Line level boost - fx loop

[gmr1]

Had someone ask me about this:

"My FX loop is too "hot" for pedal style effects (instrument level). It's fine for rack mount fx (line level). So, I'm hoping to find a pedal that has the correct level input, (signal boost)  and then the correct level output. It has to be completely invisible. It only has to have one knob with varying degrees of volume boost and an LED when engaged."

The "invisible" scares me off a little, but I did some research and found this:

http://www.psionicaudio.com/main/lumos.htm

Seems to have everything he's looking for. Any ideas what might be going on in this circuit, and the direction I might go to build something similar? Is a buffer the key here?

Thanks as always!

- Greg

[earthtonesaudio]

Heh... my guess is, it's a 10k volume pot with a remote footswitch. 

The key is to not tell the guitarist that it's really a volume cut.  No one wants to hear that an effect makes them less loud.

[gmr1]

ha! a passive cut was my original idea - turn it off when you want the boost. he wasn't going for it.

[earthtonesaudio]

Alright, here's what you do:

-Wire up a standard volume pot with in/out jacks, a switch and an LED.  Make the LED come on when the pot is bypassed.
-Goop the whole thing in black epoxy.
-Make up a good story about years of research and development leading to a breakthrough in noiseless, transparent boost with custom-made parts, huge headroom, hand-made, blah blah blah until his eyes glaze over.
-Go over to his amp and mess with the controls so he won't notice the volume drop.
-Plug in the "boost," turn on the amp, and prepare to be showered with praises.

[jacobyjd]

That is amazing.

If none of that works, you could always give him a good smack, then tell him he should go figure out his OWN too-complicated fix for his problem.

Never fails to drive me nuts when someone feels like any little change in something will destroy their precious tone...'transparent'? I wish the building 100ft away from the stage was 'transparent' so I wouldn't get all that nasty slapback echo--there are always things that will get in the way of your tone.

*huff huff*

+1 on the passive volume cut--goop and all.

[Ben N]

I think that "Lumos" thing is exactly what earthtoneaudio proposed--note that you set the volume knob for the rhythm level, not the boost. You can show him the add and tell him yours is the same but better, because it has a carbon comp pot, or such tripe.

Better yet, tell your idiot would-be customer that he can't be trusted to spend his own money, and you'll deal with his legal guardian.

[asfastasdark]

To make it more realistic, make a PCB for a ton of parts and numerous IC's, with a single trace going from the input to the volume pot. Solder in all the components, and bam. It looks impressive but none of the parts are connected.

[MikeH]

I also like how "on" is actually "off"

[MikeH]

Reminds me of this thing:

http://cgi.ebay.com/GUITAR-AMP-ATTENUATOR-POWER-BRAKE-SOAK-MASS-HOT-PLATE_W0QQitemZ200255221126QQihZ010QQcategoryZ43375QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

Not doubting it works, just saying it's not a hotplate or a power brake, just like the lumos is not a booster.

[gmr1]

I also like how "on" is actually "off"

That's funny - I actually didn't even notice that (or what a joke this product appears to be, now that I'm spending a little more time reading it's description...).

It seems the passive cut really is the easiest solution. He's not going for it, so I wished him luck finding what he's looking for elsewhere. At least I got a few laughs out of this thread, so thanks for that!

[ocg]

(yeah old topic sorry)



50 bucks for a black enclousure, 25k potentiometer,a big knob and 2 jacks.

i was thinking to make something like that to use it in the effects loop of my amp....but without the pot....just a RESISTOR(that will act like the pot set in 5 or 6) to cut my volume and a switch to by pass it.
So my idea is to play with my amp with the volume cutted all the time and just use the real volume in my solos to create the ilusion of a volume "booster".

so what do you think? it's worth?

(sorry for my english )

[Ben N]

Your English is fine.

Certainly doable, but I'm not sure why you would want to lose the pot so quickly--what if your preset turns out wrong in a different situation? If you're worried about your setting getting moved, you can try to find a panel mount trim pot, or a regular pot with a screwdriver adjustment in place of a regular shaft.
Just note that if you want to do it that way you really need two resistors, since a pot is an adjustable voltage divider. Although I suppose just a single resistor across one of your jacks ought to work, too, like the 33k-68k resistor on an attenuated amp input.

[trixdropd]

(yeah old topic sorry)



50 bucks for a black enclousure, 25k potentiometer,a big knob and 2 jacks.

i was thinking to make something like that to use it in the effects loop of my amp....but without the pot....just a RESISTOR(that will act like the pot set in 5 or 6) to cut my volume and a switch to by pass it.
So my idea is to play with my amp with the volume cutted all the time and just use the real volume in my solos to create the ilusion of a volume "booster".

so what do you think? it's worth?

(sorry for my english )

I've built that, but with a relay rather than a switch. That was it can be remote controlled from the stage while keeping cable runs short.

[mth5044]

GEOFEX has something to build about line level/instrument level. I can't remember the name for the life of me though...

[mth5044]

Here we are. The Adjusticator!

http://www.geofex.com/circuits/Adjusticator.gif

This is the first time I get to say 'read GEOFEX'! Although it may not really be what you are looking for, still a milestone