Search found 1630 matches

by cygmu
Sat Jan 16, 2021 4:52 am
Forum: Music Tech DIY
Topic: LM339 Pullup resistor value
Replies: 15
Views: 207

Re: LM339 Pullup resistor value

I've used TLV3704 for this which is available in DIP. I seem to recall reading someone saying something negative about those parts somewhere recently but I can't find it now.
by cygmu
Tue Jan 12, 2021 12:53 pm
Forum: Music Tech DIY
Topic: Utility Mixer I
Replies: 9
Views: 268

Re: Utility Mixer I

Heh, I had forgotten completely about overshoot. Thank you.

As for the euro/banana distinction, I’m a banana person too, but is it the case that shielded cables present more difficult (more capacitive?) loads than single cable banana leads?
by cygmu
Tue Jan 12, 2021 8:06 am
Forum: Music Tech DIY
Topic: Utility Mixer I
Replies: 9
Views: 268

Re: Utility Mixer I

Nicely done as usual. Can I ask about the 5.6pF caps on some of the op amps please? Usually if I see those I think they are for stability but IC3A, 4A and 6A look like being the least likely to go unstable in the whole circuit. You don't have such caps on the output op amps for example. So I wonder ...
by cygmu
Mon Jan 11, 2021 2:56 pm
Forum: Music Tech DIY
Topic: CGS 514 DUSG controls rise/fall CV attenuator reversed? or maybe not?
Replies: 6
Views: 164

Re: CGS 514 DUSG controls rise/fall CV attenuator reversed? or maybe not?

interestingly, my wiring is correct according to the most recent elby guide as well (https://www.elby-designs.com/webtek/cgs/serge/cgs514/cgs514-build.pdf) so I guess that's just continuing the mistake from the original wiring diagram? I would assume that is what happened. It's hard to tell what's ...
by cygmu
Mon Jan 11, 2021 12:17 pm
Forum: Music Tech DIY
Topic: CGS 514 DUSG controls rise/fall CV attenuator reversed? or maybe not?
Replies: 6
Views: 164

Re: CGS 514 DUSG controls rise/fall CV attenuator reversed? or maybe not?

Your description matches how it works if you follow Ken Stone's wiring diagram, so I think you have wired it as intended. However it does seem a bit counterintiutive that "clockwise = slower" on the rise/fall knob but "clockwise = faster" on the VC knob. To get it to work in a more inuitive fashion,...
by cygmu
Mon Jan 04, 2021 1:03 pm
Forum: Music Tech DIY
Topic: error analysis of a VCO CV input stage
Replies: 4
Views: 172

Re: error analysis of a VCO CV input stage

This is great, very interesting. I guess the same considerations -- with perhaps a little more flexibility in the setup -- apply to oven-type designs. There's no thermistor involved but the attenuation by the factor K is same and could be done around the op amp, in a resistive divider, or a bit of b...
by cygmu
Sun Jan 03, 2021 1:08 pm
Forum: Buchla, EMS & Serge
Topic: Poll - What firmware are you running in your v2 MARF hardware?
Replies: 4
Views: 221

Re: Poll - What firmware are you running in your v2 MARF hardware?

dksynth wrote:
Sun Jan 03, 2021 12:53 pm
fresh build as of 2 weeks back, running 2.5b3 from the get-go.
Why not run the full v2.5?
viewtopic.php?p=3347581#p3347581
by cygmu
Sun Jan 03, 2021 10:31 am
Forum: Music Tech DIY
Topic: TL074H??
Replies: 20
Views: 540

Re: TL074H??

