|Stoffie1974 ||08-20-2013 04:29 AM |
EHX BASS MICROSYNTH & DAISY CHAIN...
Got my bass microsynth just today and i read : "DAISY CHAIN WILL NOT WORK" in the manual... IS THIS TRUE??
First of all, i have THE NEW bass microsynth (true bypass, 9V, white body). I found schematics of the old (late 70's) microsynth, where the single power is converted into +12V & -12V with a NE5554, but this does not apply to the new version, the design is COMPLETELY different. Since i'm an electronics engineer, i thought let's find out on the bench and see whats in the box. My first impression?? This thing is way overpriced for the standard components i found inside (but that can be said about every pedal!!)! If you can copy the PCB & build your own with the same components, you're set with 50$... but let's call it "design & engineering". Anyway, the grounds of the 2 outputs are connected to each other, so thats OK (the external rings are isolated from the ground & body, you need to measure inside), BUT... the PS connector has a reversed polaristion diode ON THE GROUND instead of on the positive (like most circuits have). This means that the input & output ground are 0.7VDC HIGHER than the power ground. This is also the reason why they provide a 9.6V PSU. If you daisy chain this with another microsynth pedal, or a pedal with the same circuitry, it should work (although there will allways be a slight DC difference in between the pedals), but if you daisy chain this with for example a BOSS pedal... you might fry the diode or even worse other opamps inside. So the verdict goes : IT IS NOT DAISY CHAIN COMPATIBLE. Is this useful ? probably not to the musician, but they can sell an extra adapter for each pedal! And for those who wrote that it consumes 180mA... this would be for the old version, mine took only 4mA (no signal injected) with LED on. Then again, if they daisy chained it with other pedals, it might explain the higher current, because you force the other pedals to the same potential... putting stress on the diode & output opamp, something should get hot inside and you should hear it when playing. And thinking that there are pedals with AC adapters or those that run on 12VDC and 18VDC (T-REX, DOD,...). So ISOLATED power supplies are the best option, but instead of paying +200$ for a Voodoolab pedal power, i'm thinking fo building my own flightcase with integrated (isolated) power supply, it isn't so hard to do (start with 2 12V/1A transformers with 2 or 4 secondaries, regulated on 9V & 12V for each output and you're done). I prefer the good "old school" power supplies instead of those miniature switching PSU's with their HF noise, and always dying on the scene!!