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fluxmonkey
Joined: Jun 24, 2005
Posts: 708
Location: cleve
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 Posted: Thu Jul 27, 2006 1:08 pm Post subject:
Re: Thomas Henry XR-2206 VCO Page is Up
Subject description: Spiffy Low Parts Count VCO with VC Skew |
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scott,
just saw your notice on the webpage about the error in the schematic and pcb layout. thanks for the workarounds... do the schematics/pcb PDFs now reflect the fix? probably would be good to add an revision note on the pdfs themselves, just to keep everything clear.
thanx for all
bbob |
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Scott Stites
Janitor
Joined: Dec 23, 2005
Posts: 4127
Location: Mount Hope, KS USA
Audio files: 96
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| Posted: Thu Jul 27, 2006 1:32 pm Post subject:
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Hi BBob,
Nope - the PCB doesn't reflect the change. I don't have the original copy of the PCB layout. All of that came from Thomas. I'll pass that along, in case he intended to correct it, but never got around to it. I'm afraid the only (crude) means I have of correcting it may distort the scale.
Cheers,
Scott |
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bugbrand
Joined: Nov 27, 2005
Posts: 846
Location: Bristol, UK
Audio files: 1
G2 patch files: 1
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Scott Stites
Janitor
Joined: Dec 23, 2005
Posts: 4127
Location: Mount Hope, KS USA
Audio files: 96
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| Posted: Fri Sep 22, 2006 6:19 am Post subject:
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Fan-freakin-tastic!!!!
I'll link this from my TH XRVCO page as well.
Thanks Tom!!
Cheers,
Scott |
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bugbrand
Joined: Nov 27, 2005
Posts: 846
Location: Bristol, UK
Audio files: 1
G2 patch files: 1
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synth_ollie
Joined: Sep 11, 2006
Posts: 149
Location: sweden
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| Posted: Mon Jan 08, 2007 10:06 am Post subject:
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I can not find lm394 or ssm2210, but I guess mat02 will work as well ?
cheers
OLLIE |
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vtl5c3
Joined: Sep 08, 2006
Posts: 425
Location: PDX
Audio files: 13
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| Posted: Mon Jan 08, 2007 10:17 am Post subject:
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| MAT02 should be fine. I've used them in other VCOs, such as the CGS 48 VCO and no problems so far. |
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bugbrand
Joined: Nov 27, 2005
Posts: 846
Location: Bristol, UK
Audio files: 1
G2 patch files: 1
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synth_ollie
Joined: Sep 11, 2006
Posts: 149
Location: sweden
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| Posted: Mon Jan 08, 2007 4:32 pm Post subject:
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| bugbrand wrote: |
You should still be able to get free samples in Sweden from www.analog.com
(register, then order samples) |
thanks, but a friend had some mat02´s that he gave me 
Im gonna use your layout bugbrand, have you built it, is it ok ?
(I may try to get some samples from analog later.....)
also, I´d like an octave swicth on my 2206 vco, found this
http://me.ineptum.home.comcast.net/asm-1/vcoexp.gif |
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mikeb
Joined: Nov 20, 2006
Posts: 59
Location: The Automotive Capital of Canada
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| Posted: Tue Jan 09, 2007 9:00 pm Post subject:
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| synth_ollie wrote: | | bugbrand wrote: |
You should still be able to get free samples in Sweden from www.analog.com
(register, then order samples) |
thanks, but a friend had some mat02´s that he gave me
Im gonna use your layout bugbrand, have you built it, is it ok ?
(I may try to get some samples from analog later.....)
also, I´d like an octave swicth on my 2206 vco, found this
http://me.ineptum.home.comcast.net/asm-1/vcoexp.gif |
A few years ago, to do octave switching (I had 3 octaves actually) with my simple xr 2206ciruit I just switched out the timing capacitor. This is C7 on Thomas Henry's circuit and is .047uF. This is what I did:
I matched a bunch of capacitors (I was using a different value for my circuit) by building my basic XR2206 circuit and putting in different capacitors with the output hooked up to a tuner. Then I'd select two that "matched" when they outputted nearly the same frequency. Then to do the switching, I used a rotary switch to switch the capacitors to parallel, single and series. 3 different octave settings.. perfectly in tune.
