Yamaha M916 Mixer Refurb Questions - schematic included

kiira - does the M512 have that 70s gear smell? Kind of like a Value Village leather jacket? Will you lose that if you rip the guts out? Is it worth it?

There's no way I'm going to post a picture of my space without cleaning it up first....I'm in mad apprentice scientist mode right now - what a mess.

[quote author="lang_dave"]
I marked what I believe to be decoupling caps blue.[/quote]

Hi,
TA7322: pin 9 is +V, pin 5 is -V
Caps C24, 25, 32, 34 and 35 are also the decoupling caps.
You may wish also replacing the "green" elcos in the EQ with film-types;
C18 and 19 with one 270nF, C20 and 21 with one 180nF, C22 and 23 with 120nF.

The pictures below show how to mount the decoupling 100nF caps.
Regards,
Milan

Thanks, Milan.

"You may wish also replacing the "green" elcos in the EQ with film-types;
C18 and 19 with one 270nF, C20 and 21 with one 180nF, C22 and 23 with 120nF"

Let me see if I've learned anything - since the original caps are in series with each other, their values together equal the lower capacitance film cap values that you've recommended? (1/Cseries=1/C1+1/C2)

For example, C18 (.47uF) + C19 (.47uF) in series = .235uFd or 235nF which leaves me a choice between a 220nF or 270nF polyester film cap 'cause that's what's readily available? I can get a 240nF polypropylene from Digikey - since it's in the EQ section should I use as close to the original value as possible?

If I do decide to switch the EQ caps for film, would I remove the original caps and connect the film cap to the positive terminals on the pcb where originals went like this?

[quote author="moamps"]
Caps C24, 25, 32, 34 and 35 are also the decoupling caps.
[/quote]

I think you meant C24, C25, C32, C33, & C34 are also decoupling. There is no C35.

I put an updated marked schematic here:

http://www.davelang.com/m916/graphics/m916inputcapmapv3.jpg

red = coupling
blue = decoupling
green = eq

Thanks for the weekend classes in electronics / old Yamaha mixers!

So are you going to put 5532s in it? My Tascam is all tl07* and 4558s. I can't imagine any DIY more horrible than replacing g'zillions of caps and opamps on an old mixer. :?

stay frosty,

Kiira

The input channels use these uncommon TA7322P 9 pin SIP op-amps for everything but EQ. I'm going to replace the EQ op-amps w/5532s.

Word around here and on the net is that the TA7322Ps don't sound too bad.

I actually like the way the M916 sounds, it's just a little 'distant'. That's what I hope to fix. Prefer even the unchanged EQ to most of what I get from a plugin. We'll see how it turns out.

Right now I'm in the mood for a few days of repetitive tasks. Seems replacing a couple hundred caps might be just the thing. I don't really know much about this stuff, and it seems like a good way to learn.

Did I mention this mixer came with a big silver road case on wheels? With #648 stencilled on the side?

I think I've got the input strip sorted out.

Anybody feel like having a look at the program out strip for me and seeing if I tagged the caps correctly? You can see it here:

http://davelang.com/m916/graphics/m916programcapmapv1.jpg

what I think are coupling caps are red
what I think are decoupling caps are blue

Hey Dave,

If you use EXR caps they have the 0.1 caps inside them already, so no need for sepperate ones. Thatll save you a bunch of time.


M@

[quote author="lang_dave"]
Let me see if I've learned anything - since the original caps are in series with each other, their values together equal the lower capacitance film cap values that you've recommended? (1/Cseries=1/C1+1/C2)
For example, C18 (.47uF) + C19 (.47uF) in series = .235uFd or 235nF which leaves me a choice between a 220nF or 270nF polyester film cap 'cause that's what's readily available? I can get a 240nF polypropylene from Digikey - since it's in the EQ section should I use as close to the original value as possible?
If I do decide to switch the EQ caps for film, would I remove the original caps and connect the film cap to the positive terminals on the pcb where originals went like this?[/quote]

Yes, Yes, Yes and Yes

[quote author="lang_dave"]
Anybody feel like having a look at the program out strip for me and seeing if I tagged the caps correctly?[/quote]

Coupling caps are 1,2,3,6,7,10,11,12,13,16,19,19',20, 20',23,24,27 and unmarked one below MTRX MASTER1 sign.
All other elcos are decoupling.

Regards,
Milan

Oops - I made a mess out of that one. Colour scheme backwards, different caps given the same number. ARgh.

Let's try this again. Here's a fixed up schematic.

http://davelang.com/m916/graphics/m916programcapmapv2.jpg

I think coupling caps are:
1,2,3,6,7,10,11,12,13,16,19,20,21,22,23,26,27,30
they're marked red

decoupling caps marked blue

Thanks, Milan for your help.

Could anyone explain to me why 7,16,22,27 are considered coupling? They look to me like they perform the same type of function as the 10/35 decoupling caps.