Trex Comp Nova clarification.. Bongomania??

[Travis Rankin]

Hey everyone, Im using a Trex Comp Nova. I have read almost all of ovnlab's write ups and a ton of other info.. And i think i am just way overwhelmed...

The trex is a great little pedal but im having a really hard time trying to figure out what the attack nob is actually doing.. Proves the transperency of it i guess.

Any idea of the ratio or any other usefull information on it? Good settings to try??

I also have a DOD milk box, that i havent given much of a chance. Got any additional info/settings for that guy?


Thanks!!

[Travis Rankin]

Bump.. Anyone have experience with this pedal??

[bongomania]

Weeelll, IMO both the Comp-Nova and the Milkbox fall in the camp of pedals that have such limited controls, and work properly with such a narrow range of input signal, that either they sound fabulous right away with your instrument, or they never will. They are both great in their way, but only if (a) your instrument and playing style are at "the right level", and (b) you happen to like the sort of fattening and smoothing qualities they provide. If your signal level is on the low end, the pedals will sound like they are doing nothing of any use. If your signal is on the high end, they will sound squashed, muddy, and lifeless. But I still really like both of them, within that limitation.

I stopped trying to figure out the technical details of them, since knowing the ratio etc. doesn't actually help much if you don't also know where your signal is WRT the threshold. Consider them like coarse paint brushes, rather than fine pens.

[Travis Rankin]

Great answer!

I love when things start to just make sence.. I had rehearsal tonight, so I went a little early to mess around.. Well I think I found my spot.. Yesterday before anything else, I turned down the output trim pot on my internal bass preamp. This was after reading your information on the input signal usually being the cuase of compression depression. Most of the time being to high. Causing threshold woes.

Anyways, I think I found my Lil' sweet spot with the milk box having these setting:

Level=3:00
Compression=10:00
Hi Freq=7:00 (Min)
Attack=7:00 (Min)

So very minimal compression. With a little boost.

I'm sure this is because of high input signal, like you said.

Correct me if I'm wrong, but this input signal conundrum..
Is basically a resolution setting. By adjusting the input gain you are adjusting the effective operating range of the compressor.

If this is in fact the case.. Than ANY attempt to adjust ANY compressor to be in its optimum potential, without a input gain control, is completely futile.
The only possible way a person can praise and give positive review of a compressor is either a: have an input gain control and have it set optimally or b: By fluke, miraculously having the correct input level delivered to the compressor.

[Travis Rankin]

So with that said if I further lower my output, I could raise the compression on the milk box, and have a wider range of useable settings?

Possibly get closer to the range needed for the Comp Nova as well?

What would it take to add an input control to these comps? A simple pot? (of course only usefull if you want to lower it, not raise)

[bongomania]

Originally Posted by Travis Rankin

If this is in fact the case.. Than ANY attempt to adjust ANY compressor to be in its optimum potential, without a input gain control, is completely futile.
The only possible way a person can praise and give positive review of a compressor is either a: have an input gain control and have it set optimally or b: By fluke, miraculously having the correct input level delivered to the compressor.

Exactly correct. The one "twist" being that a threshold control can take the place of an input gain control (serving the same function, just in a different way).

[bongomania]

Originally Posted by Travis Rankin

So with that said if I further lower my output, I could raise the compression on the milk box, and have a wider range of useable settings?
Possibly get closer to the range needed for the Comp Nova as well?

Well, of course some signals will need to be cut, while others will need to be boosted. Depends on the specific instrument and playing style of the moment.

Originally Posted by Travis Rankin

What would it take to add an input control to these comps? A simple pot? (of course only usefull if you want to lower it, not raise)

Adding a passive volume pot can work, but it also significantly lowers the input impedance of the pedal, which can mean tone loss if you are using a passive bass. The ideal mod would be a simple opamp input buffer followed by a volume pot. What I do sometimes for testing is use another pedal that happens to be capable of transparent boost or cut, as my level-adjusting addition. An EQ set flat, or a compressor set to not compress, for example. If you have an active bass, you can just turn down its volume knob a bit.

