Treble Booster buffer friendly

[Dreadneck]

Hi!

This is my first post here! But I've been around readning tips and so on for a long time.

Now this question might have been asked before and perhaps answered allready. If that is the case I am sorry.

I'm building a treble booster, very much a clone of the Dallas Rangemaster but with switchable input caps.

Is there any way to make it buffer friendly or so that it would work later in the signal chain?

I know Magnetic Effects makes germanium pedals that does this, but I do not know how.

Any tips would be greatly appreciated!

[fryingpan]

Ideally you'd put a buffer as a first stage so as to isolate the circuit from the previous circuit's impedance (be it a buffer, your guitar, another effect, etc.). And then you'd tailor the following stage's frequency response so as to mimic the frequency response of the original pedal directly connected to your guitar. In practice, this means that a Rangemaster sounds a bit different according to the guitar you use, nay, actually according to pickup selection and volume/tone settings. Redesigning the Rangemaster's input stage to make it independent of previous circuits means losing this variability and you'll have a pedal that will respond less to guitar and settings. But it can be done and, if you never use your guitar's tone and volume controls, and the pickups are not widely different one from the other, there would practically be no difference to you.

[Vivek]

Welcome to the forum !!!!

[idy]

Welcome to the forum.

I would say, first build it and try it and then see if the buffered response is so awful that you need to fix it.

Then you can search the forum for "impedance control." A buffer mostly changes impedance, giving *usually* desirable high input and low output impedance. Adding a pot to the input of a pedal lowers the input impedance enough to load even a buffer, like the original did to a pickup.

A more complex arrangement can be called a "pickup simulator."
http://www.muzique.com/lab/pickups.htm

Both these are "anti buffers."

[fryingpan]

Welcome to the forum.

I would say, first build it and try it and then see if the buffered response is so awful that you need to fix it.

Then you can search the forum for "impedance control." A buffer mostly changes impedance, giving *usually* desirable high input and low output impedance. Adding a pot to the input of a pedal lowers the input impedance enough to load even a buffer, like the original did to a pickup.

A more complex arrangement can be called a "pickup simulator."
http://www.muzique.com/lab/pickups.htm

Both these are "anti buffers."

Simply lowering the input impedance of a pedal to load a buffer doesn't do much. A buffer (or any pedal really) usually has a mostly resistive output impedance for all intents and purposes (at least when compared to a passive magnetic pickup). Therefore, loading the buffer or the output stage of a pedal will not result in the frequency shaping that would result with a guitar as an input. Using a transformer as a way to simulate a pickup (ie. an RLC filter) is better but you should select a transformer which shows similar resistance, inductance and capacitance to a guitar pickup, otherwise you'll get a shaped response all right, but not necessarily the same you'd get with a guitar.

[fryingpan]

So basically what can you do? Really, unless the 42M/L019 transformer does actually have pickup-like specs, the most you can do is add a buffer stage right after the Rangemaster's input jack, then send the output signal to an RLC network. Try to find inductance and capacitance specs of your favourite pickup, as well as DC resistance; or you can sort-of calculate them, because manufacturers will often state DC resistance and resonant peak, and with something like this you can approximate the response, knowing that a pickup will have inductance in the multiple-henry range (a Strat pickup, apparently, is approx. 2H; a P-90 is 6H instead) and capacitance in the hundreds-of-picofarads; or just find a magnet-less wired bobbin, probably cheaper; then, like here, wire an equivalent resistor and inductor in series, and a capacitor to ground, take your signal from the inductor-capacitor node, replicate your volume and tone controls with some fixed components (or some pots if you actually want to modulate the impedance) and you have made a silent guitar in a box to attach to the input stage of the original pedal.

Or actually redesign the input stage of the original pedal altogether.

The Rangemaster is actually a pedal I really like; I like the way it sounds, if only it had a bit more gain (or at least you could dial a bit more gain) and it had a bit more treble; maybe one day I'll get round to redesigning it.

[iainpunk]

you could also use an actual pickup and a 25k pot to change the impedance matching.

make sure that the pickups is really shielded from outside influence tho.

cheers

[fryingpan]

you could also use an actual pickup and a 25k pot to change the impedance matching.

make sure that the pickups is really shielded from outside influence tho.

cheers

The problem is that with an actual pickup you are going to pick up (heh!) lots of stuff, for example stomping on the pedal itself (boom!). The most rational way to do it is to reengineer the pedal, methinks. And yet, you are going to lose the interactivity you usually have with your guitar. Of course, you could always wire it so that the volume control can be controlled with a volume or expression pedal.

[iainpunk]

i know from experience that it doesn't pop or make noise if you mount the pickup snugly inside the enclosure, wrapped in a simple cloth.

ow, i totally forgot to add,
remove magnet from pickup to inactivate it
use non-microphonic pickups (but that's a given)
place pickup INSIDE the enclosure to minimize its picking-up ability.

cheers

[Gus]

Search for the Lovetone brown source threads for ideas

[Dreadneck]

Ok, so it is in fact doable.
I do use the controls on the guitar a lot though.. Would it be better to put a buffer after the treble booster in that regard? Or how would the TB act with a buffer directly after it?
A pickup simulator is a good idea. Should work with expression pedals to clean up the guitar right?

[antonis]

Would it be better to put a buffer after the treble booster in that regard? Or how would the TB act with a buffer directly after it?

It essentially depends on particular TB configuration..

For a BJT CE amp, input impedance is quite low (mainly dominated by AC grounded Emitter) whereas output one is high (due to some kilohms Collector resistor value)..
For an FET CS amp, only the latter case stands..
For op-amp TB, neither of the above is an issue..

[iainpunk]

a range master's output impedance is 10k at worst, i wouldn't bother with a buffer after the RM.
if you put anything in between the guitar and the range master, you lose how it reacts to your volume control, no matter if that's a buffer or any other non-true bypass pedal. gain will still be dependent on volume control settings, but the tone/character change goes away.

cheers

[fryingpan]

Still, you could redesign the input stage so that it has an input level pot which can be bypassed by an expression pedal, that way you won't use the guitar's controls but you can still maintain the interactivity with a pedal, as long as the stage around that input level pot/expression pedal does respond to level changes.