Yamaha PM1000 knobs and transformers

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stevegkeezer

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Mar 8, 2022
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I recently purchased this mixer.

The mixer looks like it has already been parted out so I only have 6 channels. All the output transformers were gutted. Since I am never recording more than 6 channels, I figured it would be better to leave the mixer as is and upgrade the capacitors, psu, ect.

Right now I am feeding the output of the channels into individual busses. However, these busses are all missing the input and output transformers. Surprisingly, It actually sounds pretty good without them. Would these outputs be considered my unbalanced signal with no transformers? Only issue I noticed is it seems that the submixer input jacks don't seem to do anything now. Nor do the A and B output jacks. I am not sure if thats related to the missing transformers or not.

I am considering having two master channels with Tamuras and use some other transformers for the other two master channels for a different flavor. I am looking for (6) Tamura GA80080 transformers, as well as some knobs if anyone has some leftover from racking. If anyones got some of these please PM me.

Does anyone have any experience or recommendation on this more stock setup. Would having a direct out for each channel make a dramatic difference as opposed to using the mixer more how it was intended?
 

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JW

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You're using the un balanced trs master outs? Those are interstage in the bus channels, so not as much gain as if you were using the full circuit up through the output transformer. But they do sound good unbalanced. However, just depends what you're feeding with the mixer, but I found them to require too much gain from the input strips to get up to level, and usually preferred the transformer outputs for the extra circuit that comes before them. There are plenty of 1:1 output transformers out there, as well. Carnhill's sound very good. Somebody had some MCI 600 ohm transformers on here for $15 each.

Your symptoms make sense for the missing transformers. If the master channels don't have input transformers, that just means you can't jack signal directly into the bus channels as intended. They're not necessary for running a mix through the input strips on through the buses though.

My experience is that close miked drums and guitar amps don't need the extra amplification from the buses, but vocals and acoustic guitar or lower volume stuff can benefit from the extra stage, maybe even require it. PM1K gets a pinched sound when pushed. For a loud volume instrument that wants to be IN YO FACE, this first click or two on the input switch into distortion land can be cool, but overdone sounds thin. Just my opinion.

So, anyway, I think there are benefits for having direct outs from the input strips, which make them like the usual rack jobs. But for quieter sources, something extra is needed. But, actually, could it just be the little feed back pot needs to be brought out to the front? All the gain we need right there. . . .
 

stevegkeezer

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Joined
Mar 8, 2022
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15
Location
sf
Correct. I am using the unbalanced master as my 4 main outputs.

Lately I have been using 4 of the 6 channels for my instrument inputs. And using 2 channels to run the entire mix (L & R output) from my daw to sum out of the box. I typically boost the lows and highs slightly on these two channels. Not sure if you can really call this summing or not. I am typically making rock mixes and I think, if used lightly, it adds some nice glue to the mix.

I agree on your theory about pinching off the tone when pushing the unit. With guitar tones I get better results with cleaner tones. As soon as I push into, loud, over the top distortion, not so much. I also have more problems controlling the gain.

Ideally, I would like to install direct outs. However, I would also like to have the ability to run my entire mixes through the unit for summing as well. So maybe doing this with direct outs would perform better, since the entire mix will be loud and not require that extra amplification stage.

However, something tells me that I should just be adding the transformers to the masters and running my entire mix through those channels, because it's more how the unit is designed, with essentially the same circuit minus the EQ. Is summing mixes through the channel strip themselves bad practice or going to be susceptible to noise? Or would I be better off using the master busses?
 

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