GEQ: To be or not to be?

[elecnight]

Hey guys. I’m new here so these stuff should be obvious to you. But this is the reason I’m asking it here anyway.

It seems that basically there are 2 groups of Mesa amps: With GEQ and Without GEQ

I know the importance of GEQ to shape the exact tone one may seek. I guess my questions are these:

1- All Mesa’s have those three Bass/Mid/Treb knobs. Aren’t these EQ’s? So what is the significance of having another set of EQ’s in some models? Is it like having two EQ pedals one before preamp and one after preamp? How much improvement this Double-EQing will make for us?

2- If we get a model w/o GEQ, can we just put an EQ pedal in the effect loop after preamp and have exactly the same thing as models with GEQ? Anyone has tried this? What is the difference of this vs amp’s own GEQ?

I’m asking this, because there is a gap in demand for models with and w/o GEQ. If it can be solved by adding a simple EQ pedal, why should everybody recommend to get a model with GEQ?

Thanks.

 

[JOEY B.]

I’m asking this, because there is a gap in demand for models with and w/o GEQ. If it can be solved by adding a simple EQ pedal, why should everybody recommend to get a model with GEQ?

Thanks.

You seem to have answered your own question with this statement. 8)

 

[mr_fender]

I'll give this one a go.

1: Knob EQ (also known as the tone stack) is pre-gain in Mark series amps just like blackface Fenders. The Graphic EQ is post-gain. Having both gives a huge amount of tonal flexibility. Being in different places in the signal path, the two EQ's have very different effects on the tones you get. The pre-gain tone stack to me is better suited for tweaking the harmonic content and texture of the amps distortion, while the post-gain graphic EQ is better suited for the overall tonal shaping that most people equate with EQ's.

2: You can get a similar result with an eq pedal in the loop, however, the center frequencies of each band as well as their bandwidth or "Q" will most likely be different. For example, a Boss GE-7 has bands at 100, 200, 400, 800, 1600, 3200, and 6400 Hz. That's 7 bands equally spaced one octave apart each. The Mesa graphic EQ has only 5 bands at 80, 240, 750, 2200, and 6600 Hz. Those are about 1.5 octaves apart, so the resulting response curves of the two EQ's will have different shapes even with similar settings on the sliders. The result will be a somewhat different tone. Using an EQ with more bands like a rackmount 31 band EQ or better yet a 5 band parametric EQ would better allow you to match the Boogie graphic EQ response.

The Graphic EQ on most Boogie amps is channel assignable too, so it will automatically turn on and off when you change channels if desired. Having the graphic EQ on the amp also means one less pedal on your board. The extra circuitry and buffering you get with the Graphic EQ onboard will probably have a subtle effect on the overall tone of the amp as well, versus an amp with no EQ present.

If possible, try both and see which works better for you. As for me, the Graphic EQ on my Mark IV stays on almost all the time, and I think it really adds a lot to the tonal palette of this fine amp.

Good luck.

 

[Heritage Softail]

+1 ^ What he said....

Sounds like you may want to take a few more laps around various Boogie amp models before getting married to one. There are soooo many models with slight differences in voicing. Some take a while to learn how to tweak. Even if you spent an hour with an amp, you may only find a few good sounds, not because the amp is bad, but that it takes a little time to learn how to tweak it.

Good luck out there hunting amp!

 

[CoG]

I'm sure some people will dispute this, but there's a strong case to be made that the pre-gain tone stack is not very effective as an eq by modern standards, or even 20-year-old standards. mr_fender is correct in that they affect the gain (the Treble knob is basically just a gain knob) and feel of the amp. I know if my III's didn't have GEQs, I'd be sticking one in the loop.

Personally I do sometimes stick an MXR 10-band in the loop anyway, and a Boss 7-band before that. The sound of the GEQ on the amp is quite different-- not better or worse, just different. The GEQ on my purple stripe especially was very "organic" and natural-sounding, it didn't really sound like the amp was being EQ'd if that makes sense (note-- the EQ on that amp had a bunch of work done by Mike B in 2008 and he said the parts are not all the same, so I think it may have been a unique one.) The GEQ on my green sounds more "EQ-y" and the pedals sound even more so. If you are trying to get really heavy modern metal-type tones I think a pedal may actually be a better choice than the onboard, while the onboard is terrific for a lot of other things.

