updated: 13 May 2009

Some resources for the CP-70 and CP-80

Keywords: Yamaha CP70 Replacement Power Supply CP-70 CP70B CP-70B CP80 CP-80 CP80 CP-80B

A source for CP-70 strings!

One night I was quietly playing the CP-70 and a string broke... ka-BAM!. Scared the shit out of me. After I got my heart out of my larynx, I opened up the lid and saw that one of the double-strung notes, the G below middle C, had snapped. A local piano tech made me a new string out of a conventional wound piano wire, but it sounded goofy - it had a really predominant and grossly misplaced second harmonic. This artifact was probably caused by the replacement string having a slightly smaller gauge winding than a real CP-70 string. After a week of letting it stretch in, things didn't get any better. I couldn't take it anymore and went back to using one string for this note. I had been searching high and low for replacements, and finally found a source. The Mapes Piano String Corporation in Tennessee (423-543-3700) sells replacement strings for the Yamaha CP-70, CP-70B, CP-80, and CP-80B. They're very friendly folks, and get this: my replacement string set me back all of $6.35. Gotta love it. You'll need to know the string number (not the note number) when you call. (dtc 06/13/2001)

Replacement Yamaha CP-70 Power Supply HOWTO

Have you lost, broken, or detonated your power supply? Do you want a replacement? If so, this page is for you.

Unfortunately, I don't have one for you to buy. I'm almost certain you're never going to find a used one for sale anywhere*, but I know how you can make a replacement. One day if I get real motivated I may make a batch of 'em, because you would not believe how much email I get inquiring about replacement CP-70 power supplies. I suppose that nobody loses a CP-70, but apparently that's not true for the power supply.

I've already told you the bad news: you're not likely to find anyone who's gonna sell you a CP-70 power supply. I'm fairly certain of that. The good news is I'm going to show you how to build one, for free!

Disclaimer: I offer this information without warranty, guarantee, or anything else. These are merely observations that I have made, which I am offering to you for free. If you follow these to a T and still blow up your CP-70, that's not my problem, okay? Okay. If you can live with that, please read on.

The weird CP-70/80 power connector

As you probably know, the CP-70 power supply uses a really funky two pin XLR-like connector for the power supply. This is going to be the trickiest part, finding the connector. It's made by Cannon and the part number is XLR-2A-11C. If you use the Google on the Internets, you should be able to find it somewhere.

A couple years ago I was strolling through the stalls in Akihabara, in Tokyo's famous electronics district. It's an amazing place, not to be missed. There are hundreds of tiny stalls where you could buy, in single-unit quantities, all sorts of electrical components, relays, switches, and connectors. At one stall I found a guy selling this exact same Cannon connector. I bought one and brought it home, but I don't have it anymore. But if you've got Tokyo connections, there's a lead for you.

Update 5/13/2009

Matt writes:
I very much appreciate your article on how to make a CP-70 power supply. I just bought three of the XLR-2A-11C connectors from onlinecomponents.com, and the relevant page is http://www.onlinecomponents.com/buy/ITT-CANNON/XLR2A11C/. There is a $35 minimunm on their orders, but they have a lot of other goodies, so that wouldn't have been much of a problem for me, anyway. I got one for my Kawai EP-308M, one for a CP-70 that's in the mail, and one as a spare.

Currently they are $11.54 each for 1-24 pieces, and they have over a hundred in stock :-)


The power supply

The power supply itself is basically just a wall-wart transformer. It's labeled 12VDC @ 200mA. Basicaly, any wall-wart transformer supplying 12 volts DC and is rated at 200 mA greater should do the trick... with one very important caveat. It must be a LINEAR power supply, not a SWITCHING power supply. In early 2011 Reader David R. wrote to report that somebody is selling CP-70 power supplies on eBay - possibly having cribbed the instructions off of this page - but they used a switching power supply which induces a ton of electrical noise into the CP-70, rendering it useless. So pay attention to what kind of transformer you use. Switching-type wall warts are becing much more common because they're more efficient, and for most digital electronics it doesn't make any difference. But for a vintage beast like the CP70, you really need a linear supply. Oh, and if you're stealing this info - which I offered for FREE - and using it to sell crap on the internet, here's a little tip for you: please have the decency to test your crap before selling it.

Hooking It Up

You'll notice both on the data sheet, and by looking at the connector, that the connector is "keyed" by having a long flat side, and a rounded side. You'll also notice that the two pins are skewed at a jaunty angle, with one pin closer to the flat side of the connector, and the other pin closer to the rounded side. The end of the power supply that goes into the side of your CP-70 looks something like this:

Note that this is a mirror image of what's shown on the data sheet; they've shown the socket, I've shown the plug. Anyway, the two pins of the plug are labeled as shown. Pin 2 is +12 vdc, and pin 1 is ground. Note that the connector case is "floating" - it's not connected to either Pin 1 or Pin 2. On my genuine CP-70B power supply, I measured pin 2 at +18.5 VDC. This is under no load, fairly typical for an unregulated power supply. I could easily believe this drops to 12 volts under load.

I think this info will tell you everything you need to roll your own. If this information was useful or you have a comment, please feel free to email me at the address above.

*update: a source in Europe

Reader David Piccolo informs me that he's found a Dutch company selling these Cannon connectors as well as complete CP-70 power supplies. Check it out: http://www.ep-service.nl/.



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