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I have a long held tenet and feel very strongly, that revisions, improvement and address of the certain and fundamental limits of the stock power supplies, warrants and very much needs attention. The multitudinous implementations (several dozen) each have show improvement... are all worthwhile. That said I have stuck with beefy, expensive, large, heavy linear supplies.
I am not trying to build to a budget, or even constraints of the chassis. I am trying to advance the performance capabilities to the very highest order possible... comparing (my modest home build) results to inordinately expensive solid state and even vacuum tube gear... OTL amps. This is how I spend my time in retirement.
(at this point) these are using Hafler heatsinks / output configuration (for proof of concept testing) it has been easy to scale each step and compare the evolution along the way, staying with the basic amplifier modules that I have been using for many years.
I continue to hear notable improvements with each progressive step... I cannot encourage enough, the level of attention to the power supply, regardless of whether Linear or SMPS... the circuit will respond, merit the work [if implemented well]
At present, I have 2 supplies, using the Mundorf MLytic HC and *traditional* United Chemi-Con electrolytic. The Mundorfs are .so expensive. However, they are nearly a break through in performance... the best caps, I have tested or heard.
My (stock Hafler chassis) P230 has evolved into the test chassis which is mocked up on plywood (do not ridicule me;) as I wanted to test concept on cheaper material than 1/8" sheet aluminum, as there is a great likelihood of changes in the layout as I evolve with this project...
The choice of 8020 extrusion for mocking up my proof of concept CLC power supplies permit unlimited flexibility to change and easily adapt. The open chassis also permit easy access to work on the piece from any angle, versus being confined to a box.
The choice to test with Musical Concepts PA7 driver PCB / Hafler power modules allowed me to test the CLC supplies, side-by-side the "stock chassis" and amps that I have been using. Working with a known quantity. Admittedly, it may look funky, ill-chosen... It is effective and planned.
Edits: 02/26/21 02/26/21Follow Ups:
I have loved the look and flexibility of the 8020 stuff since first seeing it about 5 years ago. It is very $pendy though. Nice work.
"Starting in the middle of a musical sentence and moving in both directions at once." - John Coltrane.
Cpwill
Thank you. I bought all my materials from Amazon (saved a lot of money) I have averaged a little over 100.00 material costs per chassis. The isolated transformer front end [on chassis pairs 2-3] added about 30% to the cost.
The "savings" was indirectly applied to the band saw purchase, which I used to cut all extrusion and aluminum stock. The band saw paid for itself already.
I agree, with the pricing from 8020 direct, I was figuring over 350 per chassis, for cut extrusion, frame mounts, all connectors and stainless hardware... plus, it was a 3-4 week wait for the delivery after ordering.
I get 2 chassis for each 99.00 (10 pack) of 2020 extrusion, with careful planning, I had very little "waste" (3-6 inch) spare parts.
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 ~
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!!!
I have got to say, I am astounded by the attributes of the Exicon MOSFETS with Musical Concepts PA-7 driver card... driven by the Franken'amp CLC power supply. [I think] that it outperforms the XL600 power module with PA-7 and stock Hitachi MOSFETS. It is still early to make that comparison...
This is the best that I have ever heard my Magnepans sound... Among the best I have ever heard *any* Magnepans ~ ever sound ~ The classic panel / diaphragm "coloration" in the upper mid-range and mid-range is gone... The Franken'amp exerts such incredible control over the speakers, they are tighter than tight, have the cone driver speed and neutrality, without any enclosure sound and will play super loud... it is nearly scary...
I have been listening to this amp for 3 weeks, letting a few new parts parts burn in...
I finally had an opportunity to experience the "XL600" 16 output power module on the CLC power supplies... It is astoundingly powerful, refined with incredible finesse and sense of power. I drove the Maggies in ways that I have never heard from them.
The classic *bang - blur* fast leading edge, slow trailing edge, (to me) typical of Magnepan's even on world class, monster power amps... was virtually absent. The sound of the 600 power module, driven by Franken-amp CLC power supply transformed the nature of the "XL600" and the Maggies... I struggled to take it out of the circuit ~ to hear the "DH500" power module with the Exicon MOSFETS.
The improvements and refinement continues in a very linear and meaningful ways... AS WE KNOW ~ THE AMP IS THE POWER SUPPLY ~ it's abilities and/or limitations... The beefy supply helps to better hear the refinements in the amp module (the circuit) and the better circuit helps to better understand the improvements in the power supply. The lens of truth and understanding lays everything out very clearly.
Going step, by step through the various build stages of the power module... without limitations of the power supply (unregulated power supply sag) noise, etc., has been vital to linear understanding.
The DH500 shown, in the foreground now gets converted back to normal with integrated internal power supply after experimenting with the CLC supply.
My next project was in building an over the top (bordering silly) big P/S to run a Hafler 500/600 modeled amp and eventually use the Exicon T0-264 dual die MOSFETS or possibly 2 pairs per chassis, of Hypex UCD 400/700 or ICE500/1000a power modules to build mono blocks for bi-amping my Maggies. A whole other post and topic [later this year]
I chose this layout the amps differently due to using a larger 1000va toroid and the huge United Chemi Con electrolytics. This supply will drive the "Hafler 500 or 600" with great reserve and will easily have dual amplifier modules per chassis. At this point I still consider these proof of concept builds... as I am experimenting with parts and wiring layout. I have listened to the 500 heatsink with Musical Concepts PA7 driver boards for about 3 weeks and am very happy with results, it is amazing. *I chose these large 39,000 mfd caps, in that *IF* I did not like the result, I could repurpose them in a "stock chassis" of a 500 or 600 amp...
In the meantime, while I re-built the chassis pan of my XL600, using Cardas RCAs and 5 way binding posts, along with heavier gauge wiring, cleaned up the AC wiring layout and installed an IEC jack. I stripped the amp down exactly like the 500 to keep everything the same... for easy comparison. Right now the XL600 is powered by the Franken'Amp CLC supplies... I have only taken a few pictures... too busy listening. This 3 piece Franken' amp is a monster, frankly I am nearly surprised I have not popped fuses in the Maggies, not by abuse or clipping... simply putting humongous amounts of power into them. I never heard any Maggies or my Maggies play like this... I doubt the I would ever need a subwoofer... they do ~ big ~ tight ~ bass. This amp configuration exerts incredible bass control over the panels...
I needed to create room for the audio circuit (in the back 1/3 of the amps) and will admit to feeling driven to isolate the magnetics of the toroid and inductors from the audio circuitry... I pondered the parts in various layouts for over a month and finally resolved all of my goals with this layout. I wanted to keep the wiring paths short, symmetrical and tidy [rats nests make me crazy] not judging anyone else's work, I am my own worst critic.
This power supply driving "Hafler 500 and 600" has ridiculous clarity, sense of finesse and effortless ease. The Macro and micro dynamics are unparalleled, compared to any amp that I have built in 40 years...
My reference for sound has been the Futterman OTL4 sitting in the middle of the frame... I have only powered it up ~once~ the past 2 months of being blown away by the CLC designs.
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