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Wild Zebra
Joined: Apr 28, 2005 Posts: 806 Location: Ohio
Audio files: 5
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Posted: Tue Jul 05, 2005 11:02 am Post subject:
Anyone have their fine tuners hooked up |
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I hooked up the fine tuners and it doesn't seem to be doing anything from what I can tell. Just wondering if anyone else has hooked theirs up.
Maybe help figure out what is wrong. It seems like a pretty simple mod and I'm pretty sure I did it right, but obviously I didn't. _________________ "your stripes are killer bro" |
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Albut
Joined: Apr 09, 2005 Posts: 14 Location: England
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Posted: Tue Jul 05, 2005 11:58 am Post subject:
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Hi Wild Zebra,
If you have the 3 resistors soldered to the 50K pot, make sure that the 1M from the centre of the pot goes to the junction of R62,54,77 and R82 for VCO1 and to the junction of R63,57,78 and R83 for VCO2. and that should work fine.
albut. _________________ "put an egg in your boot and beat it" |
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Wild Zebra
Joined: Apr 28, 2005 Posts: 806 Location: Ohio
Audio files: 5
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Posted: Tue Jul 05, 2005 12:06 pm Post subject:
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Actually that was what I was wondering. Currently they're hookup to the pots (location AA, BB). So I should just solder onto R62 for VCO 1 and
R63 for VCO 2? Thanks, I'll try when I get home tonight. _________________ "your stripes are killer bro" |
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Albut
Joined: Apr 09, 2005 Posts: 14 Location: England
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Posted: Tue Jul 05, 2005 12:16 pm Post subject:
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Hi Wild Zebra,
Yes, but make sure you solder to the right hand side of the resistors where the ones I mentioned are all connected together.
AA and BB are connection points on the schematic , not the pcb.
Hope you get it working when you get home.
albut _________________ "put an egg in your boot and beat it" |
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Wild Zebra
Joined: Apr 28, 2005 Posts: 806 Location: Ohio
Audio files: 5
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Posted: Tue Jul 05, 2005 12:28 pm Post subject:
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Thanks much!!! The fine tuners are the only thing not hooked up. As far as I can tell everthing else seems to work properly and It sounds great. My only other prob is when my lfo indicator led is hooked up it acts as if the lfo is patched even when its not, but its very subtle. I read a post to increase 1k to ground to 3K3. I know its only cosmetic but it looks cool. Hey, I ended up using switched mono jacks(I think you suggested it) they worked out very well just need to hook up the "normalized" connections. Anyway enough rambling thanks for your advice
Much appreciated
thanks Timothy _________________ "your stripes are killer bro" |
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dnny
Joined: Mar 12, 2005 Posts: 519 Location: Helsinki, Finland
Audio files: 8
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Wild Zebra
Joined: Apr 28, 2005 Posts: 806 Location: Ohio
Audio files: 5
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Posted: Wed Jul 06, 2005 7:15 am Post subject:
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Thanks Albut, hooked it up last night works great. Its really nice having the fine tuning. Thanks also Dnny, I ended up soldering to the right leg of R62 for VCO1 and R63 for VCO2. So if anyone is leary of soldering to an IC this will work too.
thanks _________________ "your stripes are killer bro" |
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Albut
Joined: Apr 09, 2005 Posts: 14 Location: England
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Posted: Wed Jul 06, 2005 11:25 am Post subject:
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Hi Wild Zebra,
It works on the right hand side of the resistors or pin6 of the chip as dnny said, because it is the same copper track on the pcb.
Sound that you got them working ok.
albut _________________ "put an egg in your boot and beat it" |
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Wild Zebra
Joined: Apr 28, 2005 Posts: 806 Location: Ohio
Audio files: 5
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Posted: Wed Jul 06, 2005 11:37 am Post subject:
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Hey Albut,
Yep they work great! Really lets you dial in some nice tone and harmonics. Do you know anything about this LFO, OSC 2 bleed through business from the noise source? I had that problem then I fixed it now it seems to be haunting me again. I'm going to check for bridges tonight for the umpteenth time, but I'm wondering if it has to do with just finding a noisy enough transistor. Well regardless it sounds good, but it'd be nice to get those nice ocean swelling noises. Sorry for switchin posts I just figured while your here I'd ask.
thanks again
take care _________________ "your stripes are killer bro" |
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Albut
Joined: Apr 09, 2005 Posts: 14 Location: England
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Posted: Wed Jul 06, 2005 12:12 pm Post subject:
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Yeah, the fine tuners give a lot more control over what you get out of your Sound Lab. Worth the panel space.
I did have a bit of bleedthru from VCO2 on to the noise. In my case this is due to the tight looming of the wires to get it to fit into the case I used.
On the second Sound Lab I built, I used screened cable for the mixer inputs and outputs, and this has fixed it. I would use screened cables for all audio signals, but it is 3 times thicker than the 7/02 wire I use, and I don`t have space to use it.
