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mrmrshoes
Joined: Feb 19, 2011 Posts: 73 Location: Newcastle Upon Tyne
Audio files: 4
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mosheen
Joined: Jun 19, 2013 Posts: 21 Location: NC
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Posted: Mon Jun 24, 2013 6:08 pm Post subject:
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Thank you. I couldn't tell exactly what it was for. |
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elmegil
Joined: Mar 20, 2012 Posts: 2177 Location: Chicago
Audio files: 16
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Posted: Mon Jun 24, 2013 7:27 pm Post subject:
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usually I use polystyrene for those, but I'll be honest and say I'm not sure. |
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codenamerofl
Joined: May 26, 2013 Posts: 9 Location: south carolina
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Posted: Fri Jul 05, 2013 6:09 pm Post subject:
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i have an interesting problem.
built one of these, got 6 octaves out of it.
i built another one, and used a different thermistor.
the first one used an NTC honeywell thermistor that i got from mouser.
this one uses an NTC thermistor from futurlec. i cannot get more then a couple notes out of it. if i play an octave up, it goes sharp, and an octave down causes it to go flat. from a tuned C an octave up gets a C# and an octave down gets a B. I have my v/oct trimmer maxed out.
Could it be due to the thermistor? timing cap?
thanks for any help. |
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mosheen
Joined: Jun 19, 2013 Posts: 21 Location: NC
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Posted: Fri Jul 05, 2013 6:13 pm Post subject:
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Is it the correct type? The curve and rate are very important. |
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codenamerofl
Joined: May 26, 2013 Posts: 9 Location: south carolina
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Posted: Fri Jul 05, 2013 8:01 pm Post subject:
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mosheen wrote: | Is it the correct type? The curve and rate are very important. |
thanks for the quick reply. as luck would have it, i scrounged around and found an extra thermistor i had from the previous build. swapped em, and now i've got v/oct scailing on the entire scale of my x0xb0x. will get fine tuned for higher ranges once i get fresh batteries for my sh101. |
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mosheen
Joined: Jun 19, 2013 Posts: 21 Location: NC
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Posted: Fri Jul 05, 2013 8:06 pm Post subject:
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Cool. Remember too that some thermistors are positive coefficient, while others are negative coefficient. Have fun! |
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fuzzo
Joined: Nov 12, 2011 Posts: 5 Location: Lyon , France
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Posted: Sun Jul 21, 2013 8:33 am Post subject:
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Hi ,
I've decided to build a tiny analog synth and I highly consider this 555 VCO (for its simplicity). However, I'd like to know if there's a VCF better than the others to be coupled with it ?
it may be an odd question. Say , if you'll have to chose only one , what it will be ?
I though of a 24db ota's based (inexpensive and easy to build) |
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mosheen
Joined: Jun 19, 2013 Posts: 21 Location: NC
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Posted: Sun Jul 21, 2013 9:19 am Post subject:
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Oh no! Not the "best filter" debate! |
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fuzzo
Joined: Nov 12, 2011 Posts: 5 Location: Lyon , France
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Posted: Sun Jul 21, 2013 9:45 am Post subject:
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oups. sorry !
Even in synth world there's this kind of silly debate ? the same that between fender and Gibson I guess ) .
I'm not looking for the "best" (that doesn't make sense anyway) , juste idea and advices on what could be interesting to do and add. I just want directions to start my project and make the best of it.
anyway, I'll stick with the original idea and see how it sounds. |
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mosheen
Joined: Jun 19, 2013 Posts: 21 Location: NC
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Posted: Sun Jul 21, 2013 9:55 am Post subject:
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You can't go wrong with a moog ladder clone. It's cheap, easy to build and sounds great. It's the sound you probably associate with a synth filter too.
I'm just ribbing you on the "debate" part. I don't think there will be any wars fought over here about it, but it's all a matter of taste. I think it's more of which one they love more, not which ones they hate. At least that's the impression I've gotten in my short stay here. |
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mosheen
Joined: Jun 19, 2013 Posts: 21 Location: NC
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Posted: Tue Jul 30, 2013 11:17 pm Post subject:
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I need a little advice. I have had my own boards made for myself and everything seems to work great except for the ramp wave. Does anyone have any suggestions as to where I should be looking in the circuit? I've swapped all the chips just to be sure, and traced all of the connections a good ways back through the circuit and everything seems ok. I know it's a very broad question, but any starting points would be appreciated. I'm a digital guy who dove off into an oscillator for my first ever module and analogue circuit. Silly me!
This is the Ramp wave paired with the triangle. Notice it's a 1vpp square wave. The Ramp Contour trimmer does nothing to its shape, but the trimmer is changing witrh the adjustment screw when I measure it with my meter.
