Hi all, I have a query about power supply design for multiple pedals and wondered if you good folks might be able to enlighten me a bit? I ask given the cost of power supplies is non trivial these days and marketing hyperbole makes it difficult to make an informed decision. And once you fall down the rabbit hole of trying to understand something, you naturally find you have questions as you want to learn why rather than just the narrow window of how.
As I understand it, there are multiple linear power supply topologies that would be suitable for powering multiple pedals but I'm not especially clear on what the potential benefits could be. The ones I have in mind are as follows:
1. Transformer => Full Bridge Rectifier => Voltage Regulator + smoothing caps => multiple pedals connected in parallel
2. Transformer => Full Bridge Rectifier => Multiple Voltage Regulators connected in parallel, each with their own smoothing caps and each feeding a single pedal.
3. Multiple Transformers each with their own rectifier, regulator etc. Essentially an entire power supply per pedal.
I believe Option 1 is worst from a noise perspective given that both ground and 9v rails are common and noise can migrate between pedals, but it is the cheapest approach. Option 3 is best from a noise perspective given that both ground and 9v rails are (or could be) isolated for each pedal, but it is the most expensive approach. Option 2 could offer an isolated 9v rail for each pedal (I think) but ground will be common.
Questions:
a) Does anyone know if Option 2 offers any meaningful benefit over Option 1 in terms of noise?
b) If each voltage regulator in Option 2 also had its own bridge rectifier, would that likely be an improvement?
c) Are switched mode power supplies still best avoiding? I have had very inconsistent result with these over the years but maybe I've just gone for cheap stuff given there's SMPS in multifx units, etc.
d) Could there be any conceivable benefit in the use of a regulated and isolated 4.5v supply for biasing purposes?
Thanks for reading and apologies if this is covering old ground (pun intended).
As I understand it, there are multiple linear power supply topologies that would be suitable for powering multiple pedals but I'm not especially clear on what the potential benefits could be. The ones I have in mind are as follows:
1. Transformer => Full Bridge Rectifier => Voltage Regulator + smoothing caps => multiple pedals connected in parallel
2. Transformer => Full Bridge Rectifier => Multiple Voltage Regulators connected in parallel, each with their own smoothing caps and each feeding a single pedal.
3. Multiple Transformers each with their own rectifier, regulator etc. Essentially an entire power supply per pedal.
I believe Option 1 is worst from a noise perspective given that both ground and 9v rails are common and noise can migrate between pedals, but it is the cheapest approach. Option 3 is best from a noise perspective given that both ground and 9v rails are (or could be) isolated for each pedal, but it is the most expensive approach. Option 2 could offer an isolated 9v rail for each pedal (I think) but ground will be common.
Questions:
a) Does anyone know if Option 2 offers any meaningful benefit over Option 1 in terms of noise?
b) If each voltage regulator in Option 2 also had its own bridge rectifier, would that likely be an improvement?
c) Are switched mode power supplies still best avoiding? I have had very inconsistent result with these over the years but maybe I've just gone for cheap stuff given there's SMPS in multifx units, etc.
d) Could there be any conceivable benefit in the use of a regulated and isolated 4.5v supply for biasing purposes?
Thanks for reading and apologies if this is covering old ground (pun intended).
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