3EQ, 3 band EQ, BASS preamp -- what is the state of this matter?

[j-pee]

hi all,

I hope that a summarizing thread could crop up here... with knowledge and references, for both posterity and ourselves

question:
what is the best of a BASS preamp that a DIY enthusiast could possibly make?

it would be interesting to know where this thing is at -- the efforts and intentions to build a 3 band EQ bass preamp be it a pedal... or an onboard thing...


// pre:
as I see it, there are (counting...) 5 points at which the "development" of a DIY enthusiast will bump into a ceiling...


A:
the active vs. baxandall tonestack phenomenon,
namely, that although we would like a good sounding active EQ, at the end of the day it will be a baxandall "unit" put between a buffer stage and a make-up booster stage...
which is cool, but there is this thing in our heads: "active"... and we imagine active frequency boost with parametric control... and al this at low level of complexity

the problem with the baxandall "3EQ", as I see, is the lack of convincing results...
see the stingray preamp with a 3 band EQ project...
I have come across this thread at Talkbass.com, by Dominic Decosa,
who even linked his sound samples (!!)...

https://www.talkbass.com/threads/diy-stingray-3eq-preamp.883257/page-2

but however happy everybody was about the samples,
they are still not getting even near to what we, I believe, hope for...
namely, an "active" tone shaping experience with BOOST / CUT possibilities... not to mention "parametricism", so to speak

namely, our 3EQ should compete with the active basses' 3 band EQs... and beat them
which doesn't seem to happen... except perhaps for low price Ibanez's (as far as I can see it)

B:
the assumption that a 3EQ preamp is better than a 2EQ
that is, thinking that the actual results can be better of a DIY 3EQ preamp than a 2EQ's...

C:
our secret or unsaid desire to make it an onboard thing...

D:
the end of the era of reverse engineering...

I mean, the beautiful thing that we saw about the Stingray "rev en" projects, or with so many "stompboxes",
will happen less and less part of it because sizes get minimized, and circuits more complex...
and musicians more proud of their expensive gear, meaning they wouldn't like to help others in the competition in which someone has a good position thanks to her/his money situation

E:
that "sometimes" reverse engineering projects will just abort without a "happy ending"...

take that remarkable instance when one guy (don't mention his name because of privacy), was doing an extensive experimenting with a preamp, filling an entire thread with his posts, like a passionate scientist
and then, right about when reaching the endpoint, even having a guy promising that he would take pictures of that preamp pedal, it aborted... as of January 2019...
and then it showed up at effectslayout.blogspot.com <-- not a precise URL
in February 2020...
and that's it...

let me add that effectlayouts is a beautiful project, I simply love those guys, but the fact of the matter is that
in their project a tint of commerciality is already present... which is a 180 degree opposing direction to that of FREEstomboxes', for example

pre end //



So, I guess, the questions are:

• 
  can or can't DIY enthusiast musicians make a good 3EQ bass preamp, with cut/boost functionalities? with even parametric control?
  
• 
  i.e. can or can't musicians who are DIY circuit enthusiasts make a 3EQ bass preamp other than a baxandall tonestack put between a buffer and a booster?
  
• 
  can a 3EQ bass preamp, which a DIY enthusiast can build, be better than a 2EQ preamp at all?
  


• 
  what options are there, as of 2020, for bass players who are eager to build something (acoustically) stunning?




• 
  is there something like a 2 band baxandall with an active mid control? or anything?
  or this is as far as we can get? (which is absolutely fine!!! one just needs to know, I guess )
  
  I mean, there seems to be a line of "evolution" (gradual step-ups for DIYers) from a clean booster, through Albert Kreutzer's onboard preamp, to the 2 band EQ stringray(s), and the SUNN and the Bassman projects (thanks to deadastronaut), up to the 3band EQ stingray ...
  where should we say: "I've got what I wanted, so thanks, I'm out!" ?
  
  

I'm asking all this not for myself personally  
but for everyone who's about to take a plunge like "I'll buy a soldering iron and make my own circuits, and they'll rock, and I'll be able to spend much more money on instrument(s)"...

cause the point about making stompboxes is, I guess, to make what's best, and move on to spend more time with playing, that is, to enjoy the FREEDOM which building your own stompbox has gained you...

hence my questions...

[DIY Bass]

Are you asking about onboard preamps or pedal preamps?  I know of a few pedal designs.  I am sure I have seen onboard ideas as well but I haven't looked as much into them.

[Rob Strand]

can a 3EQ bass preamp, which a DIY enthusiast can build, be better than a 2EQ preamp at all?

It depends what question you are asking.    When you say 3EQ are you referring to 3EQ circuit like the Music-Man 3-band and the Albert Kreutzer (which originates from National Semiconductor) ie. a 3EQ with one opamp for the EQ part ?   In this case I'd say no.   Those circuit have there limitations and cannot be tweaked outside of a small working range.   The bass and treble do no work like a 2EQ circuit even when the mid is set flat.   You either like them or not.

