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Post by ROWUK on Sept 8, 2019 2:31:56 GMT 10
Does this thread not show how much is unclear about the audibility of dirt in the ground or in the various rails? The whole idea of power supply filtration assumes that the ground is good enough. What do the caps (or CCS) in the power supply really filter out - and how relevant is that to sound? Do cheap SMPS really "inject" fog that gets through the caps/ground or are we just hearing artifacts from another process. Could a better power supply help? Does a regeneration UPS isolate the ground or would that be the best place for a separate technical earth?
Granted, for "perception" maybe there is consolation in knowing that the switching devices are off line.
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sandyk (RIP Alex, 1939 - 2021)
Global Moderator
Posts: 226
About Me: Retired ex Principal Telecommunications Technical Officer with 43 years at Telstra (Australia)
I am also a Moderator in Hi Fi Critic Forum
Electronics hobbyist for >65 years with DIY projects including Loudspeakers, Stereo FM tuner, S/W Regen Receiver, Superhet AM ,
Synchrodyne PLL AM tuner (Phase Lock Loop),Stereo Tape Deck, Amplifiers including I.C. types, Class A, Class AB 100W/Ch. (ETI5000) 240W/Ch. Mosfet (AEM6000) ,several DACs , numerous PSUs including VERY low noise (<4uV) types etc.for myself and friends
Audio Industry Affiliation: NIL
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Post by sandyk (RIP Alex, 1939 - 2021) on Sept 8, 2019 9:31:11 GMT 10
Robin Back in the old Analogue Telephone Exchange days, even differences in the earth resistance of some exchanges, such as on opposite sides of the city often resulted in low level background hum, despite using balanced transmission feeds. The best way to improve this is with special A.C. isolation transformers having 5/8 of SFA capacitive coupling between input and output. We have a member who is highly qualified in this area, so perhaps we can get Gary to go into greater depth in this issue ? Another obvious remedy is to use battery derived power wherever possible.
Kind Regards Alex
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Post by ROWUK on Sept 9, 2019 4:34:43 GMT 10
Robin Back in the old Analogue Telephone Exchange days, even differences in the earth resistance of some exchanges, such as on opposite sides of the city often resulted in low level background hum, despite using balanced transmission feeds. The best way to improve this is with special A.C. isolation transformers having 5/8 of SFA capacitive coupling between input and output. We have a member who is highly qualified in this area, so perhaps we can get Gary to go into greater depth in this issue ? Another obvious remedy is to use battery derived power wherever possible.
Kind Regards Alex I have often thought about batteries, but have yet to hear one better than a „proper“ supply on a good electricity day. I am not convinced that the „problem“ is not clean DC - or modulating rails. I am also not sure what a battery powered device in a chain that has AC power supplies for other devices really could help.
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sandyk (RIP Alex, 1939 - 2021)
Global Moderator
Posts: 226
About Me: Retired ex Principal Telecommunications Technical Officer with 43 years at Telstra (Australia)
I am also a Moderator in Hi Fi Critic Forum
Electronics hobbyist for >65 years with DIY projects including Loudspeakers, Stereo FM tuner, S/W Regen Receiver, Superhet AM ,
Synchrodyne PLL AM tuner (Phase Lock Loop),Stereo Tape Deck, Amplifiers including I.C. types, Class A, Class AB 100W/Ch. (ETI5000) 240W/Ch. Mosfet (AEM6000) ,several DACs , numerous PSUs including VERY low noise (<4uV) types etc.for myself and friends
Audio Industry Affiliation: NIL
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Post by sandyk (RIP Alex, 1939 - 2021) on Sept 9, 2019 9:09:34 GMT 10
Robin Back in the old Analogue Telephone Exchange days, even differences in the earth resistance of some exchanges, such as on opposite sides of the city often resulted in low level background hum, despite using balanced transmission feeds. The best way to improve this is with special A.C. isolation transformers having 5/8 of SFA capacitive coupling between input and output. We have a member who is highly qualified in this area, so perhaps we can get Gary to go into greater depth in this issue ? Another obvious remedy is to use battery derived power wherever possible.
Kind Regards Alex I have often thought about batteries, but have yet to hear one better than a „proper“ supply on a good electricity day. I am not convinced that the „problem“ is not clean DC - or modulating rails. I am also not sure what a battery powered device in a chain that has AC power supplies for other devices really could help. Hi Robin I am talking mainly about using rechargeable batteries in sensitive areas such as USB Audio, where it's best to avoid even tiny amounts of capacitive coupling back to mains earth . Another alternative is to use UltraCaps in those areas , preferably with the voltage regulation BEFORE the UltraCaps , not after the UltraCaps as most manufacturers do. In many areas, the A.C. mains supply is pretty good, and you don't need to resort to Isolation transformers etc. I don't need to, but for best results with USB Audio I do use a 12V Li Ion battery followed by a voltage Regulator and JLH PSU Add-On (if needed) to power a USB Regenerator. If the file to be saved does not need enhancement (without changing the Binary Data) I often use the 12V Li Ion battery directly for the USB Regen and a USB Memory stick to improve the Signal Integrity of the A or V file that I am saving. I am able to use 12V for the USB Regen in that case, because a USB memory stick's current draw is relatively low.
John Kenny has taken this area much further than I have, as I don't use USB with a DAC, only for USB storage. If you need further info about the use and advantages of LifePo4 batteries and UltraCaps etc. , I am sure that John will be able to give you a great deal more information in this area.
If you don't live in a city, then it would be possible to use Solar Power with 48V battery storage. In that case, it would be better to use the power directly for some devices without conversion to A.C. first Regards Alex
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