Stored Code? Real Men Use Logic Gates, Flip Flops, Diodes and Transistors

A place for software, hardware and DSP-based audio gizmos. All things code and the hardware that runs it. Time and amplitude are described in bits and pieces here. Links to interesting gizmos and software.
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mediatechnology
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Stored Code? Real Men Use Logic Gates, Flip Flops, Diodes and Transistors

Post by mediatechnology »

JR. wrote: Fri Feb 15, 2019 1:37 pm
you mean like when I first suggested digital solutions, for formerly analog circuits? :lol:
Yeah, like using a 20 MIPS processor requiring an FCC Class-B certification to embed into a product to do the work of a diode, resistor, and capacitor. Something like that.

Call me a digital Ludite but today, somehow, I got reminded that my first large-scale DIY project was digital and required building clocked logic using resistor-transistor-logic flip-flops and gates.

That was 1970.
I didn't discover op amps until 1973...

Today writing code and requiring a million transistors in a large scale IC someone else made to do the same thing seems like the work of a hipster soy boy pussy. Like the Arduino clock I did :lol:

This is how real men do digital:
Sometime between 1969 and 1970 I became interested in building a digital clock.
I was about 12 at the time and began sketching clock circuits using J-K flip flop dividers.

I am "clock boy." :ugeek:


My brother had some surplus RTL (resistor transistor logic) ICs mounted on circuit cards.
I was able to buy some Amperex ZM-1000 "Nixie" display tubes and some Fairchild BCD to Decimal HV driver ICs.
The ICs are mostly MC790P J-K flip flops, some MC789 inverters and a couple of misc gates.
All-in-all there are 19 ICs. (One is underneath on a Veroboard).

I wanted a small display so a multiconductor cable was used to link the "base" logic unit to the display head.
The display sat on my headboard with the clock stashed under the bed.

This was my first major electronics project.
Looking back on it almost 50 years later I realize the logic design was pretty solid.
The execution sucked - but hey - it was my first project and I was 12.
My Dad gets credit for the solid walnut case.

Image
The clock display unit has three Amperex ZM-1000 "Nixie" displays. The hours "1" is a long neon.

Image
The clock base unit uses 19 RTL (resistor transistor logic) ICs mounted on individual plug-in cards.

Image
Most of the ICs are Motorola MC700-series RTL. A CMOS IC was installed "dead-bug" sometime in the 1980s due to failure.

Once I got a couple of Heathkit clocks I retired this unit.
It sat under my father's workbench for years absorbing sawdust, oil and dryer lint.

Sometime in the late 1980s or early 1990's I began phase one of the restoration replacing the 2N3055 regulator with a LM317.
An RTL IC failed and I had to cobble a dead-bug CMOS chip.
I later gave up because I realized it had become an unreliable pig.
The edgecards had became flakey and I didn't want to clean them and the receptacles.
The clock set in the garage and was later moved to the basement.
I decided, almost 50 years later to rescue it.

It took a can of Blue shower, a can of duster and a re-cap to bring it back to life.
Glad I did though.
Gold
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Re: Stored Code? Real Men Use Logic Gates, Flip Flops, Diodes and Transistors

Post by Gold »

The mid 1960’s clock for the Neumann lathe analog computer is a light that shines on the underside of the turntable. The bottom of the turntable is painted black and white in quadrants. There is a photo resistor that moves the clock four times per revolution.
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JR.
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Re: Stored Code? Real Men Use Logic Gates, Flip Flops, Diodes and Transistors

Post by JR. »

I am not sure why this topic generates so much anger. I guess I could be kinder in my comments so I will take some share of the blame.

By the late 60s I was working as a technician developing a DC to DC switching power supply for a Navy project (that wasn't digital of course). When I interviewed for a job on a research boat back then, a question I was asked was to explain how a simple two transistor flip-flop worked. I actually got hired for that gig but was drafted into the army before I could leave the country. :cry:

My use of digital when appropriate should be well documented in the TS-1 schematic still floating around. But more clever (IMO)was the analog glue feeding the simple counters performing an analog to digital dB readout. There was probably some simple discrete transistor logic in there too, but I am too lazy to look. I also did my share of doodling with CMOS logic (like for clocking BBD delay lines).

