Help building the 70's Maestro MPF-1

[jmasciswannabe]

Here's what I got so far. I wanted to post it as I wont have several days to get back to it. Maybe someone else can clean it up and place the drill dots and finish out the switch area. It's a start at least.

[gigimarga]

Here's what I got so far. I wanted to post it as I wont have several days to get back to it. Maybe someone else can clean it up and place the drill dots and finish out the switch area. It's a start at least.

Woow...very nice work jmasciswannabe!! Thx a lot!
The rotary switch seems a little strange to me...what I can buy here have the poles in the middle: http://www.conexelectronic.ro/produs.php?id=36908

[fuzzo]

Thank you so much.

But a question, do you want to keep the pedal like the original was ? I mean you won't include a tru bypass switching ? (the original has bypass integrated in the box, you had to kick hardly the box to engage or desengage it)

I can't find the 10K "S" taper in my regular seller, anyway we could take a 20K tone control for tubescreamer and add a 10K R in //.

Anyway, thanks for all the work about that circuit (I haven't the skills to help you tracing the PCB )

[jmasciswannabe]

yeah, I am not sure what part of the schem and layout controls the switching, but it can be removed and truebypassed, hopefully know volume drop! On my way to Arizona! I'll check back with the layout soon!

[jmasciswannabe]

Here we go:






I think I found an error in the schematic. According to the layout c3 is right off pin6 of the cd4007 and does not receive voltage on both sides. I could be wrong on this but I changed the schem and added parts numbers so it will be easier to discuss. If someone could clean up the trace that would be really awesome. Also, if anyone  decides to build, take your time and compare the schem with the layout until it is verified. There was a crazy cat lady on the plane whos cat meowed for a solid hour and I felt my brain going to mush.

[slacker]

I think C3 is fine, it goes from pin 2, which is the output of one stage of the CD4007 to pin 6 which is the input of another stage. It makes more sense if you look at the other schematic that shows the individual parts of the CD4007 or look at the CD4007 datasheet.

[jmasciswannabe]

I should have paid more attention. I could have used that schem's component numbers. It does have the .022 cap going direct to pin 6 of the IC, though. So I'm a bit confused. Does it not matter either way?

[slacker]

Just looked at it again, I didn't realise you had changed the schematic you posted, I thought you'd just added the part numbers. I think the way you've drawn C3 is correct.
Sorry for any confusion.

[jmasciswannabe]

No problem, Ian M from England and loved the echobase build, by the way!

All right, I am assuming that the 4016 does the switching that we no longer need. So could this stuff I circled be taken out letting the signal after c5 go to the r19, r22 and tl022 intersection. Would the intersection between r6 and r7 need to tie back in after c5?

[Dirk_Hendrik]

I can't find the 10K "S" taper in my regular seller, anyway we could take a 20K tone control for tubescreamer and add a 10K R in //.

Why not recalculate the thing for use with a 20kw instread of a 10kb?

[fuzzo]

yeah I meant using a 20Kw with a 10K in // .

[slacker]

All right, I am assuming that the 4016 does the switching that we no longer need.

I don't think you can ditch the CD4016 stuff, isn't it needed to switch between the different modes?
I've been trying to make sense of it all, but I haven't got it figured out yet.

[jmasciswannabe]

I thought the 4016 was one of those boss deals controlling the bypass. the mode select looks to be controlled by the 4011 and the 4pdt. I really have no idea though. Can anyone explain?

[SpencerPedals]

I feel a lot better knowing this is all bizarre to others, as well.  Maybe the boutique guys should just use confusing switching mechanisms instead of goop.  Though I think they'd want an original design first, since a FF with a weird switching setup still looks like a FF with junk on it.  I can't answer the question so this is basically a bump for hopefully one of the super-gurus.

[Rectangular]

I would suggest leaving the design as it is, and try using an adjustable rotary switch with 10 positions.  this both keeps it in line with the original schematic, and prevents any possible audible changes from occuring. generally my clones sound a bit different from the real thing (I make an effort to purchase everything I clone), so preserving the original layout would be ideal. I still can't get my polyphase to sound like a real one, for example.

[p.eat]

Hi,

I found a scan of the original service manual via google: http://s77.photobucket.com/albums/j64/Spaghettaboutit/Maestro%20MPF/
It gives a wonderful explanation of the switching and the circuit in general.

Hope it helps,

Peter

[Rectangular]

absolutely beautiful find !  really nice to see the original schematics. this is a lot easier to work from

[jmasciswannabe]

Nice!! Thanks for the manual!

[JKowalski]

Do you still need cleaned up trace version?

[Rectangular]

its weird to think this expensive vintage effect is just a few TL022s, plus some 1n4148 diodes for the distortion. you'd think there'd be more to it, but then again, moog always designed towards cheap, easily available parts.