[Travis Rankin]

Originally Posted by bongomania

Exactly correct. The one "twist" being that a threshold control can take the place of an input gain control (serving the same function, just in a different way).

Given that it is within the optimum operating range. Read: "input gain"

[Travis Rankin]

Originally Posted by bongomania

Well, of course some signals will need to be cut, while others will need to be boosted. Depends on the specific instrument and playing style of the moment.

Adding a passive volume pot can work, but it also significantly lowers the input impedance of the pedal, which can mean tone loss if you are using a passive bass. The ideal mod would be a simple opamp input buffer followed by a volume pot. What I do sometimes for testing is use another pedal that happens to be capable of transparent boost or cut, as my level-adjusting addition. An EQ set flat, or a compressor set to not compress, for example. If you have an active bass, you can just turn down its volume knob a bit.

Hmm impedance.. Another aspect I'm yet to fully grasp.. I know how impedance works, I'm just yet to fully understand the laws applying to guitars and amp inputs, I can't seem to relate to the concept the same way that I do when it applys to amp outputs and speakers. In thinking about it now.. Is the concept in reverse? As if he instrument is the speaker? Or "load" ??

Does that make sence?

[bongomania]

Every input has an input impedance "z in", and every output has a "z out". Z in is a load on z out which is a source. The bass's output is the source, the pedal or amp is the load. Z in should be a minimum of 10 x z out, for any instrument, pedal, mixer, amp input. For a passive bass though, it's best if z in on the pedal or amp is way, way higher than the bass's z out; typical accepted z in for this purpose is 1 Meg, compared to the passive bass's z out of roughly 10 K on average (z in = 100 x z out).

[Travis Rankin]

Ok, is there anyway to properly measure this?

[bongomania]

Technically yes, but an accurate measurement requires specialized equipment. Most people either calculate it based on knowing the circuit design, or use a multimeter to read the resistance, which stands in as a rough approximation of z out. I don't know a cheap/easy way to approximate z in--though if I modded a pedal with a 250 K pot at the input, I would broadly think of it as a 250 K z in. You can use Thevenin's theorem, but I honestly don't know how well it applies in this type of case.

[dave956]

The threshold control on any compressor is definitely not an input gain. Threshold determines at what level (voltage) of the incoming signal the compressor begins to function. Thus, a signal below the threshold will pass undisturbed while a signal above the threshold gets squished. The attack setting determines how long the compressor will wait to squish a signal above the threshold. An easy to visualize example: you've whacked your E string with your thumb. A large spike in the attack with a relatively quiet decay. Setting the threshold appropriately will compress the big spike to the level you have set. BUT, by setting the attack long enough the compressor will let the spike through and compress the decay. Not that you would actually do this, but it's easy to visualize. Normally you want to compress the spike and leave the decay relatively undisturbed, thus minimizing the difference between the attack and the decay.

Just bought a T-Rex Comp Nova, and I am tickled to death with it thus far. My bass has an extremely hot output but the TRCN works great.

[Travis Rankin]

[quote=dave956;11678921]The threshold control on any compressor is definitely not an input gain. Threshold determines at what level (voltage) of the incoming signal the compressor begins to function. Thus, a signal below the threshold will pass undisturbed while a signal above the threshold gets squished. The attack setting determines how long the compressor will wait to squish a signal above the threshold. An easy to visualize example: you've whacked your E string with your thumb. A large spike in the attack with a relatively quiet decay. Setting the threshold appropriately will compress the big spike to the level you have set. BUT, by setting the attack long enough the compressor will let the spike through and compress the decay. Not that you would actually do this, but it's easy to visualize. Normally you want to compress the spike and leave the decay relatively undisturbed, thus minimizing the difference between the attack and the decay.

Originally Posted by dave956

Just bought a T-Rex Comp Nova, and I am tickled to death with it thus far. My bass has an extremely hot output but the TRCN works great.

What settings are you using?