The switching supplies in my 1980's Tek 7854 don't degrade or interfere with any of the plugins which range from 10 uV/div 7A22 amp to 2 GHz spectrum analyzer plugins. In other words low noise switching supplies are not a new and difficult problem to solve. And Tek did not go to any unusual lengths to shield or isolate the supplies. They probably saved money over the shielding needed to a linear transformer they did not need.
I was surprised, long long time ago, how better was my portable headphone amp i used for recording sessions of foleys and dubbings when it was on battery, compared to AC, the first time I had to switch from a PSU to the other because the battery was near to be exhausted.
The same little amp.
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“Porsche uses MacPherson struts in front on the 911. People often consider that an inferior setup, yet the 911 still beats its more powerful rivals on track, even though they are using "better" front suspensions.”
True, however those struts are likely to be of the type that utilize a larger than standard piston, thus reducing likelihood of bind. At least on the race cars that set those standards you are referring to.
This is a case of where a single better component can make a difference...
Often in other situations, a single component an make a difference because it’s performance is stressed in situ.
True, however those struts are likely to be of the type that utilize a larger than standard piston, thus reducing likelihood of bind. At least on the race cars that set those standards you are referring to.
This is a case of where a single better component can make a difference...
Often in other situations, a single component an make a difference because it’s performance is stressed in situ.
Well, the fact remains that for the consumer -- not multi-multi-kilo dollar test instruments and what they can do --- it isnt relevant. I doesn't matter that it can be done very well if at a very high price.
The computer, the Tv, the CD player, the ADC/DAC, file server and so many more do not have such bullet-proof power supplies. Not to mention the proliferation of wall-warts to power and charge consumer products. Power line noise is getting worse from within.
THx-RNMarsh
The computer, the Tv, the CD player, the ADC/DAC, file server and so many more do not have such bullet-proof power supplies. Not to mention the proliferation of wall-warts to power and charge consumer products. Power line noise is getting worse from within.
THx-RNMarsh
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Never mind whether it can be done, fact is it isn't being done. Arguing about what is or should be possible seems rather academic when the reality one doesn't seem to find such perfection in consumer gear and at least in some professional audio gear.
As has been described already DAC-3 and AHB2 have switching power supplies that appear to be pretty good, although nobody here has measured them. And the ones I have are interconnected with short-length balanced interconnects. Empirically, a power conditioner added to the DAC helped. What else am I supposed to do but add a power conditioner? Toss out the DAC-3 and go looking for a DAC with a better power supply and that is otherwise audibly and in terms of specs as good or better than DAC-3? It is not clear if any such device exists, or if it does whether I could afford it (probably not).
However, I can afford an old, used power conditioner that to the limits of my hearing ability seems to solve the problem. What else would you guys do if it were you?
As has been described already DAC-3 and AHB2 have switching power supplies that appear to be pretty good, although nobody here has measured them. And the ones I have are interconnected with short-length balanced interconnects. Empirically, a power conditioner added to the DAC helped. What else am I supposed to do but add a power conditioner? Toss out the DAC-3 and go looking for a DAC with a better power supply and that is otherwise audibly and in terms of specs as good or better than DAC-3? It is not clear if any such device exists, or if it does whether I could afford it (probably not).
However, I can afford an old, used power conditioner that to the limits of my hearing ability seems to solve the problem. What else would you guys do if it were you?
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An interesting point is that Tek (at least in the old days) was an open book. Every piece of gear came with complete schematics and board layouts. They had house part numbers but for a PS you certainly got a good start on what to do.
I thought it was smart to start with Aristotelian 'umph' to explain what we actually see on the surface and then up it to Newtonian later on.
But quANTum now?!?
I'd hate to think that kitty was both asleep and not asleep until he checked!
PS I love "Play Hide-and-Seek with Shrodinger's famous feline!"
Poor kitty!
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Keysight was doing the same. Old Analog IC data books are full of IC schematics, some even with values.
Tektronix today won't even answer basic questions (what does this error code mean?) for their legacy test equipment, the boiler plate response is "buy our new equipment").
Times have changed. But OTOH, IC performance is hidden in the process, not the schematic. I crack opened a Keysight 250k Infiniium-Z 60GHz real time scope, and it's a Chinese quality digital controller PCB, a 3rd party power supply module, a LCD, and a sealed proprietary hybrid per channel, doing all the signal sampling and processing. What schematic would you like for this? When a sampler is gone, it's gone. A new one plus the required calibration is north of 30k.
Thanks, never seen that as a standard option. Anyone other than isolation transformer manufacturers offer that as an option?
They had great tutorial booklets and series on devices and design topics as well. AND, all in plain English, too. They were great communicators and teachers. Service publications on how to trouble-shoot this and that. How things worked. How to calibrate the thing. All a learning experience.
-RM
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yes. several. and I test them to see how well they perform according to the claims.
-RNM
<snip>
Well what I am doing is removing mains power wherever possible and where I can't such as the power amps and bluray player doing the best I can to avoid contamination. For example using optical or AES connections for SPDIF. USB is a major crud source but I use usb to optical as I don't go over 24/96 on anything.
Some good discussion here. What would be nice is if someone with the gear could characterise some of the popular SMPS used for DIY, such as the meanwell units. Simple ways to improve those would be a great help.
I have spent way too much time testing power supplies for amateur radio use (13-14 V units). While doing so I find that the many linear regulated supplies feature much of the same flaws in design as do the SMPS: common-mode impedance and regulation loop time constant for starters. Some supplies overshoot by as much as 15% on a full load to 5% load transition.
I have not tested the DIY recommended supplies, but I have a decent Maynuo 1800 W Electronic load and can characterize power supplies under varying conditions, so if anyone wants me to test a specific supply, feel free to send it...
Cheers!
Howie
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