4 Cable method, how's that work then?

[SEAN RAF]

OK, I need a lot of help with my GT-Pro set up. I’m running it through one of the many EVH heads I’ve had the displeasure of owning, hooked up to an RJM Amp Gizmo for channel switching. I want to use a Maxon 808 and an NS-2 in the front end of the EVH, obviously using the pre amp of the 5150 lll. What’s the best way of hooking everything up? I’ve been looking at the 4 cable method, but until I understand what this does, I’m loathe to use it.

Will the 4CM allow a different signal to the front end of the amp? If so, can I insert the Maxon and the NS-2 in that chain and then switch them out via patch changes?

At the moment I’m connecting the GT-Pro to the effects loop of the EVH, switching patches via a Roland FC300 midi foot controller, which also changes the channel of the EVH via the RJM Amp Gizmo. This is almost perfect, except for the fact that I still have to switch off the Maxon and the NS-2 when I switch to a clean sound.

Does any of this make sense?

I’ve had a bad year so far, someone take pity and help me…pleeeease…

[Rsmacker]

One of them is the fuse/taper, and the other is a detonator. Light blue touchpaper and retire to a safe distance.........:ROTF:

I'd love to help you mate, but your post just made my tiny brain hurt. I'll just phone the fire brigade and put them on standby.

Good luck!!

[ozzuk1]

4cm goes

guitar to GT in

GT left out to Amp return

Amp send to GT loop Return

GT send to amp input..

You should be able to run the 808 and ns-2 inbetween the alst part however I wouldnt thought the NS-2 necesarry the GT noise suppressor is quite good and you might find that usefull...

Also what the 4cm does is send the amps preamp into the GT-8 then adds the GT8 processings and then into the poweramp works very well on the valvveking combo I have, much prefer it going in that way than using it with phones or direct...

what number evh are you on now?

[thenine]

I saw this tutorial on a web-site and saved it. I hope the original poster doesnt get mad. But it should answer any q's you have Bro.

4CM TUTORIAL...

THINGS TO KNOW BEFORE TO START WITH 4CM:

-Amps can have PARALLEL and SERIES fx’s loops. A parallel loop mixes the fx’s with the crude sound of your amp: it creates an awful “comb filter” fx with the GT (I mean: a very very short delay between “wet” and “dry” tone). So, AVOID to use a parallel loop. If it’s the only solution available on your amp, set its “mix” pot full up… and pray to avoid the “comb filtering” syndrome;

-Depending on the brand and model used, THE MASTER VOLUME OF YOUR AMP CAN BE DISABLED WHEN YOU PLUG AN EXTERNAL PREAMP in it. Check it by plugging your axe in the GT and the GT output in the loop return of your amp: if the first riff played destroys your ears, maybe you’ll have to control the master level with the volume pedal of the GT…

-THE TONE STACK OF YOUR AMP CAN BE ACTIVE OR NOT WHEN YOU PLUG AN EXTERNAL DEVICE. Again, try it “live”, with the GT direct in the loop return: do your bass / mid / treble controls modify the tones from the GT? If it’s the case, choose one of these output options: JC 120/ small amp/ combo amp / stack amp. If your “tone stack” is disabled (no action from your pots), choose JC return or combo return / stack return / line-pa… The output option won’t modify the tone of your loop. But it is a key to obtain a good tone from the onboard preamps of the GT;

-FX’S LOOPS HAVE VARIOUS OUTPUT LEVELS: -20db, -10db, zero db if not +4db… the two first values imply a “guitar level” preamp. The two last values are those of a “line level” preamp. Depending on this parameter, your volume settings on the GT will be drastically different. If you don’t know what kind of loop you have, try and listen: a “line level” external preamp gives an hollow tone and a lot of (unwanted) feedback if the return level of the GT loop is set on 100/200…

-BAD CABLES CAN CREATE TROUBLES! To plug two standard guitar cables in the loop is generally increasing the noise… For your loop, use two “symmetrical cables” with one wire for the hot point, one other wire for the ground, and an overall shielding, soldered to the ground on one side of the cable only. Planet Waves cables with a “double shielding” are designed like that. You can also “do it yourself” with four Neutrik plugs and 6 meters of “three wires” high quality cable… WARNING with the “amp control” plug on the GT, which creates a ground loop: for this plug, try a cable in which the hot point (tip of the jack plug) is soldered alone, while the ground is unsoldered. Now, you can expect a silent operation.




Steps to go with the 8, now:


Connections:

- Guitar to GT input.
- GT send to amp guitar input.
- Amp loop send to GT return.
- GT output to amp loop return.



Settings:

-Set the loop in a proper place in the FX chain. Example of chain:
ac sim (fx1 or fx2) /wah/comp/od/phaser (fx 1 or fx2)/ LOOP/ gt preamp disabled/ eq/ chorus/ delay/rv… There’s many other solutions, of course: try it and enjoy!

-Set the loop on NORMAL mode.

-Input level matching: plug ONLY your guitar in the GT then the GT send in your amp main (guitar) input. Use NO fx. Set the “send” level of the GT loop around 100/200, play and listen: the volume must be the same when your axe is plugged DIRECTLY in your amp and when you play it through the GT “send”. Modify the “send” volume to obtain an even level if necessary.

-Output level matching: plug the two other cables in the loop of your amp. Leave the “patch level” (the pot near your LCD screen) around 100/200.
If the loop of your amp is a “guitar level” one, set the “return” level of the GT loop on 100/200. Start with the little black knob near the guitar input of the GT around noon (and BEWARE: the master volume of your amp could be disabled now as explained above. So, use the volume pedal on the GT)…
If you have a “line level” loop in your amp, set the loop return of the GT on 24/200 ONLY and the little black knob FULL UP (!).
Plug and unplug the “GT output to amp return” cable while you play: the volume must be the same with and without. If the sound is weak and distant with the GT loop on, rise the “return” level and / or the black knob until you reach the proper level (same level with the 4CM and with only the two first cables).
When are the “loop return” and “little black knob” levels well matched? When you obtain the SAME overall volume from your amp alone, from your amp through 4CM, and from an onboard GT8 preamp (all settings at noon) through the loop return of your amp…

-Fine tuning: the loop of the GT slightly modifies the tone of your amp, adding 1db in the high range. You can add 1db in the bass range with the “global EQ” to compensate it (and 1db in the mid range too, if you’re annoyed by a mid scoop of 1 db: here, choose yourself your “notch” mid frequency).

-Tips and tricks: you can use the “assign” functions to go back and forth between your external preamp and the onboard preamps of the GT… If necessary, add an EQ to obtain the same overall response from these “real” and “digital” preamps (after one of those digital preamps, try “high cut” = 6khz and high range = +9db, for example).


Hope to be useful… If something is not clear or if I’ve made a mistake, anybody, help me to complete the explanations above!!!

UPDATE (30/07/07): I've bought the Ebtech Line Level Shifter, a Morley device mentioned by another member: okstrat (thx a lot, okstrat).

It's a USEFUL device with a line level preamp in 4CM: it requires different settings, of course (return level = 100 or 120 instead of 24). But it improves transparency and makes the amp MUCH LESS sensitive to noise. I've been able to come back to standard guitar cables for 4CM without noticing the loud hum that it was creating before.

[DumpyWumpy]

Will the 4CM allow a different signal to the front end of the amp? If so, can I insert the Maxon and the NS-2 in that chain and then switch them out via patch changes?

Yes.

[SEAN RAF]

Yes.

Brilliant!...How?

Sorry, I'm as thick as pig shit with this kind of stuff...