Maestro - Brass Master : the corrections  [schematic]

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Re: Maestro - Brass Master : the corrections

Postby theehman » 17 Oct 2010, 11:38

R.G. wrote:
theehman wrote:Thanks, Dan. That looks to be the incorrect original layout. My clone has Q6 inserted correctly but it looks like R22 and R27 weren't swapped around yet.

It's worth noting that the layout was always correct - the pinout for the darlington was incorrect on the factory schemo, so the body diagram on the parts diagram matched the factory schemo, which was incorrect. There was a typo reversal of two resistor numbers. I believe the history is here.

If it's a problem, I can dig out the archives for you.



So, basically, everything on that layout is good except for the orientation of Q6?
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Re: Maestro - Brass Master : the corrections

Postby R.G. » 17 Oct 2010, 22:27

theehman wrote:So, basically, everything on that layout is good except for the orientation of Q6?

Sixth item down at the index page at geofex:
http://geofex.com/FX_images/BrassBlaster2.pdf
The legend on the PCB you show, "10/01/97 - 9/06/01" indicates the first version of the board, which functions correctly as noted in this run of posts in this forum, this thread:
Re: Maestro Brass Master request
by DavidRavenMoon » Sat Jan 03, 2009 4:29 pm
OK, I got it working!

gtrgeek1 is correct... there seems to be nothing wrong with the original schematic (except for Q1's supply voltage being 8V and not 9V), and RG's PCB is correct.

So here's what I did... first there was the issue where on RG's layout sheet R22 and R27 are swapped. So I removed them and put them in the correct locations. That did little to help the Brass switch, but I at least heard something when I switched it. I had tried moving where R29 connected to C13, but I switched that back to the original location.

I decided to check Q6, since that was responsible for amplifying the output of the filter and sending it back to the circuit. I looked up the pin out for the Fairchild 2N5308.. voilà! I had it in backwards. It did match the layout as far as where the flat side was, but it had the emitter and collector swapped!

So I carefully unsoldered it and flipped it around.

Here's the results. First you hear the two settings of the Brass switch, then I flip the Harmonic switch, and then switch the Brass switch again. You go from very full to very thin, just like the real thing. The very thin setting is what Squire used a lot, as in the example I play from Close to the Edge, which has the dry signal mixed back in.

Brassmaster Fixed

I don't have a real one in front of me to compare, but going from memory, this is pretty much nails the tones I remember using.

Yay!
Re: Maestro Brass Master request
by R.G. » Sat Jan 03, 2009 10:24 pm
There's no matching to be done. They're all doing different jobs, so matching is superfluous.

I'm still kinda miffed that I just believed the pinout for the darlington that Maestro put on the schematic. Boy, talk about a silly beginner mistake to make. I know better than that and still didn't go look it up. That appears to be problem with any of these ever built.

The wringing-out exercise has resulted in simulating the entire mess, reworking and updating the original layout, and the (re)design of the function into an opamps-version that should be less temperamental and will have far fewer wires hanging off the board - I cold-switched the twin t filter.

More writing to do, but I'll put the whole mess on GEOFEX when I get it documented. David and Gtrgeek were absolutely instrumental in getting this done; I've never seen a Brassmaster in real life, so getting real, on-the-spot data helped filter out some of the hash.
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Re: Maestro Brass Master request
by rcubed » Sun Jan 04, 2009 12:22 am
Awesome. So by R.G., you mean R.G. Keen's layout dubbed the Brass Blaster, the PCB that General Guitar Gadgets sells? 'cause that is the one I have but have not soldered up yet. Are you using this layout: http://www.generalguitargadgets.com/dia ... master.pdf ? If it's just Q6, then maybe R22 and R27 are correct?
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Re: Maestro Brass Master request
by DavidRavenMoon » Sun Jan 04, 2009 12:34 am
Yes, I bough the board from GGG. I'm using that layout in the link (geo_brassmaster.pdf). Install R27 where it's marked R22 (between R28 & C9) and install R22 between R26 & R18 where it's marked R27. If you look at the schematic you will see they are switched in the layout. The schematic is correct. I followed the traces on the board to verify this.

