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Vactrol question

Started by TNblueshawk, December 16, 2019, 09:02:12 PM

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TNblueshawk

So, I'm going to build a compressor called the Constrictor from PedalPCB. It calls for a VTL5C10 but I can't locate anywhere. I can however find the VTL5C9. Is it a good swap.

Below is the data sheet description. As it relates to how the compressor would act I have no idea if the '9' is swap worthy for the '10'. Anyone else have a thought or ten?
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VTL5C9 has a 112 db dynamic range, fast response time, high dark resistance, but with a more shallow slope and lower "on"
resistance at low (1 mA) drive currents than the VTL5C1. VTL510 offers a low "on" resistance at low drive currents, a fast response
time, and has a smaller temperature coefficient than the VTL5C9.
John

midwayfair

The ranges are very different, 112 dB for the 5C9 versus 79 dB for the 5C10. The timing are even farther off: The 5C9 takes 4 times longer to turn "on" (4ms versus 1ms) but its decay is only 50ms, which is very, very fast compared to 1.5 seconds (1500 ms) for 5c10.

http://sportsbil.com/mcintosh/Amps/LDR%20vtl5c9_c10.pdf

If you post a schematic, I could tell you how much this might matter. If the circuit is relying on the 5C10's slow decay (there is at least one pedal compressor that historically did this), then you have your work cut out for you if you want to sub. For instance, if there aren't timing capacitors, then the 5C9 might result in pumping because of the slow decay and very very high dark resistance.

TNblueshawk

Quote from: midwayfair on December 17, 2019, 01:05:50 AM
The ranges are very different, 112 dB for the 5C9 versus 79 dB for the 5C10. The timing are even farther off: The 5C9 takes 4 times longer to turn "on" (4ms versus 1ms) but its decay is only 50ms, which is very, very fast compared to 1.5 seconds (1500 ms) for 5c10.

http://sportsbil.com/mcintosh/Amps/LDR%20vtl5c9_c10.pdf

If you post a schematic, I could tell you how much this might matter. If the circuit is relying on the 5C10's slow decay (there is at least one pedal compressor that historically did this), then you have your work cut out for you if you want to sub. For instance, if there aren't timing capacitors, then the 5C9 might result in pumping because of the slow decay and very very high dark resistance.

Hey Jon. It sounds like I need to punt in all likelihood to sub this one in. The site says it compares to the Demeter Compulator. The only schematic I can find is contained within the PDF on the site itself https://www.pedalpcb.com/product/constrictor/

Maybe one of the other 5c's might work.  I think Small Bear had a few more. Actually maybe I just need to build another compressor!
John

midwayfair

Quote from: TNblueshawk on December 17, 2019, 04:42:28 PM
Quote from: midwayfair on December 17, 2019, 01:05:50 AM
The ranges are very different, 112 dB for the 5C9 versus 79 dB for the 5C10. The timing are even farther off: The 5C9 takes 4 times longer to turn "on" (4ms versus 1ms) but its decay is only 50ms, which is very, very fast compared to 1.5 seconds (1500 ms) for 5c10.

http://sportsbil.com/mcintosh/Amps/LDR%20vtl5c9_c10.pdf

If you post a schematic, I could tell you how much this might matter. If the circuit is relying on the 5C10's slow decay (there is at least one pedal compressor that historically did this), then you have your work cut out for you if you want to sub. For instance, if there aren't timing capacitors, then the 5C9 might result in pumping because of the slow decay and very very high dark resistance.

Hey Jon. It sounds like I need to punt in all likelihood to sub this one in. The site says it compares to the Demeter Compulator. The only schematic I can find is contained within the PDF on the site itself https://www.pedalpcb.com/product/constrictor/

Maybe one of the other 5c's might work.  I think Small Bear had a few more. Actually maybe I just need to build another compressor!

Yeah, the compulator doesn't have any timing caps, so it will behave very poorly with a vactrol sub.

You could use a 5C7, which is probably harder to find, with minor modifications I think. The 5C7 is a little slower and you'd probably want to adjust the resistor that forms a divider with it.

somnif

Banzai them, but its bloody pricey: https://www.banzaimusic.com/Vactec-VTL5C10.html

Xvive lists it as one of the vactrols they're re-issuing, but I can't find any distributors for it.

benny_profane

I was going to suggest cabintech, but they don't seem to have them listed for sale.

TNblueshawk

Thanks for looking at this Jon.

Wow, Banzai thinks highly of theirs  :o

I may just go in a different direction as there are plenty of compressor PCB's out there.
John