- This topic has 7 replies, 2 voices, and was last updated 3 months, 1 week ago by
.
-
Posts
-
Treated myself to a new bass. Figure I should have a compressor specific for it.
My last order included a NT Compressor single. I see that changing C12 to 100n or 220n should make that bass-ready. Any confirmation yet? Would it still act the same if I decide to use it with my guitar?
Alternatively, I already have a Squishy Octopus built. How’s that with bass? If it’s good and the cap change for the NT is fine with guitar, I could just use that.
Or… I could indulge in our favorite pastime with the NT: grabbing a switch and modding.Both the NT and MoRC compressors are based on the Ross circuit. There’s a nice writeup for targeting bass in the MoRC build documentation. In addition to the filtering you’re talking about (C12 in the case of the NT compressor), it was also suggested to increase the release time:
“Bass players would normally look for a faster release time than a lead guitar – limit the gain for large signals and quickly
restore the gain for following low level signals giving more of a tight rather than sustained sound…. Alternatively you could replace SW1, R17 and R18 with a 100kΩ pot and set the release time manually.”You could:
- Replace C12 with a DPDT wiring board (with the original 22nF on one side, and a 100nF or 220nF on the other).
- Replace SW1 with 100k, 150k, or 200k pot in series with a 10k resistor (FYI, Jameco has 150k linear pots…. the 10k resistor and 150k pot would give the 10k to 160k range of the original SW1 setup, and everything in between).
Couple of notes:
You don’t HAVE to use the wiring board. I think it’s neat because you can mount the caps on the bottom of the board and leave room on top for power/jack connectors. You could use an On-On-On switch by itself and wire it for 22n/100n/220, or just an On-On for 22n and one of the others for bass.
The layout example is just that. It’s set for 20mm knobs; it looks “busy” without the knobs, but I think with the knobs it’ll be clearer. Maybe setting it up for 15mm knobs might be better. Dunno. I think the larger knobs look better. It’s also 300DPI so I could post it here. I think 600DPI is way cooler.
Also, the C-T-C distance between the example’s board-mounted knobs is 33mm/1.3 inches; that’s just a guess. I don’t have the board. But my beer-math indicates it’ll fit in a 125B box OK with some toe room between the bottom knob and the foot switch. I think. The knobs could always be shifted up a little more towards the switch for additional clearance.
Yeah, trying to work this all out in my head.
I haven’t measured, but there’s plenty of room between the stock knobs and the footswitch, for anything that will fit between the enclosure and board.
I’m not an electrical engineer, though, and my brain’s worn out by this point of the day. Does the pot just solder in where the switch is, and replace the higher resistors with jumpers?Either way, I’m likely to socket all these. If nothing else, I could just add a C2 22n/220n switch (I do have a stack of DPDT boards, but fitting a switch on top out of kicking range might be problematic; my plan was a slide switch) and swap resistors accordingly.
But if I get a pot mounted right, I wouldn’t have to switch resistors around if I move it between instruments.
I’m not an electrician either. It’s just fun to fiddle with this stuff.
I think you’d wire the pot directly in place of the switch, using all 3 pads, with the left-most pad being lug “1”. If I’m in error, someone please let me know.
I was in error: you don’t need to add the 10k resistor to the pot. The numbers have changed from the above link: keep R19 (10k), remove R17 and R18. Looks like R16 (10k) was changed to R19 on the NT board. R18 (39k on both versions) traces to the left-most lug of the switch (text up); that corresponds to lug “one” of the MoRC board (the trace is on the backside).
Rather than guessing the fit/clearance, you can print a scale version of your layout on paper, white-glue it to a piece of 2-3/8 X 4-1/2 inch piece of cardboard to check the component fit. That’s an easy and quick verification.
Noting this on my printed build sheet…
Not worried about the clearance yet, either. Thank goodness for printed drill guide. And the software I use for the decals.
Honestly, I could drill it the same as the switch; if I have the right pot, I can bend wires…
Think I’ll socket and experiment once I get it going. 😀Okay, quick thought before I sleep on it.
Socketing R16-18 anyway, so no harm done if it doesn’t work.
I have some random 9mm pots that won’t see use elsewhere. Use a B200k, wired to all three pads. Swap R19 for a 5k. Leave R17 and R18 empty.
This should also give me a wider range on the attack, both shorter and longer.
- You must be logged in to reply to this topic.