Search found 791 matches

by jorg
Mon Sep 28, 2020 8:02 am
Forum: Music Tech DIY
Topic: Help Me Identify Polarity
Replies: 10
Views: 185

Re: Help Me Identify Polarity

The photo is tiny, but it looks like the "++" symbol is next to the shorter lead.
by jorg
Sat Sep 26, 2020 8:32 am
Forum: Music Tech DIY
Topic: Does this case need shielding? and how to do it?
Replies: 8
Views: 185

Re: Does this case need shielding? and how to do it?

Please provide a close-up picture of the area where the power comes in and connects to the power supply. Your photos are waaaay too far away to see what's going on. Most likely you just need to provide a cover (e.g. blank panels, possibly also a perpendicular plate) to prevent fingers from getting n...
by jorg
Thu Sep 24, 2020 1:20 pm
Forum: Music Tech DIY
Topic: Reverb tank impedance?
Replies: 1
Views: 92

Re: Reverb tank impedance?

If you are building from a kit, look at the manufacturer's recommendations for tank selection. Likewise, if building from a circuit online, they usually include recommendations on matching the tank to the circuit. Generically, I recommend circuits which drive with roughly constant current (or an imp...
by jorg
Wed Sep 16, 2020 1:23 pm
Forum: Music Tech DIY
Topic: Q: minimum case hole size for row of 8 x 6mm diameter rotary encoders
Replies: 6
Views: 85

Re: Q: minimum case hole size for row of 8 x 6mm diameter rotary encoders

Here's a trick to get them centered in the holes: Slip a piece of soda straw or a layer or two of heat shrink over each shaft, before you solder them into the PCB. Place the encoders on the PCB (do not solder yet), then slip the panel over them. Hold it all together and flip it over onto a surface w...
by jorg
Tue Sep 15, 2020 10:44 am
Forum: Music Tech DIY
Topic: Adruino PWM and Sallen Key third order
Replies: 12
Views: 217

Re: Adruino PWM and Sallen Key third order

I was just typing that you have the capacitors connected wrongly when I noticed the link from devinw1 above. Make sure you connect them properly or you won't get the response you are after. I simulated this circuit in Tina TI and it looked perfectly fine. It looks fine in an ac simulation but did y...
by jorg
Mon Sep 14, 2020 10:41 pm
Forum: Music Tech DIY
Topic: Adruino PWM and Sallen Key third order
Replies: 12
Views: 217

Re: Adruino PWM and Sallen Key third order

MikeDB wrote:
Mon Sep 14, 2020 11:03 am
I was just typing that you have the capacitors connected wrongly when I noticed the link from devinw1 above. Make sure you connect them properly or you won't get the response you are after.
I simulated this circuit in Tina TI and it looked perfectly fine.
by jorg
Mon Sep 14, 2020 10:38 pm
Forum: Music Tech DIY
Topic: Solid copper wire for builds?
Replies: 11
Views: 305

Re: Solid copper wire for builds?

It's fine, if you clean the area before soldering, and use a bit of flux.
by jorg
Mon Sep 14, 2020 12:54 pm
Forum: Modular Synth General Discussion
Topic: crash cymbals
Replies: 26
Views: 6279

Re:

http://www.soundonsound.com/sos/allsynthsecrets.htm I got pretty close in Reaktor (before my PC blew up and ate it). Starting with the SOS article, I ended up with a 3x3 array of saw oscillators at frequencies related by irrational number ratios. It was 3 FM chains, mixed together. Increasing the m...
by jorg
Mon Sep 14, 2020 11:01 am
Forum: Music Tech DIY
Topic: Adruino PWM and Sallen Key third order
Replies: 12
Views: 217

Re: Adruino PWM and Sallen Key third order

I don't know the sample rate of the PWM you're using, or whether you are outputting audio, CV, or what, and can't comment on how the Arduino might combine multiple PWMs. However, if you want to send two inputs into the filter, you could double the value of the first resistor and use two resistors, b...
by jorg
Mon Sep 14, 2020 10:29 am
Forum: Music Tech DIY
Topic: Using an old signal generator with the modular
Replies: 10
Views: 266

Re: Using an old signal generator with the modular

Your level pot is either dirty or worn out. If it was mine, I'd spray in some Deoxit. I will get :foul: :mad: :sstorm: :bang: for saying that. But the worst case (assuming you don't dribble the stuff around inside your equipment) is you end up replacing a pot that's already bad. Best case, you eke ...
by jorg
Fri Sep 11, 2020 12:58 pm
Forum: Music Tech DIY
Topic: Combining LT73 2k 3900ppm & 2k 3000ppm for Yusynth VCO
Replies: 5
Views: 101

Re: Combining LT73 2k 3900ppm & 2k 3000ppm for Yusynth VCO

Yes, but you could also use a combination of a 1k 3900ppm thermistor and 2 normal resistors, and it would eliminate 1 of the tempco resistors. 1k tempco in series with an 82 Ohm resistor, then that in parallel with 13.2k, gets you to 3333ppm (the actual ideal tempco) and a 1k net resistance. https:/...
by jorg
Thu Sep 10, 2020 2:26 pm
Forum: Music Tech DIY
Topic: Using an old signal generator with the modular
Replies: 10
Views: 266

Re: Using an old signal generator with the modular

Your level pot is either dirty or worn out. If it was mine, I'd spray in some Deoxit. I will get :foul: :mad: :sstorm: :bang: for saying that. But the worst case (assuming you don't dribble the stuff around inside your equipment) is you end up replacing a pot that's already bad. Best case, you eke o...
by jorg
Thu Sep 10, 2020 1:25 pm
Forum: Modular Synth General Discussion
Topic: Any dangers to turning on modular equipment left in storage?
Replies: 27
Views: 565

