Onboard pre with mid sweep ?

[Thumpin6string]

I looked on their site, and there's no info about the mids being sweepers

I'm taking the meaning of "sweepable" as being a cut/boost control. The Duncan 3 band has a mid cut/boost control. I have one in my 6er. All 3 controls are cut/boost. I find the tonal range to be almost infinite. With my soapbars I can get anything from a Rick tone to a Jazz tone and anything in between and beyond. I don't see a lot on the Duncan stuff here on TB, but I found it to be to my liking. Also very quiet.

 

[Zoobiedood]

How about the Duncan Bassline 3 band? I believe it has sweeping mids.

Nope, just bass mid treble, and blend. You have some options for the EQ of the slap switch, but it isn't like a sweepable mid control.

 

[LUpton]

I'm taking the meaning of "sweepable" as being a cut/boost control. The Duncan 3 band has a mid cut/boost control. I have one in my 6er. All 3 controls are cut/boost. I find the tonal range to be almost infinite. With my soapbars I can get anything from a Rick tone to a Jazz tone and anything in between and beyond. I don't see a lot on the Duncan stuff here on TB, but I found it to be to my liking. Also very quiet.

Sorry, but "Sweepable" means the ability to vary the EQ center frequency through a defined frequency range with a variable pot, then another pot provides cut/boost at the selected frequency. "Sweepable" does not mean cut/boost of a single center frequency. That's just a standard EQ control.

 

[scuzzy]

Are we using the same definition of "sweepable" mids as being semi-parametric. Sweepable mids means that you have one knob that controls the boost or cut level of the mids and another knob that controls the frequency center of the mid control. It lets you continuously sweep the frequency being affected.

I have a three band Nordstrand preamp (3B4b) and I love it but it has a fixed mid that can switch between set frequency centers by pulling up on the mids knob. This is similar to the Aguilar, Bartolini and others but isn't sweepable mids.

we are on the same page as meaning. I may not be correct on what mine does. I put an email out to nordstrand to get clarity. i have been playing with it, and can't definitively tell. but I can see how it could be that depressed it centers on 400hz, and pulled up it centers on 1000hz. I was under the impression (which may be false) that depressed controlled the boost/cut of the mid, and pulled up sweeped the mid frequency to select the center point. if my assumptions were incorrect, which seems probable, I will be better equipped to use my mid frequencies from here out!

 

[Jared Lash]

we are on the same page as meaning. I may not be correct on what mine does. I put an email out to nordstrand to get clarity. i have been playing with it, and can't definitively tell. but I can see how it could be that depressed it centers on 400hz, and pulled up it centers on 1000hz. I was under the impression (which may be false) that depressed controlled the boost/cut of the mid, and pulled up sweeped the mid frequency to select the center point. if my assumptions were incorrect, which seems probable, I will be better equipped to use my mid frequencies from here out!

I think your preamp is setup exactly like mine. Down the frequency center is 400 Hz. Boosting a touch is great for fingerstyle when favoring the bridge. Pulled up the frequency center is 1000 Hz. Cutting at this frequency is great for slap while a bit of boost is great for adding some edge when playing fingerstyle and favoring the bridge.

If pulling up swept the midrange frequency there wouldn't be any knob to control the boost and cut!

 

[Carey]

I think your preamp is setup exactly like mine. Down the frequency center is 400 Hz. Boosting a touch is great for fingerstyle when favoring the bridge. Pulled up the frequency center is 1000 Hz. Cutting at this frequency is great for slap while a bit of boost is great for adding some edge when playing fingerstyle and favoring the bridge.

If pulling up swept the midrange frequency there wouldn't be any knob to control the boost and cut!

Our preamps do not sweep. The push pull pot allows selecting 2 frequencies with the switch and the pot controls boost and cut in both the up and down positions for each respective frequency.

 

[RobbieK]

Schem.

This baffles my electrical ignorance. 9 point jack? Isn't it 2 wires (and a shield) when it hits the amp?

It looks like the pre is biased for +/- 4.5V operation. I've made many preamps like this myself. There are various advantages, but the OP has discovered the main disadvantage. The negative side of the battery is not connected to earth. So this means that a traditional stereo jack with the battery negative switching to earth from the ring connector through the sleeve of a mono plug is not an option. Those extra 6 lugs on the Noll jack are an isolated DPDT switch. I have no idea why they have both sides of the battery switched though. If there's something I've missed, I'm happy for a Noll guy to chime in and correct me, but that seems unnecessary. But even switching just one side of the battery would need an isolated pair of lugs that switch on when a jack is inserted. And there's no barrel-type jack that does this.

The original Parker Fly jacks with the isolated switch on the side would have been an option, but they've been replaced with one that has just one extra lug that switches (I would think) to earth. So for the Noll and any other preamps biased like this, you are limited to those square profile plastic jacks.

FWIW, if you know anyone who is an audio tech. It should be a relatively simple job to rebias a circuit like this with a "virtual earth". I would probably use an opamp for this, but a couple of resistors and a cap would probably work at a pinch. You'd need input and ouput coupling caps. And you may need to rewire the general earthing arrangement.

Also FWIW, I find it strange that the Noll is not wired as true-bypass. Perhaps the input z is really high...?

And finally, FYI: Notice that the top two wafers of the mid/sweep pot are working together - the two clockwise lugs are wired together. These two wafers are almost certainly a reverse-log ("c" taper) dual-gang pair and are controlled by the lower knob (sweep). The lower wafer, (for the upper cut/boost knob) would be a linear single gang. IOW, this is a custom made triple-gang pot. That's the reason a stacked control for sweep mids is pretty rare. As a designer, you'd have to custom order 1000 of these pots from a pot manufacturer. That's not cheap if you are a small buisness. It means you are also committed to making and selling 1000 of these preamps.

 

[Saetia]

My Modulus has an EMG 3 band w/ sweepable mid.

 

[jchrisk1]

I just got an Audere Classic with a three position mid switch. 250-500-750 frequency centers. This was the closest i could find to sweepable mids, in the price range I was willing to pay. Hopefully I can get it installed before work tomorrow and try it out.

 

[J.Wolf]

the East sweepable mid is fantastic. I dont love the baked in mid curve of the J Retro, but the flatter response of the Uni pre is awesome sounding, and being able to set the treble and bass frequencies inside the cavity is amazing. And then you have the sweepable mid stack. Just an awesome product.