However, you can construct a 3EQ circuit by cascading a 2EQ (bass + treble) circuit with a separate mid-eq stage.  This is a very common technique used in bass amps and in many on-board preamps.   If you set the mid control flat then you can at least get the performance of a 2EQ.

There's a about 5 threads on the other forum (free stomp org) which have schematics for many commercially available preamps.

Outside of the usual bass + mid + treble thing there's also preamp which add their own voicing like the Sadowsky and the older 2-band Music-man. 

[Sooner Boomer]

I've got two suggestions. You do the research (homework!) and see if either might be worth following up with.

1: A two- or three-band parametric eq, tuned to the bass end of the frequency range.  I personally don't build many parametric eqs, other than maybe using a kit, because most designs require ganged pots.  A hybrid design I've seen is an active Bax bass/treble combined with a single parametric bandpass filter. The parametric section is based on one of Anderton's designs.

2: A multi-channel eq based on a chip like the BA3818.  It's a 5-channel eq, but you don't have to use all of the channels.  You set the q for each stage by the values and ratios of the combinations of capacitors and resistors. The q will be fixed at each stage, but you're able to cut/boost in each band.

[bushidov]

I made a Darkglass B3K and B7K that might fit the bill

[tubegeek]

Neat trick publishing in Feb 2020 already!

To my mind, the hot ticket for a bass pre is multiband compression. Working on it but a couple other projects popped up in the meantime. I always point to the Rane DC-24, a 30-year-old unit that still gets a lot of respect from the low end community. That unit is a 2-band studio-quality compressor with adjustable crossover frequency. As soon as I debug my crossover build I will try it out and report back.

[Rob Strand]

Are you asking about onboard preamps or pedal preamps?

Good question, quite different things overall.  There's a few statements in the original post that make me think onboard preamp.

[PRR]

> a few statements in the original post that make me think onboard preamp.

Shhhh! It's a secret!

> C:
our secret or unsaid desire to make it an onboard thing...

[j-pee]

hi,

thank you guy for your kind responses...
today I've been googling, and this thread came up from all of the web's content first
and I was surprised (not just to some small extent) to see that I had posted the question... which brought about the kind and cool answers

- - -
I am surprised to see how biased I was towards an onboard pre
perhaps I was just unawares cuirious if that was the ultimate rend?
- - -

I'm not trying to reactive an old thread but to thank you for your thoughts

@ DIY Bass:
"Are you asking about onboard preamps or pedal preamps?"

I think it is a question, in the first place, whichever is "better" for someone who prefers comfort to quickness... 
and doesn't see her/himself as a hot onstage act in the limelight who needs to control the tone between two songs ASAP, and as effectively as possible

I mean, whichever is more "settled"...

I would even consider big-box (relatively bigger box, not necessary rack size) packing preamps...
bigger box means big space for circuit boards, and wires...

@Rob Strand... thank you
for explaining the limitations of a 3Band EQ with only one opamp...
(enlightening)

@ Sooner Boomer, thank you
for elucidating that in practical reality a "hybrid design" is a viable route
PS: I had done lots of googling, only when one doesn't understand all concepts clearly, googling might not be so effective

@bushidov, thanks for suggesting Darkglass B3K (!)

@tubegeek, thanks for mentioning multiband compression which I don't even have a clue of (at this moment)

@Rob Strand & RRR -> sorry for being biased
as an explanation:

at the time of posting, it sort of seemed to me as if sealed onboard preamps by aguilar, for example, were becoming the way to go..
and also, of all preamps Bajaman's Stingray seemed the most promising project, even though it is written for specific pickups, as I understand...

- - -
as to right now,
I've committed to build an EWS trilogic, the 1 opamp version, with a mid switch -- layout by John K @ guit fx lo nabble (see: http://guitar-fx-layouts.42897.x6.nabble.com/E-W-S-Trilogic-tp8442p8594.html -- 
into a 1590BB... and I'm even thinking about using a bigger box, which can sit comfortably on a table

at the same time, I've also committed (bought the parts) to build a Stringray original by Bajaman...
but I'd put that one, too, into a box...

and in the near future I'd even try John K's parametric version of the EWS trilogic...
the only reason against is the complexity of the stripboard (47 cuts? not for me..), and the fact that he had build both and said that the simpler with the switch was better...

anyway, I'd just like to have something that works pretty well, and use it
and add perhaps add some other circuits to it... but only in a "loose" modular mode

thanks for your thoughts and suggestions,


Peter





I think, like myself, ayone will find

[Fancy Lime]

