Unusual Bias Method

You just can't resist being the continual asshole, can you?

Watch for the results. I do hope you spend as much time on your own designs as you do trying to denigrate my 36 year old stuff. I _am_ happy that I can get you to spend so much time on _me_... you must _love_ me... that's the sort of thing San Fransicko's do >:-} ...Jim Thompson

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| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142   Skype: Contacts Only  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.

Stretching the facts wherever you can, 2.5mV/°C is not a valid number. Virtually all Silicon is right at 2mV/°C, with some outliers at

2.2mV/°C

It always is >:-} ...Jim Thompson

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| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142   Skype: Contacts Only  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.

I've always used 2.1mV/C for SI and 2.5mV/C for Germanium.

guess it does not matter, apples and oranges Jamie

Not long enough for a steady state (fixed amplitude) tone.

Don't let Larkin suck you in... he's the master at manipulation.

The servo still works, just not with a good margin.

The new release... a minor tweak, fixes all concerns. (Except I wasted an awful lot of current... I have no idea why, after 36 years, I suspect I started with a discrete approach and then dropped in an OpAmp instead.) ...Jim Thompson

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| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142   Skype: Contacts Only  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.

So tell us, how much of the time is Q3 on in the first place?

If this was a servo in the way you are trying unsuccessfully to treat it as, you might possibly have a point. Since it isn't you don't.

Not in the least. You just do not understand it. Glen Walpert figured it out.

?-)

Quibbling. It has a serious temperature problem. 80% of very bad news is still bad news.

Oh, I only spend a tiny fraction of the time that you spend defending (and redesigning?) it.

I _am_

Anybody who keeps calling himself a "Master Circuit Designer" should really avoid posting stupid, multiply-broken stuff. And anybody that lives in a hellhole like burb-Phoenix just looks like a dumb redneck when they criticize San Francisco.

It's supposed to increase the darlington bias up to some setpoint. Jim proudly posted a "working" simulation at 1 KHz, and it doesn't work. Maybe he doesn't understand what it's supposed to do.

But 5% tolerances on a few resistors will break it entirely, under any input conditions.

You can keep your TC if you want to... period !>:-} ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142   Skype: Contacts Only  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.

Latest version....

No time for a write-up now, too many "honey-do" projects bringing the new house up for Christmas... maybe later in the week. ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142   Skype: Contacts Only  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.

Latest version....

No time for a write-up now, too many "honey-do" projects bringing the new house up for Christmas... maybe later in the week. ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142   Skype: Contacts Only  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.

On a sunny day (Mon, 02 Dec 2013 09:05:23 -0700) it happened Jim Thompson wrote in :

Stops with error message in simulation:

Probably my error, late here, been a long day...

Thank you Jim for sharing. LTspice seems to spend most of its time in a Newton-Raphson time-domain loop. November's QEX

contains an article titled "Mathematical Stability Problems in Modern Nonlinear Simulation Programs" that blames the slowness on SPICE's time-domain approach. The authors argue that using a frequency-domain approach will speed up simulation time.

LTspice doesn't seem to offer an Application Programmer's Interface. It might be interesting to hack ngspice

to accommodate a frequency-domain approach.

--
      __ 
   __/  \ 
  /  \__/ 
  \__/ 
  /  \__  Don Kuenz 
  \__/  \ 
     \__/

Turns out that my A-B bias is STUNNINGLY better than the conventional diode-biased class-B... almost 30dB better on intermod distortion!

Intermod is what gives you those nasty atonal ear-piercing sounds when you play a Mozart wood-wind ensemble with French horn accompaniment.

After 36 years, revisiting my scheme, and fixing the bias droop, it's time for me to go back and roll my own sound system from scratch... like I did up until my late 30's... then I got "too busy" ;-)

I'll toss the TL091 and put some discrete's in there... maybe even use my TL431 diff-pair >:-} ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142   Skype: Contacts Only  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.

If you run the .CIR file I've provided, you will have no problems. However, if you draw the _schematic_ in another Spice, the symbol pin-orders are likely different.

It shouldn't be an issue, since each schematic has its own related netlist.

However, if you use say Toys-R-Us_Spice with my provided libraries, beware, and change accordingly...

I've standardized my OpAmp/Comparator symbols as follows...

I have a 3-pin OpAmp/Comparator symbol

I have a 5-pin OpAmp/Comparator symbol

I have a 6-pin OpAmp/Comparator symbol

I have a 7-pin OpAmp/Comparator symbol

(Thus 4 symbols cover virtually all types, minimizing how many symbols I need... all I do with a given symbol is type in the model name.)

In all cases, my standardized netlisting template is...

Xwhatever IN+ IN- OUT Vpos Vneg Auxiliary_Pin(s) ModelName

Thus you will have to modify my library's pin orders to match the symbol configuration of the Spice you are using. ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142   Skype: Contacts Only  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.

Betwixt the "honey-do", I ran intermod distortion, comparing class-B to my class-A-B method, zip file now updated...

...Jim Thompson

-- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at

| 1962 | I love to cook with wine. Sometimes I even put it in the food.

I don't appear to be able to open ZIP files on this mobile device of mine, but who runs Class B anymore? Getting better distortion figures than Class B seems like a pretty low bar to jump.