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In Reply to: RE: Thinking outside of the box posted by Mike Mount on February 26, 2021 at 10:28:40
I had to try this CLC supply using the exemplary $$$$! Mundorf MLyticHC caps, they are such incredible components. 4 times the cost and 1/2 of the capacitance compared to "the other" CLC supply... I have said it elsewhere / before ~ they are a break-through ~ in performance, in 4 other amps that I have built and tests, using them... We will see.
The Mundorfs are much larger, which required a different chassis layout to fit them and to get the lead lengths of the toroid and the inductors to reach. I wanted to retain the magnetic isolation of prior build, with the transformers in the front of the chassis. I still have 1/3 of the rear of the chassis to place the driver board and heatsinks, that will eventually be used (in place of the "Hafler" power modules.
I wanted a sound comparison of United Chemi Con caps and the Mundorfs to determine while I will use in my final amps design / build. I have included the commentary about various power amp configurations that I have used so far to test these Power Supplies.
I have been starring at the 3rd supply trying to reason how I want to wire it. I am very happy with the UCC capped supply... but there is not way to duplicate it with this layout, everything is different, even with 2 inches of additional (interior) chassis height... I am still somehow a bit cramped.
The massive - fat caps dictated many layout options, working with inductor lead lengths and a tidy ground buss / ground set-up... Still working to figure it out... Mean-while the UCC franken'amp is serving well with the Maggies and I have "a spare" 500 and 600 heat-sink assembly to work on... I am *completely* rebuilding the chassis pans on both amps...
~ decisions - decisions ~
Follow Ups:
Those are very impressive builds and I agree entirely about the value of a great power supply. I like the construction technique as well: very clean and sanitary. Who makes those extruded metal frames you use?
I have found that a typical commercial amp generally can not even come close to providing adequate current for transient musical events, in particular. Two very mundane examples are the popular Dynaco ST70 and SCA35. Both of these amplifiers have severely limited power supplies that are not just hot and noisy but entirely insufficient for providing the necessary current without compromise during loud passages.
For example, I measured the current at full output with both channels driven on a SCA35 to be 200mA with a 20V sag in B+. The power transformer is specified at 180mA! Installing a 250mA external supply with low impedance output totally transforms this amplifier from mid fi to hi fi!
I find that I only need a couple of power supplies for a multitude of potential topologies and tube types. I have one that is 550V @ 350mA and another at 500V @ 300mA. No electrolytic caps are used in either; I use Wima DC Link MKP4 and two very low resistance chokes at <25r @ 4 H each. The 550V is choke input only but the 500V is cap input and could be choke input for something like a PP EL84 or 2A3 SE amp to reduce the output voltage to 400V.
Here's the 550V @ 350mA supply:
Here's the 500V @ 300mA supply:
Thank you for commenting. I used 2020 extrusion from the family of 8020 offerings.
The way I built them, there limited "hazards" to the open chassis, with few exposed / contact points with voltages... I may never enclose them... not for a while anyway... I am still experimenting and learning... while, layout options keep changing ;)
I had planned to make a chassis from scratch, when a friend suggest I look at the 8020. I have all of the sheet / plate aluminum, bar stock and angle material. While I was considering layout options. I opt for the 8020 and .can. use the plate material if/when I decide to enclose them.
I like your PS, tube rectification, PI filtered and NO electrolytics (I am a big fan of WIMA caps) use the a lot for PS and as a bypass cap, as you know, they are very neutral and affordable. As a stack metal film, they cannot be beat to bypass electrolytic caps...
Dr. Low Mu (Jeff, is a long term friend) has shared many of his builds using .many. of the same things as in you marvelous builds... KUDOS!!!
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