I can draw up a little wiring diagram for how the parallel/single/series switching works if you want.. |
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synth_ollie
Joined: Sep 11, 2006
Posts: 149
Location: sweden
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| Posted: Wed Jan 10, 2007 9:32 am Post subject:
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| mikeb wrote: |
I can draw up a little wiring diagram for how the parallel/single/series switching works if you want.. |
yes please !
....and where can I find lm442´s ? |
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mikeb
Joined: Nov 20, 2006
Posts: 59
Location: The Automotive Capital of Canada
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| Posted: Sun Jan 14, 2007 2:19 pm Post subject:
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| synth_ollie wrote: | | mikeb wrote: |
I can draw up a little wiring diagram for how the parallel/single/series switching works if you want.. |
yes please !
....and where can I find lm442´s ? |
Okay, this took me a few days to draw because of all the amazing photoshop that it required... sorry about the delay:
As for the LM442 mentioned on that XR-2206 VCO page, it's actually an LF442. It's correct on the parts list pdf, but not on the website. I got them from digikey, but I just realized futurlec also has them. |
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Scott Stites
Janitor
Joined: Dec 23, 2005
Posts: 4127
Location: Mount Hope, KS USA
Audio files: 96
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| Posted: Sun Jan 14, 2007 3:27 pm Post subject:
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| Quote: | | It's correct on the parts list pdf, but not on the website |
Thanks for noticing that - it's fixed.
Cheers,
Scott |
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etaoin
Joined: Jun 30, 2005
Posts: 761
Location: Utrecht, NL
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| Posted: Sun Feb 18, 2007 11:44 am Post subject:
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I'd like to report a succesful build of the Bugbrand PCB. It is working fine, although the XR is running slightly warm. Should it do that?
 |
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Scott Stites
Janitor
Joined: Dec 23, 2005
Posts: 4127
Location: Mount Hope, KS USA
Audio files: 96
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| Posted: Sun Feb 18, 2007 11:51 am Post subject:
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Don't recall offhand, maybe Tom does.
How warm, warm as in "I feel a bit feverish today" or warm as in "Damn, that thing burned my finger"?
Cheers,
Scott |
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mikeb
Joined: Nov 20, 2006
Posts: 59
Location: The Automotive Capital of Canada
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| Posted: Sun Feb 18, 2007 11:53 am Post subject:
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| My XR-2206 gets warm as well, but not too warm to touch. I can leave my finger on there forever if I want, without discomfort. |
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bugbrand
Joined: Nov 27, 2005
Posts: 846
Location: Bristol, UK
Audio files: 1
G2 patch files: 1
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| Posted: Sun Feb 18, 2007 3:42 pm Post subject:
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...I don't know offhand -- never noticed it but hadn't much reason too, I guess.. I'm away from home still for the next week & I'll try to check once I'm back.
Glad its worked out ok for you!
_________________
http://www.bugbrand.co.uk
http://www.bugbrand.blogspot.com |
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Fernando
Joined: Dec 30, 2006
Posts: 286
Location: Barcelona & Emporda, Spain
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| Posted: Tue Feb 20, 2007 8:22 am Post subject:
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| zipzap wrote: | Have fun!
BTW, i understand that a simple circuit is what you want. If you can live with another pot and jack than consider using pin 1 for am. I had so much fun with that. Just don´t know if it can be implemented alogside the vc skew circuit. Don´t really yet understand how that´s working... |
| zipzap wrote: | Well, giving it a closer look i see that i missunderstood something there. While experimenting with the chip i was getting a ramp-wave by connecting the pulse out to the fsk in, just like in the datasheet. than the resistor value at pin 8 had the effect i just described.
Now in this case the ramp must be made somehow different. Can´t use my right hand right now. As soon as i can i´ll check this out. Good way to learn by building a design, than experimenting with values, see what happenes.
About the AM, I was writing about it in the other thread, I like that it is bidirectional with negative cv inverting the wave, like a rigmod. On the scope it looked way different than what´s going on with that vc-skew. But very often things like that sound very much the same, although the effect is created differently. So there is no benefit in adding too much, just because it´s possible. Have to force myself not to want a pot for everything sometimes.
