for PA (power amp) testing tend to have low ESR and high self-resonance so a little bit of excess real (contact or otherwise) resistance is sometimes enough to quiet the amp. I tended to include a high-value (perhaps 100-ohm) resistor parallel when testing stability with a capacitive load way back when I was doing more audio testing. Plenty high enough to show stability problems with a step input but less likely to send the amp into oscillation. Not that some won't still sing; "less likely" is as good as it gets. And you still have to worry about ESLs and some other speakers with very low HF impedance (the ESL's diaphragm is one big capacitor, but the impedance is not necessarily capacitive due to the transformer that couples amp to panel).

Speakers' input and amplifiers' output impedance change with power due to various effects, usually negligibly until power compression or clipping is approached, but thermal issues in both (among other things) can happen well before they near their limits.

I've never liked banana plugs; they are convenient but little else. I tend to just use bare wire or install spade lugs if I need to swap more often. Using them for testing high-power amps is gutsy, not surprised you are having such problems. Back in the day I had a special rig that was essentially heavy solid copper bus bars in a jig that would connect to a standard pair of banana plugs and then to my dummy load (non-inductive resistor in an oil can). I had a range of RLC networks for testing and some great big LC decade boxes used for transmitter testing that served double duty for adding reactance to the audio amplifier tests.

I keep thinking I'll get back into the hobby aspect; maybe when I retire. I got rid of my 'scope ages ago, just borrowed from work, but anymore I'm nervous about bringing home a DSO worth more than my house. And our spectrum analyzer doesn't go low enough for audio (but handles the Ka radar band just fine).

"After silence, that which best expresses the inexpressible, is music" - Aldous Huxley

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post #50 of 77 Old 05-10-2019, 08:28 PM - Thread Starter
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Hi Don,

You should get back into audio amps, so I can have more people to talk to.

Sad part is the model of the power transistors. They are very limited. The Ccb might be the worst part that when it swing to Vcb less than 5V, Ccb goes up, then also the beta change. None of the model accommodates that.

At work, I designed LNAs, Microwave Office really works. I remember an EE that design RF power amps told me none of the simulation really work that well for large signal. I took his words but never designed RF power amps. I thought audio amps should not be that hard, but I found out really fast it's not the case. I use LTSpice with models from Bob Cordell that he modified from ON-Semi already. But nothing even come close to the real circuit. The gain phase plot is a joke for sure, even the THD is wrong. Now I use LTSpice to do basic trouble shoot, after that, just work on it.

I am working on an error correction on the output circuit to reduce the crossover distortion, there are still some funny spots that the amp is not stable. LTSpice is totally blind on this.

One of my future project is using CMOS output stage, I might hit on your knowledge in the future because I am basically a BJT guy. My experience on analog IC design was on BJT IC in the good old days. At the time, we talked about CMOS, but we just never did it. I have the book "Design of Analog CMOS Integrated Circuits" by Behzad Razavi, but I yet to read it. As I get older, it's getting harder and harder to read new books particularly these are never easy reading materials!!!

I never really got into tube hifi amp design, I am more the low THD approach, Tubes are just not low THD. I'll keep my mind open, my friend is willing to bring his Jolida power amp over one day. Maybe if I listen to it, I'll have more enthusiasm on a tube amp.

To me, design and build power amps is much better than crosswords puzzles!!!


Actually equipment for audio amp is really cheap. I use the QA401 analyzer to plot the FFT, it's plenty good already. Definitely has low enough noise floor for power amp testing. I use a Tek 2465A 350MHz scope, but that's from the days when I was doing contracting work. A small digital scope from Amazon is plenty good, something like a 200MHz 2 channel is plenty good. They are like $350. Yes, it's hard to find a spectrum analyzer to go this low frequency.

Own designed power amp, own designed preamp, JM LAB Spectral 913.1 speakers, Rythmik F12SE sub.
Not hooked up: Nakamichi Stasis PA-7 power amp, Velodyne VA1210 sub, Kef Reference Series center, Kef Bookshelf speaker, Monitor Audio bookshelf speaker, Infinity rear speakers. Acurus 3X200W amp.

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post #51 of 77 Old 05-10-2019, 08:50 PM
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I've never liked banana plugs; they are convenient but little else.
Complete transparency when properly used for speaker connection applications under blind test conditions for all people, with all gear, and all music comes to mind.
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post #52 of 77 Old 05-10-2019, 08:52 PM
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@alan0354 : LTSpice is pretty good, I use it for a lot of stuff, but I am not sure it handles advanced models. Would think so since LT (now part of ADI) did mostly power chips. And the main problem is not the Spice engine but the models themselves; few models include the hooks for high power simulation. Large-signal distortion is a crap shoot; some do well, some don't. In the RF world the models tend to be steady-state large-signal models and simulators based on Volterra Series and other stuff rather than Spice time-domain models. They better model large-signal effects. Same should be true for audio since the issues are much the same (worse at RF/mW/mmW). With the right model a Spice transient simulation should be pretty good, again with the caveat that there are few good high-power device models around. The small-signal distortion (AC) analysis in Spice I found useless even for small signals as it linearizes most everything. I should look at the simulators I have at home and at work to see what they use some time.

