By way of introduction and my first enquiring post, I am not an electronics engineer nor avid/perpetual audio DIYer.
I would describe myself an occasional DIY upgrader/repairer and would like to consider myself "competent" rather than an expert (I have a physics degree and 25 years experience in electrical/mechanical/plastics manufacturing.
My long serving and long satisfying system is composed of Roksan Xerxes/Tabriz Zi/ATOC9 analogue source, currently supplied by the original DSU2/XPS 3 combo.
Recently the speed stability became degraded and my suspicion was that the DS2 was to blame. (having changed the belt and checked the motor mounting, pulley alignment, main bearing etc)
A quick look inside the wall wart revealed it to be quite a primitive design and replacing the caps restored its function, but...this has prompted me to question the performance of the supply to the motor.
With the "basic" XP7 costing £500 and indicating ripple current of <250mA I can't help thinking I could be something much better for a fraction of the cost….(did I mention I am also very reluctant to spend money?)
I already have a spare centre tapped torroidal 32-0-32V transformer which I would full wave rectify to give notional +32V, 0 ,-32V lines but what would be the most effective way to then achieve minimal ripple whilst regulating down to +26,0,-26V whilst keeping cost and complexity low?
In anticipation of perspicacious replies……
I would describe myself an occasional DIY upgrader/repairer and would like to consider myself "competent" rather than an expert (I have a physics degree and 25 years experience in electrical/mechanical/plastics manufacturing.
My long serving and long satisfying system is composed of Roksan Xerxes/Tabriz Zi/ATOC9 analogue source, currently supplied by the original DSU2/XPS 3 combo.
Recently the speed stability became degraded and my suspicion was that the DS2 was to blame. (having changed the belt and checked the motor mounting, pulley alignment, main bearing etc)
A quick look inside the wall wart revealed it to be quite a primitive design and replacing the caps restored its function, but...this has prompted me to question the performance of the supply to the motor.
With the "basic" XP7 costing £500 and indicating ripple current of <250mA I can't help thinking I could be something much better for a fraction of the cost….(did I mention I am also very reluctant to spend money?)
I already have a spare centre tapped torroidal 32-0-32V transformer which I would full wave rectify to give notional +32V, 0 ,-32V lines but what would be the most effective way to then achieve minimal ripple whilst regulating down to +26,0,-26V whilst keeping cost and complexity low?
In anticipation of perspicacious replies……
To Nigel's point a 32-0-32V transformer is going to give you around 44V unloaded, this is at or beyond the upper voltage limit of most reasonably priced voltage regulators if that is needed.
Is the current supply regulated? And it's not clear that improving the existing supply will necessarily result in any improvement in motor performance at all.
I suspect anything that actually needs to be regulated already is within the drive electronics and the +/-26V you mention does nothing more than power a pair of power amplifiers which are not going to care too much about the power quality.
Is the current supply regulated? And it's not clear that improving the existing supply will necessarily result in any improvement in motor performance at all.
I suspect anything that actually needs to be regulated already is within the drive electronics and the +/-26V you mention does nothing more than power a pair of power amplifiers which are not going to care too much about the power quality.
Thanks for the replies, for the time being I'm using the original repaired wall wart so not desperate to get an alternative. (and maybe the spare transformer I have is not really suitable).
I have to admit to having been a bit surprised at how basic this supply is - not even regulated, just a crude rectifier with 4 diodes and 2 1000uF caps - would this really have minimal impact on the function of the motor drive electronics? This question is somewhat prompted by the existence of Roksan's (expensive) DS1.5 and RPM motor PSUs.
I have to admit to having been a bit surprised at how basic this supply is - not even regulated, just a crude rectifier with 4 diodes and 2 1000uF caps - would this really have minimal impact on the function of the motor drive electronics? This question is somewhat prompted by the existence of Roksan's (expensive) DS1.5 and RPM motor PSUs.
The motor drive electronics can be as stable as the designer wanted; incredibly stable.
UNTIL the "semi-smooth DC" from the rude wall-wart turned ratty because the filter caps quit working. The pulses of DC were so extreme that the electronics could not deal with it.
I'd say you want to freshen those caps every decade or two. I don't yet see how it could be "better", considering that lifetime (oil/film) caps that large would be far more expensive than all the electrolytics it could eat in your lifetime.
UNTIL the "semi-smooth DC" from the rude wall-wart turned ratty because the filter caps quit working. The pulses of DC were so extreme that the electronics could not deal with it.
I'd say you want to freshen those caps every decade or two. I don't yet see how it could be "better", considering that lifetime (oil/film) caps that large would be far more expensive than all the electrolytics it could eat in your lifetime.
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