Perhaps more clever was a circuit of mine that never saw production, generating a 100 segment vacuum fluorescent prototype peak/VU meter. I basically used the exponential decay of an RC (e^(-t/RC) ) to gate a counter delivering a 100 dB display range. 8-) (I make no claims about log accuracy over that much dynamic range :roll: ).

Today with modern technology it would be crazy to do stuff like that the so obviously hard way. I had to address that display as ten blocks of ten segments, and multiplex it at least 3 ways for peak/VU displays (full blocks of 10, fraction of ten, and single bar for peak) of course 3 ways is not simple digital friendly so I multiplexed it 4 ways). Trivial tasks now with a micro, less trivial back then with crude glue logic.

JR
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mediatechnology
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Re: Stored Code? Real Men Use Logic Gates, Flip Flops, Diodes and Transistors

Post by mediatechnology »

It's not anger it's just sometimes using a micro doesn't make sense for someone wanting 1 or 2 or don't want to go to the hassle of writing code for a one-off when they could use a diode and op amp.

Just because you can doesn't mean you have to.

I'm going to be doing two simple meters soon:

One will be a comparator-based resistor string "flash" converter to replace the nearly-obsolete LM3914.
I still get requests for the GR-10 and GR-20 boards for people just wanting a simple gain reduction indicator or level meter for their comp projects.
They usually need only 1 or 2.

The other will be based on an Arduino and the WSM2812 RGB LEDs. It will be a simple proof-of-concept.
I seriously doubt the peak detection will be done in DSP with the Arduino.
It just seems silly for this project.
The prototype display will be a 60 dot RGB string.
Since that display ribbon is several feet long I don't see it being usable until a fine-pitch WSM2812 board is available to make an LED bargraph.

I'm pretty sure that when I do either you will piss on them.

This is DIY.
The first project virtually anyone will be able to build because its through-hole.
The second project few people will be able to build because its surface mount.
I don't want to have to support surface mount builds and my customers don't want them.

Unless I wanted to gear up and make several hundred display boards with presoldered CPUs and WSM2812's the second will likely never see the light of day.
Just about anyone who's ever soldered could make the comparator-based board.

Not everything needs to go through the mass-produced/high volume design filter and review process.
For DIY it's buzz and idea-killing.

It has little to do with something being digital or analog but what people are able to actually build.
Software adds some complexity but surface mount adds a lot.
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Re: Stored Code? Real Men Use Logic Gates, Flip Flops, Diodes and Transistors

Post by JR. »

mediatechnology wrote: Sun Feb 17, 2019 12:53 pm It's not anger it's just sometimes using a micro doesn't make sense for someone wanting 1 or 2 or don't want to go to the hassle of writing code for a one-off when they could use a diode and op amp.

Just because you can doesn't mean you have to.
yes... I have known those guys...
I'm going to be doing two simple meters soon:

One will be a comparator-based resistor string "flash" converter to replace the nearly-obsolete LM3914.
I still get requests for the GR-10 and GR-20 boards for people just wanting a simple gain reduction indicator or level meter for their comp projects.
They usually need only 1 or 2.

The other will be based on an Arduino and the WSM2812 RGB LEDs. It will be a simple proof-of-concept.
I seriously doubt the peak detection will be done in DSP with the Arduino.
It just seems silly for this project.
The prototype display will be a 60 dot RGB string.
Since that display ribbon is several feet long I don't see it being usable until a fine-pitch WSM2812 board is available to make an LED bargraph.
for years I have pondered making a generic version of my PIC meter design. There never seemed enough interest for me to do one. I could make it very flexible and use programming pins to allow it to cover the entire LM39XX series on steroids, + more.
I'm pretty sure that when I do either you will piss on them.
Can you predict the future? I can't, but you keep poking the bear. Do you think that will improve my attitude?
This is DIY.
The first project virtually anyone will be able to build because its through-hole.
The second project few people will be able to build because its surface mount.
I don't want to have to support surface mount builds and my customers don't want them.
I spent a bunch of time working with a analog mixer company who "knew" what their customers wanted (it seems they didn't).
Unless I wanted to gear up and make several hundred display boards with presoldered CPUs and WSM2812's the second will likely never see the light of day.
Just about anyone who's ever soldered could make the comparator-based board.
I pondered simple semi-custom boards (with SMD processor and LED driver chip), but even that involves an up front investment. If the customers don't care enough, I am surely not going to work on selling solutions they don't already want. Agreed minimum economic run is hundreds of assemblies. Not a lot of money if there was interest, but too much to gamble if there doesn't seem to be any, and I am clearly not a great salesman (kids get out of my yard).
Not everything needs to go through the mass-produced/high volume design filter and review process.
For DIY it's buzz and idea-killing.
sorry... I used to kill ideas as my day job (at peavey for a while I reviewed outside ideas, and gonged every single one). Maybe that is a personal problem, and why they gave that task to someone else.
It has little to do with something being digital or analog but what people are able to actually build.
Software adds some complexity but surface mount adds a lot.
I found out some time ago that the latest and greatest parts are not even available in thru hole technology,,, adapt to progress or.... don't. :roll:

