Issue profiling amp - amp being profiled sounds terrible!

okstrat · December 18, 2013 at 9:34 PM

Tried to profile my Ceriatone Trainwreck. Here's an important thing to remember - I've profiled this amp before. Successfully. No problems. So... this is driving me nuts.

It's not that the profiling doesn't work, but the 'wreck sounds like CRAP with the guitar plugged into kemper and the kemper plugged into it for profiling. Just sounds terrible, like a busted fuzztone. However, the amp sounds great if I plug a guitar directly into the amp input. Here's what I've tried to remedy the situation... and again, remember that I have profiled this amp in the past successfully.

1) swapped cables from guitar to kemper and also from kemper to amp with different ones. No change.
2) I used a direct box with a small transformer in it I built to profile fuzz boxes and some overdrive pedals between the kemper output and the amp input. This didn't work either.
3) Plugged in a boss pedal on bypass to try the built in buffer between kemper output and amp input. Didn't help.

When I did my first wreck profiles, I hadn't had the kemper very long and the profiles were done in a much earlier version of the firmware. Could an update have caused this? Could I have goofed a setting or missed one? This is driving me nuts.

meambobbo · December 18, 2013 at 10:55 PM

have you tried rebooting the kemper?

something is wrong with some part of my setup, because every few months, I have to unplug everything for 10 secs or so, then replug it all in. the KPA is usually the most tolerant of whatever demons are getting me, but my interface is not - it starts working incorrectly, and i need to unplug it and reboot my computer, then reboot after plugging it back in.

Ampsound · December 19, 2013 at 12:55 AM

Sounds like a KPA issue. Try another amp to rule out any other possibility. If it still sound crap you probably have a fault within the KPA (i.e. audio board)

okstrat · December 19, 2013 at 1:55 AM

no problem with other amps... this wouldn't bug me if I hadn't been able to profile this amp in the past. Weird!

and44 · December 19, 2013 at 9:10 AM

Press and hold Output, have your "direct out" settings changed at all?

This happened to me once. and took me a while to sort out!.

okstrat · December 20, 2013 at 12:34 AM

Yeah, I checked the direct output settings, had rebooted the Kemper before, and installed the latest firmware (I was running the beta, not the production). Nothing helped. I've known almost from day one that the signal the Kemper sends is not just like a guitar signal, it's impedence or something is off because some devices just go crazy when you plug them in line for profiling, mostly fuzztones but some guitar pedals. I guess what really bothers me is that I've used this amp before and it worked perfectly before, and other amps work fine still, so I don't think it's a hardware FAILURE on the kemper as much as something changed in a newer firmware. I hate swapping firmwares around but maybe I need to load something older in there just to see if it makes a difference.

Thanks to everyone who has chimed in with suggestions, I appreciate it.

mDan · December 20, 2013 at 7:55 AM

A system reset often helped with any output issues in the past - did you try that?

okstrat · December 20, 2013 at 10:43 PM

Quote from mDan

A system reset often helped with any output issues in the past - did you try that?

I"m about to. Thanks for the idea!

timo · December 20, 2013 at 11:59 PM

Quote from mDan

A system reset often helped with any output issues in the past - did you try that?

This usually doesn't solve anything. You need to find the root cause which might be a parameter or something.
OP didn't even post the firmware version...

okstrat · December 21, 2013 at 4:22 AM

Quote from timo

This usually doesn't solve anything. You need to find the root cause which might be a parameter or something.
OP didn't even post the firmware version...

Yeah, I checked the direct output settings, had rebooted the Kemper before, and installed the latest firmware (I was running the beta, not the production).

okstrat · December 21, 2013 at 4:53 AM

System reset didn't work either. This is a real head scratcher, I know that most of my amps don't weird out like this, but I have profiles I pulled previously of this exact same amp that were awesome and didn't have this issue.

