DIY - Elektor Vocoder - General Build Thread

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nologin
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Re: DIY - Elektor Vocoder - General Build Thread

Post by nologin » Wed Feb 19, 2020 5:52 pm

Yes, i removed it and soldered another, 7905, still the same problem. :doh: I'm going to try one on another circuit, maybe they are faulty. :hmm: It's strange.

KSS
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Re: DIY - Elektor Vocoder - General Build Thread

Post by KSS » Thu Feb 20, 2020 6:43 am

elmegil wrote:
Wed Feb 19, 2020 11:24 am
Verify that you actually have a 7905 regulator and not a 7915?
And that you don't make the common mistake of thinking the tab/back of 79xx is GND. It is on the the 78xx, so these cannot touch each other -typically through shared H/S- or wierd things can happen. Keep your 78xx isolated from any 79xx.

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nologin
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Re: DIY - Elektor Vocoder - General Build Thread

Post by nologin » Thu Feb 20, 2020 12:33 pm

Yes KSS, if i had done that reversal 78xx/79xx, regulators would have burned out.
Here, i've got this at IC20 and no short circuits:

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elmegil
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Re: DIY - Elektor Vocoder - General Build Thread

Post by elmegil » Thu Feb 20, 2020 1:29 pm

Test another 7905 from that batch separately. It is labelled correctly but depending on your supplier, it could conceivably be mislabelled.

The other thing I would look for would be a short between the -5 and -15 rails.

KSS
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Re: DIY - Elektor Vocoder - General Build Thread

Post by KSS » Thu Feb 20, 2020 6:23 pm

nologin wrote:
Thu Feb 20, 2020 12:33 pm
Yes KSS, if i had done that reversal 78xx/79xx, regulators would have burned out.
I didn't say anything about reversal. I said if there is contact between the tabs of 78xx and 79xx, weird results can and do show up. And this does not necessarily blow the Vregs. It's as much a reminder warning for anyone reading this thread asfor you personally. It's happened enough times to others besides you to beworth mentioning when 78xx and 79xx share a PCB. /fix typos

Croodey
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Re: DIY - Elektor Vocoder - General Build Thread

Post by Croodey » Sun Feb 23, 2020 7:47 am

so,... now after many hours because i dont undrstand the adjustment instructions i hope i did anything right with the adjustment on the filters. it is very suspicious that I have to turn the trimmer for the "DC offset" all the way down to the stop in order to achieve the minimum output level. did I do it right at all? (Solved: the reason was, i took the 1m resistors on r200 and r201 AND a 10k trim too :doh: )

I'm currently at the "Switching interface adjustment".
my first questions:

Bridges of G-H and I-J? (Yes No?)
Signal in carrier?
Voice and Out 100%?
what should I adjust to what? optical signal on the LEDs, or acoustic?
acoustically silent with "s" sounds or with noise?
is a hum normal when "a" and "s" are audible? (ok,... i think i have the hum fixed with the grounded case)

why is there no audible crackle for me, no matter what the settings on the dedecting board are?
:despair:

please help me to finish this nice project :hail:
87195844_512893686075511_4677636886229942272_n.jpg
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yan6
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Re: DIY - Elektor Vocoder - General Build Thread

Post by yan6 » Mon Feb 24, 2020 9:42 am

I hope you are able to push forward with this project and help document the deficiencies in the calibration documentation. I fell flat on the calibration and could never figure it out, now mine sits in a bin :cry:

Croodey
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Re: DIY - Elektor Vocoder - General Build Thread

Post by Croodey » Mon Feb 24, 2020 4:39 pm

Yesterday i got some infos in german lenguage. I will test it and translate it😉
But for the first loint yesterday i have seen, i made the fixing mod for the offset wrong. Now i must start again to adjust the bandfilters.

:bang:

Croodey
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Re: DIY - Elektor Vocoder - General Build Thread

Post by Croodey » Thu Feb 27, 2020 6:37 am

Now, i have read the instructions from the elektor magazin 1980. The instructions on the page from this DIY is the same and really good. In the magazin are maybe a little bit more infos witch helps to understand (in case of my own).
Yesterday i did step 1 and step 2 of the filtercalibration.
For step one i take the noise from my SH-101 into the voice inputterminal of the elektor with inputlevel on max volume. No carrier. On the outputterminal (level max) i put on my oszilloscop and adjust the trimpotis between 20mv and 40mv.
The next step is to connect a mic into the voice terminal and the outputterminal to your mixer and send 200mv on the point "in" on the boards. I turned the gain to the point, where i hear a little bit noise. Than i turn the trimpoti on the filter for the second step so far to the point where it comes a loud noise. Turn it back to the nearly point where it is between qiuet to get loud.
The 3rd step is easy.

I hope i does it right. But it looks like.
I will see it in the afternoon, when i adjusted the voice/unvoice and noise.



EDIT:

it is easyer if you turn all trimpotis to the centerposition before you start to adjust.

Croodey
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Re: DIY - Elektor Vocoder - General Build Thread

Post by Croodey » Thu Mar 05, 2020 5:26 am

Next Vocoder, next problems :hmm:

Does someone got this version of circuitboards? It is without the places R200 / R201
Maybe there you have a old BOM or buildinguid.
I changed now on p1 (offset) the 100k to 10k but it doesnt work really good an have 27mv and more
88198839_135100451212036_1194129546853482496_n.jpg
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