Hi,

I missed this thread the first time round. I am a bit unclear what you mean by "better". I have tried many commercial onboard preamps and found all of them terrible. Any of my simple pedal preamps kicks the ass of even the most expensive boutique bass preamp on the market *in my ears*. But that is because I built them the way I wanted them to sound. "Better" is a matter of taste, is it not? That being said, there are many people on this forum who can design a bass preamp, on or off board, that is easily on par with the best (whatever best means in that context) units on the market. The problem if commercial companies is that they need to design something that will please a wide variety of customers. The advantage of diy is that you can design something that is exactly taylormade to your taste. It is the same difference as buying a suit from, say, Armani, or from an old fashioned taylor. The Armani suit may look flashier and may feel like it fits ok but the one that is made for you specifically will fit perfectly. At least if you have a competent taylor. For my personal taste though, ripping out the active electronics is still the best upgrade you can give any bass, cheap or expensive. I never has a Sadovsky but if I ever got one I would almost certainly end up ripping out the onboard pre. There are certain limits to the noise floor and dynamic range that cannot be overcome in a technically feasible battery operated preamp. Plus I tend not to like the EQ voicing on these things. So I just go passive an right into a nice overdrive or compressor. But that is my personal taste. This forum is a great place to learn how to design whatever suits your personal taste better than anything money can buy.

Cheers,
Andy

[iainpunk]

i echo Andy and would like to add this:

you talk about an active 3 band eq, but you totally forgot what the original Baxandall or James tonestacks were designed for...
they were designed to have the ability of a 3 band tone stack, but with one less control.
want a mid scoop? crank bass and treble
mid push? take out B+T
the two individual controls are way more powerful than the controls on a 3 band, this is to compensate for the lack of the mid control.

then you have the tilt + mid control, an even better two knob wonder IMHO,
there are multiple ways to achieve it,
i like the big muff tone control followed by a mid boost at the same frequency as the BMP's scoop, especially usefull if you mod the BMP control to have a deeper scoop and add a powerful mid boost at the end.

cheers, Iain

[Rob Strand]

I've committed to build an EWS trilogic, the 1 opamp version, with a mid switch -- layout by John K @ guit fx lo nabble (see: http://guitar-fx-layouts.42897.x6.nabble.com/E-W-S-Trilogic-tp8442p8594.html --
into a 1590BB... and I'm even thinking about using a bigger box, which can sit comfortably on a table

There's some discussion on the fsb forum about what is the real EWS and what is not.

[j-pee]

Hi,

[...] I have tried many commercial onboard preamps and found all of them terrible.
[...] For my personal taste though, ripping out the active electronics is still the best upgrade you can give any bass, cheap or expensive.
[...] There are certain limits to the noise floor and dynamic range that cannot be overcome in a technically feasible battery operated preamp.
[..] So I just go passive an right into a nice overdrive or compressor.

[...]

thank you Andy, your thoughts are truly liberating...

as to the dynamic range and the battery operated preamp's limitations,
is it only the headroom, or there's something else, too?

[j-pee]

i echo Andy and would like to add this:

you talk about an active 3 band eq, but you totally forgot what the original Baxandall or James tonestacks were designed for...

wow, I've read a lot about it, but (and) you're totally right!
thanks for explaining it

[Fancy Lime]

Hi,

[...] I have tried many commercial onboard preamps and found all of them terrible.
[...] For my personal taste though, ripping out the active electronics is still the best upgrade you can give any bass, cheap or expensive.
[...] There are certain limits to the noise floor and dynamic range that cannot be overcome in a technically feasible battery operated preamp.
[..] So I just go passive an right into a nice overdrive or compressor.

[...]

thank you Andy, your thoughts are truly liberating...

as to the dynamic range and the battery operated preamp's limitations,
is it only the headroom, or there's something else, too?

Headroom is one issue but there are more. My biggest problem is noise. Any active circuit generates noise. Complex circuits, such as multi band EQs necessarily generate more noise than simple ones, such as a simple buffer or booster. If that happens at the beginning of the signal chain it is worse then if it happens later. It it happens before a compressor or drive pedal it is much worse. So if you ever use a compressor or a drive pedal, you normally want these to be the very first active circuit that your signal sees. So do me personally, that pretty much rules out complex on-board electronics because I really like me some overdriven bass.

The situation is made worse by the fact that there are always trade-offs between noise and current consumption. The least noisy 3-band EQ that you can possibly design will consume way too much current to be feasible for battery operation. That is a fundamental physical problem stemming from the fact that all resistance creates noise and low current at a given voltage requires higher resistance. You could reduce the voltage but then you loose headroom. So in the end you need to balance battery life and noise but no compromise is perfect. Do you want to change your batteries after each song, after each gig or once a year? And how much does the additional noise really bother you in your particular setup?

If you move the EQ off board, many problems simply disappear. You can put it after the compressor or overdrive, which will make the whole combination less noisy and will make the EQ more effective. You can power it with an external supply of 9V or more, even really high voltage if you like, and you can run it at much higher currents than would be doable with a battery.

Ultimately, I think an onboard preamp is a crutch that is a little useful in some situations but takes away too much flexibility for optimization for my taste. If someone gave me money and insisted I design an onboard preamp for them, I would go with a phantom powered option. That alleviates many of the problems. A well designed Baxandall 2-band is really all that I would ever consider useful for onboard. Nobody is going to fine adjust a 12-dand EQ while rocking out (slight hyperbole). I may also want to include a good but simple compressor.

Hope that helps,
Andy