Tube preamps (can) have very low distortion; power amps less so do to the output transformer, low feedback, and high output impedance. My ancient ARC SP3a1 had something like 0.001% THD with 5 Vrms output, good for the time before marketing wanted more 0's.

My BJT/HBT background is much stronger than my CMOS background; most of my work was above what CMOS could do at the time, and CMOS low-level circuits were too noisy for audio (or RF -- close-in phase noise too high) without special circuitry. Most good audio FET op-amps use JFET inputs, not CMOS, at least last I looked. For power amps I'd probably use SiC HBTs, IGBTs, or something like that. Note at high powers CMOS output transistors can exhibit thermal runaway; don't ask how I know this.

Crossover glitches are usually solved with a little more bias and careful feedback design; they can insert what look like impulses into the feedback path, so loop gain and bandwidth (lag) can be critical, especially for high-power amps.

A millenia or so ago Behzad and I both gave papers at a conference, no idea exactly which one or when. Might have been one of the old EDN conferences; Frank Goodenough roped me into presenting on SiGe devices, and friend had me do a workshop on RF/mW DACs around the same time (probably mid-1990's). He (Dr. Razavi) is quite a guy. We did not overlap at UCLA; I got my master's there a few years before he joined. I have his book along with a bunch of texts on shelves in my office but most of them are in boxes in the basement. Like you either don't need them or no time to read them.

"After silence, that which best expresses the inexpressible, is music" - Aldous Huxley

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post #53 of 77 Old 05-10-2019, 09:28 PM - Thread Starter
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Hi Don

Yes, I should be more specific, The model is everything, LTSpice is only a tool, it's only as good as the model. That lies the problem. Apparently Bob Cordell actually modified the models of the power transistors, but still it's no where close. The result is only as good as the model.

I kind of regret quitting the Exar job on designing IC. At the time, IC was still very simple devices with too much limitations. System level is where the challenge was. I found a job designing the front end of the Ultra Sound medical scanner with Seimens and I left. I never thought of one day the IC design takes over all the complicated systems, it's system on a chip. All we system type of engineer just read the data sheet, hook up the pcb trace ( of cause transmission lines and all) and call it a day. Like that whole USB controller is within a micro controller with ADC, DAC, memory etc. All we did is put in the differential USB connector and analog input and output. The fun is all in the IC design. At the time, the frontend ultra sound scanner were designed with discrete transistors, it was very challenging. The scanner was a rackful of pcbs. Now, the whole thing is like a laptop!!!! Everything on one or two chips, you guys have all the fun.

BTW, in my days, we only had single layer of metalization on the the chip, that was really limiting. How many layer of metalization you guys are doing now? I looked at so die pictures, you have transmission lines, inductors all on the chip, that would be so much fun to design.

Anyway, my days are long passed. I stop working in 2005, they called me back to develop the next generation system 4 years ago. I worked as a contractor for a year and half and completely retired again two years ago. I was reluctant to accept the contract, but they allow me to work at home designing the circuit, so why not!!! Now, it's just on the power amp. I do spend like 10 to 20 hrs a week, so it's not exact relaxing either.

I am laying a front end circuit inspired by Mark Levinson. Different front end topologies do give different sound even though THD are very low, again, don't ask me why. Mark Levinson use dual LTP configuration where the first LTP driving a second LTP. It's different from the standard Krell type of complementary LTP and VAS configuration. This will be my very next project. I built an amp with pcb that I can disconnect the front end and just use the power amp section. I just connect the front end pcb to the output section by a 3 pin connector. I can change to different frontends. I always put the new design on a small pcb and try it on this chassis first. If it sounds promising, I'll layout a complete board with the power output section and all. It's cheaper this way.


Nelson Pass uses MOSFET for the frontend LTP!!! Noise floor is really not a problem for power amp. I want to try MOSFET output stage because the crossover characteristics is totally different from BJT. I think BJT has more higher harmonics. I bet the MOSFET output stage will sound different.

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Not hooked up: Nakamichi Stasis PA-7 power amp, Velodyne VA1210 sub, Kef Reference Series center, Kef Bookshelf speaker, Monitor Audio bookshelf speaker, Infinity rear speakers. Acurus 3X200W amp.
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Hi Don


I looked at the Audiograph cube, that's really fancy, I bet it's very expensive. I don't think I need those.