For my drum tuner I had little choice but the fab a PCB to test my SMD (only) class D chip. It was worth the trouble BTW.

JR
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Re: Stored Code? Real Men Use Logic Gates, Flip Flops, Diodes and Transistors

Post by mediatechnology »

I spent a bunch of time working with a analog mixer company who "knew" what their customers wanted (it seems they didn't).
Did their customers build and assemble their own consoles? No. https://proaudiodesignforum.com/forum/p ... f=7&t=1059
sorry... I used to kill ideas as my day job (at peavey for a while I reviewed outside ideas, and gonged every single one). Maybe that is a personal problem, and why they gave that task to someone else.
Pattern matching can be used to predict the future.
Past proves future. Future proves past.
...And the fact that you gonged every single one makes prediction easy.
I found out some time ago that the latest and greatest parts are not even available in thru hole technology,,, adapt to progress or.... don't. :roll:
Who cares about the latest and greatest?
Mastering engineers want relays and big-ass multi-pole multi-deck switches.
A simple CMOS transmission gate is a big non-starter.
I'm not going to tell them that they're wrong.

Some, perhaps all of us haven't taken full advantage of the fantastic through hole parts that have been available for decades.
Like the TL431...
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Re: Stored Code? Real Men Use Logic Gates, Flip Flops, Diodes and Transistors

Post by billshurv »

It's also true that there are a lot of stupid ideas out there! Sadly these days it seems a lot of them get to market (Nest for example).

I think the big issue is that, if you are building one of something you can do what the hell you want and it doesn't matter.

If you are building 10 million of something you do a lot of what you want as suppliers will make the parts you want and keep lines alive for you.

If you are building thousands of something you run into problems. Volumes not high enough to lube up the silicon vendors and R&D budget not big enough to try all the fancy parts out there. Whole additional world of design pain.

The fun of DIY is you can do things that would never pass design review, not for performance reasons but for business/production ones.

P.S. Found out last night that the power amp I am currently using that I was given by a friend uses TL431 for the output stage bias. Which seems an eminently sensible use for it :)
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Re: Stored Code? Real Men Use Logic Gates, Flip Flops, Diodes and Transistors

Post by JR. »

mediatechnology wrote: Sun Feb 17, 2019 6:55 pm

Who cares about the latest and greatest?
When making a battery powered product, using a class D audio amp IC has merit, for extended battery life. My first generation tuner used a class AB driver with discrete transistor buffers running from a 9V battery.

The class D IC made more power from a lower voltage rail, with higher efficiency, requiring less PCB real estate and less extra glue components.

I would have loved using a thru hole part to bread board the circuit, but had no choice but to go straight to a SMD layout.

JR
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Re: Stored Code? Real Men Use Logic Gates, Flip Flops, Diodes and Transistors

Post by mediatechnology »

@Bill
I think the big issue is that, if you are building one of something you can do what the hell you want and it doesn't matter.
+1.

@JR
You didn't use the latest and greatest because it was the latest and greatest.
You used it because it was the right part for the job. Fine.
No one makes you defend your choice.
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Re: Stored Code? Real Men Use Logic Gates, Flip Flops, Diodes and Transistors

Post by JR. »

mediatechnology wrote: Mon Feb 18, 2019 4:59 am @Bill
I think the big issue is that, if you are building one of something you can do what the hell you want and it doesn't matter.
+1.

@JR
You didn't use the latest and greatest because it was the latest and greatest.
You used it because it was the right part for the job. Fine.
No one makes you defend your choice.
but my larger point was that the right part for the job is increasingly not available in thru hole technology. This is likely to get worse as manufacturing math favors SMD or even less DIY friendly device packages...

JR
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