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John Warren

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Everything posted by John Warren

  1. On target. I heard a couple of tunes from a 1990s mix on Amazon Music and was like, "umm, what did I just hear?"
  2. I've been listening to the recommendations btw! It also highlights the range of musical tastes of folks, excellent!
  3. A few more photos perhaps. This doesn't look like a factory EV unit. The EV cabinet shop was located in Buchanan, MI. EV cabinet work was excellent, best in the industry and comparable to JBL. EV horns were, if memory serves, all 3/4" thick stock. I don't think they ever sold a "decorator" type unit.
  4. Oh my! and yes, University of Virginia, 1994, PhD Materials Science and Engineering. Unfortunately, products with the goofiest claims in audio are associated with materials science, more specifically, metallurgy. However, the absolute STUPIDEST thing in audio is a non-existent physical phenomenon that cable "lifts" are solving, the so-called interaction between the electrons passing thru the cable and the floor. FFS, Maxwell would get a laugh out of that one!
  5. How exciting, thank you Travis for taking the time and effort!
  6. Excellent, thank you all for the nice comments. I have a pair of MC60s here and one power supply transformer isn't providing any output voltage on the filament tap suggesting either a broken lead, or an open secondary. I haven't gone into the transformer but it might be as simple as a cracked lead. It the leads are ok something a bit more drastic will be required.
  7. Now time to work on the second unit. It's a bit different than the first unit. I think it's an earlier production asset based on SN. This is what I salvaged from the OEM assembly. The power and output transformers, the capacitor frame, the phenolic circuit board and the tube sockets. The electrolytic multi-section caps will be replaced with CE Mfg equivalents. The transformers show the extent of the potting encapsulant poured into each. The output transformer is shown in the top and in the second photo. Note the band strap clamp protruding from the potting.
  8. Call me old-fashioned but the OEM power cable should be replaced with a 3-C cable with Earth prong. Safety First! Green is Earth White is Neutral Black is Death
  9. The customer provided tubes were worn but still able to provide a respectable 0.12% THD+N at 16.9VRMS out into an 8Ohm load @1kHz.
  10. The amplifiers power supplies and rectification for both B+ and the bias supply are located on the capacitor frame. This assembly takes the bulk of the labor to rewire on this project. The board holds capacitors for the tube circuits on one side and the resistors on the other. The finished amp came out quite nice.
  11. And here we are about halfway thru the restoration.
  12. The MC40 chassis from the Korean supplier are really quite nice. I had the factory bottom covers chem-etched and painted.
  13. Truth and good advice, thank you.
  14. Info here: North Reading Engineering
  15. Thank you gents! Yes, it is. I always liked the look of the -1C, the cabinets are old school, 1" thk particle board. Note the equalizer sitting on the tuner. Without either the MQ101 or 102 equalizer the ML systems will have poor bass response so, if you buy a buy a pair without the equalizer, you will be unhappy.
  16. Something a bit different. Retiring from full time work, had time to design a little 7591 p-p amp. Solid state, power supplies for HV and bias suppliers. non-inductive B+, metal film resistors, microphone cable for all small signals. separate circuits for chassis and 0V references, filtered AC input, all metal construction, no sheet metal screws. Top plate is CNC machined, black anodized, 1/4" Aluminum plate stock. Bottom section 300 series mirror stainless, CNC formed directly from my CAD files using SolidWorks. Can use Lundahl or Hammond transformers. Everything but the output transformers sourced from USA. The graphic overlays are the same material plastic lenses for eyeglasses are made from (optical polycarbonate). There's a very cool hifi store a few miles from my place where we gave it a listen for most of the afternoon on a pair of Focals and they'd like to have the amp to show in their listening area. I'll set up but I'm a wee bit hesitant to become an amplifier manufacturer, could be fun but some hassles to. I'd have to set up a facility. Then there's the "how do you compete against the Chinese $800 everything tube amps?"
  17. I'd say that McIntosh used the assembly methods and parts distributors typical of their peer competitors. I agree there's nothing particularly special about their amps other than a somewhat unique output transformer design, i.e. the Unity Coupled Output transformer. Even here however I'd be hard pressed to hear a difference when comparing to other excellent amps of the era. My favorite amp from the late 50s early 60s is later production HK Citation IIs, the units with the Stancor or Magnetics Windings output transformers of which I have two in my own gear.
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