But --- maybe fast AM and slowly modded skew will sound great, unheard? I don´t know... |
I'd like to know how you did AM to pin 1.
Could be implemented with a switch? (to have skew control or AM)
I'd love to have AM on a VCO internally saving an vca. Turning signal negative with negative cv can be interesting too.
Maybe you did some experiments from that July '06 post? |
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mikeb
Joined: Nov 20, 2006
Posts: 59
Location: The Automotive Capital of Canada
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| Posted: Tue Feb 20, 2007 3:46 pm Post subject:
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Fernando>
For AM on an XR-2206 @ pin 1, the amplitude is 0 at VCC/2. So if you're using TH's XR-2206 circuit, it's at 7.5V.
so 7.5V is 0 amplitude.
11.5V is 1 (full) amplitude.
3.5V is -1 (full, but flipped) amplitude.
So I'd connect a Pot up, one end to +15, one end to -15 and the wiper going to the AM pin. This will be the "amplitude center" adjustment. That is, adjust it to output 7.5V if you wish it to be centered at 0 amplitude.
Then connect up a jack going to the AM pin as well, and there's your voltage control input.
Worth a try! Try it in conjunction with the skew, it should just make weirderness i THINK Otherwise, add a switch as you mentioned to disable the skew when you want... |
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Fernando
Joined: Dec 30, 2006
Posts: 286
Location: Barcelona & Emporda, Spain
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| Posted: Tue Feb 20, 2007 3:59 pm Post subject:
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great, thank you!!
but, to use it while the skew circuit is present, one should isolate that AM input somehow? A voltage mixer or something?
Or it's OK in the raw way you described?
...raw because it works well like that? or driven by a wild experimental spirit? |
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mikeb
Joined: Nov 20, 2006
Posts: 59
Location: The Automotive Capital of Canada
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| Posted: Tue Feb 20, 2007 7:14 pm Post subject:
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| Fernando wrote: | great, thank you!!
but, to use it while the skew circuit is present, one should isolate that AM input somehow? A voltage mixer or something?
Or it's OK in the raw way you described?
...raw because it works well like that? or driven by a wild experimental spirit? |
This isn't anything I've actually TRIED yet |
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Fernando
Joined: Dec 30, 2006
Posts: 286
Location: Barcelona & Emporda, Spain
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| Posted: Wed Feb 21, 2007 2:28 am Post subject:
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hehe, okay!
| mikeb wrote: | | Fernando wrote: | great, thank you!!
but, to use it while the skew circuit is present, one should isolate that AM input somehow? A voltage mixer or something?
Or it's OK in the raw way you described?
...raw because it works well like that? or driven by a wild experimental spirit? |
This isn't anything I've actually TRIED yet :) |
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mikeb
Joined: Nov 20, 2006
Posts: 59
Location: The Automotive Capital of Canada
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| Posted: Wed Feb 21, 2007 2:56 pm Post subject:
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| Fernando> I'll give it a try tonight or something and report back the results. My only issue that I see happening is that reliably getting VCC/2 exactly (to produce 0 amplitude) is going to be hard, so I can always picture a bit of audio leaking out. Which isn't a big deal if you want to just send an LFO to the fake "VCA" portion. But if you want to make a proper controller for the audio, like a foot pedal or something, then getting that VCC/2 point would be tricky I think. |
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Fernando
Joined: Dec 30, 2006
Posts: 286
Location: Barcelona & Emporda, Spain
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| Posted: Wed Feb 21, 2007 4:44 pm Post subject:
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maybe you could open a switch and let the voltage you want to pass thru.
That voltage being constant, you only let the door open or close.
Two complementary doors for two voltages (2 and 0 V) |
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para
Joined: Oct 16, 2006
Posts: 276
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| Posted: Thu Mar 29, 2007 3:32 am Post subject:
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i just finished up 3 of bugbrands XR boards, switchable to lfo so i'm wondering if and how i can add a speed indicating led?
any guesses
steven |
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