19 thoughts on “Request: Maestro Brass Master

  1. I built this today, after failing to make a pcb from England work.

    It fired right up!

    It Sounds killer with a P bass!

    Thank you SABRO TONE!

  2. I’ve had a quick look at the discussions and it sounds like GGG had a mistake on an earlier schematic. I’ve based the layout on an updated GGG schematic that also matches the “correct” schematic from geofex, so not sure this is the problem. I’d happily build this right away to help you find the problem, but I’ve promised to build this one with a couple of friends and it’s taking a while for us to get there, sorry.

  3. Btw, the resistors that need swapping according to the FSB thread are R22 and R27, they need to change place with each other. Also the thread states that the darlington 5308 need to be turned 180 degrees on the GGG design.

  4. I had two sets of parts for this build so there was different ones either of them.
    Seems like the -R transformer differ in terms of pinouts, i will try to turn it 180 degrees and se if that helps. For transistors i’ve quadra checked them, only problem i can see there is if they’re a bad batch or the pinouts are messed up by having E or B in the middle position. I also tried swapping the two resistors noted in the FSB thread which seems to be wrong in the GGG layout but didn’t help me really. I will try to make another board of this, tonight maybe and use the suggested resistor swap as well as turning the 5308 180 degrees and also check the transformer, im getting new batches of the transformers and 5308’s in the mail today from banzai this time. If you by any chance build this before i complete the mystery could you please tell me? 🙂

  5. Sorry to hear this, Jimmie. Since you got the same result from both vero and GGG board I’m thinking it’s an issue with one or more parts rather than the layout itself. I guess the most obvious suspects are, as you note, the transformer or the transistors, but I’m afraid I have very little to offer at this point other than searching for and reading build reports from others on the GGG project. Just to rule things out, did you reuse any other parts than the transistors and transformer between the two builds, and if so might it be that one of the other components are broken?
    I have scheduled this project as my next one, and when I do get around to trying it I’ll have more feedback. Getting a bit worried now, though, and hope we can solve this.

  6. I’m really frustrated by this build now 🙁
    I even went on and etched the PCB from GGG but had the same results as with this verodesign. My transformer reads TM018-R on the side of it, bought from musikding, that is the correct one right? Other then that i tripplechecked the pinouts of the transistors etc, i get dry signal through both the Vero build and the PCB but nothing else, just that the volume of the dry signal is lower then the bypassed signal. I probed it as well and couldent hear anything besides a clear signal at some points, no fuzz tones at any place.
    What to do? 🙁
    Could the transistors be swapped for something else to try? The ones im using now is the ones specefied by your Vero design.
    Thanks Harald!

  7. Jimmie, did you add all the trace cuts too, even the ones under the transformer? There’s two things I’d try at this point; first a voltage reading of the transistors looking for anomalies. And also try injecting a signal or strumming a guitar while following the audio through the circuit and see where it stops. Make yourself an audio probe if you haven’t already (more on that in the debugging section), get the schematic from http://www.generalguitargadgets.com or http://www.geofex.com (part numbering matches the vero layout) and use the schematic as a map as you listen to the signal from input to output across your vero build. Since you apparently have a “dry” signal I’d pay special attention to the audio path through the transformer part of the circuit; the one that starts at the sensitivity pot (lug #2) and onward.

  8. Yup, rev 1 version.
    Double checked all the pinouts and those seems ok. I have no idea how to continue this. I looked for everything really. The strange thing is that the signal passes clean.

  9. Was just about to suggest you check the transistor pinouts… I’ve now compared the layout to both the GGG and geofex schematics, and it all looks good. Just to be sure, you’re working off the “rev. 1” layout, correct?

  10. found nothing wrong with the pinouts of the trannies and all parts are on the right spots, either i must have made a huge mistake with the offboard wiring or there have to be a mistake in the circuit haha. tell me when you know more!

  11. great! in the very moment im searching for errors in my build and so far nothing, just cleared all the strips for possible bridges and nothing changed, just checked all the cuts and counted and currently going over each component and pinout of the transistors.
    as i said, only working knob is the volume and the signal is pretty much like the bypass signal, only diffrence is that the effected signal is a little bit darker and lower in volume but not massively.

  12. Just finished this and plugegd it in, resulted in a dry signal which is pretty much the same as the bypass signal, only pot working is the volume one for me. Might be that i have a unwanted bridge somewhere, i dont know really. Could be the pinout of the trannies as well. Could you take a quick look and see if the design looks alright?

  13. Probably giving this a go shortly, i’ll let you know if you can verify it 🙂

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