Author Topic: power mod  (Read 3912 times)

Offline jim

  • Mark I
  • ****
  • Posts: 743
    • View Profile
    • http://www.myspace.com/cyberjimpatterson
power mod
« on: October 11, 2005, 09:34:12 PM »
hello,
can anyone give me any information on how to modify a 1973 suitcase amp from using US 120volts to Australian 240 volts???
i noticed in the schematics in the service manual that the later year models include "export version" transformer schematics, but there doesn't appear to be any export version information for the earlier fender rhodes's.
cheers, Jim.

Offline jeffwuollet

  • Sparkletop
  • ***
  • Posts: 90
    • View Profile
power mod
« Reply #1 on: October 17, 2005, 08:19:47 AM »
There are companies that make step down trasformers that can go to 240V. It's not about making the unit run on 240, but changing 240 to 120 out of your wall socket-into the rhodes.

Transformers can be either internal or external. If you know how to solder, you can install a step down Xformer and hot wire it to a 2-pole ON-ON switch to change from US to Aussie incase you happen to gig around the world tomorrow.

The switch should be AFTER the Xformers to keep things safer and make it easier to replace them later if you have to...
If you want to know where to find the booze, ask the engineer...

Offline jim

  • Mark I
  • ****
  • Posts: 743
    • View Profile
    • http://www.myspace.com/cyberjimpatterson
power mod
« Reply #2 on: October 20, 2005, 01:39:58 AM »
i was thinking i could just change the transformer so that it gives the same voltage (35+ 35-?) as the US transformer does.
so like, where 120v is turned to 35v,  240v is turned to 35v instead.

it seems silly to me to change the power twice when i could just do it once.

no?

Offline jim

  • Mark I
  • ****
  • Posts: 743
    • View Profile
    • http://www.myspace.com/cyberjimpatterson
power mod
« Reply #3 on: October 20, 2005, 01:40:46 AM »
by change i mean replace.

Offline jeffwuollet

  • Sparkletop
  • ***
  • Posts: 90
    • View Profile
power mod
« Reply #4 on: October 25, 2005, 11:23:32 AM »
I guess I made a mistake as well. I'm taking the hard way by adding a second x-former. I need to find the circuit diagram for those old marshall stacks that can switch between 120-240 volts only using one transformer.

I have a sound city amp that has this feature and curiosity now has the best of me. I'll crack it open and see if I can't draw out the signal path for the switchable input voltage. I'll check it out today after I gain the strength to get outta' bed...
If you want to know where to find the booze, ask the engineer...

Offline jim

  • Mark I
  • ****
  • Posts: 743
    • View Profile
    • http://www.myspace.com/cyberjimpatterson
power mod
« Reply #5 on: October 25, 2005, 11:40:17 PM »
hey i actually figured it out.. (or learned it from several sources)
there are four wires going into the transformer from the 120V side. These are connected in parrallel for 120 V.
so if you connect the two middle wires it will be in series. so 2 times 120 is 240!!   and i did it and it totally worked!! hasn't blown up yet!!

Offline jeffwuollet

  • Sparkletop
  • ***
  • Posts: 90
    • View Profile
power mod
« Reply #6 on: October 28, 2005, 12:45:30 AM »
Ask that dude if he has wiring schematics for any rhodes gear. That would make mods and fixes easier, but I can't find any online.
If you want to know where to find the booze, ask the engineer...

Offline jim

  • Mark I
  • ****
  • Posts: 743
    • View Profile
    • http://www.myspace.com/cyberjimpatterson
power mod
« Reply #7 on: October 31, 2005, 05:16:24 PM »
i got the info from searching for transformer i think on the rhodes yahoo group.
i think it may have been peacefreak that said it?? i'm not sure,