Advice on Hand Drawing a Schematic

[Hi-Fi-Mogul]

Hello all,

Well, I did it again, dang it !

Found this pristine 1957 Dynavox record player,
that when opened up reveals a spaghetti bowl wiring set-up.

There are no Dynavox 1950's schematics to be had,
so I would like to draw my own for future reference.

This is a 50C5 PP, 12AX7, Selenium rectifier circuit.

Where do I start with this effort ?

Thank you !

[TC Chris]

As to the schematic, you need to ask the guys who worked for Sams. They had a system for making the circuits clear.

But lacking a contact among retired Sams guys, maybe find a similar amp in that new schematic site, and use it as a general guide to schematic layout, substituting actual component connections and values.

Chris Campbell

[William]

That is a good looking unit, Mr. Mogul, very clean, and except for the spaghetti looks to be well built. And, it has a VM changer so it can't be all bad. As far as a schematic goes, I can barely read a Sam's let alone give you advice on how to draw your own. Will this unit be a keeper?

Bill

[TC Chris]

I was going to comment on your photo, observing that they certainly didn't waste any money on steel for that chassis. But then I thought, it's a typically American reaction. We all think that more, heavier, bigger is better. Look at our vehicles, or of more relevance, the ultra-high-end hi-fi components touting their faceplates milled from billet aluminum. But then, if it works well, maybe "less is more." That chassis is hidden away from fingers. It might also ventilate better with the minimal steel. I look forward to a full performance report.

Chris Campbell

[electra225]

I think the idea of drawing your own schematic is an intriguing one. And for a simple phono amp, it would be the ideal place to start.

I might suggest that you study similar schematics of record player amps to see how Sams would draw one. Start with the power supply, and end up at the speaker, just like Sams does it. Find the rectifier, solid state in this case, then find the filter caps, then find B+ to the first audio section, then B+ to the audio section and so on. Draw it like you see it, but straighten out the wires like Sams does.

[Hi-Fi-Mogul]

I already had the same thought of finding a similar
Push-Pull amplifier using the same tubes and selenium rectifier.

The RCAs from the mid-50's used this type of chassis
in many of their table top and consolette models.

I have several versions of that chassis to use as an
initial guide.

I searched the web for some generic tube amp templates to print,
but none found.

I don't wish to spend time now learning software that enables
one to create such templates.

I'll buy some graph paper which might be useful for hand drawing.

I will start the Dynavox project over in "Record Players", so you
guys can assist me over there !

Thanks.