The triangle wave is on the 2V scale, that's why it shows 5vpp right now.
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mosheen
Joined: Jun 19, 2013 Posts: 21 Location: NC
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Posted: Wed Jul 31, 2013 8:17 pm Post subject:
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I figured it out. I accidentally nuked a single rat line when designing it.
Guess it's time to break out the 30awg....
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Sony Crocket
Joined: Sep 27, 2010 Posts: 13 Location: Madrid, Spain
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Posted: Tue Sep 03, 2013 7:41 am Post subject:
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Hi!
Im populating the fonik´s PCB, and I am stuck on the 2k tempco.
So hard to find them, and the only one I found on a shop is 4 euros for a 1k tempco. Is it a critical component? I don´t need perfect tunning stability, but wonder if it will work and get the full oct range with a standard 2k 1% resistor.
I can´t figure how to solder it on the PCB. Q2 and Q3 does not give much room for it. Can I solder it on the back of the pcb?
Could someone show me a photo of the tempco mounted on the board?
Thanks a lot! |
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oculus
Joined: Oct 30, 2011 Posts: 35 Location: Iceland, Reykjavik
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Posted: Tue Sep 03, 2013 10:15 am Post subject:
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i have made both the TH Vco-1 and the XR-2206
just using regular 1% 2k resistors as i didn´t have any tempcos,
there´s a littlebit drift in much heat change
but they are completely usable , iv´e already made some songs with them,
but i plan on ordering tempcos and put them in instead.
Sony Crocket wrote: | Hi!
Im populating the fonik´s PCB, and I am stuck on the 2k tempco.
So hard to find them, and the only one I found on a shop is 4 euros for a 1k tempco. Is it a critical component? I don´t need perfect tunning stability, but wonder if it will work and get the full oct range with a standard 2k 1% resistor.
I can´t figure how to solder it on the PCB. Q2 and Q3 does not give much room for it. Can I solder it on the back of the pcb?
Could someone show me a photo of the tempco mounted on the board?
Thanks a lot! |
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oculus
Joined: Oct 30, 2011 Posts: 35 Location: Iceland, Reykjavik
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Posted: Tue Sep 03, 2013 10:20 am Post subject:
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i just breadboarded the core of the VCO-555, (first page of the schematic)
im currently not getting anything at the ramp and triangle output.
shouldn´t i be able to make it work without the waveshapers for the sine and square ? (so without breadboarding the page2 of the schematic)
nevermind, got it working, i had a broken LM13600
thanks kind regards
Oculus |
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fonik
Joined: Jun 07, 2006 Posts: 3950 Location: Germany
Audio files: 23
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Posted: Wed Sep 04, 2013 4:33 am Post subject:
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Sony Crocket wrote: | Hi!
Im populating the fonik´s PCB, and I am stuck on the 2k tempco.
So hard to find them, and the only one I found on a shop is 4 euros for a 1k tempco. Is it a critical component? I don´t need perfect tunning stability, but wonder if it will work and get the full oct range with a standard 2k 1% resistor. |
no problem at all (see comment above).
Quote: | I can´t figure how to solder it on the PCB. Q2 and Q3 does not give much room for it. Can I solder it on the back of the pcb?
Could someone show me a photo of the tempco mounted on the board? |
don't have a good picure on hand right now, however, the tempco is supposed to be mounted ON TOP of the transistors. both transistors and the tempco PTC should be in a termal contact to each other. since you plan to use common resistors there is no need to mount it on top. you could mount it to the reverse side of the PCB instead.
anyways, here is a picture of a PTC mounted on top of a super matched pair for a 555VCO. i think you get the idea:
Thanks a lot![/quote] _________________
cheers,
matthias
____________
Big Boss at fonitronik
Tech Buddy at Random*Source |
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Sony Crocket
Joined: Sep 27, 2010 Posts: 13 Location: Madrid, Spain
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Posted: Wed Sep 04, 2013 7:58 am Post subject:
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Thanks for your responses.
Matthias, this is the photo I needed! Didn´t knew the tempco should be in contact with the transistors... yes, I´m a newbie...
Regards! |
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flyweight303
Joined: Sep 04, 2013 Posts: 3 Location: Praha
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Posted: Wed Sep 04, 2013 8:02 am Post subject:
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I cannot sleep i cannot eat can't stop thinking about the VCO 555.
Man i want 3 pcb's for the VCO 555. really bad.
Is there gonna be anothe run??