KSS wrote:
Sun Jan 03, 2021 5:12 am
JFET and MOSFET have important differences. Either or both may be used in an IC.
Does this imply that the answer to my question is that guest suspects they’ve moved to MOSFET for this new part?
by cygmu
Sun Jan 03, 2021 4:57 am
Forum: Music Tech DIY
Topic: TL074H??
Replies: 20
Views: 540

Re: TL074H??

looking at some of the other new opamps they have, like the TLV9304, which is also listed as "cost optimized" we see similar noise curves, and its FET. the real clue here is that they took "JFET" out of the title of the datasheet. why not just give it a new part number? I am not sure what you are g...
by cygmu
Fri Jan 01, 2021 4:06 am
Forum: Music Tech DIY
Topic: Panning with the 2164
Replies: 12
Views: 558

Re: Panning with the 2164

Ah, yes, it's 5K or 10K, if I remember correctly. Thank you for the warning. I don't really understand where I could put the op amp for that. Another option might be to put a trimmer there. I actually have both V2164 and SSI2164 at hand, so I might just try as well. Yeah, "trim to taste" might be a...
by cygmu
Thu Dec 31, 2020 5:09 am
Forum: Music Tech DIY
Topic: Panning with the 2164
Replies: 12
Views: 558

Re: Panning with the 2164

If I understand what you are doing here, the 1.2k resistance in series is creating a voltage divider with the input impedance of the 2164 control port. I wonder whether things might be a bit more predictable or stable if you do that attenuation externally, which may mean another op amp. The reason I...
by cygmu
Sun Dec 27, 2020 4:57 am
Forum: Music Tech DIY
Topic: CGS ssg couplers (G H) differences
Replies: 6
Views: 196

Re: CGS ssg couplers (G H) differences

I reached out to the admin of the SDIY wiki and he's already fixed the image issue. You may need to clear browser cache to see the fixed pages properly.
by cygmu
Wed Dec 16, 2020 6:32 am
Forum: Music Tech DIY
Topic: Transforming a circuit in a current source for LM13700
Replies: 71
Views: 1225

Re: Transforming a circuit in a current source for LM13700

although, whats the maximum number of channels anyone would want to scan anyways? Probably 8. Heh, the Haible one had 9 :) The main use-case there was as a chorus unit, where each scan output tapped a different point of a delay line. This is quite an interesting question becuase it is super easy to...
by cygmu
Tue Dec 15, 2020 5:58 pm
Forum: Music Tech DIY
Topic: Transforming a circuit in a current source for LM13700
Replies: 71
Views: 1225

Re: Transforming a circuit in a current source for LM13700

I wonder if some variant of this circuit by you-know-who (guest!) might be used as the ADC and sawtooth generation element of this setup.
viewtopic.php?p=3119119#p3119119

I love this thread! All my favourite concepts are coming up here. Thanks everyone for this.
by cygmu
Tue Dec 15, 2020 11:37 am
Forum: Music Tech DIY
Topic: Negative voltage reference with zener diode ?
Replies: 16
Views: 346

Re: Negative voltage reference with zener diode ?

Getting to the edge of what I know about now... I believe that the reason to do that is that the different capacitors respond a bit differently, i.e. respond better at different frequencies. So that may be the most optimal thing to do but it is probably also overkill.
by cygmu
Tue Dec 15, 2020 11:15 am
Forum: Music Tech DIY
Topic: Negative voltage reference with zener diode ?
Replies: 16
Views: 346

Re: Negative voltage reference with zener diode ?

Yes, that's the table. The stable region is the region outside the curves, so I was looking at the area outside curve A. Your suggested cap values should be stable, and then the question is whether a small cap is good enough for your needs --- if you don't anticipate large spikes in current draw for...
by cygmu
Tue Dec 15, 2020 10:02 am
Forum: Music Tech DIY
Topic: Negative voltage reference with zener diode ?
Replies: 16
Views: 346

Re: Negative voltage reference with zener diode ?

This could be a stability issue -- perhaps your -2.7 to -3V is not steady but the result of an oscillation. Have a look at the Stability Boundary Conditions in the datasheet. For generating 2.5V (reference voltage = cathode voltage) the output cap is meant to be below 60nF or above 3uF. These device...
by cygmu
Tue Dec 15, 2020 4:07 am
Forum: Music Tech DIY
Topic: Negative voltage reference with zener diode ?
Replies: 16
Views: 346

Re: Negative voltage reference with zener diode ?