 

[mr_fender]

What CoG says is very true. I think that is why so many people say that these amps are so hard to dial in (even though they aren't). They expect the knob EQ to work just like it does on a Marshall. They turn the mids down expecting it to get scooped sounding, but it doesn't. They turn the bass up high to get a fat sound but it just gets farty. Pre-gain EQ works very differently in a high gain amp. It works fine for the clean channel just like in black face Fenders. High gain is a whole different ball of wax. I love having both pre and post gain EQ. There's so much tonal variation available... warm and creamy, raspy crunch, sharp focused violin like tone, scooped nasal thrash fun, etc., etc.

 

[elecnight]

Thank you guys. All responses are very useful. I think many people will find these information quite useful.

Now, I feel that a unit w/o GEQ but with Series effect loop and an EQ pedal will be as good as a unit with GEQ.

The problems is many older models w/o GEQ got parallel loops, so either onboard GEQ or a mod to series loop is necessary anyway.

I agree that EQing before preamp is very different from EQing after gain. This might be one reason that some solid state amps with a good EQ after preamp may produce an ok scooped tone. While with some basic tube amps (EVJ or Fender Champ or Killer Ant with 1 or 2 knobs and w/t a series loop), using an EQ pedal between guitar and amp may never give a scooped tone.

 

[Boogiebabies]

Thank you guys. All responses are very useful. I think many people will find these information quite useful.

Now, I feel that a unit w/o GEQ but with Series effect loop and an EQ pedal will be as good as a unit with GEQ.

The problems is many older models w/o GEQ got parallel loops, so either onboard GEQ or a mod to series loop is necessary anyway.

I agree that EQing before preamp is very different from EQing after gain. This might be one reason that some solid state amps with a good EQ after preamp may produce an ok scooped tone. While with some basic tube amps (EVJ or Fender Champ or Killer Ant with 1 or 2 knobs and w/t a series loop), using an EQ pedal between guitar and amp may never give a scooped tone.

Huh ? All Mark II's, IIC+'s, III's and IV's have a series effects loop. The optional GEQ is a parallel effect that feeds the signal from the V2 into the phase inverter.
Only a factory EQ is parallel. Anything else is in the preamp chain. An EQ pedal is not made up of Hi Fidelity Inductors and Mil. Spec hermetically sealed capacitors
either.

 

[elecnight]

Well when I wrote that, I was thinking about DC-5 which is one of the amps I like to have (another one is Mark III). DC-5 has a parallel loop I think.

GEQ in parallel is a bit weird. The whole signal should be EQed. So in fully loaded DC-5 and Mark III with GEQ, the 2nd EQ is parallel !?

This means that if we put an external EQ pedal in the parallel loop of a DC-5 w/o GEQ, we'll get a DC-5 with GEQ. And if we do that mod and change the parallel loop to series, by putting an EQ pedal in the loop, we'll have a more tweakable amp. (Even better than a DC-5 with a factory installed GEQ but parallel).

Am I missing something?

 

[JOEY B.]

^^^^ Get ready for some information overload. :lol:

 

[Fronzil]

Thank you guys. All responses are very useful. I think many people will find these information quite useful.

Now, I feel that a unit w/o GEQ but with Series effect loop and an EQ pedal will be as good as a unit with GEQ.

The problems is many older models w/o GEQ got parallel loops, so either onboard GEQ or a mod to series loop is necessary anyway.

I agree that EQing before preamp is very different from EQing after gain. This might be one reason that some solid state amps with a good EQ after preamp may produce an ok scooped tone. While with some basic tube amps (EVJ or Fender Champ or Killer Ant with 1 or 2 knobs and w/t a series loop), using an EQ pedal between guitar and amp may never give a scooped tone.

Huh ? All Mark II's, IIC+'s, III's and IV's have a series effects loop. The optional GEQ is a parallel effect that feeds the signal from the V2 into the phase inverter.
Only a factory EQ is parallel. Anything else is in the preamp chain. An EQ pedal is not made up of Hi Fidelity Inductors and Mil. Spec hermetically sealed capacitors
either.

doesn't the Mark IV A have a parallel loop?

 

[elecnight]

doesn't the Mark IV A have a parallel loop?

But that model comes with a GEQ anyway [even if it is in parallel]. Our concern is those models without GEQ and without a series loop.

 

[Boogiebabies]

Thank you guys. All responses are very useful. I think many people will find these information quite useful.

Now, I feel that a unit w/o GEQ but with Series effect loop and an EQ pedal will be as good as a unit with GEQ.

The problems is many older models w/o GEQ got parallel loops, so either onboard GEQ or a mod to series loop is necessary anyway.

