Dead Winter
Read this and understand it before trying anything (my method is further down in this post):
http://www.bossgtcentral.com/modules.php?name=Forums&file=viewtopic&t=11871
As long as the "Loop" is set to on in the GT-8, your Amp's preamp will be in your gt-8's "Loop". Position the "Loop" in the desired position in the GT-8's effect chain.
Most users of the 4CM with the GT-8 have reported a slight loss of punch after sending through the GT-8's effects loop (I guess it's not that transparent). A few Marshall users on that GT-8 Forum have had a few more problems than others, I seem to have noticed.
Here is the front page:
http://www.bossgtcentral.com/modules.php?name=Forums
Make sure you check out the "GT8 Connections" Thread, before posting any questions, they will most likely have been answered.
A typical effect chain for the 4CM that I use is (along these lines):
Wah>OD>PRE>LOOP>
NS>EQ>FX1>FX2>CHO>DEL>REV
NS - Noise Suppressor isn't normallly there for me (usually near start of chain) but the GT's Loop introduces some noise so put the NS here to get rid of it.
The "Effects Return" LEVEL is very important to get right. Read the tutorial thoroughly.
I used the tutorial as a guide, and went a bit further to level match the sounds by micing my cab and looking at an Input Level Meter in my recording software. I did the following with the amps Master Volume on 5 to check that the level matched at decent volumes.
MAKE SURE YOUR GT8'S EFFECT RETURN IS ON 24 (DEFAULT 100) IN CASE AS MENTIONED IN OTHER TUTORIAL IN CASE YOU HAVE A LINE LEVEL ON YOUR AMP (AND NOT AN INSTRUMENT LEVEL)
Step One:
Guitar>Amp Input - play your guitar and note the largest input volume
Guitar>Gt8 Input>GT8 Send>Amp Input - make a new patch with NO preamp or effects ON and set "Effect Send" Level to 100. Play guitar and note level (is it the same as with no GT-8? If yes good, if NO make sure "Patch Level" is on 100 (no other effects, EQ are on, etc...) and adjust GT-8 "Effect Send Level" until it matches (it should be close anyway, if not firstly make sure your "input level" is set correctly on the GT-8, mine is set at -3db for my EMG pickups for example)
Guitar>Gt8 Input>GT8 Output (left mono for example)>Amp Return
MAKE SURE "OUTPUT LEVEL KNOB" ON BACK OF GT8 IS ON MINIMUM AND ADJUST THIS UNTIL YOUR LEVEL MATCHES THE ORIGINAL GUITAR>AMP INPUT LEVEL You shouldn't need to adjust this again, I covered mine with some duct tape. This is slightly different than in the other tutorial, but makes more sense to me, but who am I
.
Guitar>Gt8 Input>GT8 Send>Amp Input>Amp Send>GT8 Return>GT8 Output (left Mono for example)>Amp Return
MAKE SURE YOUR GT8'S EFFECT RETURN IS ON 24 (DEFAULT 100) IN CASE AS MENTIONED IN OTHER TUTORIAL IN CASE YOU HAVE A LINE LEVEL ON YOUR AMP (AND NOT AN INSTRUMENT LEVEL)
Play your guitar and note the level, if too low, raise the "Effect Loop Return" on the GT8. If your amp's Loop is Line Level it should be 100 (or slightly higher to allow for the loss from the GT8's loop). Don't go too much higher, you will hear it. It will introduce too much noise and mod effects will be muddy, etc...
As an example, I am using a Krank Revolution, I have read someone from Krank saying that their effects loops are not designed for individual pedals but for rack type units with Send/Returns due to the pedals having some sort of compounder thing or something that keeps the levels at guitar/instrument levels. This gave me the impression that I would need ot set the "Effect Return" Level low. I tried it and the level was far too low. I raised ti to 100 and was much closer. There is a slight loss of volume, but I thought it is better to be slightly under than over so not to boost the input to the poweramp. It does take away some of the crunch as well (ever so slightly but noticeable, and still useable).
I think that's about it. Once those levels have been set up, when you make new patches, just be careful not to introduce any clipping from the GT8 by using the Level meters in the GT8 and move through the effects chain to make sure you are keeping unity gain with each effect.
DISCLAIMER: THIS IS JUST MY ROUGH GUIDE, USE AT YOUR OWN RISK.
You can now use your amps tone in your GT-8's loop when the "LOOP" is switched on, or turn the loop off and use the GT-8's preamps into your amps poweramp. The cool thing is that things like your wah, pickup simulator, OVERDRIVE (put that Tubescreamer on and boost the REAL Amps preamp), etc... is before your GT-8's preamp or your REAL amps preamp (if the loop is on and the gt8 preamp is off) and mod effects, delays are after the preamp where they should be, as you can see here:
Wah>OD>PRE>LOOP>
NS>EQ>FX1>FX2>CHO>DEL>REV
where "LOOP" is your REAL Amp's preamp and "PRE" is the GT8's preamp.
Overall this 4CM is
not perfect (due to the small losses and introduced noise - remember to have the noise suppressor after the LOOP), but is easy useable/tolerable with my amp at least, I hope it works for you, even though a few guys with Marshalls are having problems with it as I mentioned. Good luck.
Here is a quick clean sample I did the first day I got my Krank Rev. It is the Kranks clean channel (in the LOOP of the GT-8 ) with the GT-8's chorus and delay after it going back to the Krank's poweramp
Chain:
BC Rich EMG85 (Neck)>Boss GT-8>Krank Revolution>Mesa Trad 4X12>SM57>M-Audio Firewire Solo>Cakewalk Guitar Tracks. No post EQ, anything (raw recording) just volume boosted.
It was just a test recording one-track, one-take, bum notes and all.
http://www.keepmyfile.com/download/c7601b1144870
Hope this post helps, I know its rough, but I'm in a bit of a hurry.