Own designed power amp, own designed preamp, JM LAB Spectral 913.1 speakers, Rythmik F12SE sub.
Not hooked up: Nakamichi Stasis PA-7 power amp, Velodyne VA1210 sub, Kef Reference Series center, Kef Bookshelf speaker, Monitor Audio bookshelf speaker, Infinity rear speakers. Acurus 3X200W amp.
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Originally Posted by m. zillch View Post
.0008% points to be exact.
Or 36% more.
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post #56 of 77 Old 05-10-2019, 11:31 PM - Thread Starter
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Or 36% more.
Yep, that's a big difference when I am trying to shave off a little at a time. How does this translate to real world sound, I have no idea. It's just a piece of information people here might be interested.

Bottom line is when one gets down to the finest detail, everything matters. It's like in Olympics, 0.1sec is only a blink of an eye, but that might make a difference between gold medal and not even qualify in the final in Olympic competition.

I am not using spade connector right now because I am testing and swapping stuffs quite a bit. The existing setup make it hard to use spade connectors. But when my old tv craps out and buy a new one, I will totally change the setup and make it a lot cleaner. I definitely will go to spade connector.

I have talked many times how critical the speaker cables are. It was the similar discovery like this that convinced me. In short, I measured the THD along the speaker cable and the farther I go towards the speaker load, the higher the THD. That is, even if you measure very good THD at the amplifier output, THD is very high at the speaker end. That's how I got into how to design the cable to give me the minimum amount of THD AT THE SPEAKER END.

That also tell me why people keep saying low THD is not important. The reason is because it's the THD at the speaker that matters, not on the amplifier side. I designed the knitted cable and proofed that it gave lowest THD on the speaker load end and improved the sound quite a bit in real listening.


When one gets into the fine details, everything matters, the system is only as good as the weakest link of the system.

Own designed power amp, own designed preamp, JM LAB Spectral 913.1 speakers, Rythmik F12SE sub.
Not hooked up: Nakamichi Stasis PA-7 power amp, Velodyne VA1210 sub, Kef Reference Series center, Kef Bookshelf speaker, Monitor Audio bookshelf speaker, Infinity rear speakers. Acurus 3X200W amp.

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post #57 of 77 Old 05-11-2019, 12:06 AM
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. . . I actually measured with instruments that show quite a bit difference. I am talking about from 0.003% TO 0.0022%, that's a big difference.
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Originally Posted by alan0354 View Post
How does this translate to real world sound, I have no idea.
Here:

.003% distortion is -90.46 dB down
.0022% distortion is -93.15 dB down

This test, played at a loud level, will give you a rough idea of why this 2.69 dB difference between one awfully quiet level for distortion products* to another, slightly different, awfully quiet level for distortion products*, in typical home use, probably just doesn't matter:

Audible Dynamic Range Sound Test

Keep in mind this test measures how quiet you can detect the target sound, the speaker's voice, in the absence of any simultaneous content. I real world use, music, our concern is can we hear the quiet distortion products while the music is simultaneously playing. The music, in many instances, will act to mask our ability to hear these faint distortion products even more due to the phenomenon called "masking".

*[probably inaudible in most real-world, actual use]

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post #58 of 77 Old 05-11-2019, 12:21 AM - Thread Starter
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Here:

.003% distortion is -90.46 dB down
.0022% distortion is -93.15 dB down

This test, played at a loud level, will give you a rough idea of why this 2.69 dB difference between one awfully quiet* level for distortion products to another, slightly different, awfully quiet* level for distortion products, in typical home use, probably just doesn't matter:

Audible Dynamic Range Sound Test

Keep in mind this test measures how quiet you can detect the target sound, the speaker's voice, in the absence of any simultaneous content. I real world use, music, our concern is can we hear the quiet distortion products while the music is simultaneously playing. The music, in many instances, will act to mask our ability to hear these faint distortion products, even more, due to the phenomenon called "masking".

*[probably inaudible in any real-world, actual use]

Like I said before many times, all three of my amps are very low THD, all three has identical output stage, same speaker cable, same speaker, same speaker position, same preamp and same source with same song. They sounded different. If things are that simple, they all should sounded like a wire with gain, but they are not. All three designed and tested to have EXACT gain so the output amplitudes are EXACTLY the same level during comparing.


There are things that cannot be explained.

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Not hooked up: Nakamichi Stasis PA-7 power amp, Velodyne VA1210 sub, Kef Reference Series center, Kef Bookshelf speaker, Monitor Audio bookshelf speaker, Infinity rear speakers. Acurus 3X200W amp.
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post #59 of 77 Old 05-11-2019, 12:26 AM
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Like I said before many times, all three of my amps are very low THD, all three has identical output stage, same speaker cable, same speaker, same speaker position, same preamp and same source with same song. They sounded different. If things are that simple, they all should sounded like a wire with gain, but they are not. All three designed and tested to have EXACT gain so the output amplitudes are EXACTLY the same level during comparing.


There are things that cannot be explained.
No, you just don't understand them.
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post #60 of 77 Old 05-11-2019, 01:05 AM - Thread Starter
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No, you just don't understand them.

And you do? And I am the one designing them.
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