I don't gig again until after January, may just grit my teeth and put a really old firmware on there and see what happens.

timo · December 21, 2013 at 10:51 AM

Quote from okstrat

Yeah, I checked the direct output settings, had rebooted the Kemper before, and installed the latest firmware (I was running the beta, not the production).

You are running 2.2.1 Public Beta or Release?

and44 · December 21, 2013 at 11:32 AM

Can you explain your full setup (in detail please) so we can see what the problem may be..
detail as in what type of cables/trs/Xlr, to > from etc etc...There has to be a resolve if you have profiled the same amp previously.

okstrat · December 21, 2013 at 11:45 PM

Ok, I figured it out. Bear with me, it's a bit of a story but could have some good info for some of us.

When I first bought my Kemper in February of 2012, I kept my Kemper in my control room, and my profiled amp and cab in another room, with a long cable running from the kemper to the amp. This didn't work well, because where I live has a lot of RF interference - I would pick up radio stations when profiling high gain amps. I don't think it affected the profiles, but it was irritating.

So, I took a line6 Relay wireless, and ran it in place of the Kemper output to the amp. So Wireless transmitter hooked up to kemper, wireless receiver to input on tube amp. Worked great, no RF interference.

I used the Kemper like this for awhile (and also when I first profiled my Trainwreck clone) and then started profiling with the amp in the control room, and running a long speaker cable to it, and short cables from the Kemper to the amp. This worked perfectly until I tried to profile the Trainwreck clone again.

So, the Line6 wireless buffers or preamps the signal somehow so it works with the input on the Trainwreck better. Might even interface with fuzz pedals and such better also.

My new wish list for the Kemper or it's successor: Please make the profiled amp input signal the same as the guitar signal would be direct to the amp. It's obviously not. Thanks!

Pete

okstrat · December 22, 2013 at 6:28 PM

Here's a clip of the amp, successfully profiled... it worked before, just had no dynamics and gain, sounded really flat. I'm pretty happy here.

Trainwreck clone clip - feedback and touch sensitivity

r_u_sirius · December 22, 2013 at 10:36 PM

Quote from okstrat

My new wish list for the Kemper or it's successor: Please make the profiled amp input signal the same as the guitar signal would be direct to the amp. It's obviously not. Thanks!

Pete

+1

this could improve profiling amps with fuzz boxes or amps with extreme gain settings!

ckemper · January 8, 2014 at 11:28 PM

According the Trainwreck webside, it has one megohm input impedance.
That means - unlike fuzz pedals - it should not be coloured by any input device of regular impedance.
This is how every tube amp reacts.
It is hard to believe that the buffer amp in the profiler (low impedance output) will affect the sound, and can be recovered by a higher impedance device inbetween.

Beside that it is virtually impossible to create a faithfull guitar impedance simulation for running lower impedance devices such as fuzz pedals.
The reason is, that every Pickup has a different complex impedance, and is dependend of the PU switch and the setting of the volume pot.
Every PU simulator is just an approximation, unfortunately.

ucnick · January 9, 2014 at 6:04 PM

As an aside, I believe okstrat also mentioned he had tried using a Boss pedal as a buffer between the Kemper out and the TW in and it no effect. As I recall, the Boss has an emitter follower buffer and for example the OD3 has an output impedance spec of 1 kohm. I didn't see an output impedance spec for the Kemper direct send, but I would think it would be in that neighborhood. That would seem to take the buffer aspect out of the equation. Seems to me that the KPA expects to be driving a high-impedance load (most tube amps have similar values) so it is already taken into account by use of the buffer. There is more going on here than meets the eye. Perhaps the wireless is not behaving exactly as a cable (it is an active device, after all). Maybe some sort of level issue that the TW is sensitive to that the Line 6 masks and that is not present when the guitar is plugged in directly? Also, the Line 6 Relay series have a "cable tone" simulator - was that on, or does it make a difference at different settings? Just tossing out ideas.