Check the 2N5308 you are using. The Fairchild part I used had to be installed with the flat side facing the left, which is the opposite of the layout. You want the emitter to be the top pin, and the collector to be the bottom. I neglected to check this before I installed it, and didn't think about it after.


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Re: Maestro Brass Master request
by rcubed » Sun Jan 04, 2009 12:49 am
I just changed around Q6 and there it is. Everything works. I feel about calling the schematic wrong in terms of the diagramming of the circuit. Turns out the only wrong is the pinout of the 2N5308 on there with respect to the Fairchild parts we are using. Glad to finally get this all figured out. Thanks for all the help.
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Re: Maestro Brass Master request
by R.G. » Sun May 03, 2009 6:51 pm
controller700 wrote:I would prefer to use R.G.´s updated layout, but cannot find the PCB files for it! The PCB at GGG looks not the same as in R.G.´s new layout... any suggestions?

Same suggestion as by email. The board from GGG has been confirmed to produce correct sounding units when corrected with the two or three steps noted at GEOFEX. Those consist of
1. turn around the darlington 180 degrees. The factory schematic shows the incorrect pinout, and I correctly used the incorrect pinout.
2. two resistors are swapped.
3. I deliberately made the switching easier by changing switching between two resistors into paralleling two resistors. By actual builders comments, this produces little change, but by recalculating the resistors you can get *exactly* the same values as in the original.

No one has licensed the new layout, and I don't make PCBs to sell. If one of you wants to buy a license for making the new layout, cool. Contact me.



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Re: Maestro - Brass Master : the corrections

Postby jwpartain1 » 06 Jan 2011, 22:38

Hello! Just received one of these pedals today, as a bass-friend of mine is letting me borrow it. I'm experiencing a problem with it though. The signal fades in/out randomly while not in bypass while the bypass signal is fine. It's playable yet unpredictable and unreliable. This bass-friend claims to have stepped on the footswitch too hard and pushed it through the casing (which is now fixed in place). I'm having doubts that the footswitch is the problem what with it fading in and out, without any funny pops or crackles. Any ideas?

Also! I was wondering what I could play with to make the pedal less.. IN YOUR FACE. Whenever the SENSITIVITY is above 9 o' clock, it's all fuzz-gated-madness from there. Not saying it's not cool, but where would I start to making this pedal less of a one-trick-pony?

Thanks, fellas and lady-fellas. I enjoy reading and learning in this forum and hopefully I'll have something useful to offer sooner or later. :)
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Re: Maestro - Brass Master : the corrections

Postby DavidRavenMoon » 11 Sep 2011, 17:28

jwpartain1 wrote:Hello! Just received one of these pedals today, as a bass-friend of mine is letting me borrow it. I'm experiencing a problem with it though. The signal fades in/out randomly while not in bypass while the bypass signal is fine. It's playable yet unpredictable and unreliable. This bass-friend claims to have stepped on the footswitch too hard and pushed it through the casing (which is now fixed in place). I'm having doubts that the footswitch is the problem what with it fading in and out, without any funny pops or crackles. Any ideas?

Also! I was wondering what I could play with to make the pedal less.. IN YOUR FACE. Whenever the SENSITIVITY is above 9 o' clock, it's all fuzz-gated-madness from there. Not saying it's not cool, but where would I start to making this pedal less of a one-trick-pony?

Thanks, fellas and lady-fellas. I enjoy reading and learning in this forum and hopefully I'll have something useful to offer sooner or later. :)


I had one of these back in the day, and now have the RG version. The trick is to start off with the fuzz level on zero, set your bass level, and then mix the fuzz in. I used to keep the sensitivity on the low side for more percussive tones. For fuzzier tones I would switch to one of the thinner fuzz tones and blend that in. It's a very bright fuzz, so you only need a little.
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Re: Maestro Brass Master request

Postby deeno » 12 Nov 2011, 10:25

I took the liberty of making all the traces on this layout black and adding holes on the pads. It's also resized to print at 134x63mm (at least from Photoshop) which I measured the original to be from the gutshot using the the 9V battery (49mm long) as a reference.
Image[/quote]

I guys,
I'm new on this forum, I write from Italy.
I read all the discussions on the Maestro Brassmaster and I want to make one of this.
Much files are no longer visible (like the layout in the quote above) because this discussion is old.
I wonder if you can send me the files via e-mail or re-post here.
Thanks for any help and for your grat work!
Regards
Dino
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Re: Maestro Brass Master request

Postby xaxxop » 14 Feb 2012, 13:24

unbeliever wrote:Here are some pdfs produced from the file gtrgeek1 sent me. Do I need to do a PCB at the right size also? Let me know. And good work!

http://prophecysound.com/freestompbox/BrassMasterOverlay.pdf
http://prophecysound.com/freestompbox/BrassMasterPCB.pdf


Morning, the links aren´t working, anybody can to put new links? thank you so much people for share. have a nice day!
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Re: Maestro Brass Master request  [schematic]

Postby DavidRavenMoon » 14 Feb 2012, 14:29

xaxxop wrote:
unbeliever wrote:Here are some pdfs produced from the file gtrgeek1 sent me. Do I need to do a PCB at the right size also? Let me know. And good work!

http://prophecysound.com/freestompbox/BrassMasterOverlay.pdf
http://prophecysound.com/freestompbox/BrassMasterPCB.pdf


Morning, the links aren´t working, anybody can to put new links? thank you so much people for share. have a nice day!


Luckily I saved a copy!
You do not have the required permissions to view the files attached to this post.
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allan_belt (23 Jul 2012, 01:11), modman (11 Jun 2012, 21:49), xaxxop (14 Feb 2012, 15:00)
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Re: Maestro - Brass Master : the corrections

Postby chicago_mike » 04 Jun 2012, 21:13

Are the fuzz controls sensitive? Like REALLy sensitive?

I built the GGG one and finally after like a year, boxed it up. :D

Also..the dry sound, could be me, but the dry sound is just a tad thin. And just a sco' noisy..or trebly.

but The switches work and everything does as its supposed too.


Now to make a clone of the vintage one with mojo parts... :roll: :applause: :horsey:
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Re: Maestro - Brass Master : the corrections

Postby DavidRavenMoon » 04 Jun 2012, 23:36

chicago_mike wrote:Are the fuzz controls sensitive? Like REALLy sensitive?


Turn down the sensitivity knob. You get some more interesting tones with it down. Originally the clone layout assumed that would be an internal trim pot, but you really need to adjust that to get different tones.

I built the GGG one and finally after like a year, boxed it up. :D

Also..the dry sound, could be me, but the dry sound is just a tad thin. And just a sco' noisy..or trebly.

but The switches work and everything does as its supposed too.


The bass channel doesn't have the best fidelity. Even on the original I used to own, it lacks a little low end, and is a bit grungy sounding. But you can use that as an effect too.

I used to plug an Electro Harmonix Mole bass booster into the Brassmaster. That gave a thick low end and then you could mix the fuzz into it.
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Re: Maestro - Brass Master : the corrections

Postby chicago_mike » 05 Jun 2012, 02:52

Gotcha. :)

I do have a blender pedal...may as well put it thru that.
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Re: Maestro - Brass Master : the corrections

Postby rudeez » 21 Mar 2013, 11:37

reviving a dead thread!
iv'e etched the pcb avilable from the GGG site and also made a vero from sabrotones page:
http://www.sabrotone.com/wp-content/uploads/2012/12/BrassMaster.gif
i have the same issues with both builds, i get clean signal through the circuits but nothing else, volume pot works and the other pots do some slight change in tone but nothing more.
iv'e used the original parts specefied, 2n5308 and the 2n3392, the transformers reads TM018-R on them.
iv'e gone over the circuits several times checking for bridges etc but can't really find anything. also tried flipping the 2n5308 without any difference.
im out of ideas and would be really glad to hear if someone have suggestions for me, it's strange that the circuits behave the same.
has someone else experienced this or have suggestions? im really frustrated with those builds now...
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Re: Maestro - Brass Master : the corrections

Postby Emanuele II » 24 Jul 2013, 15:39

I was reading the whole topic to correct a clone I made years ago, wich never sounded good..so looking at the schem I wondered if the part of the BRASS swtich is correct..won't it be more sensed if placed beetween C13 and C14 instead of misbiasing Q7?
I'm referring to this schem http://www.geofex.com/PCB_layouts/Layouts/Maestro_BB-1_Bass_Brass_Master.jpg
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Re: Maestro - Brass Master : the corrections

Postby DavidRavenMoon » 24 Jul 2013, 18:22

Emanuele II wrote:I was reading the whole topic to correct a clone I made years ago, wich never sounded good..so looking at the schem I wondered if the part of the BRASS swtich is correct..won't it be more sensed if placed beetween C13 and C14 instead of misbiasing Q7?
I'm referring to this schem http://www.geofex.com/PCB_layouts/Layouts/Maestro_BB-1_Bass_Brass_Master.jpg


Everything else is correct. The only mistake was the filter driver transistor being backwards.
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Re: Maestro - Brass Master : the corrections

Postby Emanuele II » 25 Jul 2013, 00:01

DavidRavenMoon wrote:
Emanuele II wrote:I was reading the whole topic to correct a clone I made years ago, wich never sounded good..so looking at the schem I wondered if the part of the BRASS swtich is correct..won't it be more sensed if placed beetween C13 and C14 instead of misbiasing Q7?
I'm referring to this schem http://www.geofex.com/PCB_layouts/Layouts/Maestro_BB-1_Bass_Brass_Master.jpg


Everything else is correct. The only mistake was the filter driver transistor being backwards.

Cool! it sounds a lot better in the way I "corrected" it! :roll:
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Re: Maestro - Brass Master : the corrections

Postby DavidRavenMoon » 25 Jul 2013, 01:56

Emanuele II wrote:Cool! it sounds a lot better in the way I "corrected" it! :roll:


"Better" is subjective. But does it sound like a Brassmaster?

I owned a real Brassmaster, and the GeoFX/GGG version sounds like the real thing as long as you put the transistor in the right way. The schematic shows the transistor pins incorrectly, but maybe that's what the part was like that they used.
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Re: Maestro Brass Master request

Postby modman » 11 Feb 2015, 15:06

ElectricCo wrote:I' built this pedal using GGG schematic, is it normal that harmonic switch involve also a big volume delta ?
I've already flipped the 2N5308 but still have volume difference issue.
What I should check ? Or it is ok ?
Thanks

DavidRavenMoon wrote:
rcubed wrote:Awesome. So by R.G., you mean R.G. Keen's layout dubbed the Brass Blaster, the PCB that General Guitar Gadgets sells? 'cause that is the one I have but have not soldered up yet. Are you using this layout: http://www.generalguitargadgets.com/dia ... master.pdf ? If it's just Q6, then maybe R22 and R27 are correct?

Yes, I bough the board from GGG. I'm using that layout in the link (geo_brassmaster.pdf). Install R27 where it's marked R22 (between R28 & C9) and install R22 between R26 & R18 where it's marked R27. If you look at the schematic you will see they are switched in the layout. The schematic is correct. I followed the traces on the board to verify this.
Check the 2N5308 you are using. The Fairchild part I used had to be installed with the flat side facing the left, which is the opposite of the layout. You want the emitter to be the top pin, and the collector to be the bottom. I neglected to check this before I installed it, and didn't think about it after. :oops:
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Re: Maestro Brass Master request

Postby ali_b » 10 Nov 2016, 14:32

rcubed wrote:I did a couple of mods. I added the suggested input and output pull down 1M resistors. This virtually eliminates the sound of the switch coming through the signal when the switch is toggled. I also increased the values of the input and output caps (C1 and C7) and the caps going into the sensitivity and bass volume controls (C2 and C8). Retains the lowend of my 5-string bass very well.


What cap values would you suggest to maintain the low end integrity of the dry signal?
Any other suggestions?

thanks
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