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 Forum index » DIY Hardware and Software » The Repair Shop
Rene Schmitz 4069 VCO
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PERFORMANCE



Joined: Jun 11, 2020
Posts: 36
Location: Germany

PostPosted: Sun Nov 15, 2020 2:04 pm    Post subject: Reply with quote  Mark this post and the followings unread

This post might even be relevant to appear in the general DIY board since I suspect many people to be interested in RS works, right?

P.S.: I couldn't reactivate my more-than-a-decade old account over so don't blame me for being overly demanding for a newbie, hehe, theoretically I am not one....
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crazeydazey



Joined: Feb 15, 2007
Posts: 303
Location: England
Audio files: 4

PostPosted: Mon Nov 16, 2020 2:08 am    Post subject: Reply with quote  Mark this post and the followings unread

Hi,

I know this circuit pretty well now I have studied it quite a lot, first with having to fix my own, then I decided I want to modify it, so I built it all on breadboard then started changing things to see what happens Very Happy

it wasn't a massive success but I did learn a lot about the circuit.

I've not had much chance to look at what you've done, but the first thing that I noticed was that you might need to move it around a little bit, R4, R5 and R6 should all be 10k NTC temp co and should be bonded to T1 and T2, it will still work ok but will be more stable with 1V/Oct this way Wink

I'll have a better look when I have a bit of spare time...

also (I think this advice is in this thread actually ??) - you need to make sure you put the invertors in the same order that Rene did as I think you can run into problems otherwise ?? I don't know as I have always made it the same way he says to, but unless you take that from the prototype design that's pretty difficult as he doesn't label the pins on the schematic...

yep found it ...
JovianPyx wrote:
I had asked Rene for help while I was developing the linear current sink for it. I was getting a nasty "hash" noise in with the sawtooth. Emails back and forth later, Rene gave me the exact pinout he was using. When I wired mine to match - problem solved, no more hash. He's helped me several times with experimental stuff.

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PERFORMANCE



Joined: Jun 11, 2020
Posts: 36
Location: Germany

PostPosted: Mon Nov 16, 2020 9:07 am    Post subject: Reply with quote  Mark this post and the followings unread

Quote:
I've not had much chance to look at what you've done, but the first thing that I noticed was that you might need to move it around a little bit, R4, R5 and R6 should all be 10k NTC temp co and should be bonded to T1 and T2, it will still work ok but will be more stable with 1V/Oct this way Wink


Yeah, haha, I know I should use thermistors instead of regular resistors but for now i think I'll stick to the average ones...until my next order of supplies or my next visit to the electronics store. thanks anyway!


Quote:

also (I think this advice is in this thread actually ??) - you need to make sure you put the invertors in the same order that Rene did as I think you can run into problems otherwise ?? I don't know as I have always made it the same way he says to, but unless you take that from the prototype design that's pretty difficult as he doesn't label the pins on the schematic...

yep found it ...
JovianPyx wrote:
I had asked Rene for help while I was developing the linear current sink for it. I was getting a nasty "hash" noise in with the sawtooth. Emails back and forth later, Rene gave me the exact pinout he was using. When I wired mine to match - problem solved, no more hash. He's helped me several times with experimental stuff.


AH, thanks for pointing that out! Are the exact pinouts to find anywhere? Since the individual Schmdit Triggers even in the schematic are ordered in sort of groups of three I wasn't even thinking about that (although I would have expected each does the same - but still it is just a CMOS-thing without proper opamps...).

Thank you so far![/quote]
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bow_and_error



Joined: Sep 03, 2020
Posts: 1
Location: USA

PostPosted: Tue Aug 17, 2021 11:19 am    Post subject: Reply with quote  Mark this post and the followings unread

Sorry to resurrect this old thread, but I'm giving this a go and may have found a few corrections.

I believe the connections to the Q1 2N3904 are mixed up:
- R1 (100k?) should go to the Base
- 100k connected to the Emitter should actually be connected to the Collector (in parallel with the 68k from Pin 9)
- There should be a 10k from Emitter to -12V

If you move the ground trace from Pin 6 to Pin 7, that should fix that section at least. I can't confirm the rest of the layout yet, but I'll give it a go in DIYLC and highlight connections to double check.[/list]
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