Search found 696 matches

by nigel
Sat Feb 20, 2021 7:39 am
Forum: Music Tech DIY
Topic: Suitable pots for passive attenuator ?
Replies: 13
Views: 603

Re: Suitable pots for passive attenuator ?

I would say so. As far as I know, when you look on the poti from the front, the left pin is ground, the middle one is the output and the right one is the input pin. So i guess thats correct. Isn't it? Right. So the LFO is going to the right pin of the pot, and you are connecting the middle pin to y...
by nigel
Fri Feb 19, 2021 6:28 pm
Forum: Music Tech DIY
Topic: Suitable pots for passive attenuator ?
Replies: 13
Views: 603

Re: Suitable pots for passive attenuator ?

Are you sure you have the input and output the right way around?
by nigel
Tue Feb 16, 2021 11:31 pm
Forum: Music Tech DIY
Topic: Kassutronics VC Slope
Replies: 23
Views: 950

Re: Kassutronics VC Slope

A bit late, but I thought this deserved a comment: first of all this might be a novice thing to ask but I guess changing the shape is supposed to change the attack and rise time as well? As in, logarithmic shapes are slower than linear shapes and exponential shapes faster? Not really, Ideally, you w...
by nigel
Fri Feb 12, 2021 8:54 am
Forum: Music Tech DIY
Topic: Monotribe Drums - Eurorack version?
Replies: 43
Views: 841

Re: Monotribe Drums - Eurorack version?

paperCUT wrote:
Fri Feb 12, 2021 3:27 am
I've also given each comparator a different trip point so when their inputs are normalled together you can use a single voltage sweep to trigger each of the 3 drums :)
:party:
Now that is a smart idea!
by nigel
Sat Feb 06, 2021 6:01 pm
Forum: Music Tech DIY
Topic: Eurorack Guitar Pickup?
Replies: 17
Views: 320

Re: Eurorack Guitar Pickup?

What you are looking for is a "Pitch to Voltage converter", so searching for that term will get you started. There have been commercial analog units around since the 80's or so, like the lovely Roland SPV-355 , although those early versions required very clean playing to get a usable result. There a...
by nigel
Tue Jan 26, 2021 3:30 pm
Forum: Music Tech DIY
Topic: Problems building FC Monograf
Replies: 2
Views: 79

Re: Problems building FC Monograf

I could track it down to pin 15 of the AS3340 doesn't get voltage. But there are a lot of mod sources and I can't trace back, where the normalized and external voltage should come from. Pin 15 is a virtual ground pin, so it's always going to be at the same voltage (probably 0V) when it's working co...
by nigel
Tue Jan 26, 2021 7:11 am
Forum: Music Tech DIY
Topic: please have a look at my first build
Replies: 8
Views: 268

Re: please have a look at my first build

soundsculptor wrote:
Tue Jan 26, 2021 4:45 am
On a similar topic, I have found conflicting information on this - is it OK to clip component legs after soldering? I guess when the solder is hard it should be fine?
Sure.
by nigel
Mon Jan 25, 2021 11:27 pm
Forum: Music Tech DIY
Topic: Adding CV IN to any parameter...?
Replies: 11
Views: 6792

Re:

Hi Dave, I'm not quite sure I understand the "normalled switch connection". By looking at the schematic it didn't make much sense either. Would you be so kind to explain a little better how such a connection can be made? I am interested in pulling off that neat trick but I'm struggling to figure ou...
by nigel
Mon Jan 25, 2021 5:59 pm
Forum: Music Tech DIY
Topic: please have a look at my first build
Replies: 8
Views: 268

Re: please have a look at my first build

R10 is a case of where the solder didn´t go through from the back to the front of the PCB. I later discovered I have to push the component leg just a little bit while the solder is hot, so it goes to the other side. I hope it´s correct to do it like this. Don't worry about the solder appearing on b...
by nigel
Fri Jan 22, 2021 7:40 am
Forum: Music Tech DIY
Topic: Shunt Regulator math / Circuit current draw
Replies: 6
Views: 208

Re: Shunt Regulator math / Circuit current draw

Another way of looking at it - ignore the shunt for now. The op amp negative input is a virtual ground, so RS and R59 form a voltage divider between 12V and ground. The top of that divider is at 12 V x (10 / (10 + 3.6)), which is 8.8 V. There's no voltage left to regulate down to 10V.
by nigel
Wed Jan 13, 2021 10:01 pm
Forum: Music Tech DIY
Topic: DIY Modular Synth Problem - Voltage between power supply grounds
Replies: 9
Views: 256

Re: DIY Modular Synth Problem - Voltage between power supply grounds

hi jamos, here's the schematic for the power supply I'm working with [...] See this thread . That schematic is incorrect, and does NOT match the circuit on the PCB. On the PCB, one of the AC inputs is connected to 0V, the other to both diodes. If you are trying to drive two of those from a single A...
by nigel
Fri Jan 08, 2021 8:59 am
Forum: Music Tech DIY
Topic: diy partial-kit frustration rant
Replies: 55
Views: 1491

Re: diy partial-kit frustration rant

Reading the parts list to discover these problems is simply one of the new skills that you have to learn when moving from complete kits. (And I don't think that's obvious when you start - I haven't seen any instructions that begin with "make sure you can still find all these bits".) Like any other s...
by nigel
Wed Jan 06, 2021 11:24 pm
Forum: Music Tech DIY
Topic: Patch Cable DIY
Replies: 16
Views: 424

Re: Patch Cable DIY

For me it is a quality thing, a personalisation thing and, as I discovered, also a Zen-like thing as I find making my own cables a good way to empty my mind (which otherwise tends to be very busy more or less 24/7 :mrgreen:). I find making my own cables a good way to fill my mind with rage and frus...
by nigel
Mon Jan 04, 2021 7:18 pm
Forum: Music Tech DIY
Topic: Available depth in portable Eurorack systems ?
Replies: 5
Views: 184

Re: Available depth in portable Eurorack systems ?