Re: Any dangers to turning on modular equipment left in storage?

teleport wrote:
Wed Aug 26, 2020 8:29 pm
... the chassis became a home for a spider who would attempt to attack from within the housing by thrusting it's little arms out through the space around the buttons whenever a new patch was being selected.
That is so cute! :mrgreen:
by jorg
Thu Sep 10, 2020 10:00 am
Forum: Music Tech DIY
Topic: FM control of reverse avalanche oscillator
Replies: 6
Views: 138

Re: FM control of reverse avalanche oscillator

Welcome to MuffWiggler, the_fig! Definitely posted in the right place! I know nothing of the lmnc reverse avalanche oscillator so can't provide any input. Sometimes it's helpful to assume we don't know what you're referring to -or we arent familiar with it- and providing us a link or schematic mean...
by jorg
Thu Sep 10, 2020 9:17 am
Forum: Music Tech DIY
Topic: FM control of reverse avalanche oscillator
Replies: 6
Views: 138

Re: FM control of reverse avalanche oscillator

Yes, a vactrol is probably your simplest option. It won't modulate very well at high audio rates, but would probably do something. To attenuate the FM, attenuate the LED drive to your vactrol (but you should also include a resistor or pot to mix in some DC bias to the vactrol's LED).
by jorg
Wed Sep 09, 2020 2:47 pm
Forum: Music Tech DIY
Topic: How to minimise unintended noise from a module intended to generate noise?
Replies: 3
Views: 159

Re: How to minimise unintended noise from a module intended to generate noise?

I think you may be over-playing this in your head. If anything, a transistor white-noise module is less likely to create noticeable problems than a typical oscillator module. Just make sure you follow good power decoupling practices and you'll be fine.
by jorg
Wed Sep 09, 2020 2:23 pm
Forum: Music Tech DIY
Topic: toggle switch protection
Replies: 9
Views: 239

Re: toggle switch protection

floris wrote:
Sat Sep 05, 2020 2:55 pm
I happen to accidentally hit toggle switches when playing live.
Do it again, and then smile. :hihi:
by jorg
Wed Sep 09, 2020 10:58 am
Forum: Modular Synth General Discussion
Topic: Understanding random voltage
Replies: 9
Views: 254

Re: Understanding random voltage

I like to take a sequence or an arpeggio, add a little noise or low frequency noise, then quantize it. I can dial in the amount of randomness so my sequence repeats, but not exactly.
by jorg
Fri Sep 04, 2020 3:00 pm
Forum: Music Tech DIY
Topic: Nagra 4.2 tape recorder with problem
Replies: 11
Views: 179

Re: Nagra 4.2 tape recorder with problem

I'd do the easiest things first. Look at the pressure pad and whatever presses the pad against the head. Or maybe it's done entirely with tape tension? It looks like there's no pad, so I guess it's all down to tension. That large drum at the left must be the tape tensioner. make sure it's pressing t...
by jorg
Fri Sep 04, 2020 1:42 pm
Forum: Music Tech DIY
Topic: Nagra 4.2 tape recorder with problem
Replies: 11
Views: 179

Re: Nagra 4.2 tape recorder with problem

Yup definitely on the record side - now need to narrow it down to electrical versus mechanical. In my (limited) experience with tape equipment of similar age, you guess about mechanical is a pretty good one. If the playback is good, I would think that means the tension must be good. Your heads all l...
by jorg
Fri Sep 04, 2020 12:29 pm
Forum: Music Tech DIY
Topic: buffer mandatory when adding outputs on resistors ?
Replies: 7
Views: 254

Re: buffer mandatory when adding outputs on resistors ?

OK sorry can't answer without knowing what the resistors are. However, perhaps this resource could help you:
https://iamcomputo.wordpress.com/2014/0 ... nd-videos/
by jorg
Fri Sep 04, 2020 9:56 am
Forum: Music Tech DIY
Topic: Explanation of how modules "putting noise on the ground" bus?
Replies: 32
Views: 1177

Re: Explanation of how modules "putting noise on the ground" bus?

While I have much admiration for Bob Pease's pioneering work and achievements at National Semiconductor you should not take his remarks out of context. He had as much experience of modern complex audio systems as I have of semiconductor fabrication. Not only is this advice wrong it is impossible to...
by jorg
Fri Sep 04, 2020 9:08 am
Forum: Music Tech DIY
Topic: 4 or 8 Channel Mixer with Switches
Replies: 20
Views: 265

Re: 4 or 8 Channel Mixer with Switches

I just had an idea. I've been looking at the Mutable Instruments Links module. It has a 3-to-1 mixing section. Could I add another input jack with a 100k resistor and put manual switches in series to do what I want? I don't need to be able to adjust or attenuate the inputs. Yes, what you propose wo...
by jorg
Fri Sep 04, 2020 8:58 am
Forum: Music Tech DIY
Topic: Changing the power switch of a hammond maverick
Replies: 3
Views: 57

Re: Changing the power switch of a hammond maverick

You need to post a picture of the switch. I am not familiar with the Maverick. I don't think it's tonewheel-based though. Tonewheel hammonds have a start switch for the motor; it has a spring return on it, so you hold it in the Start position for a while, then release it and it stays in the "On" pos...
by jorg
Fri Sep 04, 2020 8:52 am
Forum: Music Tech DIY
Topic: buffer mandatory when adding outputs on resistors ?
Replies: 7
Views: 254

Re: buffer mandatory when adding outputs on resistors ?

Your question can't be answered without more context. What is this circuit? Do you have a schematic?

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