A loud "noise' transistor helps to mask bleedthru, so use a socket for it and try to find the best one you can.
albut _________________ "put an egg in your boot and beat it" |
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Wild Zebra
Joined: Apr 28, 2005 Posts: 806 Location: Ohio
Audio files: 5
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Posted: Wed Jul 06, 2005 12:20 pm Post subject:
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Thanks again,
When you say "screened" is that the same as shielded cable. Yeh mine wiring is tight and I made the mistake of not tying my cables as I went along thinking it would be easier to follow them, boy was I wrong. So with that said thats probable the bleeding prob. I just swap trannies till I find a real loud one. Thanks I'll keep this all in mind for my 2nd SL thats far, far off in the future
take care[/quote] _________________ "your stripes are killer bro" |
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Albut
Joined: Apr 09, 2005 Posts: 14 Location: England
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Posted: Wed Jul 06, 2005 12:30 pm Post subject:
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Yes, shielded is the same as screened in small gauge audio cable. Only connect the outer screening to 0v at one end of the cable for it to work.
I find it easiest to connect it to 0v on the pots.
albut _________________ "put an egg in your boot and beat it" |
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Wild Zebra
Joined: Apr 28, 2005 Posts: 806 Location: Ohio
Audio files: 5
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Posted: Wed Jul 06, 2005 12:47 pm Post subject:
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Thanks I got it _________________ "your stripes are killer bro" |
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v-un-v
Janitor
Joined: May 16, 2005 Posts: 8933 Location: Birmingham, England, UK
Audio files: 11
G2 patch files: 1
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Posted: Mon Jul 11, 2005 12:14 am Post subject:
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Albut wrote: | I used screened cable for the mixer inputs and outputs, and this has fixed it. I would use screened cables for all audio signals, but it is 3 times thicker than the 7/02 wire I use, and I don`t have space to use it.
A loud "noise' transistor helps to mask bleedthru, so use a socket for it and try to find the best one you can.
albut |
Is the 'real' reason because the internal mixer is passive? Or that IC7 takes on the duties of both LFO and noise generation?
What would happen if one were to use a proper TL084/ LF442 based design instead? (ie the RW ultra simple mixer design?) _________________ ACHTUNG!
ALLES TURISTEN UND NONTEKNISCHEN LOOKENPEEPERS!
DAS KOMPUTERMASCHINE IST NICHT FÜR DER GEFINGERPOKEN UND MITTENGRABEN! ODERWISE IST EASY TO SCHNAPPEN DER SPRINGENWERK, BLOWENFUSEN UND POPPENCORKEN MIT SPITZENSPARKSEN.
IST NICHT FÜR GEWERKEN BEI DUMMKOPFEN. DER RUBBERNECKEN SIGHTSEEREN KEEPEN DAS COTTONPICKEN HÄNDER IN DAS POCKETS MUSS.
ZO RELAXEN UND WATSCHEN DER BLINKENLICHTEN. |
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Albut
Joined: Apr 09, 2005 Posts: 14 Location: England
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Posted: Mon Jul 11, 2005 2:33 pm Post subject:
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Hi v-un-v,
I don`t think there is any problem with a passive mixer. I don`t get the bleedthru anymore using screened cable. An op amp mixer should be better, but you could get distortion or added noise if it isn`t designed and built properly. Also more space and power needed.
I also don`t think there is a problem with the noise and lfo being in the same chip, but I don`t have much electronics knowledge to know for sure.
Ray is the first to admit that the Sound Lab has its limitations, but for the size and cost it is a versatile little synth.
Albut _________________ "put an egg in your boot and beat it" |
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v-un-v
Janitor
Joined: May 16, 2005 Posts: 8933 Location: Birmingham, England, UK
Audio files: 11
G2 patch files: 1
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Posted: Mon Jul 11, 2005 5:25 pm Post subject:
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Albut wrote: | Hi v-un-v,
An op amp mixer should be better, but you could get distortion or added noise if it isn`t designed and built properly. Also more space and power needed.
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Hi Albut,
It's quite feasible to lower the gain in the circuit round the op amp. I'm just trying to angle in on the idea of the mixer becoming a mixer for both oscillators and whatever else you fancy attenuating.
Have you tried running the unit on +/-12v? wouldn't this help s/n ratio and boost dynamic range a bit?- just curious.
I've still got to get my case finished before I start on wiring the electronics. Past experience has taught me that it's best to get the case right as the wiring and electronics is the easy and fun bit. Anyway I'm also quite brassic right now- and it's far easier (and cheaper) to fart around with tweeking my (now) heavily patched out front panel- (hello zebra!-sorry, got a bit carried away- I'm getting my transparent case later this week :))
Tom |
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Wild Zebra
Joined: Apr 28, 2005 Posts: 806 Location: Ohio
Audio files: 5
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Posted: Tue Jul 12, 2005 7:35 am Post subject:
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Quote: | heavily patched out front panel |
wow now I'm really intrigued. v-un-v your right on case before wiring.
Mine is a mess because I did it before. It's the same way when I make stompboxes, but usually I get excited and want to make sure it works before I pack it all up. Not sure about all this mixer biz, but my noise bleed through went away after going through about 20 2n3904's. _________________ "your stripes are killer bro" |
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rollmottle
Joined: Feb 01, 2011 Posts: 2 Location: Los Angeles, CA
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Posted: Sun Jan 01, 2012 10:19 am Post subject:
7 year bump - question about fine tuners |
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7 year bump!
Instead of the 200K resistors called for in the schematic, I used 220K resistors for the +/-9V connection. Didn't have anything that added up to 200K at hand. It works as expected, but maybe it's supposed to work "better."
What are the consequences of using 220 instead of 200?
HNY. _________________ Rollmottle
http://www.soundcloud.com/sentrall
http://twitter.com/rollmottle |
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