Thanks in advance,
Kindest regards, |
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HansRL
Joined: Nov 17, 2012 Posts: 15 Location: Norway
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Posted: Fri Sep 06, 2013 4:18 am Post subject:
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fonik wrote: | I still have PCBs and eurorack front panels ... |
Are PCB still available? If so, it seems I'm to stupid to find my way around your web site to find it.
TIA |
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fonik
Joined: Jun 07, 2006 Posts: 3950 Location: Germany
Audio files: 23
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Posted: Sat Sep 07, 2013 2:43 pm Post subject:
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HansRL wrote: | fonik wrote: | I still have PCBs and eurorack front panels ... |
Are PCB still available? If so, it seems I'm to stupid to find my way around your web site to find it.
TIA |
my DIY pages have not been updated for a long time... you will find all info in the fonik's place subforum.
anyways, the 555-VCO is currently sold out, however, i am running a waiting list. i could re-order any quantity of ciruit boards any time. it is just that some people like to get the eurorack front panel and front panel components PCB as well. and for the front panels i need at least 30pcs minimum of interest.... _________________
cheers,
matthias
____________
Big Boss at fonitronik
Tech Buddy at Random*Source |
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widdly
Joined: Jun 25, 2007 Posts: 268 Location: singapore
G2 patch files: 2
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Posted: Wed Oct 16, 2013 6:13 pm Post subject:
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I've built 3 of these so far and found that some LM13600 don't give linear tracking. I know the schematic specifies LM13700 but I didn't have any on hand.
One of the three I built could not be tuned accurately for more than an octave. I swapped the LM13600 with one of the properly working builds and the tuning problem followed the LM13600. I tried 7 different chips and 3 wouldn't give proper tuning. Interestingly these were from different manufacturers.
So if you have a lot of trouble getting this VCO to track properly then you should try swapping out a few different OTA's.
BTW. These are the best VCO's I've ever built. The tracking is great, the waveshapes and level are spot on and the frequency range is amazing. They cover your VCLFO needs too. |
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mosheen
Joined: Jun 19, 2013 Posts: 21 Location: NC
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Posted: Wed Dec 11, 2013 11:01 pm Post subject:
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So...now that I've played around with this for a while, how do you tune it? I know to use a 1V CV difference and go back and forth until the slope is right, but how do the 1V/oct and HF trim pots relate?
What is a good octave to start and end with? If I tune across say 5 octaves, and the turn the coarse pot left or right will is skew the tuning?
If anyone has any input or a definitive guide I'd appreciate it. |
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mosheen
Joined: Jun 19, 2013 Posts: 21 Location: NC
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Posted: Tue Dec 17, 2013 1:02 am Post subject:
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Figured it out.
Turn the HF trim knob all the way to its stop whichever way lowers the frequency.
Turn the V/Oct trimmer to the stop and then turn it back 15 turns to center it.
Don't try and adjust the second reading to an absolute, just turn the trimmer one rotation at a time and go back to 0v and use the fine pot to reset the first frequency. Lather, rinse, repeat. |
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jukingeo
Joined: Oct 24, 2007 Posts: 166 Location: The dark side of the moon
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Posted: Sat Jan 25, 2014 10:27 am Post subject:
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Hello All,
I just stumbled upon this thread today while looking into some ideas for module VCO's and VC-LFO's.
Up to now I been dealing with MFOS and I have bought some boards from them. I am currently constructing the DIY-Experimenter Synth. The thing isn't even built yet, and I am looking into more options.
For the LFO, I am completely nuts over the Variable Skew LFO on the MFOS site. The trouble is this isn't a supported project anymore and as such there isn't a PCB available. Not too much of a problem as I can try to strip board it. The problem with it is that it isn't a VC-LFO, but I do intend to build a couple anyway.
Now for the VCO, the issue I am having with the MFOS design is that I feel it is overly complex and it seems there is a fairly long calibration process. Naturally I am wanting to look for something simpler and less complex, but nearly offers the same features as the MFOS design.
After a quick search I came across this post on a 555 based VCO created by Thomas Henry. After reading through this thread, it seems that it is accepted that this is the arguably the best VCO out there currently. What I like it is that it uses quite less parts than the MFOS design, and a fellow in Germany is making boards for this. So I have a few questions:
1) Is this really the better picks of the VCO's out there and does it compare to the MFOS VCO or does this clearly blow the MFOS one away?
2) Is there someone here in the US that is distributing the boards?
3) One feature I liked on the variable skew LFO is the ability to adjust the waveform of the triangle wave to a saw or ramp wave and anywhere in between. Could this feature be added to the 555-VCO?
4) I would assume that changing out the timing cap could easily make this an LFO, correct?
Thank You,
Geo _________________ Lover...I won't take a back seat, tonight. Got some dancin' to do. |
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