The current that is not drawn by the rest of the circuit will flow through the shunt reference, so it won’t disrupt the operation of the circuit as a whole but it does use up some power. That’s one of the trade-offs with using a shunt. You can specify the resistor to match your needs more closely as...
by cygmu
Mon Dec 14, 2020 11:47 am
Forum: Music Tech DIY
Topic: Negative voltage reference with zener diode ?
Replies: 16
Views: 346

Re: Negative voltage reference with zener diode ?

I placed a 1.5k resistor from the power rails to the tl431 (in the top circuit from the -12v rail to Anode and in the button circuit from the +12v rail to Cathode) but I'm not sure why other then it was recommended to me earlier in the forum. I guess different values will limit the current that goe...
by cygmu
Mon Dec 14, 2020 7:46 am
Forum: Music Tech DIY
Topic: Clock fan-out limits
Replies: 3
Views: 102

Re: Clock fan-out limits

A non-inverting buffer will draw very little current, just the input bias current for the op amp I think. Your 4027 will be perfectly happy there. The next question is how many circuits the op amp can drive, but the answer is likely to be "quite a few": if the input impedance for the circuits being ...
by cygmu
Sat Dec 12, 2020 6:24 am
Forum: Buchla, EMS & Serge
Topic: Bagoly Frequency Shifter (LW-format) Quick Patch
Replies: 22
Views: 777

Re: Bagoly Frequency Shifter (LW-format) Quick Patch

I think the resonator is the most extraordinary thing, my new favourite module I'd love to read about or hear what you're doing with that. The Dixon frequency shifter is introduced in the big Dixon thread in the DIY forum. Here's a post with a demo. https://www.muffwiggler.com/forum/viewtopic.php?f...
by cygmu
Fri Dec 11, 2020 2:46 am
Forum: Music Tech DIY
Topic: cgs Analog Shift Register
Replies: 11
Views: 363

Re: cgs Analog Shift Register

I believe the OP builds circuits on stripboard and I'm wondering if it is even possible to implement a guard ring on a stripboard circuit. On the other hand, isn't it the case that one of the things the guard is protecting against is leakage via conduction in the surface of the PCB? If so then I won...
by cygmu
Thu Dec 10, 2020 3:47 am
Forum: Music Tech DIY
Topic: Transforming a circuit in a current source for LM13700
Replies: 71
Views: 1225

Re: Transforming a circuit in a current source for LM13700

the folding ADC produces both the triangle and gray code you need, and eliminated glitches. the downside is that it uses a lot of opamps to do the folding. Couldn't we use the already inherently available waveforms of the folding process? Diagrams from here: https://www.analog.com/media/en/training...
by cygmu
Thu Dec 10, 2020 3:38 am
Forum: Music Tech DIY
Topic: Transforming a circuit in a current source for LM13700
Replies: 71
Views: 1225

Re: Transforming a circuit in a current source for LM13700

I think the folding process is exactly the thing that uses a lot of op amps! The rectifiers for each stage. In the dixon quantizer 3 opamps per bit/stage: https://www.muffwiggler.com/forum/viewtopic.php?p=3349834#p3349834 Exactly. It depends what we mean by "a lot" -- guest's design is super econom...
by cygmu
Thu Dec 10, 2020 3:26 am
Forum: Music Tech DIY
Topic: Transforming a circuit in a current source for LM13700
Replies: 71
Views: 1225

Re: Transforming a circuit in a current source for LM13700

the folding ADC produces both the triangle and gray code you need, and eliminated glitches. the downside is that it uses a lot of opamps to do the folding. Couldn't we use the already inherently available waveforms of the folding process? Diagrams from here: https://www.analog.com/media/en/training...

Go to advanced search