RCA BC-2B tube console restorations

[emrr]

Tackling some of the insanity around here.  I have three RCA BC-2B's in various states, that are in process towards two functioning consoles.  Only one of these consoles was complete when I found them.  This also required sourcing some loose related parts beyond what the three console frames held.  A stock console came with two preamp chassis (2 channels per chassis), with a space for a third at extra cost.  I've loaded these with three apiece.  I pulled Lassoharp in on this one for some of the basic rebuild, and so far we put in about 4 days together.  Right now the amps and power supplies are all fully recapped, all resistors checked and replaced if needed, and some number of modules tested and measured.  I have significant time in them before that, and plenty left to do.  I am debating some amount of rear panel connectorization, somewhat like a patchbay, so that each amp can be used by itself, or patched for original console flow.  This isn't too hard, as all inputs and outputs connect on christmas tree type terminal blocks, with various sections solder strapped, or connections broken for patching.  More to come. 

Two RCA BC-2B consoles with power supplies.

Consoles open.

Consoles open, another angle. 

All modules in.

Some modules out.

Consoles under restoration.

Console 1 under restoration.

Console 3 under restoration.

Program amp and preamp with old caps removed. 

Program amp recapped. 

Program amp recapped, and preamp with old caps removed. 

Rebuilt program amp.

Pile of rebuilt preamps, monitor amps, and a PSU. 

Power supplies, recapped, ready to go back in cases. 

 

[michal_k]

Looks amazing, congrats!

 

[jackies]

This is awesome!
You can probably turn your house into a museum, where people come to see 'em!

 

[ruffrecords]

I am soooooooooo envious. Local radio did not start in the UK until the 70s by which time there were no tube consoles in use so we do not have this lovely heritage to draw upon.

Cheers

Ian

 

[alexc]

Supoib !

Thanks for the high qual pics too 

 

[Dr Gris]

Adopt me!!!

//M

 

[soapfoot]

beautiful. Will you put these to work as sidecars, or mainly as preamps, or stitch them together and track 6-track recrords on them? All of the above?

 

[emrr]

Ideally finished off for all of the above.  Mainly preamp use (can use all 8 amps), but some of everything. 

 

[emrr]

Finally back to this. All the amps are tested and working fine. The Christmas tree connector blocks are cleaned up and I've decided on tie points to break for external 'insert' connections. They'll have dedicated patchable ins and outs for every amp, with the monitor amp 600 ohm and low-Z speaker connections brought out separately. This means the PGM and AUD buses will also have outputs, should one want to use different external mix amps. You should be able to do dual mono mixing (think early USA hard-panned Beatles) if patched that way, you could also just use the MON amp as bus 2 and take it's 600 ohm output. I'll wire up the bridging parallel output of the PGM amp on the existing 'external monitor' patch so there's a monitor path when using it in mono with the MON amp dedicated to non-MON usage. Best use of labor is probably to have someone make 'professional' connector panels I can add to the back skirts, since I'm at 28 audio connectors.


Here's a question: The PRE out Z is 150, it hits a tie point that straps to another which goes to a 150/300 ladder. This means using the return tie point for line in is fixed 150 ohm unbal input; too low. Is it reasonable to change the PRE outs to 600, and add buildout resistance on the return side so any other line patched in sees 600 rather than 150? Probably as a pair of parallel 230r so anything unhappy with being grounded on one side will see 230r above ground, 610r total. Since the ladder output is also essentially 150r when switched onto the bus, the Z is fixed on that side anyway. The PRE's won't care, and done to all mixer input channels, I'm not sure there'd be any disturbances on the bus either. I'm thinking the loss from slight buildout will actually be welcome with the sort of levels we send these days. PRE from 150 to 600 is +4, adding build out to make the 150 ladder look like 600 is -12, netting -8 total. Seems acceptable so long as it works fine. I'd like to go even higher, but it turns into a big pad fast.

Changed this plan slightly:
https://groupdiy.com/threads/rca-bc-2b-tube-console-restorations.53576/page-3#post-699075

 

[micaddict]

Incredibly cool, Doug!

You should be able to do dual mono mixing (think early USA hard-panned Beatles) if patched that way

The Jim Reeves album "Songs To Warm The Heart" was done that way.
Recorded December 9th and 19th, 1958 and January 21st, 1959.
RCA Victor Studio, 1610 Hawkins Street, Nashville, Tennessee. (Now known as Studio B.)
They did call it stereo BTW.  Well, maybe they just used two mics and there's no mixing down? Probably not. In any case, there's hardly any lead vocal on the right channel.

http://www.youtube.com/watch?v=oteZWLRpm9M



Henk

 

[emrr]

Nothing like Jim Reeves!  The easy way to describe these old mixing systems to me is the original language; mono, dual mono, L/C/R. Defines what you can't do pretty well.  Sell it to the kids on a record, you gotta call it mono or stereo. 

 

[micaddict]

Hey, that's a quick reply, Doug. I've added a link and a question to my post. Thanks.

 

[emrr]

I'm sure it a mix printed live to 2 track tape, left that way on the LP.  Man, what a voice. 

 

[micaddict]

Yeah, that's what I figured, especially since the lead vocal mic is used pretty intimately, in the typical Reeves way.

Man, what a voice.

Yeah, nothing quite like it. Next July he'll be gone fifty years. I'll be doing some (humble) tribute performances.

And man, how I'd love to record a couple of songs in your studio!

 

[emrr]

Come on down!

Here's a paper mock-up of the connector panel.  Thinking about Switchcraft 14B's for the pre-out/mix-in connections, so they'll normal properly without need for patch cables at all times.  Bus outs to PGM/MON inputs will require short XLR patches at all times, seems unavoidable if I want to have PGM and MON amps available for stand-alone preamp/etc use. 

 

[idylldon]

Beautiful work, Doug!  You have some of the most amazing gear I've ever seen!

Can't wait to see this one all finished up.

Cheers and happy holidays,
--
Don

 

[micaddict]

Come on down!

Thanks, Doug.
I'd love to.
Trouble is, I'm in Europe.
Also, I have fear of flying.
Last time I had enough courage was in 1991.  :-[
But I did cross the big pond then and while I was at it, I did visit RCA's studio B. 

Anyway, the pictures are very tempting indeed.
A couple more of those and I might get myself a transatlantic ticket after all. 

 

[crochambeau]

Glorious! I'd love to see your finished I/O panel, how are you planning to side step the louvers? Beautiful units, the BC-2B makes the BC-3C look a little cheaper side..

 

[emrr]

I'm gonna have to steamroll over the louvers; cut the whole skirt slightly smaller so the panel is an overlay.  There's enough space above and below for corner screws to mount. 

I'm going for something that's never existed here; a fully patchable version of an old console with onboard connectors, such that it forms a reasonably portable system.  All these old broadcast boards were always permanent installs, at best all the connections put on a patch bay.  I want this thing to be pretty much plug and play in a way that it can be swapped in and out of workflow easily. 

These do make a BC-3/5/6 look kinda cheap when you look at the guts side by side.  The later series has great iron, but those early PCB's don't make for sexy viewing at all.  They also don't have the breakable internal watchpoints like the BC-2B, so less configuration flexibility. 

Thanks Don!

Micaddict, let me know if you ever make it over again!

 

[micaddict]

Micaddict, let me know if you ever make it over again!

Will do, Doug!


Henk