• TalkBass has been independent since 1998. Add your voice.
    Create a free account to reply to discussions, view embedded media, and browse with fewer display ads.
    Join free Log in
    Want zero display ads or expanded classifieds tools? Compare plans.

What's Up with the Mesa Walkabout Mid Knob?

#61
lomo said:
I just took the manual as indicating the passive mid to be a cut only control that's flat when "dimed", but the freq response chart posted early in this thread is quite conclusive that it is boost only (to my untrained eye)-can an EE comment on that? I cannot make out the x axis scale-maybe it's lows and highs that are relatively boosted??. In any event, I get my magic dust with it set at 10 o'clock on both my WA and M9.
Click to expand...

The manual says nothing about 'flat when dimed'. Again, if you read through this thread and the other links to the many discussions on this, the Mesa mids are actively boosted AFTER that passive mid control in the signal chain, and the 'passive mid control' is then used to reduce (i.e,. passive cut only) that 'post mid control active mid boost'. Celinder uses the same exact logic in their onboard preamp made by Greengrove, with an active treble boost inherent in the preamp voicing then 'controlled/reduced' by the passive treble knob.

Pretty cool circuit, and most hear the Mesa's as 'relatively flat' with the bass and treble at noon, and the passive mid circuit set around 10 o'clock or so.

Nice to see this old thread again, since that knob continues to confuse people when they read the pretty poorly written Mesa manual.
 
#63
wateroftyne said:
Cheers Ken

I'm working really hard to try and understand it. My burning question at the moment is... What's the advantage of this kind of circuit?
Click to expand...

I can't speak for Mesa, but Greengrove feels that a 'fixed active boost' with the ability to passively cut back to flat (or the level that the user desires) is superior regarding both signal to noise and also 'naturally and musically' controlling those frequencies.

Who knows!?!? I do know that, for example, dialing back a passive treble control on a J Bass cannot be mimic'd very well by reducing an active treble control (even one with adjustable shelving start point).

So, purely guessing, since the Mesa amps 'live in the midrange' IMO, Mesa spent a lot of time making the control and voicing of that frequency range of their amps 'perfect' to their ears.
 
#64
Thanks KJ. Now I get it. Since the manual doesn't tell you the initial signal is boosted B4 it reaches the mid knob, the flat when dimed conclusion seemed logical. As with all subjects, a little info can be more dangerous than none at all.
 
#65
Her's what little I know:
The manual is more or less unenlightening; and I don't know for sure how the nthing works in technical terms.

But, I don't care, because the dang thing sounds so great in a live mix, and whatever it's doing works well.

FWIW, I typically have mine set at about 10 oclock.
 
#68
wateroftyne said:
Cheers, all - I'm starting to understand it.

As you turn the mid dial CW, you allow more of the mid boost back into the circuit.. yes?

So... how would you achieve a mid cut?

Just intrigued - I'd never use a scooped tone.
Click to expand...

Since a 10 o'clock setting seems to be somewhat close to flat (i.e., the passive mid control is cutting that post active boost back to 'neutral'), that means anything below 10 o'clock will actually start to scoop the tone profile. However, since that mid circuit seems to have a very wide Q (i.e., it impacts a WIDE range of mid frequencies), it's probably better to use one of the semi-parametrics to slice out a thinner, more precise slice of mids if you want a more 'modern' tone (e.g., cut a little bit at 1K to smooth and 'hi fi up' the top end by taking upper mid gank, or cutting a bit around 400hz to 'widen' the feel of the amp and soften the mid mids, etc., etc.).
 
#69
So it's settled then - it's an Activepassive Boostcut Only that is "flat" when fully CW and fully CCW.

My take on it :

- Yet another of Mesa's many and frequent gaffes. It'd be an easy company to dislike and avoid if the amps weren't so good. I seriously wonder if they take seriously any feedback from actual 3rd-party customers/players. That said, I have had 3 Walkabouts, currently happily own 2.

