[PCB] Thomas Henry's 555-VCO, 2nd run! check PMs

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fonik
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Post by fonik » Thu Feb 19, 2015 8:49 am

drip.feed wrote:
fonik wrote:
drip.feed wrote:https://www.modulargrid.net/e/fonitroni ... -s-555-vco

P.S. do you agree with the suggested price??
i would not build and sell you one for this price :D
Better now?
yep. worldwide shipping included :D
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Cryosion
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Post by Cryosion » Fri Feb 20, 2015 4:44 pm

Any chance to buy these now or in the somewhat near future?

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fonik
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Post by fonik » Sat Feb 21, 2015 8:14 am

PCBs and panels are on backorder and will be available again from thonk (UK) and synthcube (USA).
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Heavy Metal Kid
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Post by Heavy Metal Kid » Sun Feb 22, 2015 3:18 pm

Thanks, guys! I ordered some TLC555CP, the ones that woodster recommended.

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eonz
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Post by eonz » Mon Mar 30, 2015 3:55 pm

So I seem to be having a little issue with the "sync" input on my vco555.

It (somewhat) responds to a incoming square or saw when plugged but once I start turning the "course" knob with something plugged into the sync, it only seems to respond around the 10 o'clock to 2 o'clock range...any higher or lower and the audio just cuts out.

After looking at the schematic, I decided to swap C2 (470pf),R31 (100k),D2 (1N4148),Q1 (2N3904) and R15 (4.7k)...I also swapped the two TL074 and the TLC555, and still the same issue. The only IC I didn't have on hand was the LM13700...perhaps this could be the issue?>

Anyone have any thoughts on this>?
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woodster
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Post by woodster » Mon Mar 30, 2015 5:01 pm

Heavy Metal Kid wrote:Thanks, guys! I ordered some TLC555CP, the ones that woodster recommended.
:tu:

Hopefully a bit of TLC will sort your builds out.
Did you do any transistor matching ?

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Heavy Metal Kid
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Post by Heavy Metal Kid » Tue Mar 31, 2015 2:36 am

woodster wrote:
Heavy Metal Kid wrote:Thanks, guys! I ordered some TLC555CP, the ones that woodster recommended.
:tu:

Hopefully a bit of TLC will sort your builds out.
Did you do any transistor matching ?
Yes, the TLCs sorted them out. Didn't match the transistors, doesn't seem to be a problem. :hihi:

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search64
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Post by search64 » Tue Mar 31, 2015 6:30 am

Can someone tell me whether or not this will work for the C4 timing cap?

https://www.conrad.nl/nl/kemet-polyeste ... 35243.html

I''m not sure what to look for in the specs, but it's a polyester cap at least...
:despair:

Also, the BOM says 100k linear pots, but somewhere else I saw 50k. What would you recommend?

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humax5600
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Post by humax5600 » Wed Apr 01, 2015 11:42 am


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search64
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Post by search64 » Thu Apr 02, 2015 1:37 am

humax5600 wrote:On my TH555 VCO, i use this C4 :http://www.reichelt.de/Styroflexkondens ... ANGUAGE=EN

and for the pots i took this :http://www.reichelt.de/RK09K113-LIN100K ... H=100k+lin
Thanks! I had a look though, and Reichelt doesn't have a 100 ohm trimmer, or in fact a 25k or a 50k. It seems it's impossible to find one vendor that has everything you need for this project... annoying :S

Btw, those pots you linked to, are they D-shaft, and how long is the shaft?

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humax5600
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Post by humax5600 » Thu Apr 02, 2015 11:54 am

No D-shaft and shaft is about 17mm.
Btw, all the pots on the VCO have the same value
Image


100 Ohm
50kOhm
20kOhm
100kOhm

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search64
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Post by search64 » Fri Apr 03, 2015 1:52 am

humax5600 wrote:No D-shaft and shaft is about 17mm.
Btw, all the pots on the VCO have the same value
Image


100 Ohm
50kOhm
20kOhm
100kOhm
Right. Apparently I've overlooked those. Thanks! :)

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jasonh23
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Post by jasonh23 » Mon Apr 27, 2015 9:59 pm

Any more available, or did I miss this run :doh: ? I'd be very interested in two sets, please!