My little home brew case is around 95mm deep.
case.jpg
Could be taken to gigs, in theory...
by nigel
Sat Jan 02, 2021 11:54 pm
Forum: Music Tech DIY
Topic: VCO-1 by Thomas Henry - some questions
Replies: 15
Views: 405

Re: VCO-1 by Thomas Henry - some questions

But why not to connect the pots straight to the +-12V of my circuit ? Did you encounter issue connecting the pots straight up to the +-12V ? Because the power supply voltage is not necessarily perfect. In particular, if it is overloaded, then the voltage may drop, or there might be noise or mains h...
by nigel
Sat Jan 02, 2021 9:18 am
Forum: Music Tech DIY
Topic: VCO-1 by Thomas Henry - some questions
Replies: 15
Views: 405

Re: VCO-1 by Thomas Henry - some questions

Thanks for your very detailed answers! A small questions regarding the Tri to Saw circuit above: shall I also add a 1k resistor at the input (in series with the triangle out) of the circuit and also at the Saw output? the BC550 could be replaced with BC547 as well? No (tri to saw) / yes (saw out). ...
by nigel
Fri Jan 01, 2021 8:18 pm
Forum: Music Tech DIY
Topic: VCO-1 by Thomas Henry - some questions
Replies: 15
Views: 405

Re: VCO-1 by Thomas Henry - some questions

As I'm planning to build two of the vco-1 I wanted to know If I can normalised the Sin output of vco1 to the switched lug of both the lin FM input and exp FM input of vco2 and vise versa (vco2 sin out tip lug to exp and lin FM switched lugs of vco1) Can I just solder a wire from the tip lug of the ...
by nigel
Thu Dec 31, 2020 7:05 pm
Forum: Music Tech DIY
Topic: Tremolo sync mod
Replies: 3
Views: 129

Re: Tremolo sync mod

Are you using this as a guitar pedal, or as part of a modular system? If it's a guitar pedal, what kind of trigger are you using? You can't easily convert an arbitrary square wave to a sine without some kind of memory, because you can't tell the frequency phase of a square from its current value. [E...
by nigel
Fri Dec 18, 2020 12:26 am
Forum: Music Tech DIY
Topic: 2164s vs OTAs (13700) what are the differences?
Replies: 26
Views: 528

Re: 2164s vs OTAs (13700) what are the differences?

The main functional difference is that the 2164 has an exponential control response, while the 13700 has a linear response. Other differences - the 13700 chip contains two VCAs, while the 2164 has four VCAs. The 2164 has (I'm fairly sure) lower noise and distortion. The 13700 also has two output buf...
by nigel
Sat Dec 12, 2020 6:14 pm
Forum: Music Tech DIY
Topic: Barton vca and Thomas Henry vca
Replies: 3
Views: 241

Re: Barton vca and Thomas Henry vca

The major difference is the lack of a mixer/buffer on the signal inputs, and the decision to use a 4.7k / 10R resistor divider on the signal input to the 13700. I've built a couple of the Barton VCAs and I always replace these with a 100k / 220R pair instead, to give a more usual input impedance. (I...
by nigel
Sun Dec 06, 2020 4:11 pm
Forum: Music Tech DIY
Topic: Help me understand this Electro Harmonix Schematics
Replies: 19
Views: 540

Re: Help me understand this Electro Harmonix Schematics

The footswitch on my unit has six lugs, and it seems to act/work as a momenraty switch (maybe it's broken, or it has been replaced?). It's a footswitch, so it's designed to be stomped on. If you just push it with your fingers, you might be pushing it hard enough to change the contacts but not enoug...
by nigel
Wed Dec 02, 2020 3:28 pm
Forum: Music Tech DIY
Topic: Info on Euroack physical standards
Replies: 20
Views: 689

Re: Info on Euroack physical standards

Some American makers are doing 4-40 Because it's really important that we don't stick to the few standards that we have. :sarcasm: and it’s so similar you can almost cross thread them. They're so similar that you will cross thread them. Now you need to buy new rails. :bang: Stick to metric, for goo...
by nigel
Sun Nov 29, 2020 7:38 am
Forum: Music Tech DIY
Topic: Best course of action to remove a power connector?
Replies: 21
Views: 573

Re: Best course of action to remove a power connector?

I would try to remove the plastic frame first (either cutting it up with a sharp knife, or getting underneath it and sliding it off the pins), and then desolder the pins one at a time.
by nigel
Fri Nov 27, 2020 5:59 pm
Forum: Music Tech DIY
Topic: The 2020 Show Us Your DIY Builds Thread!
Replies: 532
Views: 47604

Re: The 2020 Show Us Your DIY Builds Thread!

Any chance of getting a schematic? Looks like a lovely delay and has all the features I would want as well. I started doing right angle front panel boards for my DIY builds although I use right angle headers for more mechanical strength. Did you CNC mill the board? I'll have to draw up a clean circ...
by nigel
Fri Nov 27, 2020 2:09 am
Forum: Music Tech DIY
Topic: The 2020 Show Us Your DIY Builds Thread!
Replies: 532
Views: 47604

Re: The 2020 Show Us Your DIY Builds Thread!

My homemade take on the PT2399 delay. I wanted a couple of things: it should be usable both standalone (like a guitar delay pedal), and as a simple signal in, delayed signal out module for building complex patches. It should also have voltage controlled delay (because if it's not voltage controlled,...

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