Haney
New member
Hi all. I'm trying to track down the power capabilities of the +-7 volt "phantom power" as per the Roland 13 pin guitar MIDI spec. In this particular case its for the Axon 100 MKII pitch to midi converter. Pin 12 is +7 and pin 13 in -7, but my search for current specifications has failed.
I'm building a custom bass that has quite a lot of bells/whistles (lights, motors, stuff...) and the inevitable large power draw. Batteries (especially Li-ion) are not COMPLETELY out of the question, but I'm severely disinterested in them as an option.
Typical hexaphonic preamps have a 9 volt auxillary output for the main magnet preamp (which draws from pin 12/13)... but mag preamps tend to use a whole 1 mA, so I'm doubting they would have left much more available juice in the specifications.
I'm currently tempted to bypass the magnetic and power signals altogether and provide a dedicated, transormer balanced output for the mag. I'd couple that to a floor box with a matching transformer in reverse to bring it back up to impedance and a PSU tossing 18v back towards the bass (for an 18v mag pre). From there, step down DC-DC converters in the instrument itself to supply the 12, 9, and 4 volts necessary for other doodads. Oh, and of course 1/4" out from the floor box after we're back up to impedance. I'm terrified of ground loops in this setup, but I'm under the impression the transformers should provide a degree of isolation?
I just happen to have a pair of unused Jensen JT-DB-E trannies in my possession, so this solution grows sexier by the minute.
I have heard relatively negative things about the Axon's (noisy) guitar output... and I don't particularly like the idea of having the mag signal buffered at the Bartolini/Aguilar pre, AGAIN at the Graphtech hexpander pre, then AGAIN at the Axon output. That's 2 unnecessary buffers, both of which are doubtfully up to par with the Bart/Ag, and a good deal of cable to traverse for essentially nothing.
Ideas, thoughts, suggestions?
Thanks.
I'm building a custom bass that has quite a lot of bells/whistles (lights, motors, stuff...) and the inevitable large power draw. Batteries (especially Li-ion) are not COMPLETELY out of the question, but I'm severely disinterested in them as an option.
Typical hexaphonic preamps have a 9 volt auxillary output for the main magnet preamp (which draws from pin 12/13)... but mag preamps tend to use a whole 1 mA, so I'm doubting they would have left much more available juice in the specifications.
I'm currently tempted to bypass the magnetic and power signals altogether and provide a dedicated, transormer balanced output for the mag. I'd couple that to a floor box with a matching transformer in reverse to bring it back up to impedance and a PSU tossing 18v back towards the bass (for an 18v mag pre). From there, step down DC-DC converters in the instrument itself to supply the 12, 9, and 4 volts necessary for other doodads. Oh, and of course 1/4" out from the floor box after we're back up to impedance. I'm terrified of ground loops in this setup, but I'm under the impression the transformers should provide a degree of isolation?
I just happen to have a pair of unused Jensen JT-DB-E trannies in my possession, so this solution grows sexier by the minute.
I have heard relatively negative things about the Axon's (noisy) guitar output... and I don't particularly like the idea of having the mag signal buffered at the Bartolini/Aguilar pre, AGAIN at the Graphtech hexpander pre, then AGAIN at the Axon output. That's 2 unnecessary buffers, both of which are doubtfully up to par with the Bart/Ag, and a good deal of cable to traverse for essentially nothing.
Ideas, thoughts, suggestions?
Thanks.
