JP-2C loop issue?

[mboehm88]

Hey all, was reading rig-talk and an issue on the JP-2C loop is being discussed over there:

http://www.rig-talk.com/forum/viewtopic.php?f=3&t=177413&p=1985045#p1985045

Figured folks interested in the amp would wanna read this to see if it's going to be a problem for them. I just read it after my amp shipped so I'm really hoping I can live with it...

 

[dlpasco]

I'm sure not losing any sleep over it. I've been using a Nova Delay with mine and have no complaints.

I sure as hell would not be returning my baby over that.

Cold dead fingers, man. Cold dead fingers.

 

[barryswanson]

So if the repeats from the delay are carrying over to the clean channel after its switched why don't all amps do this? From my limited knowledge I gather its from where the fx return enters the circuit. So how does a Mark V for example stop the delay repeats from being amplified in the power section?

 

[Silverwulf]

So if the repeats from the delay are carrying over to the clean channel after its switched why don't all amps do this? From my limited knowledge I gather its from where the fx return enters the circuit. So how does a Mark V for example stop the delay repeats from being amplified in the power section?

I don't pretend to understand the technical nuances of how the loop is designed. But, I can say the "issue" is there. My understanding from others is that Mesa didn't want to compromise the integrity of the original circuit, therefore this artifact is a byproduct.

That all being said, it's not an issue for me. I noticed it, thought "that was strange", turned off my delay going into the clean channel, and it was gone...so I went about my day. It's obviously not an issue for Petrucci however his rig is configured, as he's using a pair of them in stereo on tour with no complaint from anyone.

Most of those guys on the other board have never even played one, let alone owned one. There's guys over there that have praised $4k SLO 100's with unusable loops, but then bash an amp they've never even played based on a few iPhone clips with the volume practically off. Gotta love the Internet... :mrgreen:

 

[Buster Leggs]

The short time I had with mine I didn't have effects running. Based on Silverwulfs comments, I think I'm misunderstanding what the issue even is. I'm just going to spend a week or so with it before I even comment on the amp. I've spent too much time reading about it and very little time playing it (because I wasn't home ) but I am now. Seems like the loop issue may be a much smaller issue for my situation than I made it out to be. That's what my wife's driving dose to me.

 

[Silverwulf]

The short time I had with mine I didn't have effects running. Based on Silverwulfs comments, I think I'm misunderstanding what the issue even is. I'm just going to spend a week or so with it before I even comment on the amp. I've spent too much time reading about it and very little time playing it (because I wasn't home ) but I am now. Seems like the loop issue may be a much smaller issue for my situation than I made it out to be. That's what my wife's driving dose to me.

It's audible given that circumstance people noted, don't get me wrong. It's just not been an issue for me personally, nor do I see it being one. If you left delay on all the time and switch a lot back to your clean from your dirty, I'm sure it may get annoying, though less noticeable at band levels and in a band context.

I can't drive that home enough to folks - you'll notice all kinds of things when you're playing by yourself, at home, at lower levels, in a quiet room. Not just with this amp, but with many. However, those same things you notice come out in the wash at higher volumes and in a band mix.

It's not an issue for me now, and if it's not been an issue on tour with Petrucci, then obviously there are ways it's not an issue at all. If his tech can sort it out, I'm sure I can too with some experimenting... :mrgreen:

Even if a "mod" is offered, I'm going to keep mine exactly as it is. I'm digging it. YMMV.

 

[Silverwulf]

UPDATE: As was pointed out by some folks, the manual clearly states that the dirt channels (2 and 3) are like the original IIC+ in that the gain (Lead Drive) knob sets the fx level send. However, it's the volume knob on the cleans that do the same. I can fully understand why this was done (to preserve the integrity of the original IIC+ circuit, while giving folks a better knob as the fx send in cleans, as people will run the volume much higher than the gain on the clean channel).

