Callins capacitor?

I have some similar epoxy sealed aluminum electrolytics from the mid

1970s made by Roederstein (now incorporated into Vishay). At the time they cost only a few percent more than metal can/elastomer seal capacitors. There is absolutely nothing special about the electrical characteristics needed of C6 and C7 in that unsavoury circuit and my guess is that the assemblers just randomly picked that brand.

piglet

Excellent observation! There's actually a 25 V Callins on the board itself. So, there's definitely a mistake on the schematic.

Danke,

--
Don, KB7RPU 
There was a young lady named Bright Whose speed was far faster than light; 
She set out one day In a relative way And returned on the previous night.

Thank you for confirming my suspicions. It turns out there's a typo on the schematic. The actual Callins capacitor on the board is 25 V.

As an aside, perhaps the circuit's relaxation oscillator looked a little less unsavory back in the hazy 1970s, back when Woz won Bushnell's bonus to minimize the chip count. :)

Danke,

--
Don, KB7RPU 
There was a young lady named Bright Whose speed was far faster than light; 
She set out one day In a relative way And returned on the previous night.

People get nostalgic about all sorts of things. And it's OK with me if they spend good money to make the object of their obsession a perfect replica in every way. Some people pay a lot more for questionable fine art.

It turns out there's a typo on the schematic. The actual Callins part is rated at 25 V. Regardless, thank you for taking the time to confirm my suspicions about it.

Danke,

--
Don, KB7RPU 
There was a young lady named Bright Whose speed was far faster than light; 
She set out one day In a relative way And returned on the previous night.

The old bakelite Black Beauty film (or maybe paper?) caps are highly prized/priced because some people can hear the difference.

If I paid $25 for a 0.022 uF cap, I bet I could hear the difference.

I wonder how many of these sorts of things are Chinese fakes.

--

John Larkin      Highland Technology, Inc 

The best designs are necessarily accidental.

I think so. So it's one ordinary cap potted.

--

John Larkin      Highland Technology, Inc 

The best designs are necessarily accidental.

Was it designed that way?

That circuit was barely designed at all. What's it supposed to do?

--

John Larkin      Highland Technology, Inc 

The best designs are necessarily accidental.

Lytics usually have a pretty good overvoltage tolerance, and a little leakage wouldn't do any harm in a power supply filter. It may have failed by drying out over the years and been replaced by whatever was handy.

--

John Larkin      Highland Technology, Inc 

The best designs are necessarily accidental.

Your question restates the gist of this thread.

How can you know the circuit was barely designed at all if you don't even know what's it supposed to do?

Danke,

--
Don, KB7RPU 
There was a young lady named Bright Whose speed was far faster than light; 
She set out one day In a relative way And returned on the previous night.

Engineers make mistakes? Never!

(ducking)

John :-#)#

Because it's full of trimpots and selected values. It was probably futzed until it worked. What's it supposed to do?

--

John Larkin      Highland Technology, Inc 

The best designs are necessarily accidental.

My guess is it was some kind of analog synth VCO, inputs EFG are summed and make the ramp, square and triwave outputs at jacks HDJ.

Dig the 3.6V D3 zener in the path, the 3.9Meg and 680R R19 R20 and the kooky voltage follower Q3 Q11 Q4 - the unijunction Q2 is probably the least nasty part of it all.

Thats why I used the word unsavoury!

piglet

I recall there being an oversupply of non-polarized electrolytics at one time, mainly because of their perceived mark-up value.

The value was due to their predominant sale to low-volume hobbyists.

The Callins part is polarized and of no special importance to the circuit in which it was employed.

The Hafler circuit was the DH110, which used descrete transisators of both polarities in complimentary pairs. I still don't see the C109 part in the schematic.

RL

^^^^^^^^^^^^^^^^^^^^

Every time I see that, a vision of them congratulating each other comes to mind.

It's complementary. -

Jeroen Belleman

P.S. Oh, and 'discrete'.

It's the VCO module from an old synthesizer. It has three triangles on its face-plate and it's right above the left hand side of the keyboard in the first image shown here:

Danke,

--
Don, KB7RPU 
There was a young lady named Bright Whose speed was far faster than light; 
She set out one day In a relative way And returned on the previous night.

I flipped a coin with complementary. Discrete has no excuse.

It was the DH100, not 110, using ICs, that had the C109 issue in it's docs. If I had a board, I'd make the schematic alteration.

Looks like all pns 100+ were added post-design. Stuff like RF filtering on inputs, belt and braces decoupling, grounding leakage paths etc. Most show up.

RL

Audiophool market.

For a number of years, I was involved with pickups for electric guitars. (A friend of mine made such guitars.) These pickups are variable-reluctance, sensing motion of the steel guitar strings.

There were many debates on the relative acoustic goodness of this or that picky/capacitor/design/etc.

What was missing was double-blind A-B comparisons. Now in music, double blind comparions are in fact common: When one applies for an orchestra job, it is typical for there to be a screen between the candidate and the audience of musicians. Neither can see the other, and the audience does not know which candidtae is playing.

Also mixssing was precise measurements of such things as component capacitance and coil self-capacitance. These vary by at least +/-

20%, and often 50%, which is easily heard, and was confounding the debates - supposed apple-apple A-B comparisons had inadvertently let a kumquat into the picture.

Many. And Americans have been known to partake as well. And there is a German firm that patented a coaxial dispersion compensator that claimed mitigate dispersion in coaxial audio cables. The patent does make electrical sense, and achieves a max compensation of ten picoseconds.

Which at 20 KHz is a phase error of 1.25 microradians. Can we even measure such a thing, let alone hear it? But the Germans knew that their audience had no idea what a picosecond might be.

Joe Gwinn

There must be some audio magic inside the Callins, but I see it difficult to get any advantage in a power supply filter. If you're not happy with a garden-variety aluminum, get a tantalum one, and please, with a little more than 6V rating, as the power line is nominally 6V.

--

-TV

I'm a dolt.

C9, C109 set the LF gain corner of the first IC's gain stage.

Part numbers above 100 are right channel, not repeated in schematic.

. . . Q has hovered for some decades in rubbish area of skull.

RL