The first switch mode supply (as far as I know) in an exotic piece of HiFi was introduced by Meridian with their MCA in about 1990. We tested it for wide band noise, as we were cynical it would be a good idea for HiFi, yet it passed with distinction. The designers at Meridian were the tour de force pairing of Allen Boothroyd and Bob Stuart. Have a look at the MCA it is a fascinating design. There have been a few greats in audio and these two belong in that company.
@@jim9930 Yeah but they are so easy to filter. What were they just listening to the mains? I don't on first glance take that seriously at all. Majority of switching supplies will be like a small radio station with plenty of noise, unless you design it out. The radiated portion is most difficult to address and of course none of that with a big bit of iron.. I will watch thanks.
@@jim9930 I watched it. Blimey he talks all over the place! Sure the only noise you need to deal with on a traditional linear supply is 120/60 100/50 and their harmonics. Plus any mains noise that survives. Surprise, surprise worst of the noise from a switching supply will be outside the audio band. I think what he showed was a very average linear supply, (He was looking at -65db and worse), which is pretty poor, best amplifiers even those with zero PSRR expect -90db noise levels -( even in the 1950s) Although I didn't watch much of it so may be making a mistake.
@@jim9930 I forgot about Chord amplifiers. The guy who developed Chord was a power supply designer and he built his amp around his power supplies. He came to see us with the prototype and told us he worked in the MOD designing supplies on the Tornado aircraft and he wanted the 'tightest' supply he could make to be the heart of his amp. That would have been in the early 1990s too. Impressive amplifier.
4:30 - 4 x 4.7 MilliFarad ?? I stopped and rewound the video. That is misleading for people not paying 100% attention, and a very strange and non-standard way to describe the Capacity. What is actually being discussed is 4 x 4,700 uF (MicroFarad) caps!
I have watched Eddys video about his SMPS intention for your JAT501 and I like it very much. Especially I like the idea to use a relatively simple forward converter topology. It is powerful and the effort is relatively low. If you have a stable mains voltage a forward converter doesn't require secondary regulation. The winding ratio determines the secondary voltage. And even if you want to control it, it is easy to do by use of an additional secondary winding. optical feedback ist not required for isolated secondary regulation. I wish you good luck and success for this collaboration.
Please do a video if possible on variable power supply making using Linear or Switching method & explain which one will be noise free at higher current & voltage output. I am asking this because many power supply modules based on linear & switched mode methods are available in market but we don't know which one is better for testing all types of circuits including audio amplifier circuits & also many people can't afford to buy those costly bench power supplies from popular brands
Hi John! I used toroid double secunder (2x24VAC) coiled transformer, with graetz bridge, without capacitors and two DC-DC step down SMPS. It is makes stable +- 17VDC for me. Isolation is solved, stability solved, and power factor much more than it would be with capacitors after the gratez bridge.
Really really impressive noise performance! Really makes me want to build some even more because my desktop speakers are incredibly sensitive and like to show off an amp's noise floor.
How well do you think that amp would preform with 32v 5A center tapped transformer (2x16v) I am asking because i would like to build it and i have a salvaged toroidal transformer that is just sitting in the box and doing nothing, It would be nice to use it. I would be fine with around 40-50w into 4 ohms.
I would say 48v not 42v or you could have auto-sensing circuit, and what about current draw what maximum current are you looking at? I would say 700-800 w for high-powered amplifiers need that or even more the extra headlam helps as well i think in a cleaner less demanding on the power supply. especially that wattage for high power consumption valve amplifiers you need the 700watts
