Home > Studio Recording DIY Projects> Yamaha PM1000

I missed taking a few pictures... basically, I replaced the filter switches with DPDT so that I can mount them easily in the chassis.

Closeup of the switches. The left switch is the high-pass filter switch (disable, and 40Hz), selectable. The right switch is the mid-filter frequency select. Currently 1Khz, and 2Khz setting.

These are the inductors used by the PM1000 for the EQ section... bass, mid, and treble frequencies.

This is a closeup of the input transformer. The transformer provides coupling and is center-tapped. The 48V phantom power is connected to the primary center tap.

This is the schematic diagram printed from the PM1000 PDF, downloaded from the Yamaha website. I used the schematic to figure out how to wire the filter switches and where to tap the output.

The PM1000 has a gain selector knob. I think each click is 5dB gain step.

And these are the parts that I removed from the PM1000 during the operation... You can see the edge connector, cue switch, filter switches, and echo1 and echo2 knobs, plus the 4 bus selector switches.

Ready to RACK!

I'm getting ready to rack the preamp strips taken from a Yamaha PM1000 console.

But first, I did some sound tests to make sure this is worth racking.

I think the EQ will be useful... adds that volume and warmth to the sound. What do you think?

This is the original audio clip. I used an iRiver mp3 player. Recorded the sound and here is the result. (Sorry, one channel only... left speaker).
Original audio clip

And this is the same clip after going through the PM1000 preamp, with the preamp EQ adjusted for some flavor.
Passing through PM1000 preamp

Again, the EQ of the preamp is worth saving because it is totally IC-less... no opamps here, just inductors and capacitors... the way a Pultec EQ does it... totally passive. There is a makeup gain circuit after the EQ to boost the signals, again, no IC... just discrete transistors.