Reverb "adds" an e.q on the channel

[Roadrunner]

I wonder if someone else noticed this, when engaging the built in reverb, the sound changes, become a little more compressed, it's like a mid cut, some of the frequencies in the middle feels like backing down, its noticed specially on the blue channel and a little on the red.

 

[JDH85]

Before one of the knowledgeable folks chime in, I'll offer my half-baked theory. Engaging a tube-driven reverb engages an additional tube, adding compression (which enhances both lows and highs) giving the impression of less mids.

 

[bandit2013]

I will throw my 2cents in.... no comment..... ha, fooled you.

this may be true that the reverb will alter tone. It is after all an electro-mechanical effect using a transducer and springs with a pickup at one end, but it works.

So in other words, the reverb tank acts like a feedback circuit. the signal is takend off the front end of a series resistor on the signal path used to drive a separate tube circuit that controlls a transfomer to drive the transducer in the reverb tank. the mechanical vibrations in the springs are converted into a low voltage and current are used to drive an isolated triode gain stage and then fed back into the same signal path but at the other side of the series resistor. This will act like a form of negative feedback depending on the frequency of the return signal. Thus enhancing some frequencies or cancelling others depending on phase relationship. Also there will be considerable delay between the reverb return signal and the instantaneous guitar signal. The reverb is lagging behind the guitar so some change in tone should be expected. Unlike a digital processor using the send signal to process everything before it spits it back out to the return, the delay or phase relationsip may or may not be present. Some may sound realy good or some may sound sterile or less rewarding.

the Royal Atlantic as a comparison has only one return level control. If set to high has that compression effect and can literally swamp the tone and casue reduction in output levels. the TC seems to be an improvement but if you use too much reverb on your selected channel it will swamp the originating signal. this is probably true with all electro-mechanical reverb circuits.

 

[Mookakian]

Your deefinately not alone, the sound becomes quite noticably darker to me as well, so i just use my neunaber wet stereo reverb instead.

Once i set up the Boss ES8 im hoping i can add mids and bring bach the brightness by engaging the EQ pedal in the loopas i engage the mesa tc50 reverb, but i do feel this is something that should be done when building the amp... Maybe Mesa could have intergrated something into the circuit to boost mids when the reverb is selected so the feel remains in tact and all we notice is reverb...

Similar to what happens when we activate the fx loop... But even more apparent when you engage the reverb. Two small but annoying flaws IMHO

 

[CoG]

Yep. I find the reverb to be a tone-wrecker on the RA. I can dial around it if Multi-Soak is off, but otherwise it's just too much trouble. I don't find the fx loop very useful for the same reason - basically I have to sit down and dial in the amp to use either reverb or the loop. I don't mind if the tone changes a little but like people mentioned, both seem to cut mids and lower the perceived level. This isn't a huge deal for me since I've been pretty much a guitar => (maybe)boost => amp guy for years and I don't mind running the delay in front on the rare occasions I use one, but it's just the "how much did I pay for features that are really hard to use" factor.

I'm guessing that the issue is that Mesa wants to offer the option of being able to cut them in and out of the signal path, which, um, in itself seems to create the reason why you'd wanna cut them out of the signal path...

 

[Roadrunner]

Similar to what happens when we activate the fx loop... But even more apparent when you engage the reverb. Two small but annoying flaws IMHO

Exactly! I was playing few days ago and as I’m currently without my FX unit, I was playing amp only and was trying reverb on/off to see which I like most and then tried the FX loop and again, there is a difference in the tonality,
I don’t like this, I don’t think an amp this level / quality company should have this kind of flaws, I want my sound to be consistent.
lucky for me I’m running Axe FX for all FX so no reverb etc but there are folks who love the built in reverb…

 

[DrKev]

I wonder if someone else noticed this, when engaging the built in reverb, the sound changes, become a little more compressed, it's like a mid cut, some of the frequencies in the middle feels like backing down, its noticed specially on the blue channel and a little on the red.

I found this thread while researching because my Express 5:25 does a similar same thing. With the reverb knob set to 9 o'clock it's an unusable, huge mid scoop, like there's a phase issue. The reverb then sounds fine from 10:30 - 12 o'clock, but turning it up higher doesn't add more reverb, just adds volume and treble to everything. This is not normal behavior for other tube-driven reverb circuits. But Is it normal for Mesa/Boogies? Is there a fix?

 

[bandit2013]

I discovered something about the RA100. Not sure if this is true with the TC as they are somewhat similar. I had made the assumption that the RA100 is just a simple effect that taps off signal and injects it back into the signal path across a large value resistor. This is what is done with the Mark V and Roadster. I had assumed that Mesa did much the same with the RA and perhaps the TC. The Reverb signal is pulled from the cathode follower circuit on the send stage (12AT7). It runs through a pair of op-amps so it can drive the reverb driver triode to run transformer. The recovery stage then inserts the reverb signal into the FX recovery gain stage. In other words, the reverb circuit runs in parallel to the FX loop. There may be a similar circuit design in the TC series. Always wondered why the amp could get swamped with a high setting on the reverb, not due to the effect of the reverb but more of a tone issue like described. I normally just use a Strymon BigSky in the FX loop and do not use the on-board reverb.

 

[bandit2013]

Just for S&G's I got the TC50 out to run a test. Was curious if the reverb was in parallel to the FX loop like it is with the RA100. Inserted to patch cords into the FX send/return with nothing connected to the other ends. I did not have the footswitch connected. Set the mini toggle on the back panel next to the FX loop to on and was swamped with some nasty feedback. Was hoping just to hear the reverb signal but the amp did not like the open circuit connection. I did this with the reverb turned on. I did not try it with the reverb in the bypass state. I assume it may be a parallel circuit to the FX loop. I was also using the clean in normal mode. The dog got pissed off at me and ran out of the room in a hurry when that happened. The Triple Cown is not your typical amp in general. Forgot how good the amp sounds so I had to play through it for a while.

I would agree that the reverb will affect tone as it is a signal that gets added to a gain stage, probably the FX return. Frequencies that may be out of phase with the original signal will tend to cancel out or become reduced. The reverb is an electro-mechanical device since it takes the electrical signal and converts it into mechanical energy by a linear motor at a small scale, almost like a speaker to cause vibrations in the springs of the reverb. At the other end of that is another transducer that converts the mechanical energy back to an electrical signal. There will be some phase variance and delay where it gets recombined into the signal path. I can see that altering the tone. You get a similar effect with other amps too. The California tweed does the reverb quite well so it is not as intrusive on your tone. Come to think of it, the Mark VII does reverb well too. I actually like the clean channel reverb.