- Some had said the mid sounds flat when fully CCW. Sounds scooped to me. I agree with those that say it sounds balanced (who knows what 'flat' is given all the variables outside the amp?) when around 10 o'clock ... anywhere between about 10 and 2 o'clock really, depending on the circumstances, same as all the other EQ.

- that being the case, all the fancy and powerful EQ is kinda overkill and as silly as it is effective, given a very narrow range sounds good in any given situation. That also makes it plug & play in my book, set things relatively "flat" (12 o'clock) and it sounds great. Unlikes some amps with a very "simple" EQ that you can twist all day with no success, which ironically makes those too complicated for me.

- If it's somehow tied to a boost, it's effectively active for all intents and purposes even if the knob itself in isolation can be said to be "passive". Semantically, OK maybe the knob itself is passive, but if the entire effect is active then the manaual's explanation gets a "fail" (as does congratulating the customer for the purchase at the outset of the manual - very poor form) and it should have been revised long ago. The amp itself has been revised plenty of times. Sadly it's not unusual to see manuals that are an embarrassment for a company, and even an insult to owners. The DB750 was only a page yet was (is?) rife with grammatical and factual errors, and it remained that way for a long time (still is?) even after I sent them a corrected version (I was an owner of the amp at the time, so I cared - see "amps with simple EQ that no amount of knob-twisting can make effective").
 
#70
swerve:
yessir, the amount of websites, promotional materials and user manuals that are poorly written and full of factual and grammatical errors is pretty stunning.
easy to feel let down, or be put off by that stuff.

despite this, i really like the walkabout and M6, and can tolerate the manuals for the product.
 
#72
SMASH said:
So it's settled then - it's an Activepassive Boostcut Only that is "flat" when fully CW and fully CCW.

My take on it :

- Yet another of Mesa's many and frequent gaffes. It'd be an easy company to dislike and avoid if the amps weren't so good. I seriously wonder if they take seriously any feedback from actual 3rd-party customers/players. That said, I have had 3 Walkabouts, currently happily own 2.

- Some had said the mid sounds flat when fully CCW. Sounds scooped to me. I agree with those that say it sounds balanced (who knows what 'flat' is given all the variables outside the amp?) when around 10 o'clock ... anywhere between about 10 and 2 o'clock really, depending on the circumstances, same as all the other EQ.

- that being the case, all the fancy and powerful EQ is kinda overkill and as silly as it is effective, given a very narrow range sounds good in any given situation. That also makes it plug & play in my book, set things relatively "flat" (12 o'clock) and it sounds great. Unlikes some amps with a very "simple" EQ that you can twist all day with no success, which ironically makes those too complicated for me.

- If it's somehow tied to a boost, it's effectively active for all intents and purposes even if the knob itself in isolation can be said to be "passive". Semantically, OK maybe the knob itself is passive, but if the entire effect is active then the manaual's explanation gets a "fail" (as does congratulating the customer for the purchase at the outset of the manual - very poor form) and it should have been revised long ago. The amp itself has been revised plenty of times. Sadly it's not unusual to see manuals that are an embarrassment for a company, and even an insult to owners. The DB750 was only a page yet was (is?) rife with grammatical and factual errors, and it remained that way for a long time (still is?) even after I sent them a corrected version (I was an owner of the amp at the time, so I cared - see "amps with simple EQ that no amount of knob-twisting can make effective").
Click to expand...

The funny thing about this is that if they would have just voiced the taper of that knob to be relatively 'neutral' at noon versus closer to 10 o'clock, and left that blurb about 'passive boost only' out of the manual, no one would give it a second thought!

I agree, it acts just like any other mid knob, and for all practical purposes, is a cut and boost (even though technically it isn't).

I do think there is something to the design of a fixed active boost circuit with a passive control to 'control' the active boost (from talking to the Greengrove guys who incorporate this type of circuit in their on-board pre's), but mostly, it shouldn't matter to a plarer.
 

Latest posts

Top Bottom
Back