That being said, this explains the clip that was posted on the other board, as the guy has his gain cranked up to around 3:00 (which is also the send level to his fx loop) and then switched back over to his clean channel where the volume was almost shut OFF (meaning there's was little to no signal being fed into the loop), so naturally there was a volume jump on the repeat. I mentioned the low volume a few times, but most people were dismissive of it.

Read your manual folks. They're your friend... 8)

 

[dlpasco]

UPDATE: As was pointed out by some folks, the manual clearly states that the dirt channels (2 and 3) are like the original IIC+ in that the gain (Lead Drive) knob sets the fx level send. However, it's the volume knob on the cleans that do the same. I can fully understand why this was done (to preserve the integrity of the original IIC+ circuit, while giving folks a better knob as the fx send in cleans, as people will run the volume much higher than the gain on the clean channel).

That being said, this explains the clip that was posted on the other board, as the guy has his gain cranked up to around 3:00 (which is also the send level to his fx loop) and then switched back over to his clean channel where the volume was almost shut OFF (meaning there's was little to no signal being fed into the loop), so naturally there was a volume jump on the repeat. I mentioned the low volume a few times, but most people were dismissive of it.

Read your manual folks. They're your friend... 8)

Yep, that sounds like exactly it. Not concerned about it at all, either.

 

[kippiejr]

I have many originals and none do this. So the original circuit theory by Mesa seems a bit confusing. However, who plays with delay on constantly at the exact same delay time for all three channels and most importantly almost no volume and chokes the chord and jumps to clean :lol: ? Except this guy.. Now that being said, if it does it at gig volume or at rehearsal levels while playing continues and there is a volume jump going to a clean passage and the delay tails jumps above that, then no bueno. Yet to be seen for mine arrives Friday. On a side note. I found a volume jump in the V25 when I was trying different things when experimenting with the amps circuitry, But the scenario was a none issue for I would personally never set it up that way to play live.. Probably the likely scenario for the JP2C. Come on seriously who switches their amp channels with full multiple effects going at once more than Mr Petrucci himself, without an issue :lol: in stereo!

 

[Silverwulf]

The jump is there, no doubt about it. I've tried other effects in the loop without it happening, though. I've only seen it happen with delay so far.

I unfortunately don't have my switcher at home with me, but I'm betting that when switching between delay pedals or different patches on a Strymon Timeline for example...you won't have any issue with it. I won't be able to test that theory for a bit though.

 

[kippiejr]

I heard the clip, Only happens with delay? Weird? The loops can detect a pedal type? Sounds more like a setting on the amp or the delays...
Anyway we will know soon enough.

 

[Silverwulf]

I heard the clip, Only happens with delay? Weird? The loops can detect a pedal type? Sounds more like a setting on the amp or the delays...
Anyway we will know soon enough.

I can't speak for everyone, but it only happened to me when using delay. Granted, I didn't try reverb, but with chorus, flange, etc...it wasn't a problem.

If the delay of turned off, no problem. So, that leads me to believe that if you had a switching system (like a Gigrig or BOSS ES-8) and were switching pedals, used a Strymon Timeline where you were switching patches, or a multi FX unit like a Fractal FX8 and were changing delay settings with the channels, you wouldn't have the "issue" happen.

Considering I don't use one delay setting among all my channels, I don't think I would have ever even noticed this. Who uses the same delay setting on clean, crunch, and lead? But, I can't test it out because my other FX aren't with me. I just have my BOSS DD-2 at home at the moment.

 

[kippiejr]

I'm with you, Also his decay and feedback where set high...

 

[SamuelJ86]

So all this loop talk has me curious. If mesa says they don't want to fix this little oddity because they don't want compromise with the circuit, how close is it to the original? I mean, does the original c+ have this quirk? And does the JP2c pass the loop test? Just wondering. :idea:

 

[dlpasco]

If you've ever used an old Mark (like a Mark III, for instance) as a preamp for another amp, it'd make more sense. This setup is consistent with how the fx loop send is handled on those amps.

