mid boost

[jzilla]

can anyone point me to any mid boost projects ala a mid boost switch usually found on single coil guitars or http://www.demeteramps.com/products/accessories/mb2b.html ?

thanks for any hints...
-j

[Ben N]

Take a look at this:

http://aronnelson.com/gallery/album102/Freq_booster. The EMG midboost is reputed to resemble this circuit very closely.

or this:  http://www.blueguitar.org/new/schem/_gtr/ec_schem_fact.jpg.

or a Tubescreamer schematic without clipping diodes and the gain turned down most of the way!

In fact, you can turn any simple BJT or FET booster into a mid-boost by rolling off lows with either a high value input cap (like a Rangemaster) or a suitable value bypass cap on the source/emitter (like a Marshall input stage), and shunting highs with a simple fixed LP filter (series R + cap to ground) on the output.

As far as an onboard control, I imagine some onboard "mid-boosts" are passive, and are therefore really bass+treble cuts, leaving the mids emphasized, rather than true boosts. There used to be a circuit like that at the Torres Engineering web site, IIRC, and also a French guitar wiring site, if you can find it. IIRC, basically a dual-gang pot, one gang wired as a rheostat bypassing a series cap, the other as a standard treble-cut tone control.

hth,
Ben

[tol]

http://www.aronnelson.com/gallery/v/Lenwood-Designs/gus_overdrive_Perf_layout.gif.html

I've got this one perfed but then I realized I don't understand why it has 2 9v connections? Does it run at 18v or do I just connect the two to the 9v? Sorry...this is only my 2nd perf project.

[snoof]

do I just connect the two to the 9v?

yes

[km-r]

bandpass filter?

[jlullo]

i'd make a rangemaster and play with cap values

[petemoore]

  Cut Bass using a staging or input capacitor of 'X' value [HP filter].
  Cut Treble by shunting HF's from SP to ground through 'X' value capacitor [LP filter].
  What's left in between? ... mids.
  ROG : Speaker [and some amp] Sims : check out the two pole filters...IIRC Thunderchief has a 2P LP filter `at the output.

[boogietube]

You could use this:
http://www.runoffgroove.com/tonemender.html (I think that this is by far the cleanest and most versatile boost available to DIY-THE SOUNDCLIPS DO NOT DO IT JUSTICE)
or this:
http://www.runoffgroove.com/mreq.html
or this:
http://www.tonepad.com/project.asp?id=48
or this:
http://www.tonepad.com/project.asp?id=47

[Mark Hammer]

Take a look at this:

http://aronnelson.com/gallery/album102/Freq_booster. The EMG midboost is reputed to resemble this circuit very closely.

This is a terrific flexible little circuit that can be made as complicated or simple as you want.  The nice thing is that it is easily cancelled with a simple SPST switch.  That means you can get yourself a pot with a SPST switch and turn the boost "off".  Alternatively, you can do it with a toggle or push-pull pot.

Note that this is a resonant booster.  This means that a) it has no effect on content above or below the area of boost, and b) it provides no cut, only boost (turning down the boost simply restores normal tone not scoop).

[Gus]

http://www.diystompboxes.com/pedals/gusOverdrive.gif

A circuit to see what I could do with one BJT transistor no pots and no bias adjustment needed. 

I draw grounds and power supply connections seperate so the schematic is easier to read.  All the +9s at connected and so are the grounds

It does not have to be a 2n3904 it could be a 2n2222a,2sc--- etc try different  small signal Si NPN transistor

Bootstrapped input(for a higher input R than a circuit like a LPB), mid freg boost by the cap and resistor in the emitter leg then a low pass after so it is a kind of bandpass.

I see someone made a sweep control in the layout link, Nice

I built a few and the people I gave them to did not want the vol pot they liked it as a boost just with the fixed values But mod it what you want it is good starting point I believe as it is posted

It is also a bit different than a rangemaster

Anyone that built it any feedback good or bad?