My first profile - Morgan RA37 Combo

Hello everyone! I just got my Kemper in the mail a couple of days ago, and I'm blown away by this thing. I was fairly skeptical until I cued up rmpacheco's AC20 profile (my main gigging amp), and was amazed at how much it felt like my real AC20! Think of all the gear I will no longer need to lug around!

I decided to profile my other Morgan today, as there wasn't a profile of it up on the site. It's an RA37 combo, serial #1 (one of only two made according to Joe Morgan). It's loaded with a Celestion G12H. I profiled it running 6V6s (it can also use 6L6s), volume knob at around 9:30 (just as it starts to really break up), bright switch on bright. I spent a few hours learning how to refine the profile. I mic'd the amp with an SM57 slightly off axis around where the dustcap meets the cone, as well as an AKG C414 B-ULS at the edge of the dustcap. The 414 is blended in with the shure at around -6db. This is my go-to mic scenario for most sessions that I do with this amp, as the 414 provides a nice smoothing balance to the 57.

I ran both the mics as well as the main output of the kemper into my Pro Tools rig, so that I could simultaneously record and directly compare the two using the same exact guitar signal. I refined the amp in a number of different ways until I could A/B the kemper and the mics with basically any style of playing, any effects, etc. and not be able to tell the difference. It took a while, but it's now to the point where I cannot tell the difference between the amp and the kemper in blind listening tests.

This is one of my favorite amps; I hope some of you enjoy it as well!

You can find it by searching either my handle or simply "Morgan RA37."


Here's a picture of the amp:

[Blocked Image: http://i.imgur.com/Kpm2MkP.jpg]

Let me know what you think! Definitely try rolling the gain nearly all the way off as well - this amp has some of the most beautiful cleans I've ever heard!

Quote from bigb6611

If I may ask a question: you used your Protools rig (audio interface) as a mixer to mix both mics and feed them back to the Kemper, correct?

I actually didn't use Pro Tools to mix the mics, as I didn't want to introduce latency into the signal chain (though I'm of the impression that latency doesn't affect the profiling, I didn't want to take any chances). I use an RME FireFace audio interface which allows me to mix inputs and loop them back into the outputs with no AD/DA conversion, and thus no latency. So I sent the mix of mics back to the Kemper directly, and was also able to record them post AD conversion into Pro Tools.

Quote from Trazan

Hm...are you sure about that? There's no buffer latency introduced, but the mixer is still digital so there has to be AD/DA conversion involved, no?

Yeah, definitely sure - the mixer software is indeed digital, but it flashes the device when you change settings on it and doesn't use the software at all when actually mixing the signals to the outputs. You can use it as a standalone mixer with no connection to the digital software in this fashion as well by flashing it with the settings that you like, then simply unplugging it from the computer. The FireFace itself does all the mixing analog; the software just operates as a sort of occasional controller for it.

Quote from bigb6611

I think your profile sounds great! I'll definitely try it on some recordings, see how it turns out in the mix.

I'm so glad you're enjoying it! I just used this amp for about 70% of the tracks on a pop/rock album I laid tracks on, and it performed exceptionally well in the mixes. Let me know how the profile works out for you after putting it through its paces!

Quote from Trazan

Still not convinced... I have an RME UCX myself. For that mixer to control a pure analog path there must be a full vca matrix in there! I'm preeetty sure the only thing adjusted analog is the in/out reference levels. But the converters are extremely quick, at least on this UCX. For both AD and DA there's a total of about 0.2 ms at 96 kHz!

Wow, I stand corrected - after much poking around, it seems I was indeed wrong. Odd though, as they advertise the TotalMix system as 'zero latency' when it's actually 'so low you can't really tell' latency. Totally thought the mixer was analog until now after much poking around. Thanks for the insight! I've never noticed any latency when monitoring through TotalMix or doing any loopback recording or whatnot, so I was totally unaware until now.

That being said, it shouldn't affect the profile, as I recall reading elsewhere on the site that the Kemper auto-corrects for any latency during the profiling phase. I can't find the link right now, but I distinctly remember reading that here. Someone please let me know if that isn't the case!