That sounds like a design issue. Why make an amp where the controls have to be in some weird configuration to sound like what most of the target audience wants? Then again you build EQ sliders into your amp, you are inviting complexity.
The Hellcat in the studio doesn’t really do different sounds, per se. If you put it on high gain, and you put the knobs in the middle, that’s what it sounds like. It’s not that it can’t get a bad sound, just that someone would not be likely to put the knobs in those positions. Nobody is going to think, “hey, let’s dime the treble and cut all the bass, that might sound good”. I would expect that to sound odd. And it does.
Anywhere in the middle of the travel, maybe lower or raise the bass/mids/treble a little to your liking, it will sound great. And most people will be able to get that sound because it’s how you would expect simple-appearing controls to operate. That to me is doing amp controls right.
Because back in 1984, when they first produced the C+ revision of the MkII, they had no idea what the target audience was going to be. It wasn’t designed to be a heavy metal amp, it just became one. I think the intention was to offer something that had a lot of versatility and tone shaping options primarily for 80’s LA studio session players (like lukather) that were likely to use wildly different tones depending on the session. They didn’t know James hetfield was going to use it, scoop all the mids out of it, and use it to record one of the most iconic heavy metal records of all time.
This is the generalized nutshell below, it’s gets way more detailed, but I doubt many people would want to or really care to know much more.
Passive tone controls, particularly the FMB used in nearly every guitar amp, are very simple circuits (and not even the most effective passive network from an engineering standpoint). But where they are placed within the circuit makes a pretty big difference. Most amps that use passive, post distortion generation FMV EQ’s (your hellcat is one of them, most marshalls, slo’s recto, engl, VHT, Diezels etc.) are like that, they don’t wildly adjust much, just serve as a final adjustment of the preamp eq. Passive eq’s can only really cut what’s there - they can’t add anything, and they already typically operate with a preset 8-20db mid range dip by design depending on amp (minimum insertion loss) so they are already working with a substantial enough mid dip. You can adjust most passive eq’s to be flat by turning the mids to 10, and bass and treble to zero. In that setting you just get the 8-20db insertion loss.
The Mesa mark series is a bit different in its initial eq placement, and borrowed aspects of 60’s and 70’s Fender designs that have the passive tone stack situated rather early in the design. This sounds pretty good for clean guitars, but not so great for overdriven guitars, where you typically need to limit both low and high frequency bandwidth into overdriven stages for a good sounding distortion. This is why you see the unorthodox settings on the first eq of the Mesa marks where the lows are cut, the mids are moderate, and the mid mids, high mids boosted (treble shift is pulled out most of the time, which shifts it’s response lower to the mid mids and upper mids). The post overdrive GEQ which is a form of active, is then set to compensate for this, and has the most radical influence over the final sound of the amp.
Some people are fiddlers and like to have the tonal options available, others just like plug and play.
Yes know about the passive aspect of the Hellcat EQ. Whatever they do with the preamp circuit that comes before that, it must output a lot of stuff in all registers, i.e. to give the passive knobs enough to chip away at. Because you can make it sound extreme, but you have to go wild.
The bass and treble controls are shelving, like on a rack unit or mixer. I don’t know if turning the treble all the way up removes its influence entirely, or just allows the most signal to get through. But if you do that, you really do get a lot of high end that will sound icy picky and brittle. The effect can be extreme.
I just don’t see why anyone would actually do that. The design is suggesting that you put things in a certain spot, and that makes sense to me. That’s the kind of UI I want on a “retro” style piece of hardware like a guitar amp. By comparison, the deep notch people dial in on the Mesa sliders, I assume that’s something you’d have to fiddle with to figure out, or hang out on forums and ask about. And certain users might not. That seems like bad design to me.
If I’m paying 3K for some boutique thing, I actually don’t want a million sounds. I want the designer to make choices for me. If I don’t like those choices, I’ll choose another model or someone else’s amp. If I wanted a complicated “guitar tone construction kit” I’d buy a modeler and fiddle around with a million parameters and speakers / IRs and software. I just don’t like doing that when I want to play guitar. Totally different head space.
So there’s three main things going on in the hellcat, and this an over simplification. The first is that they don’t cut high frequencies to extremes before the eq. In that amp, but they don’t peak them either in the pre any more than the artifacts of distortion will anyway. They do limit low end to keep low end from becoming muddy.
Next, The tone stack in that amp is set using a -12db loss (likely a bit more since it’s fed at a high z) over a wider area of the midrange with the treble control acting on frequencies 3.3khz and above. this -12db minimum will also give you the impression of a bigger apparent boost in highs and lows over this set loss.
The last and probably most important is that there is no local -fb around the poweramp. This has an effect on the interaction between the amp and speakers, and allows them to remain largely undamped. Most 12” guitar speakers will exhibit a huge resonance in the 80-100hz range (impedance will be way higher than nominal), subdued lower mid range (where nominal impedance is most accurate), with another rising impedance starting in the upper mids. Because tubes are relatively high impedance, they will have a much easier time driving the speaker in the areas they exhibit higher impedance when the Output tx reflects this back. Conversely, removing the -fb for this upper and lower range of frequencies is precisely how the presence and resonance or depth controls on most amps that have them work, and is nearly entirely dictated by the characteristics of the speakers and cab used.
Put all this together, and there’s your big bass and treble response available in that amp.
Historical context. It (Mesa mark) wasn’t ever really intended to be used that way, and you can get a myriad of other usable sounds for other genres with the amp, and they are great for fusion (which was the original design focus) but that’s how James Hetfield set it to get the MOP sound, and because of that, the amp became synonymous with THAT sound, and that’s why people like John Petrucci, and other metal heads started to use them and set them that way. It’s not that you can’t get a good sound out them any other way, it’s just that they have to be set up that particular way to get the sound they became famous for in heavy metal circles, which are the group mostly buying them. Mesa could very easily preset all of this and offer something plug and play if they wanted to. it could be as simple as a two control gain and volume amp.
Plus it was the 80’s. The 80’s were all about that. ADA MP1 anybody?
@Fossegrim pretty much explained the whole reason why it’s a finnicky amp. Definitely a ton of useable tones for other things, but this kind of tone stack doesn’t work like the Hellcat @Troy mentioned. From my understanding, the tone controls are “filters” that feed into the preamp, so all at “0” actually becomes almost silent from what I recall. I remember the guy at guitar center selling me the amp putting all the tone knobs at 5 and sounding like straight ass for heavier tones.
The BadCat I have is also hard to dial in, mainly because it’s essentially a Matchless DC-30 (which is all about chime and whatnot). it just so happens that one of my favorite heavy guitar tones used that amp, so it’s my curse lol.
The pedal I mentioned is more like what @Troy would dig (and honestly I dig it because of it): all knob settings are useable, the extreme settings are wrangled in enough that anyone could quickly get a sound they like.
