Author Topic: THE ENGINEER'S THUMB... At last, a better compressor!  (Read 269156 times)

rankot

Re: THE ENGINEER'S THUMB... At last, a better compressor!
« Reply #780 on: April 08, 2022, 02:10:00 PM »
Most of the modern vactrols have much faster rise time and it's not easy to find some with 500ms rise anymore.  >:(

GL55 series LDR have fall/rise time in the range of 20-30ms. So that wouldn't be the problem for NG.
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60 pedals and counting!

jhsa

Re: THE ENGINEER'S THUMB... At last, a better compressor!
« Reply #781 on: April 08, 2022, 04:55:27 PM »

You might find that an LDR is not quite fast enough for a gate operation, they typically go low resistance in about 10-20ms, and high resistance in about 0.5s, this is almost ideal for an audio compressor, but might cut off the beginning of notes when used in a fast application like a noise gate. I do like LDRs for compression, but I would generally stick to a JFET, THAT VCA, OTA or something similar for very fast opening of a gate.
Thanks for your input Jonny. very much appreciated. The LDR seems quick enough to me. Perhaps my hear is not good enough but it seems to be OK. I have just finished building it and installed it on my PedalBoard. Please follow the link below to the project's topic. All schematics are there.


Quote
Be careful with regards to the body diode if you are using MOSFETs as a variable resistance. I generally prefer JFETs for this purpose. Let me know how you get on!

I used two Mosfets connected Source to Source, so the body diodes will cancel each other. No audio will pass unless the Mosfets turn ON :)
jFETs have quite high resistance (a few hundred ohms) when ON if I want to use them to mute the Audio to GND. This is why I do prefer the Mosfets. I use this configuration on my Pedal's relay bypass to mute the audio while the relay is switching. It works quite well.

Please check the link below. The latest schematics are on the last few posts as I cannot edit the first post unfortunately. :(

https://www.diystompboxes.com/smfforum/index.php?topic=128883.msg1244523#msg1244523
« Last Edit: April 08, 2022, 04:57:21 PM by jhsa »

PRR

Re: THE ENGINEER'S THUMB... At last, a better compressor!
« Reply #782 on: April 08, 2022, 10:26:58 PM »
.....go low resistance in about 10-20ms, and high resistance in about 0.5s, ....might cut off the beginning of notes when used in a fast application like a noise gate. ...

LDRs can float. Put the LDR in the series element of an L-pad. Get signal, light beats on the crystal, resistance falls fast, signal passes. Signal fades, crystal's trapped charge slowly drains out, signal slowly goes away.

And as said, modern crap LDRs are fast both ways, so you can tailor the electronic time constant to taste.

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jhsa

Re: THE ENGINEER'S THUMB... At last, a better compressor!
« Reply #783 on: April 23, 2022, 09:36:50 AM »
After building my Noise Gate with LDR and playing with it for a while, yesterday while messing with my PedalBoard, I did notice some very light slow attack when playing very high pitched notes only. I am talking about the high G or A notes on the first string. Perhaps I will try to decrease the resistor I have in series with the attack pot, and see if it helps. If not, then it is the LDR. Currently I have a 2k2 resistor in series with the Pot.

DUCKFACE

Re: THE ENGINEER'S THUMB... At last, a better compressor!
« Reply #784 on: June 20, 2022, 11:00:07 AM »
IV build the noisegate part from the Redux but only thing that gets out of the effect is a sound like a fart. Iv changed the LM 13700 with 13600 and the fart is more pleasent .. but still a fart. Anyone has the same problem and whats the sollution. The schematic is as follow :

edit:
power supply is -9 and +17.5v
« Last Edit: June 20, 2022, 11:02:08 AM by DUCKFACE »