Trying to get an 80's budget radio console running

The student radio station where I do some engineering got this console in a donation a few years ago. It didn't come with any kind of documentation, and sat unused because no one could figure out how to hook it up. I am hoping to get it up and running if possible, but am currently stuck. I contacted the company that made it originally, but they want a lot of money before they'll give anything out. The station budget is currently zero, so that isn't possible.

It is an Arrakis 2000SC Audio Console.
Here is a picture:


And here are several hi-res pictures for detail of the insides. Be warned that they are HUGE, and for the most part blurry. The last few are pretty good for detail.

I found the power supply for it and most of the bus lights are working properly. I haven't been able to get any audio into or out of it yet. Has anyone seen/used one of these before?
Any help is greatly appreciated :grin:

Wow, lots of chips in there. What, exactly, is the problem? Have you checked the power supply? Have you figured out how to connect audio in and out?

I see a lot of tantalums in there. Third step would be to trace the power and (4) trace the audio through the circuit. A tant may have shorted. A power regulator may have gone. Etc.

So, there's four steps to systematically pursue right there. You don't need documents from the company, probably, to get that far.

I don't know anything about the board, but those are the first steps to conquer.

Other option is to buy a cheap, used Mackie mixer.

Have you talked to Arrakis about it? I had to deal with some other Arrakis equipment years back - I won't comment on fidelity or quality of components employed in their products; but I can say they were easy to get parts and documentation from.
-Darren

> Has anyone seen/used one of these before?

It is a standard Program/Production board. Two Stereo outputs. One goes to your transmitter, one goes to a recorder so you can do off-air production work in the same studio as your program. (It can also be used for AM/FM stations with different or same program to both outlets.) You are not familiar with such boards? (I have not used one in decades; maybe it is an obsolete concept.)

> I haven't been able to get any audio into or out of it yet.

Inputs are clearly the screw terminals at the front of the main board. See -+L G +-R? The resistor pad array above that is presumably input pads; at least not long before this, most inputs were MIC and you'd wire a 40dB pad in front to take Line. However I'm not sure what it has for Mike Preamp, so it may be line-only.

Above that is a 5532 dual-opamp, and what appears to be space for a second one, so this may be the low-feature configuration.

Then several SSM2013 voltage controlled amplifiers, which suggests the slide-pots carry only DC and gain is set in VCA.

More 5532 utility amps.

"GI" is relays, appear to be two stereo per input, which should be controlled by the two buttons per input and drop signal to the PROG or PROD buses. There are 6 (or 7) bus runs: you will have a CUE bus for setting the phono needle or listening for remote cut-away cuing.

Mix bus amps are more 5532 (I like this board) and are marked Al Ar Pl Pr Pm Am. This suggests "Audition" and "Program", L R and Mono. There is also Ul Ur and below that a "Utility" screw-strip, so you have a stereo output for miscellaneous purposes. Below that the screw strip gives an EXT IN for the monitor system, and a MIC in and out which in this position is probably a utility cuing/slating mike, not a program mike. And below that seem to be the main AL AR PL PR Pmono Amono main outputs, also EARphone and Cue speaker outputs. MUTE RELAY links to logic to kill the studio monitor speaker when the studio mike is open to prevent howl. There will be jumpers on channel strips to designate which inputs should activate the mute.

Put signal at the screws and start tracing up. The SSM2013 will need some DC control voltage from the sliders to pass/control signal. The busses are surely zero-impedance and will show zero volts signal (unlike my board-hack which was a bunch of 560Rs into a mike amp), but the bus amp outputs should show signal.

There are lots more 5532s and SSL2013s. It would be logical for there to be a Master Gain and yet not impossible that it is not DJ-accessible. The Monitor system is surely stereo yet the knob is a mono pot, so monitor volume must be a VCA thing.

The eight heatsinks appear to be 4 power amplifiers. They could be two stereo pairs, but I'd expect a mono CUE speaker function; the DIP-switch may give you a choice of second pair or two utility amps. Since the power is +/-15V and these are 2W heatsinks, expect 8W in 8 ohms with possible overheating in sustained test-tone testing, entirely adequate for real program material. (These could instead be the main program outputs line-drivers, but they seem over-built for that.)