The Mark III and the Mark II both have the overall amp volume governed by the Master Volume and Lead Master Controls. The common Volume control on the old amps set the amount of dirt on both the clean and lead channel and also set the loop send level for the clean channel.

As a result, trying to use my Mark III as a preamp for my stereo rig played hell with things because I had a terrible time getting consistent outgoing levels set for the clean, R2, and lead channels. I also had problems using the Mark III as a power amp for my stereo rig because handling other amps as preamp to its FX return also caused problems.

So, short story long: yeah, this happened with the old amps, too, it just wasn't exposed in regular behavior. Updating this as a multichannel amp has exposed some problems that existed in the original circuits that have always been there because it wasn't ever really intended to be used this way in the first place.

Since recreating the C+ circuit faithfully has been a problem for at least six year (when the V came out), I'm guessing that they are done trying to tweak the **** thing are not going to mess with it.

As it stands, this seems like a small, manageable edge case to me.

And this amp is the freaking bomb. I spent a couple hours recording tonight and I'm just...floored.

People have said that the cleans on the IIC+ are overlooked. I think they were right. My god. The cleans...

 

[kippiejr]

FWIW, Orignal C+'s do NOT have this quirk since both channels share the same effect send knob. Not the case in the JP-2C there are actual 3 send level knobs. Its in the manual....

 

[Authorized 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.

The feedback suggests that for many, the Effects Loop is operating satisfactorily and within the performance parameters needed. Those players may not want to part with their amplifiers for a week or two to receive an update even with the shipping cost covered and the update free of charge. For those of you experiencing difficulties matching levels, we can send a UPS Call Tag, have the amplifier picked up and update it and return it to you within a week (shop time) free of charge. Regardless of which of these categories you might fall into, should you be unable to be without your amp or simply choose to wait until time permits that, rest assured we will be happy to do the same for you or subsequent owners at no charge any time during the 5-Year Transferrable Warranty.

The update addresses the concerns most commonly associated with the feedback we have noted on the forums. These concerns arose in applications where the playing volumes were low and/or a high setting of the MASTER in Channel 1 (as compared to Channels 2 and 3) produced excessive volume in the first repeats using a Delay. The update addresses these concerns and provides a well-matched Effects blend–again–when the amplifier is used for the intended use stated above and the Channels are relatively close volume-wise.

However, since performance of the Effects Loop is greatly affected by the settings of both the preamp (GAIN and Tone Controls) and power amp (MASTER and PRESENCE) in each of the Channels, it is still possible to experience SEND and/or RETURN level differences under certain conditions. Namely those which deviate from the Clean/Gain/Gain Channel dedication noted above and/or extreme GAIN and MASTER differences Channel to Channel. In an amplifier with this much GAIN and output power, as with any hot-rod, an application must be determined and a relative tuning for that application applied to achieve stability for the widest number of “drivers”.

We are very sorry for any inconvenience this may cause and appreciate greatly your willingness to help us address this concern early on and assure the greatest level of satisfaction from your new amplifier.

Sincerely,

MESA/Boogie, Ltd.

 

[kippiejr]

Way to go Mesa!!!!! I knew you would fix it...

 

[kreatorkills]

"it is still possible to experience SEND and/or RETURN level differences under certain conditions. Namely those which deviate from the Clean/Gain/Gain Channel dedication noted above and/or extreme GAIN and MASTER differences Channel to Channel".

so they are saying there will still be a problem under certain conditions even after the fix?
and does this now change the circuitry that they wanted to keep original so bad?
will the fix effect tone at all?
should mesa have given up on their desire to keep the circuitry supposedly 100% original if the tone wasn't effected to forego this issue, considering they made so many updates from original anyways?

 

[Authorized Boogie]

We moved the location of the Ch1 Master pot, from before the Send to after the Return. This change only affects Ch1, and does not affect the tone at all. The Gain control now becomes the Send level, instead of the Master. Thanks!