New year, new mic...RCA type MI-10002 Uni-Angular Electrostatic (experimental build)

[abbey road d enfer]

I see that the RCA Mixer MI-10279, A, B had anode and heater power supply taps as well.

Almost anything with tubes has a B+ and a heater voltage.

 

[emrr]

Very rare mixer, I've only one set of pictures from an auction years ago. 9 pin tubes.

I see that the RCA Mixer MI-10279, A, B had anode and heater power supply taps as well.

 

[pinchemotherloaf]

Almost anything with tubes has a B+ and a heater voltage.

I mean, on tap for (tube) microphones to draw upon at input connector. I'm not sure there were any (or many) microphones using transistors in 1958?

 

[abbey road d enfer]

I see that the RCA Mixer MI-10279, A, B had anode and heater power supply taps as well.

I'm not sure I get it. Do you mean the mixer had connectors with heater and B+?

 

[pinchemotherloaf]

I'm not sure I get it. Do you mean the mixer had connectors with heater and B+?

Well, looking at the schematic by RCA the power supply is either in the 'pre-amplifier', the MI-1005 mid cable devise or the mixer. I'm not really sure now where the power supply would reside, but power must arrive from somewhere. In configuration 'B' it looks like the mic connects to the 'boom' cable, then the MI-1005 (which I think is the RC network and transformer), and then the 'stage' cable to the mixer. Could I assume that the suffix ', A, B' on the MI-10279 mixer stands for A+ and B+ voltage outputs? I really don't know and take back my original conclusion. Question is what is , exactly, the MI-1005 devise and does it supply power?

 

[abbey road d enfer]

Well, looking at the schematic by RCA the power supply is either in the 'pre-amplifier', the MI-1005 mid cable devise or the mixer. I'm not really sure now where the power supply would reside, but power must arrive from somewhere. In configuration 'B' it looks like the mic connects to the 'boom' cable, then the MI-1005 (which I think is the RC network and transformer), and then the 'stage' cable to the mixer. Could I assume that the suffix ', A, B' on the MI-10279 mixer stands for A+ and B+ voltage outputs? I really don't know and take back my original conclusion. Question is what is , exactly, the MI-1005 devise and does it supply power?

After more thorough reading of the datasheet and the schemo, It looks like "A" is teh heater supply at 6.3V. "B" is HT.
The MI-1005 provides additional filtering to B+ and distributes power to the tube's plate and to the capsule. The heater volatge is passed directly.
It requires a separate PSU.

 

[pinchemotherloaf]

After more thorough reading of the datasheet and the schemo, It looks like "A" is teh heater supply at 6.3V. "B" is HT.
The MI-1005 provides additional filtering to B+ and distributes power to the tube's plate and to the capsule. The heater volatge is passed directly.
It requires a separate PSU.

It's interesting that the RCA document doesn't show the power supply connected in configuration 'B' and that in configuration 'A', where the MI-10005 is missing (or rather relocated to the pre-amplifier), the power supply is missing as well. I can only assume, like you mentioned, that there is a separate power supply that is inserted either at the MI-10005, pre-amplifier or mixer or that the power was integrated into one of these three devises.

 

[emrr]

After more thorough reading of the datasheet and the schemo, It looks like "A" is teh heater supply at 6.3V. "B" is HT.
The MI-1005 provides additional filtering to B+ and distributes power to the tube's plate and to the capsule. The heater volatge is passed directly.
It requires a separate PSU.

Yes, standard USA, as in 'A' battery and 'B' battery. 'C' for bias battery.

The pics of the mixer show multipin jacks that would support A and B distribution to mics. I can't think of another American mixer like this, offhand. Just some very early mixers that supplied power for carbon mics.

 

[pinchemotherloaf]

Yes, standard USA, as in 'A' battery and 'B' battery. 'C' for bias battery.

The pics of the mixer show multipin jacks that would support A and B distribution to mics. I can't think of another American mixer like this, offhand. Just some very early mixers that supplied power for carbon mics.

Very interesting

 

[mjrippe]

Not sure if this was posted previously...I saw the schematic but not this page.

 

[pinchemotherloaf]

Not sure if this was posted previously...I saw the schematic but not this page.

So that doc says the there are 2 receptacles on the MI-10005 but no mention of a 3rd for power injection. Also says 'power derived from higher voltages'. As emrr mentioned, the mixer looks to be the source for A and B power. Would be interesting to see the front end schematic for this mixer.

 

[abbey road d enfer]

So that doc says the there are 2 receptacles on the MI-10005 but no mention of a 3rd for power injection.

It's the connector on the right; it has inputs for HT and heaters, in addition to the mic level output.

 

[emrr]

The mixer.......looks like it also has an external supply, probably battery and AC options like most.

 

[abbey road d enfer]

The mixer.......looks like it also has an external supply, probably battery and AC options like most.

Yes, so the mic is connected to the intermediate box, which in turn connects to teh 6-pin XLR's.

 

[emrr]

Cannon P connectors and a single XLR, odd mix.

 

[pinchemotherloaf]

Yes, so the mic is connected to the intermediate box, which in turn connects to teh 6-pin XLR's.

The mixer.......looks like it also has an external supply, probably battery and AC options like most.

Wow, that's well built stuff