Author Topic: CP-70 Power supply  (Read 404 times)

Offline EauClaireGuy

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CP-70 Power supply
« on: September 11, 2018, 04:38:02 PM »
Hey guys. Im looking to modify a power supply to fit my CP-70. I have the coveted cp-70 2 pin xlr, the cable is just shot. Im on too tight of a budget to pay $75 for someone to have made one that I could have done myself.

Offline Tim Hodges

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Re: CP-70 Power supply
« Reply #1 on: September 20, 2018, 07:06:06 AM »
You want to buy a 18v DC power adaptor with enough current to power the piano.

The CP70b only takes 40ma so go with something higher than that. All the aftermarket supplies I see online use 500ma - 600ma so they provide more than enough power.

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Offline Tim Hodges

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Re: CP-70 Power supply
« Reply #2 on: September 20, 2018, 07:17:42 AM »
I'd use one like this:

Mean Well, 15W Plug In Power Supply 18V dc, 830mA Level VI 1 Output, P1J Switched Mode Power Supply

The bonus of this supply is that it accepts voltage from 90v - 260v so can be used internationally without any problems. It outputs 830ma so more than enough for the Yamaha.

The only problem I have with these aftermarket supplies is that the cables are very thin and can be easily damaged. The original supplies had a 5 or 6mm cable to protect them when they were on tour.
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Offline EauClaireGuy

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Re: CP-70 Power supply
« Reply #3 on: March 19, 2019, 02:48:53 PM »
You want to buy a 18v DC power adaptor with enough current to power the piano.

The CP70b only takes 40ma so go with something higher than that. All the aftermarket supplies I see online use 500ma - 600ma so they provide more than enough power.

Does this need to be linear or can it be switching?

Offline sean

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Re: CP-70 Power supply
« Reply #4 on: March 21, 2019, 01:44:01 AM »

Twenty years ago, I would have said you must have a linear power supply for any audio gear.  Clearly, that was based on prejudice, bad information, and primitive switching designs. 

However, modern switching power supplies are quiet, clean, light, and efficient.  They are used in all kinds of audio gear today.  Modern switching power supplies don't switch in the audio frequency range, they have effective output filters, and their efficiency is unbeatable.  Get one that is spec'ed correctly for your project, and you will be happy.

Linear power supplies are comparatively bulky, heavy, and electrically inefficient (so they create a lot of waste heat).  But they work, and they aren't ugly expensive.

Make sure you buy the plug adapter with that Mean Well power supply!  The Wisconcin-specific plug adapter is sold separately! 
The MeanWell GE12I18 units are indeed switching power supplies (the only hint on the spec sheet is the hiccup-mode overload protection).

There are cheaper and smaller power supplies (like Triad WSU180-0450 or WSU180-0450-R), but Tim's right - new power supplies have wimpy cables.

If this were my piano, I think I might get rid of the 2-pin XLR connector and replace it with something else.  Three-pin XLR would be cheap and easy, but might cause confusion and mishaps on stage.  Maybe I would leave the original 2-pin XLR, but add a 2.1mmID/5.5mmOD connector nearby (like Switchcraft  721AFMS, or 721A, or one of the similar locking jacks).


Sean