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ACG onboard preamp (ACG/John East design)

#221
Hi Angus.

I don't actually instal a 02 pre-amp very often I use the 01 version. However I understand your point about retro fitting pre-amps with boards into cavities they were not specifically designed for.
I will take a picture of the next bass I finish. I find it is usually the ground wires that clutter up the cavity. I have a belt and braces approach to grounding so it results in 5 ground wires in the cavity all joining the main jack ground. I am working on a shielding/grounding tutorial at the moment as I have found most of the problems people have with the installation are grounding based.
 
#224
Skelf said:
Hi Angus.

I don't actually instal a 02 pre-amp very often I use the 01 version. However I understand your point about retro fitting pre-amps with boards into cavities they were not specifically designed for.
I will take a picture of the next bass I finish. I find it is usually the ground wires that clutter up the cavity. I have a belt and braces approach to grounding so it results in 5 ground wires in the cavity all joining the main jack ground. I am working on a shielding/grounding tutorial at the moment as I have found most of the problems people have with the installation are grounding based.
Click to expand...

Looking forward to it!
 
#227
thanks^
Usually It's easier to get technicals on stuff like that, ma absorbment and so on pdf or whatever.

I was checking there and there to see frequency range and stuff like that (to understand How It would react to pickups i have )
and above all ,

If that Pre could be used to simulate different pickup position through emphasis on resonance.
It's just an assumption,
But a while ago a german Guy did the same stuff (filter lowband +resonance ) for the same porpouse ,
stating it could be a possible tone-approach .

Til now Just i got that lower cutoff is around 70hz and reach abot 3khz ,pretty wide so i believe a slight touch could alter tone a lot.
And many "famous" resonances i believe are in that range (found a tab on the net)
Interesting .


Still dunno which range could cover the Highpass ,though i did read on bestbassgear it can go as low as 1khz,
and also wonder , if the 2 controls high-lowband "crossfade" on the same frequency region ,what happen to the tone there.

I'm an ignorant on that theme,and Technically i can't possibly understand everything , but i'm quite intrigued by the sonic possibilities ,honestly.


**************
EDIT:sorry went a bit out of thread
***********
An external Unit like a PEDAL maybe would be Much more appealing ,leaving the choice to try the approach on Guitars or different basses,
since this "Commervial" version works on the blended signal and do not process resonance for every pickup.
Well ...i guess i went out ,since this thread is dedicated to the onboard pre..sorry i'll edit
 
#228
You can't simulate pickup position with preamp filtering like that, because pickup position resonance is string specific and dependent on the tuning of the string. You'd need a separate output for each string feeding it's own filter (Like on a Roland V-bass or whatever it's called).

EDIT: You'd also need several bands of "cut" filtering to simulate the comb filtering effect of pickup position, and a source that hasn't already been subject to it, like a piezo (or a mag extremely close to the bridge)

Back OT:
It should be possible however, to simulate the different resonance characteristics of single coil/series/parallel/overwound/underwound pickups, but you probably knew that.

Question: Are there any plans of adding a bass EQ control to the circuit?
 
#229
Having only played with the Wal, Alembic, and Bartolini EZQ systems and not the ACG, I generally found a wide range of usable settings (along with a lot of "iffy" ones), but I don't think it's a particularly effective way to simulate different pickup positions.

As LowB-ing said, the resonance is specific to each string. Think of the changes in tone from the neck to the bridge pickup as more like a change in which harmonic overtones are emphasized and which are de-emphasized. When you change the pickup's location under the vibrating string, the balance among all those overtones changes, and specific frequencies of each of those multiple overtones depends on which note the string is tuned to, so it's not just a question of boosting or cutting a specific frequency range.

Mike
 
#230
LowB-ing said:
Question: Are there any plans of adding a bass EQ control to the circuit?
Click to expand...

That is the one thing I missed a bit on my Wals--the ability to just bump up the bass a little bit without affecting anything else. Fortunately, that tends to be more of an "overall" setting rather than an on-the-fly tonal change, so it's pretty easy to take care of with the amp's EQ.

You could probably add on of the East stacked bass/treble units into the circuit, but it starts to seem like overkill on something that's already a pretty sophisticated EQ.

Mike
 
#233
LowB-ing said:
You do know that Wals have a regular bass EQ control (per pickup!) but it's hidden inside the control cavity. Right? ;)
Click to expand...

Yep.

Actually, it's not a regular bass EQ, just a variable bass cut, and was not included on the early 4-strings. Rumor has it that when the Wal 5 first came out, Ian Waller was afraid the low end might overwhelm some amps, so he added the low cut control.

Mike
 
#234
mikezimmerman said:
Yep.

Actually, it's not a regular bass EQ, just a variable bass cut, and was not included on the early 4-strings. Rumor has it that when the Wal 5 first came out, Ian Waller was afraid the low end might overwhelm some amps, so he added the low cut control.

Mike
Click to expand...

Ah, didn't know it was cut only. I guess it didn't come "maxed" from the factory, as I've heard that one could turn the bass up with that trimpot. Meaning less bass cut.
 
#236
Yes Guy You are allright
"it's not just a question of boosting or cutting a specific frequency range":well that would be a normal eq onboard job.

Abut as i said You are right saying that First Somehow you would have to cancel The inherent Resonance of the pickup , before to apply /forcing an "external resonance" .
ANd YEs ,thinking more deeply ,in that" canceled case " (which is not possible anyway) it should be able to simulate just the pickup "charachter" (j,dual,series ,etc) and not the position of the pu to the string.

(...And yes it should be Roland "V-bass" ,maybe the most difficult bass Gear i met in a shop in my entire life,though the fretless simulation was stunning)
_____
Thanks guys ,very interesting thoughts.
 
#237
Hi Skelf,

I just bought ACG EQ 2 Dlx plate type and had set it into my Fender J American Dlx (with single coil), and yes it's awesome preamp.

My question is about possibilities adding mini switch for Series/Pararel between neck and bridge pu ?
I'd like to put mini switch on control plate but which type of swicth will work for system ? 3 way or just enough 2 way switch ? Advice for wiring diagram maybe ?

Thank you

JENDRAL
 

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