Dual Reamper build

got asked to build a reamper - well, not one, but two.
the idea is that in a studio environment, it can be a lot of fun to run just about anything from your DAW through a pedal+amp setup again.
even more fun is the possibility to run everything in a nice wide stereo.

so, what we decided on:build two mono reampers in a single box, for convenience.
more convenience is provided by Neutrik Combo Jacks.
we want the possibility to run just one input to both outputs (mono in, stereo out), to use two different amps on one guitar at the same time, for example. or to layer two effect chains - you name it.
that does require the extra possibility to flip the phase, if you want it done right.

i thought about having 'master' functionality where one set of controls would control both paths at the same time, but since the whole idea of this setup is mostly to be able to use two different chains, they will probably require their own settings anyway. so that idea got scrapped.

a little google session gave me a couple of interesting links.
i used the same Edcor brand xformers as they do here, which basically uses a variation on the classic Jensen schematic. no need to reinvent the wheel there.

while Jensen proposes a 10K:10K, some schematics use a different ratio xformer, like 10k:600. terminating the secondary with a resistor closest in value (680R). i tried both varieties, and i must say the 10K:600 doesn't quite cut it for me, levelwise. it just doesn't provide the punch of the original signal to my ears.
the 10K:10K, on the other hand, provides ample level and will play very well with dynamic recording levels in your DAW.. read: if you're not pushing up against 0dB all the time it's about plug-and-play without too much fiddling with the level control. so that'll be the transformer of choice here.

as for phase switching, i found several people hinting at just swapping the wires of the (isolated) output jack. while that might do the trick in a standalone mono box, it didn't seem to play nice in the dual box i was building. so i flipped phase right at the secondary, before going into the level pot. that works well.

one thing i was sort of worried about, was feeding two transformers with a single signal, without a buffer of sorts. worried about impedance issues and whatnot.
testing with my own soundcard, there was no problem at all - no audible difference on the outputs while feeding one or two chains. no problem, no problem solved. hah.

here's the full schematic of the build.
who knows, someone might have a use for it.
someday.

huh? ...how long was i out for?

it's been over a year since the last post.
well, my last post here, not The Last Post.
managed to avoid that, thankfully.

and what a year it's been.
but i won't bore you with the details.

relevant stuff for this space:
played some shows, quit some bands, started some new ones.
made some records. and an exhibition.
cobbled a new-ish guitar together.
built a 40-slider autofading tremolo shizzamathing for Floris Vanhoof.
built a laughing organ for Michele Matyn.
more on those later.

will try to keep the updates coming more regularly.
and for now: a late happy new year.

Jagmaster. Jazzuar. Partscaster.

came across a pair of Teisco Gold Foils in the parts bin that had been out of use for several years.
hooked up a jack, tried them - and boy, do these deserve to be in a guitar!

so, on the lookout for a body donor guitar.
i ended up buying a Fender Classic Player jazzmaster body from Stijn Kenens, all-round good guy who also happens to be the luthier down the hall.
the Classic Player is the model where they moved the trem closer to the bridge to increase the break angle. so not truly 'vintage correct' - but whatever. this was never going to be vintage correct anyway, and it was on the cheap.
stripped it of its black finish, and out came a rather nice alder body (according to Stijn.)
i thought it looked just a little too light in colour, and as i was looking for a way to avoid heavy chemicals, i ended up staining it with walnut bistre. which turned out great - except you need to dilute it with water, so any oil or waterbased laquer i would put on there would instantly ruin my staining job. even after it dried. so far for the nontoxic plan - and i reached for the clear laquer spraycan.
which worked out just fine.

since i have this Squier VM jazzmaster with a built-in fuzz in lieu of the rhythm circuit, and since i'm sort of addicted to that, i was thinking of doing another effects-laden axe.
thing is, jazzmaster pickguards are a bitch to take off and put on - so jaguar style control plates seemed a nifty solution. making the wiring job easier, easier battery switching etc.
only problem there: i couldn't just put on a jaguar pickguard, because the body size, scale and therefore bridge position differs from the jazzmaster. and i couldn't for the life of me seem to find jazzmaster pickguards without pickup routing.. and the gold foils are considerably smaller than JM soapbars.
so i ended up routing a pickguard myself, based on a JM routing template i borrowed from stijn, cut short at both ends to make room for the chrome jag plates.
i slightly fucked up the routing for the pickup selector plate, but it's not too bad for a first attempt :) and no one will ever notice from a distance. and, oh yeah, whatever, anyway.

i bought myself a second hand squier jazzmaster Affinity neck.
seems to play ok, will see if it will hold for the long run.

tried several wiring options - phase switch, series, parallel, whathaveyou.
in the end i went with series wiring and a phase switch for the mid position.
the actual tonal difference between parallel and series was negligable, but series was way louder. and therefore better suited for the out of phase sound, where you will lose some volume anyway.
and hey, if this kinda wiring works for Brian May..

tried several values for the volume and tone controls, tried treble bleed circuits, extra resistors like in the original jag wiring, yadiyadiya. ended up with just a 500KB volume, ran the full hot signal into a 10K resistor + 500KA tone pot with a .01uF to ground. the 10K keeps everything from going into full closed-tone-pot-shutdown, a sound that's too dark and unusable to my taste.

now i just need a black tremolo tip, and i need to decide what to put in the rhythm circuit.
fuzz is always good, methinks - but trem can work with two controls just as well.. hmm.

pic below: still working on the tone control values at the time, by now it's got two knobs and that black trem tip. she's a beauty.