• 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.

An unusual idea for a Preamp

T

The Basement

Sep 21, 2014
6
7
49
#1
I have this idea for a preamp that I wan't to air with you all. I would really like a preamp with a regular passive tone control together with a mid control(boost & cut)with sweepable center frequency.

That is, the preamp has unity gain and no bass control or treble control. The only additional feature - compared to the regular passive control layout - is a mid control that let's you boost or cut the mids at a selectable frequency.

The bass in mind for this would be my pbass. I really find the option to alter the mids to really help when trying to fit the bass in a mix. Other than that, I have no need to change the inherent sound or control layout of my bass. I understand that this would mean installing another pot on the bass. I'm thinking a stacked pot for the mids.

What's your thought? Does such a thing already exist? Is it stupid?
 
  • Like
Reactions: Swamp_Ronin and John the Bassist
#2
That’s a great idea, one that’s been mentioned by others, and one that’s actually easy to implement. All you need is to insert an active mid control into the normal passive circuit, just before the output jack. Something like the Invalid Link Removed or the John East Mid Sweep , both of which are top quality and compact. All you need is room for the unit, room for the battery, and an additional hole for the control.
 
  • Like
Reactions: scuzzy, spatters, Riff Ranger and 2 others
#5
Deceptively tricky to DIY, at least in the same form factor as the EMG unit. Easy if you're OK with having separate knobs for boost/cut and frequency sweep.

There are lots of schematics on the net for DIY EQs. That's the easy part. Just find a 3 band DIY design you like, leave off the bass and treble controls, and build it with unity gain - leaving you with a mid control. The usual way to implement a mid is basically a high pass filter and a low pass filter set up such that they overlap (the high pass filter cuts off lower than the low pass filter) and you end up with control over a mid frequency range. To make that sort of control have a sweepable variable frequency, you need to move both filters in lockstep - most sweepable mid controls are implemented with a dual gang pot, i.e. two pots on the same shaft, such that each gang of the pot can move one of the filters, respectively.

So, if you want to have sweep AND boost/cut on a typical stacked pot, you need a pot with three elements - two on one shaft (for the frequency shift) and a third on a separate shaft (for the boost/cut function).

Such pots exist, as that's what EMG uses for their VMC. But my suspicion is that they get them custom made, as I've never actually seen one sold by itself out in the wild, and they're not listed in any normal datasheet for any of the normal pot manufacturers.

Another DIY option would be to use a push/pull pot to switch separate resistors into the filters, such that you could have two preprogrammed mid frequency points instead of a sweepable control.
 
#6
There are quite a few pedals that are just this - a mid control "preamp" of sorts. The Ritter preamp has sweepable mids as does the Audere. I haven't heard of anything with just sweepable mids, that's why I went the pedal route.
 
#12
One experiment you could try to see if you're onto something is getting the EBS pedal that does just that. You'll know immediately if you have had a great idea. Then you can get about hacking up your bass.
 
#14
Dragan said:
Im not being sarcastic here, just asking - why not using any quality outboard preamp ( tone hammer, ebs etc ) and set the controls to your liking?
Click to expand...

I’m not OP but I have gone down this road and my finding was that many “high quality” options don’t have sweepable mids and passive tone control in the same unit. At the time push/pull mids with 2 frequencies that you may or may not like were kind of common and I don’t remember many at all that included passive tone control.
 
#15
The Basement said:
I have this idea for a preamp that I wan't to air with you all. I would really like a preamp with a regular passive tone control together with a mid control(boost & cut)with sweepable center frequency.

That is, the preamp has unity gain and no bass control or treble control. The only additional feature - compared to the regular passive control layout - is a mid control that let's you boost or cut the mids at a selectable frequency.

The bass in mind for this would be my pbass. I really find the option to alter the mids to really help when trying to fit the bass in a mix. Other than that, I have no need to change the inherent sound or control layout of my bass. I understand that this would mean installing another pot on the bass. I'm thinking a stacked pot for the mids.

What's your thought? Does such a thing already exist? Is it stupid?
Click to expand...

Not a bad idea, I would prefer the addition of a sweepable Q control too though to the mids equalizer, to be able to set the width of the curve around the center frequency as well.
 
#16
It might be easier to just get a sweepable midrange EQ pedal such as the JHS Haunting Mids. This type of device will get you what you want in terms of mid shaping also, and have the advantage of being able to easily be used with other instruments.
 

Latest posts

Top Bottom
Back