Author Topic: 4 or 5 pin? & suitcase power supply problem  (Read 4051 times)

Offline zsarrr

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4 or 5 pin? & suitcase power supply problem
« on: May 17, 2004, 06:52:22 AM »
First of all great site! It's so good to gather so much information on these beauties even from this far (Hungary)!

And now:
I own a 1978 Mark I which originally used to be a suitcase. As the speaker part is missing the guy I bought it from converted it to be a stage piano by adding legs. However the only thing he could do with the preamp part is to change the power amp cable slot to a 1/4" jack slot and added a separate slot for a 12V mains adapter which powers up the preamp. I have the following problems/questions:
- when I use the preamp the sound crunches when I hit the keys harder
- the volume knob and the EQ faders work fine but the vibrato does not
- the guy said 12V is enough though I have the feeling the it should be 15V (?)
- if I use the piano with a cable directly from the harp assembly I have a much clearer sound but very weak signal to use directly with a PA system

What could be wrong with the preamp?
By simply looking at the age of the piano (22/1978) can you tell which power amp slot could the piano have originally: 4-pin or 5-pin?
Would buying the Rhodes suitcase power supply from CAEsound and changing the power amp cable back to 4 or 5 pin slot solve my problem of vibrato/signal etc?
Any other solutions?

Thanks for your help in advance!

Take care,

Dan

Anonymous

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4 or 5 pin? & suitcase power supply problem
« Reply #1 on: May 24, 2004, 07:42:21 AM »
Hi :-)
If you have a Piano top with sliders (as i assume by your text) you'll need a dual +/- 15 V supply...this might the cause of the distorted sound you get and the tremolo not working.

If you have a 4-pin Piano-top (all controls rotary) you'll need a single 24 V supply. Becuase of the bulbs in the tremolo circuit, the preamp will draw roundabout 250mA current, so you need a slightly bigger supply than a standard wall-wart.

22/1978 should definetly be a 5-pin Piano top.

Make sure that the accessory loop has propper connection. One of the sockets is a switching socket which can get dirty and cause interruptions. Just try a patch cable into these jacks and seen if the problem is gone. If so, clean the switch inside the socket...this should solve the problem.

regards, Jens

Offline zsarrr

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4 or 5 pin? & suitcase power supply problem
« Reply #2 on: May 24, 2004, 08:03:34 AM »
Thanks very much for the info. I will check it out!

Take care,

Dan