RICKENBACKER P.A. -120 4 CHANNEL MIXER

brian · Post by **brian** » Tue Jun 08, 2004 5:32 am

This is different, I haven't seen one of these before, but I guess that doesn't mean they are rare. Are these very common ?

http://cgi.ebay.ca/ws/eBayISAPI.dll?ViewItem&category=23785&item=3728827948&rd=1&ssPageName=WDVW#ebayphotohosting

tracy · Post by **tracy** » Tue Jun 08, 2004 5:53 pm

I have two. They're 'okay' I guess. I use mine for keyboards. 120 real watts. Parts are hard to get. Good luck!

brian · Post by **brian** » Tue Jun 08, 2004 6:46 pm

Hm, I think I'll pass

jingle_jangle · Post by **jingle_jangle** » Thu May 05, 2005 1:34 pm

Hey--I just acquired one of Tracy's amps.

Anybody got any info, manuals, schematics?

Another piece of history for JJ's home studio.

ozover50 · Post by **ozover50** » Thu May 05, 2005 2:50 pm

Gorn!!!

jingle_jangle · Post by **jingle_jangle** » Thu May 05, 2005 3:20 pm

Howard, what does that Aussism mean? Something like...Jeez?

I sent you an e-m the other day. No Reply. We're still, erm, speaking, aren't we?

ozover50 · Post by **ozover50** » Thu May 05, 2005 3:45 pm

More like, gone, departed, defungerated, vapourized, etc..... Paul.

Yes, we certainly are, Ollie!! Sorry I haven't got back to you - the attachments were 4.9Mb and it took 2 days to download (well......not quite).

I've been so flat out with work, football and the appeasement of the lovely lady that I haven't gotten to responding yet. I'm dreadfully sorry, mate. Haven't even had time to pick up the Ricks!!.... that is a worry!

I'm having trouble looking at the shots because they are so big! I've got a quiet day at the office so expect a reversion very soon.

PS - having a coffee in the Rick mug at present!!

admin · Post by **admin** » Thu May 05, 2005 3:51 pm

Paul: I sent you off an email. I think the scematic for your amplifier is here.

ozover50 · Post by **ozover50** » Thu May 05, 2005 3:57 pm

Peter: I haven't sent you an email (just in case you were wondering).

admin · Post by **admin** » Thu May 05, 2005 4:08 pm

Howard: I figured you may be working on the "case" as it is Friday afternoon in OZ.

jingle_jangle · Post by **jingle_jangle** » Thu May 05, 2005 4:27 pm

Ah, so. Still on 56k, eh, aitch?

I should've reduced them. I sent 'em fresh out of the camera. Sorry.

jingle_jangle · Post by **jingle_jangle** » Thu May 05, 2005 4:29 pm

Thanks for the schematic, Peter! Somehow, my brain is not functioning. I never even thought that it could be found on RIC's own site!

ozover50 · Post by **ozover50** » Thu May 05, 2005 4:37 pm

Sure is, Peter..... and not a boss in sight!!

What the hell am I going to put on my timesheet?

jingle_jangle · Post by **jingle_jangle** » Sun Jun 12, 2005 3:23 pm

Well, it's June 11th and, now that I'm out of the apartment and into a nice cottage in the hills, all my equipment has been dusted off and considered for residency. (50% at least was in storage, pending more space).

I had two large PA monitors on order; was told they were "in transit", and found out after 3 weeks that they'd been stolen off a loading dock. Yup, "in transit" to some thieves' cavern, no doubt. So I cancelled the order, got a refund, and ordered up some smaller ones, which arrived in my office on Friday. Took 'em home and uncorked the 120 Rick PA amp (it's in a HD Tolex-covered plywood case with removable front and back, hinged cord storage compartment, etc.

Hooked everything up, plugged the unit into an outlet in my house which is switchable from a wall outlet, for lamps. Everything was turned off at the wall switch. The lamp was turned on, but would not light until the wall switch was turned on.

The Rick PA amp was turned off, too. When I plugged it into the wall outlet, the lamp lit up, as if I'd thrown the wall switch.

But I hadn't. Uh-oh! No wonder one of the two fuses on the 120 was blown. A short in the power cord must be causing a continuity between the ground pin and the neutral pin of the 120's plug, I reasoned.

Bought two new fuses and took the 120 apart to get at the power cord. As I poked and probed the three leads from the cord inside the 120, the insulation just fell off the wiring on both the neutral and the ground wires. Yup.

So I shortened the power cord (which was the 120's original, judging from the solder joints). As I was stripping the insulation from the ground and neutral leads, it flaked off in big chunks. Interestingly, the hot lead (black) was still good.

So I cut into the cord near the plug--fully 4 feet away from where it went into the amp's chassis. The white and green wires had bad insulation all the way to the plug!

That was the source of the short circuit.

I pilfered an old computer power cord. stripped the insulation, and proceeded to solder things to the chassis. Popped the strain relief back in, replaced the fuses, and fired her up.

(This amp and speakers will be used for my keyboards, which apparently is what Tracy used it for, as well.)

The amp is powerful, all controls still work with no scratchiness evident, and the built-in reverb is a plus, although not very deep. There's a large VU meter with the RIC script logo.

Pulling it apart, let me tell you--this is one heavy-duty piece of kit! Everything is built like a tank. Each preamp channel occupies its own circuit board, there is a fifth preamp for the reverb tank alone, another for an anti-feedback circuit. Transformer is huge and probably accounts for about 1/3 of the weight of the unit by itself.

The power amp section has its own board with the power transistors bolted to a large finned heat sink which protrudes through the back of the cabinet. There are separate "outs" for speakers and monitors. The monitor volume is controlled by a heavy-duty, completely-enclosed L-Pad.

And you can get at everything by removing eight screws. With a power screwdriver, this is a minute's work at worst.

As you can tell, I'm very impressed with the quality of this 25-year-old solid state amp. Although in today's world of compact 400-watt, 21 pound amps it's a dinosaur, it's the perfect companion to my 30-year old analogue combo organs and looks and feels like it will last into the next century. And, at $1 a watt on eBay, it was good value and a little bit of Rickenbacker history to boot.