FM3 4 cable method help

[Snouttrout]

I’m having a difficult time setting up the FM3 using the 4 cable method with my real JP2C.

I setup my channels with the fx loop off and tried to get them set approximately the same volume. When the FM3 connected as described in the manual, I’m getting a lower volume on channel 3. I’m not sure why. (This does not happen if I hook up my Carbon Copy delay pedal through the loop: in that case, I just get some delay. The amp channel volumes and tones are the same.)

Output 2 is maximum and output 1 is up pretty high. Please take a look at this preset and let me know if you have any suggestions.

Should I set the balance on all of the effects to -100.0?

 

[Snouttrout]

I removed all of the effects and started from scratch. I was getting volume loss through the muliplexers and the delay. I think the problem was associated with the parallel setup. Everything is now in series and volume is correct.

Now I’m trying to find the source of the tone suck. There is a noticeable tone difference (with all effects bypassed in the FM3) when I engage/disengage the JP2C effects loop.
The amp response feels a bit sluggish with the FM3 in the loop.

 

[Rex]

From Boogie:

Dear MESA/Boogie JP-2C Owners,

Feedback from all sources in the musical world is important to us, but none more so than from our own customers. We’ve been watching the feedback regarding the JP-2C from several of the popular forums, and while we are deeply flattered by most of it, it’s come to our attention there is a potential for mismatched Effects Loop levels between the Channels for some players under certain settings conditions, particularly those that use the amp at lower volumes. Consequently we have a voluntary update that addresses this possible discrepancy and creates more balanced Loop levels throughout the Channels when the amp is used for its intended purpose (a Clean sound in Channel 1 and two high gain overdrive sounds in Channels 2 and 3) at these lower playing volumes.

 

[Snouttrout]

From Boogie:

Thanks, but my amp has the upgraded loop.

 

[Rex]

Sluggish? Is there an actual delay between when you play and when you hear it?

 

[Snouttrout]

Sluggish? Is there an actual delay between when you play and when you hear it?

Rex, it is difficult to explain. It feels that the amp doesn’t respond as quickly. I’m not hearing a delayed effect, but it feels like the response is not as quick. I tried using the FM3 for effects only and experienced the same thing.

I do not experience that when I use my Carbon Copy delay.

 

[Rex]

Build a new preset, completely from scratch. Start with an empty preset. No effects at all. Just Input and Output blocks. Is the issue still there?

 

[Snouttrout]

I did that. Please see my second post.

 

[Rex]

I did that. Please see my second post.

In your second post, you said you removed all of the effects. I mean to start from a truly empty preset that never had anything in it to start with. We're removing variables here.

Also, make sure your global output EQs are completely flat.

 

[WelshLukather]

Agree with @Rex here, you need to start with a completely fresh/blank preset and build it up from there.

I have the full fat V which is is similar to the JP2C and I have no such issues with tone suck, volume loss, attack or anything it’s completely transparent - make sure your loop level on the back of the amp is set correctly (so there’s no difference when you switch loop out) - mine has a small indent in the pot travel which is where it should be really - remember your individual channel volumes act as FX sends as they always have on Boogies - I run my channels around the 9 o clock mark and use the Master to control overall volume - don’t run the channels too high, its pointless and won’t “hit” the Poweramp more to get more gain, Boogies are all about preamp gain....

Also, make sure you have the line level set correctly in the FM3 - I actually use the Output2 method for 4CM (I think Bakerman on here shared a good diagram and explanation for it a while ago) - the Output 2 method IMO gets rid of a lot of the unknown with Unity Gain which has a big bearing over how the FM3 behaves in the loop of a real amp.

 

[Snouttrout]

Thanks for the information. The JP2C has no effects level on the amp. In addition, each channel has its own Master; there is no global master.

I will try what you’ve both suggested as soon as I can.

I tried to use the FM3 with the 4 cable method today with the amp at rehearsal, but I had clipping issues. I thought output 2 is supposed to be maximized for unity gain.

