Yamaha PM1000 mod--clarifications--please!

[BoTTanist]

Well...here we go again.

Forgive my ignorance (definition: "not knowing"), but no one here has yet clearly and methodically described sup with modding an intact desk...and I'd like to keep it intact.

I recently bought an unmodded Yamaha 16 channel PM1000 at a pawn shop in Van Wert, Ohio for $300. I understand that it is a 16x4 desk. I would like to have 16 but at least 8 direct outs to record with. I also am guessing, by vague inferences in other threads, that one needs an output transformer (GA 80080) for each of the channels that one wants to have a direct out on. Upon pulling the three different kinds of modules, which have what I'm guessing are the output transformers, I see a total of 15 GA 80080s.

-Three in each of the four master modules (12)
-Two in the echo module (2)
-One in the talkback module (1)

15 total GA 80080s in the unmodded desk.

So...the way I seez it, if I pirate all of the output transformers from each of the 4 master modules, the 2 out of the echo module and the 1 from the talkback module, I could use those 15 output transformers to direct out 15 of my channel strips, correct?

I would then, of course, have no use of the 4 busses or the echo or the talkback, correct?

If I wanted to leave the busses, the echo and the talkback intact, I would have to buy 16 more GA80080s to have 16 direct outs, correct?

Or I suppose I could leave it alone and record old-school and just buss the 16 channels into the 4 master outs. Correct?

Also, I presume the can near the fader is an input transformer?
=========================================

Now then--on to re-capping.

I have read that recapping the modules improves high and low-end eq performance. So...which ones does one replace? Some? All? I count (what I presume are) 23 capacitors. 21 blue ones and 2 black ones. Do we change the values and if so, why?

Thanks very much for your time and PATIENCE!

[Matt Syson]

Hi
If your cabling to the recorder is short you probably don't NEED the transformers. Simply take a signal post fader perhaps via a 47 Ohm 'safety' resistor out to the recorder.
Recapping, start with the electrolytic types. Simply replacing new for old will probably help considerably but from then on you could consider 'modding' but it should be done 'inteligently' as simply changing things may not actually change much if circuit conditions are not 'demanding'.
Matt S

[jeremycox]

whats the circuit for the 47ohm safety resistor?

[Matt Syson]

Hi
Simply in series with the output .
It's purpose is to provede a bit of protection in case you short circuit the output and it 'decouples' the extra capacitance of your cables from the op amp output.
Exact value is not critical and anything from 33 to 100 Ohms would be fine.
You could be a little 'flash' and use a similar resistor in the 'ground' connection and wire it balanced and this would give an 'impedance balanced' output.
Simply put the resistors in series with the wire that you take out of the module. Put a bit of sleeving on it to prevent accidental short circuits.
Look up other threads on balancing. This is used on insert sends on things like SSL4000 channel strips and many other places.
Matt S

[BoTTanist]

Thanks Matt!

What distance do you consider 'short?'

Where, specifically, on the circuit board should I tap for post fader?


-Don