I agree that EQing before preamp is very different from EQing after gain. This might be one reason that some solid state amps with a good EQ after preamp may produce an ok scooped tone. While with some basic tube amps (EVJ or Fender Champ or Killer Ant with 1 or 2 knobs and w/t a series loop), using an EQ pedal between guitar and amp may never give a scooped tone.

Huh ? All Mark II's, IIC+'s, III's and IV's have a series effects loop. The optional GEQ is a parallel effect that feeds the signal from the V2 into the phase inverter.
Only a factory EQ is parallel. Anything else is in the preamp chain. An EQ pedal is not made up of Hi Fidelity Inductors and Mil. Spec hermetically sealed capacitors
either.

doesn't the Mark IV A have a parallel loop?

No sir.

 

[Boogiebabies]

Well when I wrote that, I was thinking about DC-5 which is one of the amps I like to have (another one is Mark III). DC-5 has a parallel loop I think.

GEQ in parallel is a bit weird. The whole signal should be EQed. So in fully loaded DC-5 and Mark III with GEQ, the 2nd EQ is parallel !?

This means that if we put an external EQ pedal in the parallel loop of a DC-5 w/o GEQ, we'll get a DC-5 with GEQ. And if we do that mod and change the parallel loop to series, by putting an EQ pedal in the loop, we'll have a more tweakable amp. (Even better than a DC-5 with a factory installed GEQ but parallel).

Am I missing something?

The whole purpose behind a parallel loop is to maintain the integrity of the original preamp signal.
Instead of modifying the entire signal via op-amps and a digital processors "ADA" conversion through a series
loop, depending on how "Wet" you make your effects/EQ mix/cut/boost is the proportion that will mix side by side
with the original signal. Most parallel loop amps also have a mix level so you can adjust the portion of the "Wet" processed signal
to the power amp. A DC5 has a parallel loop and it gets it input signal right off the output of the GEQ and sends the signal
right to the PI or the end of the preamp. It still maintains enough of the processed signal to hear the mix, or any cut or boost in frequency.
Like the GEQ on Mark series amps, it's mixing an EQ'ed signal in unity gain side by side with the original signal. It been this way since the MK I.
The perceived volume is the same, but is greatly effected by the 750 HZ band when highly cut or boosted. A GEQ in parallel is not weird. Their are
so many different benefits of each type of loop as well as detractors. EQ'ing to me is not one of them and has it's own pros and cons for each loop
and type. Reverb, Delay, Compression, Chorus and other effects will drive one insane trying to find the right type of loop. Some effects like chorus and gating
work best in a serial loop and others are just better suited to parallel loops and post gate setups.

 

[lyman]

GEQ in parallel is a bit weird. The whole signal should be EQed.

I agree that a GEQ in series is best. If you have a parallel loop that lets you turn up the dry/loop balance to 100% loop, that's a suitable workaround for using GEQ w/parallel loop. But like I said, if the blend knob goes up to 100%......I'm sure some don't let you do this.

 

[Boogiebabies]

GEQ in parallel is a bit weird. The whole signal should be EQed.

I agree that a GEQ in series is best. If you have a parallel loop that lets you turn up the dry/loop balance to 100% loop, that's a suitable workaround for using GEQ w/parallel loop. But like I said, if the blend knob goes up to 100%......I'm sure some don't let you do this.

I've never seen or bought and amp with a parallel loop that did not have at least a mix function. If there is one out there, adjusting the output level
of the GEQ will have to do. Again, it's not always what is unequivocally best in ones opinion, but what works best for you and what options you have at hand.

 

[lyman]

GEQ in parallel is a bit weird. The whole signal should be EQed.

I agree that a GEQ in series is best. If you have a parallel loop that lets you turn up the dry/loop balance to 100% loop, that's a suitable workaround for using GEQ w/parallel loop. But like I said, if the blend knob goes up to 100%......I'm sure some don't let you do this.

I've never seen or bought and amp with a parallel loop that did not have at least a mix function.

Me neither. The point i actually made was that not every single amp lets you go 100% wet. Some only go up to 90%.

 

[elecnight]

Considering the importance of onboard GEQ, the question is why all of the current products (except Mark 5) come without GEQ? Does Mesa expect users to put their own GEQ in the loop? Or they see GEQ a fancy option provided only on Mark series?

 

[CoG]

Considering the importance of onboard GEQ, the question is why all of the current products (except Mark 5) come without GEQ? Does Mesa expect users to put their own GEQ in the loop? Or they see GEQ a fancy option provided only on Mark series?

because the tone knobs on their other products actually work. seriously, I think the GEQ was there basically as a workaround for the limits of the Mark preamp design.