> buy a cheap, used Mackie mixer.

A proper radio program control board is far better suited, for this purpose, than a Mackie. The CUE function: you turn the fader past zero and it clicks, now that input is fed to a 2" speaker. You can hear to line-up a phono needle or hear cues from remote; you know it is not on-air because of the crappy sound. Yes, you can and probably do do the same with a Makie's SOLO system, but not the same: in a radio studio it is real sweet to have this on the knob's sub-zero point. Likewise the monitor mute function is essential to DJ/operator use. I'm not sure this board has it, but older/bigger systems have multiple inputs to each fader so you can have more sources than knobs: most radio is not mixed, it is switched and faded. Anyway a Mackie has way too many knobs. You don't make EQ or reverb decisions on-air. You don't make major GAIN trims on-air. All that stuff is set by the PD and locked away. The operator interface must be CLEAN.

This thing, working, must be the cat's-meow for 1970s style radio. If the goal of skrasms' student station is to turn out budding radio professionals, I'm dubious. I have the feeling that all pro radio is getting done on computers. At least WCBS-AM now does screw-ups which would be unlikely on a conventional board but easy on computer interface.

Thanks for the replies!
I did try contacting Arrakis about it in the past, and they wanted a lot of money for any kind of manual.

The power supply is working, as are at least a couple channels. The first channel I tried wouldn't show up on any bus, so I assumed I was doing something wrong just going right into the +-L G +- R. I tried other channels and they worked fine.

Thank you very much for that overview, PRR. One thing I'm still not sure of is how the mute relays are configured. I imagine nc and no are “normally closed” and “normally open,” but what about w and the number below each terminal? What controls the opening/closing?

The goal of station is just to get students broadcasting their own shows. There is a professional station on campus, but they offer little in the way of letting students broadcast. We're just AM plus web streaming right now. The station has money to spend on equipment so rarely that almost all our gear is donations from other stations that have either upgraded or closed down.

Sorry, I wasn't suggesting a Mackie for radio work. I thought you were trying to scavange this for use in a home - studio environment, thus my suggestion, where a used Mackie would solve all your problems.

Yes, I've used this type of console in a radio station on air too, and PRR's points about cueing are on the money. Good luck.

> how the mute relays are configured.

Get most other stuff working first. "Probably" the relay contacts are available, but do nothing, until you wire the CR speakers -through- them.

> What controls the opening/closing?

It has been a looong time and a simpler board. Each channel had a 3-way key switch. ("Key" in telephone parlance, an operator's switchboard switch.) Center off, left Program, right Audition. Aside from routing the audio, a spare contact put DC on a bus, or not, depending on a jumper option. The DJ mike channel had the jumper, the others did not. When you threw the key from Off to Prog, the DC hit the relay (may have been a buffer to reduce arcing on the key). The main monitor amp was wired through the relay to the control room speakers. Turn on the mike, no speakers, no feedback howl. And usefully, the absense of sound usually "forced" the DJ to throw the key Off when done talking... fewer live mike accidents. (Of course some DJs lived under headphones, which were not muted, and did leave the mike open, and broadcast things which they did not mean to say on air.)

> Location: Gary/Purdue-Lafayette
> We're just AM plus web streaming right now.

I just made the connection. The Purdue student-run Dorm radio is famous. It was one of, if not THE first, such operations, which became routine in the 1960s, and fostered many minds. I got $10/week for what you are doing, but the experience of on-air pressure was worth much more.

A unique (though fictionalized) historical tour of the Purdue radio system appears in the Carl & Jerry stories.

Wired Wireless - The boys trace a mysterious jammer of Parvoo's carrier-current AM station. Popular Electronics January 1962: V16 #1
http://www.copperwood.com/carlandjerry.htm

You may also enjoy: Tunnel Stomping The boys meet a female ham at Parvoo while exploring the steam tunnels. March 1962: V16 #3

"Parvoo" is the setting for many of the later C&J tales. Though most of them could be set anywhere, a few are pretty specific.