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Post by BARE BONES » Tue May 26, 2015 10:56 am

R55 doesn't appear on the part list, what value are people using for this?

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search64
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Post by search64 » Tue May 26, 2015 11:11 am

It's in the first post of this thread: 5.6k

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Post by BARE BONES » Tue May 26, 2015 11:35 am

doh, thanks :)

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search64
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Post by search64 » Thu Jun 18, 2015 9:28 am

The linear FM on my 555 is quite weak. As in, almost unnoticable at times :hmm:

Is there a trimmer that needs to be tweaked for this, or should I change out a resistor somewhere so I can make it deeper?

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batchas
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Post by batchas » Thu Jun 18, 2015 3:00 pm

search64 wrote:The linear FM on my 555 is quite weak. As in, almost unnoticable at times :hmm:

Is there a trimmer that needs to be tweaked for this, or should I change out a resistor somewhere so I can make it deeper?
Same here. Never asked cause I'm fond of the expo. FM, but interested in the solution now that the question has been asked.
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search64
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Post by search64 » Sat Jun 20, 2015 7:30 am

Nice to know at least I'm not the only one :)

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masterofstuff124
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Post by masterofstuff124 » Fri Aug 21, 2015 10:08 am

I also will buy a board/panel when available!

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Post by mcop » Fri Aug 21, 2015 11:43 am

search64 wrote:The linear FM on my 555 is quite weak. As in, almost unnoticable at times :hmm:

Is there a trimmer that needs to be tweaked for this, or should I change out a resistor somewhere so I can make it deeper?
Try droping R48 to somthing like 100K

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The Big Ear
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Post by The Big Ear » Sun Aug 23, 2015 3:49 pm

Heavy Metal Kid wrote:Like some others, I have a problem with this module. I have built two identical VCOs, and they both have the same behaviour.

In short, it seems like the circuit has difficulties going into oscillation, which means I need to start the power several times over in order to get up and running. And sometimes it stops oscillating if it the pitch goes too high while is being synched from an external VCO. I suspect that it somehow goes into a monostable state. When it goes silent, turning the pitch potentiometer yields some clicks around the 12 o clock mark.

A theory I read earlier was that some 555 chips were causing this problem. I have tried a couple of different makes that I had lying around.

Similarly, I have a hard time getting the LFO mode to work on the 555ADSR module, I suspect a better 555 will help there too.

Can anyone recommend me a 555 that is known to be cooperative for these circuits?
I'm having the exact same issues on my builts. Was this solved by changing the 555's?
Cheers,

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The Big Ear
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Post by The Big Ear » Wed Sep 23, 2015 2:33 pm

The Big Ear wrote: I'm having the exact same issues on my builts. Was this solved by changing the 555's?
Cheers,
So, it did. Changing the 555 to the ones mentioned solved the issues.
Cheers,

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Post by Outtatune » Fri Nov 27, 2015 8:32 am

Arghh. My 7th DIY build and my first failure. No sound coming out of it. I'm using the Fonik Euro combo and driving the 1V/Octave IN with my known good 0-5V LFO.

After checking the solder joints, cap polarity, diode polarity, chip and trannie orientation... what's the best way to troubleshoot this?

I'm a newb but have a 'scope and a DMM and would love to hear and learn generic (or specific) ways to find out what went wrong and how to fix it.

I have two sets of these to build and this is my first, so I have a spare everything.

Is there a "how to test failed builds" thread I've missed?

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qfactor
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Post by qfactor » Fri Nov 27, 2015 9:09 am

Well, if you read the above, you'd see that the most common thing to check is whether you used a CMOS 555, first? :despair:
"The 'clockwise' end is the pin that the center wiper connects to when you turn the pot shaft clockwise." - daverj

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