Schaller tone circuit

[newey]

We've had discussion hereabouts about the use of passive low and Hi-pass filters, and bandpass filters, in guitar circuitry, as opposed to the standard tone pot arrangement.

I ran across this schematic which I found interesting. This is from a Schaller website, discussing vintage pickup/pickguard units for use on hollow-body jazz boxes. These units have a pickup and electronics attached to a "floating" pickguard, for installation on the typical Jazz guitars. Schaller made these for Framus back in the day. Originally, they used std V and T pots, but later versions dropped the tone control for a DP4T switch:



Position 1, labelled "T-", supposedly gives a Lo-pass "tone control at 0" sound, while 2 gives a bandpass effect. 3 is a direct out setting, while 4 gives a Hi-pass sound (Can you say "icepick", SG?).

I suspect that the choices of component values might be biased towards the Jazz sound, but some experimentation may be in order.

Interestingly, these were apparently made with all the electronics covered in the back by a copper box sealed with lead seams- early non-RoHS shielding!

Any comments on the efficacy, or lack thereof, of this circuit, which is apparently nothing new?

[D2o]

Jan 4, 2010 21:33:35 GMT -5 newey said:

Any comments on the efficacy, or lack thereof, of this circuit, which is apparently nothing new?

It reminds me of the old Esquire you were discussing with treguiers.

D2o

[newey]

D2o-

Sort of like the E- type, but not really.

The Esq. had a std 3-way Tele switch, using a cap to cut the highs in one position, which would roughly correspond to T- on the above diagram. It had a tone pot bypass position; this guitar has only the switche(s) for tone, without a pot. What I (perhaps confusingly) called a "direct out" at pos. 3 is really just no filters applied, it still goes through the V pot. The 3rd position on the "E" was just the regular V and T pots engaged.

The E-type has no setting to correspond to #2 and #4 on this set-up, as there is no hi-pass filter.

[newey]

BTW, here's a photo of one of these units: