hi people,
there have been some rumours about the brassmaster lately, see this thread for instance: http://www.diystompboxes.com/smfforum/index.php?PHPSESSID=b42a513333f2785ed4ecd0558b791fb8&topic=56690.0 (http://www.diystompboxes.com/smfforum/index.php?PHPSESSID=b42a513333f2785ed4ecd0558b791fb8&topic=56690.0)
i am the guy who was mentioned in this thread that found out about the mislabelled resistor, here is a link to a pic that has the info (also missing cap and resistor labels written in there):
http://forum.musikding.de/gallery/displayimage.php?album=random&cat=10491&pos=-2236 (http://forum.musikding.de/gallery/displayimage.php?album=random&cat=10491&pos=-2236)
i built my brassmaster according to the pic i posted (long ago). my harmonics hi/lo switch works in the brass hi position and makes a significant change to the sound, it get´s a bit brighter. generally, the brass lo setting yields a lot more volume in my build, but then again, i never heard an original.
today i tried to implement the changes that mountainking suggested in the linked thread above, and it did not work. the harmonics hi/lo switch stops working when the changes are done.
i reverted my build to working condition.
anybody else that has tried that and can confirm ?
the whole thing got me interested again because there´s a lot of brassmaster talk over at the talkbass.com forum, a company is building brassmaster clones, they say that the schematics on the net are wrong (including the one over at geo) and that they traced an original. in their build (from what i can tell from the soundsamples), the harmonics switch also seems to work in the brass lo position ...?...
comparing the factory schematic and r.g.´s version, can somebody tell me why the twin t filter section is different in the geo version ??
cheers,
lowstar
Hmmm I didn't know anyone had suggested a solution... Yeah, that switch is pretty useless as is. Would be nice if it did something noticable... all that trouble getting a 3pdt toggle... :P
the switch IS WORKING in my build, because of the changes/mistakes i found (check the link).
cheers,
lowstar
Well I can tell you why it's different in my version - I worked from the factory schemo which may or may not be what they actually built. I did not trace one out. I modified how the switches were used to simplify the switching. There is always the possibility that I made a mistake, as I do that from time to time.
I'd be interested in seeing what the actual manufactured version looks like. Never seen one in real life.
Quote from: lowstar on May 17, 2007, 12:59:04 PM
the switch IS WORKING in my build, because of the changes/mistakes i found (check the link).
cheers,
lowstar
OOOHHH!(the other link!) Wow, thanks... 8)
is there anybody on this board with a real maestro brassmaster ? with some good pics, we could solve the mystery once and for all... :icon_biggrin:
cheers,
lowstar
Quote from: lowstar on May 17, 2007, 12:42:38 PMtoday i tried to implement the changes that mountainking suggested in the linked thread above, and it did not work. the harmonics hi/lo switch stops working when the changes are done.
Did the changes fix the problem with the brass switch? Also, how does changing the way the components are labeled/numbered change the way the circuit work? I'm not trying to be a smart ass, I'm just alittle confused by what you wrote.
Alan
yeah, my post is quite long... ;)
if you look at my post, you see in the link to the pic that what is called r22 is actually r27...so if you put a 22k resistor in the place where the 6.8k should have gone, it might make a difference...(plus, vice versa, whatcha gonna put in where the 6k8 should be ? maybe the 22k)
QuoteAlso, how does changing the way the components are labeled/numbered change the way the circuit work?
if a component on the schem is labelled differently than on the layout (e.g. the layout has only numbers and no values), and the numbers don´t correspond, it will change the way a circuit works.
to answer your first question: when i implied your suggested changes, the switch stopped working. after i put the board back to the original state, the switch worked again.
cheers,
lowstar
Hey I just looked at this thread again http://www.diystompboxes.com/smfforum/index.php?PHPSESSID=b42a513333f2785ed4ecd0558b791fb8&topic=56690.0 and I looked the changes Moosapotamus made to the filter section again and I think what he drew was more likely correct, then the changes I suggested. Both changes will give similar results but Charlie's will probably yeld better ones. I thought he was trying to show the changes that I was suggesting and since it wasn't exactlly what I was trying to describe I guess I didn't take a good look at what he had draw. I should have taken a closer look.
Quote from: lowstar on May 17, 2007, 04:08:02 PM
yeah, my post is quite long... ;)
if you look at my post, you see in the link to the pic that what is called r22 is actually r27...so if you put a 22k resistor in the place where the 6.8k should have gone, it might make a difference...(plus, vice versa, whatcha gonna put in where the 6k8 should be ? maybe the 22k)
QuoteAlso, how does changing the way the components are labeled/numbered change the way the circuit work?
if a component on the schem is labelled differently than on the layout (e.g. the layout has only numbers and no values), and the numbers don´t correspond, it will change the way a circuit works.
to answer your first question: when i implied your suggested changes, the switch stopped working. after i put the board back to the original state, the switch worked again.
cheers,
lowstar
Ok, I understand now. Thats makes things much clearer. Sorry I'm abit of a scatterbrain sometimes.
Alan
Quote from: lowstar on May 17, 2007, 12:42:38 PM
i built my brassmaster according to the pic i posted (long ago). my harmonics hi/lo switch works in the brass hi position and makes a significant change to the sound, it get´s a bit brighter. generally, the brass lo setting yields a lot more volume in my build, but then again, i never heard an original.
So, you built yours based on the pic at Musikding? What layout did you use?
Quote from: lowstar on May 17, 2007, 04:08:02 PM
...so if you put a 22k resistor in the place where the 6.8k should have gone, it might make a difference...
"...might make a difference..."? I thought you just wrote that it DID make a difference.
I'm sorry... I'm still a bit confused about what you actually did to get yours to work. RG's layout at GGG, for example, is based on the scheme that the pic at Musikding was taken from. So, I still don't see how switching around the component labels would make any difference. What am I missing?
BTW - mountainking... In the drawing I posted in that other thread, I actually was trying to interpret the fix that you were describing. 8)
~ Charlie
Quote from: moosapotamus on May 17, 2007, 04:36:54 PMBTW - mountainking... In the drawing I posted in that other thread, I actually was trying to interpret the fix that you were describing. 8)
~ Charlie
Thats what I was trying to say. You drew what you thought I was trying to describe, but you ended up drawing something alittle different and I think what you drew might actually work better then what I suggested. Make sense?
QuoteYou drew what you thought I was trying to describe, but you ended up drawing something alittle different and I think what you drew might actually work better then what I suggested. Make sense?
Ah... I know that you think you understand what you think I meant, but I think that what you understood means that I said it wrong...
In other words - gentlemen, which schematic is correct with the component values in the right places? I can correct nomenclature and labeling easily enough once we know which component value connects where.
Yup 8)
~ Charlie
I've had mine in pieces ever since I started that thread. I also couldn't get the changes suggested in there to work. I'll try this one, hopefully that will get it up and going. I actually know a guy who has a brassmaster, I should see if I can get some gut pics of it.
QuoteSo, you built yours based on the pic at Musikding? What layout did you use?
who said i built the thing according to a layout at musikding ? the pic shows the r22/r27 switch, i used RG´s layout.
QuoteRG's layout at GGG, for example, is based on the scheme that the pic at Musikding was taken from.
of course it is the same scheme of RG´s project file, i used a section of the scheme to show which resistors you have to switch, just like you did in the thread of mountainking.
Quote"...might make a difference..."? I thought you just wrote that it DID make a difference.
of course it DOES make a difference, i used the word "might" as a more general way of describing that using 22k instead of 6k8 will make a difference, like saying "crashing a car with 220mph instead of 68mph
might make a difference in terms of how badly you´re gonna be injured".
QuoteSo, I still don't see how switching around the component labels would make any difference. What am I missing?
all that you are missing you can actually read in my post before, but i´ll care to elaborate some more. RG´s project file has a schematic with numbers and values, and a layout with just numbers. so, it happens that r27 and r22 are switched...the resistor that you will solder in as r22 should actually be 6k8 and not 22k, because the 22k resistor is numbered r27 on the layout, the schem says r22...so i posted the corrected labeling...and, chances are when somebody uses the 22k for r22, he might use the 6k8 for r27...oh god, i used the word "might" again... ;D
QuoteIn other words - gentlemen, which schematic is correct with the component values in the right places? I can correct nomenclature and labeling easily enough once we know which component value connects where.
QuoteI'll try this one, hopefully that will get it up and going.
thanks, that´s my intention and the reason for this whole thread. try out the values that i posted in the little pic, see if it works...i´m eager to find out.
QuoteI actually know a guy who has a brassmaster, I should see if I can get some gut pics of it.
that would be fabulous ! :)
cheers,
lowstar
Just throwing this out there...
I looked at the geofex.com pdf and if I were to build as-is, I'd be in a little trouble. Q7 is flipped on the parts layout. E should going to R18 R22/27/whatever C11. Also, the trace from C12 should stop at R28. The schematic does not show C12 connecting to R28/R25/C10/switch.
I'd love to build one of these some day.
I think mountainking may have nailed it. With his solution you get this:
http://users.rio.com/senorris/junk/brasstwint.gif
The other way you got me and a bunch of poor electrons scratching our heads...
[quoteis there anybody on this board with a real maestro brassmaster ? with some good pics, we could solve the mystery once and for all... ][/quote]
I've got one. It'll be at least a week until I can get a chance to look into it, if I can even remember where it is. I finally got a digital camera so I should be able to post pictures or at least read component values.
I frankly don't see what the big deal is about this pedal. It sounds like about a million other fuzz pedals to me. I bought it for $40 after it sat in a music store for about a year (mind you this was 10 or 15 years ago, but even then Big Muffs and Tube Screamers were selling for more than that).
Quote
I frankly don't see what the big deal is about this pedal.
On guitar, it just sounds like a bad fuzz, but on bass the thing is incredible. It lets thru a whole lot of bottom end, and will do a decent octave/fuzz even when driven by a Hog's Foot. It likes to be driven by other pedals in general! Also, I've found the gating to be very practical... when ya stop playin this thing shuts up right away!
What it lacks in sustain can be made up for by driving it with a compressor- instant transformation into a distortion.
In fact, the more I use it, the more I like it. It has bumped off my pedalboard both my ds-1 and BMP.
Oh, BTW, ya know that tuba sound Jack Bruce got in early Cream? Drive the Brassmaster with a Hog's Foot, then cut the highs after the Brassmaster yet again, and it NAILS that sick sound. :icon_twisted:
I've found that just adding an ordinary volume and tone(lpf, it already has a hpf) to the tail end of it both makes it more practical and more versatile.
All this without the switch being functional! So, yeah, I believe this is a worthy investigation! ;D
Hey guys, I just wanted to let you know that I am now determined to figure this thing out and over the next few days I'm gonna try to do some experimenting and I'll get back to you with my results. Until then, here are some things that I'm thinkin' after doing a little experimenting last night. I will do my best to explain this in a way that will make sense.
First, I think that the brass switch connections on the factory schematic http://filters.muziq.be/files/schematics/maestro_bb-1_001.gif are drawn correctly. If you look at it, you'll see that each pole of the switch puts one of the resistors into the circuit while taking the other one out. On RG's schematic one resistor is always connected in the circuit and the switch simply connects the other resistor in parallel with it. Now someone with a real brassmaster could easily figure this part out for us by looking at the brass switch and letting us know what kind of switch it is and how many of its terminals have something connected to them. Also, the factory schematic shows (parts list in upper left hand corner) that the brass switch is a dpdt switch. This obviously is another mistake, although I'm really starting to think that these mistakes/errors were intentionally done. Doesn't it seem strange that the only part of the circuit that isn't drawn carefully and in an easy to understand way, is the filter section?
Second, I'm pretty sure that there is a cap missing from the schematic. With the changes that I had suggested in the other thread, there needs to be a coupling capacitor between the twin t filter and the "filter amp." Without a coupling cap the "filter amp" will get mis-biased and will result in some bad sounds. I've tested this theory. With the cap, deep solid low end heaviness, without the cap, harsh nastiness and other bad things.
Anyway, I probably won't get a chance to get back online til early next week, so hopefully when you hear back from me I'll have some more solid information for you guys. Take it easy.
Alan
Here's a pic I had saved from a long time ago. Unfortunately I have no trace side. I count 17 caps, which is how many are in the schematic.
(http://homepage.mac.com/sonicvi/BrassMasterInside.gif)
OK, I got out the schemo and the circuit simulator.Yes, there are several errors in the factory schematic. It ... can't... work properly that way.
Here are a couple of big ones:
1. The switch is a 3PDT slide, as the photo shows and as the schematic shows, not a DPDT as stated on the parts notes.
2. I believe the 82K at the base of Q4 is on the wrong side of the 0.1uF cap leading to that base from the transformer.
3. I thought there should be another cap between the 150K attached to switch 2 and the pole of switch 3. It turns out that I'm probably right, but that it makes not too much difference in the waveforms coming out for small signals. That's a maybe. I'm guessing that this is the cap that Alan thought was missing. Maybe so. Where did you put your cap, Alan?
I think that if I did another layout, I'd use either a CD4066 or CD4053 switch to do the three sections of SW3.They're all at a reasonable bias voltage and should work fine. An SPST or SPDT would then select the filter frequency.
The filter amp produces a peak at either 700Hz or 3.2kHz depending on the Brass 1/Brass 2 setting. Harmonics high/low dumps in more bass content when the switch is connected. I'm guessing that's the "harmonics low" setting.
The diode ring and transformer modulator produces odd squarks of ringing on every other zero crossing. I may not have had the signal levels right.
QuoteR.G. The diode ring and transformer modulator produces odd squarks of ringing on every other zero crossing.
Squarks?!
I have no idea what a squark is but I'm intrigued!
The filter type and twin-T connection needs to be resolved first!
This thread redraws the filter connection errors as a twin-t notch filter:
http://www.diystompboxes.com/smfforum/index.php?PHPSESSID=b42a513333f2785ed4ecd0558b791fb8&topic=56690.0
This thread redraws the filter connection errors as a twin-t band-pass filter:
http://www.diystompboxes.com/smfforum/index.php?topic=48636.0
My understanding is the "brass" voicing is a band-pass filter. RG's comments imply that too.
Quote from: George GibletMy understanding is the "brass" voicing is a band-pass filter. RG's comments imply that too.
I'm sorry, I wasn't being clear.
It is resolved. It is definitely a bandpass filter, the twin T being a notch filter in the feedback path of the filter amp. The notch in the feedback path is converted to a forward loop peak, just as in the Twin T wah at GEO.
The peaks are either about 19db at 3.2kHz or about 8db at 700Hz, depending on the Brass 1/2 setting.
The picture helps as well. I used too big a transformer. I could have picked a smaller one, but I was trying for as much bass response as possible, it being a bass effect.
hi r.g.,
QuoteThe filter amp produces a peak at either 700Hz or 3.2kHz depending on the Brass 1/Brass 2 setting. Harmonics high/low dumps in more bass content when the switch is connected. I'm guessing that's the "harmonics low" setting.
did you run the simulation with the circuit as in your schematic/layout ?
does the harmonics hi/lo work in both settings of the brass hi/lo switch in your simulation ?
if the filter works as it is supposed to in your layout (=if the filter part is right in my build), i could try to make those changes that you suggested in points 2 and 3 and listen to the result...
funny how this thread fell asleep again...
cheers,
lowstar
So... basically, so far it's the factory schematic's switching, move 1 cap, and add another...? Am I missing something?
Hey everyone, I'm fairly new around here, but watching this thread with interest. Hoping someone can sort out this mystery once and for all. I made one from GGG, and like everyone else got it partially working. Even partially though, this sounds great on bass, so I'm hoping for a fully functional unit. Thanks to everyone for providing this info! :icon_biggrin:
someone should ask Josh at Malekko what schematic he and Barker based the B:Assmaster on. I hear its a pretty Convincing clone.
Quotefunny how this thread fell asleep again...
I guess it depends on how urgently you want a brassmaster how funny it is.
I'm waiting to see what mountainking thinks before I do any work that might then need to be trashed.
Quote from: $uperpuma on May 25, 2007, 05:34:47 AM
someone should ask Josh at Malekko what schematic he and Barker based the B:Assmaster on. I hear its a pretty Convincing clone.
They reversed it from an actual pedal. He hasn't told me wha's wrong with the GGG/Geofex layout but he's offered to mod my clone for me so it must be something pretty simple that's off. My switches both make big changes in the sound so I haven't taken him up on it yet. I may next time to drive over to Austin.
Does anybody actually have a non- cloned one? The pic SonicVI posted is the first and only time I've ever seen any part of one...(thanks for that, very interesting!). Just curious... because a pic of the other side of the PCB(and a tedious reverse engineering) could clear this up a bit...
Yeah, I guess that's a stupid question, but I went and asked it anyway... ::)
QuoteDoes anybody actually have a non- cloned one?
Yep, that's really the question.
I can diddle the factory schem into what I think it should be, but who knows what they really were?
Then again, if it sounds good, I guess it dosen't make any difference. As I see it, there's a possibility that an educated guess would sound better than the origional...
Origional isn't always necessarily better... Even Edison didn't always find the BEST way to implement his inventions, although he would never dream of admitting that.
>It is resolved. It is definitely a bandpass filter, the twin T being a notch filter in the feedback path of the filter amp.
Thanks for the clarification.
Hey guys, sorry it took me so long to get back to you, but I've been real busy this past week. Looks like some you figured out some of the same things I did. I was hoping to get back with all of the answers, but honestly all I really have to offer is more possibilities. I spent several hours experimenting so I guess I might as well tell you guys what I did. Hopefully it won't just be a confusing collage of words.
My initial thought was that the actual twin t filter was passive and that it was connected between the "filter drive" and the "filter amp". The first thing I did was to tack just the filter circuit on to the output of another bass fuzz that was already on my breadboard and it gave it a nice deep sound. Next I breadboarded the brass master(with the filter hooked up the way I described in the first sentence). It sounded lousy, lots of harsh highs and very little low end. So I sat back and stared at the factory schem some more. I noticed(as mentioned) that filter was connected in the feedback loop of the "filter amp" which would make the filter active. I had noticed this before, but the filter section of the schematic is so screwed up that I figured that this was also a mistake. Well I figured wrong, because once I placed the twin t filter in the feedback loop of the "filter amp" (look at the colorsound inductorless wah schem) I got some cool resonant filter sounds and the brass and harmonic switches both seemed to change the sound in a useful way. Thanks to SonicVI we know that the brass switch is definitely a 3pdt, which makes sense, and that there are no caps missing from the schematic. Let me try to explain again why I thought there was a missing cap. Between the output of the "filter drive" and the input of the "filter amp" there needs to be a dc blocking cap to avoid mis-biasing problems. Now since there are no missing caps from the schem then the .05uf must go where I thought the "missing cap" was suppose to be right?, but on the schem it seems to show the .05uf on the output of the "filter amp" which made sense to me, I just thought the "filter amp" should have a input AND a output cap, although in my experiments leaving out the output cap didn't cause any real problems.
I spent alot of time plugin', pullin' and rewiring, listening for something that I realized that I wouldn't recognize if I heard, since after all, I had never played through an original brassmaster, and I eventually got to the point where I thought, "this is gonna take a hell of a lot more time to decode then I thought it would and I really have to get back to working on my own designs", so I ripped the mess off the breadboard and got back to my things.
Determination...frustration....surrender.
I hope something I wrote was useful in some way, sorry if it wasn't. Maybe we'll have to wait for some crazy person to take apart his(or her) rare and valuable brassmaster and tell us its innermost secrets. I'm gonna go now and drink some(more) beer. Have a good weekend, I'll check back in when I get a chance.
P.S.-Hey R.G., I heard those odd squarks.
Quote from: Meanderthal on May 25, 2007, 06:47:58 PM
Then again, if it sounds good, I guess it dosen't make any difference. As I see it, there's a possibility that an educated guess would sound better than the origional...
Origional isn't always necessarily better... Even Edison didn't always find the BEST way to implement his inventions, although he would never dream of admitting that.
Very good point by the way.
Bump.... anyone ever figure this out??
Does anyone just have a Paul Barker Assmaster they could compare to the schematic to see what was missing? I understand the change was very minor.
It looks like R.G.'s schem does have an error - here is the original schem with the connection missing from R.G.'s schem circled:
(http://img211.imageshack.us/img211/1385/brassbasscircledpe4.png)
And the easier to read R.G. schem with the missing connection in red:
(http://img509.imageshack.us/img509/5521/bassbrassfilterconnectnu3.png)
Also note, the filter is properly connected to ground by way of the 2.2k resistor to ground on Q7, as circled in blue.
Yet another thing to note is that the 'filter amp' transistor 2n5308 is a Darlington, which may make a difference in simulations and builds. :icon_smile:
Quote from: Meanderthal on May 17, 2007, 11:57:49 PM
Quote
I frankly don't see what the big deal is about this pedal.
On guitar, it just sounds like a bad fuzz, but on bass the thing is incredible. It lets thru a whole lot of bottom end, and will do a decent octave/fuzz even when driven by a Hog's Foot. It likes to be driven by other pedals in general! Also, I've found the gating to be very practical... when ya stop playin this thing shuts up right away!
What it lacks in sustain can be made up for by driving it with a compressor- instant transformation into a distortion.
In fact, the more I use it, the more I like it. It has bumped off my pedalboard both my ds-1 and BMP.
Oh, BTW, ya know that tuba sound Jack Bruce got in early Cream? Drive the Brassmaster with a Hog's Foot, then cut the highs after the Brassmaster yet again, and it NAILS that sick sound. :icon_twisted:
I had a real one back when they were new... used to plug a EH Mole into mine. I loved that thing... one day it mysteriously died, I think at the hands of my keyboard player who hated the thing. The circuit board had traces scratched off! I tired to fix it but it never worked after that. They go for so much money these days it's crazy!
You can also hear a Brassmaster on Close to the Edge by Yes.
I just built one using RG's board, and am going to see if this mod fixes it.
I'll post back here and let everyone know.
BTW I love that old jack Bruce tone. I had the first Peavey Bass amp that had the distortion control on the first chanel, and it also nailed that tone. Also good for playing BBA stuff.
See other thread.
David, try it both ways.