I’ll make a new preset from scratch and see if that helps.

 

[Snouttrout]

What do you mean by “Line Level”?

 

[WelshLukather]

If you are using Out2 then Line Level doesn’t apply, but essentially you can from the I/O menu on the FM3 set the line level to be either +4dBu or -10dBu but from memory that only affects Out1 - it’s worth though making sure you have the pad on INPUT 1 set correctly - start at 0 and work your way around from there using the INPUT leds or VU meter.

 

[WelshLukather]

Hmm, yeah, the JP2C is bit of a funny one with regards to the loop - looks like channel 1’s volume is the traditional channel master = fx send but channels 2 and 3 use the gain knob as the fx send to fully mimic an old IIC+ - I bet that amp will be a pig to get levels right to the FM3 and you might have to use the IN/OUT blocks’ channels to mess around with levels.

 

[Snouttrout]

Hmm, yeah, the JP2C is bit of a funny one with regards to the loop - looks like channel 1’s volume is the traditional channel master = fx send but channels 2 and 3 use the gain knob as the fx send to fully mimic an old IIC+ - I bet that amp will be a pig to get levels right to the FM3 and you might have to use the IN/OUT blocks’ channels to mess around with levels.

I’m working on it now. The problem is I’m getting clipping when using channel 1 and 3. If I reduce output low enough to prevent clipping across all channels , then the volume is greatly reduced.

I built a preset from scratch with no effects. There is still a difference in tone, even when I get the volume levels matched with loop engaged/bypassed.

I may just avoid using the FM3 in 4 cable method with this amp. I might need a different solution.

 

[Rex]

I’m working on it now. The problem is I’m getting clipping when using channel 1 and 3. If I reduce output low enough to prevent clipping across all channels , then the volume is greatly reduced.

I built a preset from scratch with no effects. There is still a difference in tone, even when I get the volume levels matched with loop engaged/bypassed.

I may just avoid using the FM3 in 4 cable method with this amp. I might need a different solution.

1) What clips?

2) Try just a jumper cable from your JP2C’s send to its return. Does the tone still change?

 

[Snouttrout]

Output 1 is clipping. I think I’ve solved the problem with output 2, but I’ll have to crank it up loud before I’m certain. I’ll try the jumper cable as you suggested.

 

[Snouttrout]

1) What clips?

2) Try just a jumper cable from your JP2C’s send to its return. Does the tone still change?

Output 1 clips unless I turn the it down really low. In that case the difference between the FX loop engaged and disengaged is significant.
I tried the jumper cables of various lengths as you suggested, and I did not find that the tone changed.

 

[Rex]

Output 1 clips unless I turn the it down really low. In that case the difference between the FX loop engaged and disengaged is significant.
I tried the jumper cables of various lengths as you suggested, and I did not find that the tone changed.

If Output 1 is clipping, then turn down the level that’s feeding it. Then make up the difference by turning up Output 1’s Level knob.

Can you upload a clip showing how the tone is changing?

 

[Snouttrout]

If Output 1 is clipping, then turn down the level that’s feeding it. Then make up the difference by turning up Output 1’s Level knob.

Can you upload a clip showing how the tone is changing?

Rex I might have found the problem! I went back to the basic FX only option, and I used my humbuster cables. This time I didn't hear much difference in tone with the loop engaged/bypassed. There was a very slight volume difference though, not too bad. Then I figured there must be something wrong in my FM3 setup in 4 cable method. I normally setup my FM3 and AF3 with output 1 set to +4db. I thought I was supposed to turn that down to -10 db while using 4 cable method for some reason. When I switched it back to 4db, it seemed to work. I'm not hearing much difference in tone or volume right now when I engage/disengage the loop! I am currently running the amp at low volume, so hopefully it will work when I turn up loud in rehearsal. Fingers crossed.

Is it normal to have a slight volume drop with Mesa amps when using the FX loop? My JP2C doesn't have any loop levels on it.