Yamaha PM1000 Recapping/Upgrade

[wilcofan]

Anyone know how to mod direct outs on a PM1000 input channel?

 

[wilcofan]

OK, the direct outs look like they will be complicated installing on the back of the console. There are lots of XLR outs already there but all the connector positions are full leaving the input module:

However, I have an idea to use the hole from this send on channels I use for effect returns and a couple more always left open anyways:

I could use a TRS balanced output. Now maybe someone can remember what they did to do this? ;-)

 

[Jonathan Hayward]

I found a slightly better schematic of it on my hard disk (which doesn't crop the end).
Are you thinking of input amp out/EQ in insert?
It looks like you could probably just take the signal to the jack after the the cap (after the last gain switch) - it looks like a .47U cap (which sounds small for an output cap), then put in another capacitor on the way back in from the return jack. This assumes that the levels at this point will not be obscure, in which case you may need to rethink and try the levels elsewhere (say post EQ).
Suck it and see before hacking the board about.

 

[wilcofan]

[quote author="Jonathan Hayward"]Are you thinking of input amp out/EQ in insert?[/quote]

No, I mean just a way to drive the DAW inputs without going the extra distance through to the Master outs, which have transformers. I imagined there might be a way to actually install output transformers inside the input channels.

Is this crazy?

 

[Jonathan Hayward]

I think there would be enough power at c37 (after the post-channel-fader amp) to drive an output transformer.

You would need to decide on the arrangement for the buss assign (straight after it), and how to switch between transformer direct out (to the DAW) and to desk in 'normal mode'. It may even be that the amp can drive both at the same time which would be useful for monitoring.

 

[tubejay]

Here's some info that was sent to me from someone I met on the TapeOp forum. I believe his name was Dug, or something. Unfortunately I can't find his original email. I had just copied all of the info he had sent me into a word file, now I can't find him. I know I had seen him at tech talk before, so hopefully he'll find his where here.

Anyway, do you guys think this sounds right for impedance balancing the circuit. My plan was to impedance balance 10 modules first, then take the output transformer from the 4 B-Buss outs and make them direct outs, and the 2 xformers for the aux sends, and make those direct outs on two channels, then leave everything else as is for bussing and routing.

He doesn't talk about transformer balancing it, I'm guessing you'd tap the same points on the board to do it??

Here's what he wrote:

1. I want direct outs, even if unbalanced at first.
This is easy. Do you have the schematic? It is in the manual which you
can
download from yamaha's website. Let me know if you can't find it. You
just
tap off of C37. There are a variety of things to try. If you have
spare
transformers that would be nice. Also you can "impedance" balance it
by
wiring It up like this.

Coupling Cap(C37?) + -> 33R -> Pin 2
Ground -> 33R -> Pin 3
Ground -> Pin 1

Also, you can toy with replacing the coupling cap, with a foil cap. Or
just
providing your own coupling cap. For you direct output. I was thinking
of
doing it a bunch of ways and then deciding on my favorite.

Then he wrote again on impedance balancing:

It is for "impedance balancing"

It makes the gear "seem" balanced.
Of course, common mode rejection would still work without it, but it makes it play nicer with other gear.
Since the amp can drive a 33R load then that is a nice choice.

I think alot of mackie stuff that is "balanced" is "impedance balance" I've also heard is called "psuedo balanced"

:sam:

So that being said, I already quadroupled the value of C37, would that effectively make this a more reasonable prospect?? That's something I never asked him.

 

[Guest]

If anybody is having a hard time finding the output of C37, it's labeled as B0 on the bottom of the circuict board. Right next to the Echo 2 pot.

Cheers,

elco
:shock:

 

[tubejay]

[quote author="elco"]If anybody is having a hard time finding the output of C37, it's labeled as B0 on the bottom of the circuict board. Right next to the Echo 2 pot.

Cheers,

elco
:shock:[/quote]

Ahhh, that is very helpful, thank you!

 

[wilcofan]

1. I want direct outs, even if unbalanced at first. This is easy. You just tap off of C37.

Does "tap off" mean leaving the circuit as it goes and branching off another wire? I would appreciate the basic definition of "tap off" first.

Then I assume the new output transformer installed in the input module would take this new wire? Doesn't the output transformer need two leads? Sorry, I'm really green here but I want to learn. I'm off to read more electronics stuff on the web, thanks for any info.

Bob

 

[wilcofan]

Can anyone tell me why there are input transformers on the Master Busses? Is this used by the input modules summing there or is this probably for the Playback Ins and Sub Ins?

Would the input transformers on the Master Busses be bypassed by the input channels if this is the case?

 

[tubejay]

I can't help you with your transformer question, but I too would love to know...

Elco passed me a link, that anyone working on a PM1000 should check out. It talks about changing the EQ points to that of Neve or API, to help make the EQ more useful. I asked about this over at TT, and nobody knew, so this is good info:

1 http://www.krashjones.com/pm1000/ Go to the bottom and he talks about altering the EQ points. Very good reading!

Elco also had this link with info on how to calculate the EQ points based on the value of the inductor, and the frequency you'd like to end up with.

2. http://www.opamplabs.com/cfl.htm Here is a online Java based LC calculator. you can plug in your own values. Keep in mind that when you use the calculator, it will spit out very precise values. In real life you will have to round up or down for commonly used capacitor values.

Thanks Elco, that information is SUPERB!! I had a nice read last night...

 

[axisdreamer]

Hello everyone! I am a new member on here and wanted to pass along that I will be selling a bunch of yamaha pm1000 ch. strips and other parts as well in the next few weeks. I am building a custom pm1000 16 ch console into an Auditronics frame that I had laying around.I will have around 10 pm1000 ch strips for sale and all 4 buss modules. I might even part with some output transformers and the power supply.Let me know if anyone needs anything.I will be getting the stuff this week coming up.

Regards,axisdreamer

 

[opacheco]

I can't help you with your transformer question, but I too would love to know...

Elco passed me a link, that anyone working on a PM1000 should check out.  It talks about changing the EQ points to that of Neve or API, to help make the EQ more useful.  I asked about this over at TT, and nobody knew, so this is good info:

1 http://www.krashjones.com/pm1000/ Go to the bottom and he talks about altering the EQ points. Very good reading!

Elco also had this link with info on how to calculate the EQ points based on the value of the inductor, and the frequency you'd like to end up with.

2. http://www.opamplabs.com/cfl.htm Here is a online Java based LC calculator. you can plug in your own values.  Keep in mind that when you use the calculator, it will spit out very precise values. In real life you will have to round up or down for commonly used capacitor values.

Thanks Elco, that information is SUPERB!!  I had a nice read last night...

Dear tubejay,

Do you have a copy data of  the data in order to modify the eq section???...Do you have the schematic for this mixer??

Thanks a lot,
Opacheco