Katsumi mc902 speech processor build

[Jay_rystl1]

Ellow all, i was looking at the schematics of a Katsumi speech processor, what if i could build one?
I found sources for all major components but one, the transformer used in the compression feedback loop. I have a winder and done specialised transformers before.
Anybody willing to do some measurements?

katsumi.PNG

[Strawberry]

Hi
it's an interesting project mate, I like Katsumi stuff myself, I have a Katsumi Morse key.
I saw one of these on ebay a few days ago, I thought I might have a bid on it myself until the bids went up by a lot more than I wanted to pay, it went for over 120 squid in the end and it wasn't in great condition either.
https://www.ebay.co.uk/itm/266886162240 ... iZA&edge=1

I had a look at the circuit and it doesn't look so complicated like it couldn't be er.. replicated.
I also did a quick Duck duck image search to see if I could find a picture of the innards and found this Japanese site which shows the transformer in question.
https://jr2jhg.livedoor.blog/archives/916608.html

It looks to me very much like a standard 600 ohm audio transformer.
Another clue as pointed out by my son to it being a 1:1 transformer is that it is actually drawn with the same number of winding's each side, that might not mean much but the mains transformer is drawn with a lot more turns on the primary which means that this circuit diagram was drawn by someone who cares about such things.

BTW are you any good with KiCad, my son is a whizz but it's hard to get him interested in anything unless it's guitar related, it would be a great project though.
All the best with it anyway.
Neil

[14CS06]

Hello

Hello

https://www.ham-international.eu/pages/katsumi902.html

https://www.ham-international.eu/pages/ ... MC902.html

@+
Claude

[Strawberry]

Would anyone, (UK, maybe EU depends on postage), be interested in a PCB for this project?
My son says if enough people are interested he will start on a KiCad design for it.
Neil

[Jay_rystl1]

Thanks for the replies, it might be a 600/600, i have plenty of those but a little smaller form factor, wonder why they used a tansformer after all, maybe to reduce circuit load by the rectifiers...
As for kicad, i've done 20+ projects with it.
If the size can be kept below 102/102mm boards can me made real cheap.
Of course these days you would use a DSP for such application.
I used to own a tatung rf clipper, easy to replicate if you can find some coils....
For now all just a thought exercise