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mwl168 last won the day on July 31

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About mwl168

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  1. Quantity of 1 for the mini T2 represents a pair of left and right channel boards.
  2. mwl168

    Speaker Porn

    Need a bigger TV.
  3. mwl168

    Voluntary amp builders?

    At the risk of stating the obvious regarding measurements; there is a key factor of “correlation”. I remember more than 20 years ago I read an article to the effect of the three legs of measurements- “What do you measure? How you measure it? How do you interpret the measurements?”. As an example, it’s obvious that measurements of an amp’s physical dimensions have no direct correlation to how it sounds. I always wonder, much like many research in medicine, if some day someone(s) will eventually figure out a comprehensive set of measurements that truly have a direct correlation to how a device sounds to human ears (if that’s even possible).
  4. mwl168

    Happy Birthday johnwmclean

    Happy Birthday John!
  5. mwl168

    current feedback electrostatic amp

    1. I use the digital volume on my DAC but you can easily add a volume control to the amp. 2. This chassis I use is quite small - dimension is 160mm x 70mm x 311mm. It's only for the amp circuits and you cannot fit the entire amp in it. There is a PSU in a separate chassis. As an example, you should be able to fit the entire amp including the PSU in a chassis like this. 3. My rough estimate for parts alone would be about $700 US that also covers chassis, transformer, connectors, wires and a reasonable 4-gang volume pot. Like most things these days, labor is the biggest investment. Cost can escalate quickly if you start getting into fancy chassis, volume pot and boutique parts (resistors, capacitors, wires, etc.).
  6. mwl168

    The Headcase Stax thread

    Depending on how small is small. You can consider Kevin's current feedback design which is the smallest desktop electrostatic amp I have built to date. All parts are current, simplistic power supply and very good sounding to my ears. Even though money saving isn't the main reason for me to go the DIY route, this current feedback amp is also the cheapest to build. The amp board (per channel) measured 184mm x 64mm. There is a thread in the DIY forum dedicated to this amp.
  7. mwl168

    The Headcase Stax thread

    The good news here is that for the KG electrostatic amps that are often mentioned here (such as Blue Hawaii, KGSSHV, Carbon, Grounded Grid, etc.), there are proven PCB's for both the amps and the PSU's that many have built working and reliable amps with, myself included and I do not have a science degree and never forged a knife in my life! Extra safety precaution does need to be followed strictly given the high voltage involved! With that said, if you source correct parts from reliable vendors (Mouser, Digikey, etc., not eBay, not Taobao...), stuff the right parts in the right spots on the PCBs, exercise good soldering practice (many good tutorials on Youtube) and pay attention to layout of components (circuit boards, transformers, connectors, etc.) and wiring, your success rate is very high. On top of that, many knowledgeable people here will come to rescue should some things do go wrong provided that you have done your homework! It's lots of fun and a very rewarding experience!
  8. mwl168

    The Headcase Stax thread

    It's never too late to pick up the soldering iron. If you invest the effort to learn, with diligence and good common sense those DIY amps you mentioned in your posts are really not that difficult to build.
  9. mwl168

    The Official Head-Case Photography Thread.

    Found this photo from quite a few years back. Canon 5D II with 135mm/F2 lens.
  10. mwl168

    Head Case Motorsports

    To me, in actual driving the car actually feels much torquier than the number suggests. You may be pleasantly surprised. The chassis is very well balanced. Too bad the car is heavier and way too complicated than I would prefer. Wish I also had the carbon roof!
  11. mwl168

    current feedback electrostatic amp

    Where I live, the ambient temperature at this time (end of August) is around 70 F, about 22 Celsius. The heatsink temperature of the amp gets to about 45C fully warmed-up. When I first cased the amp, the ambient temperature was around 27 Celsius and the heatsink was ~ 48C not quite 50. I can see the heatsink hit high 50's C in Taiwan where the ambient temperature can easily hit low to mid 30's C this time of the year.
  12. mwl168

    current feedback electrostatic amp

    Finally cased my ES CFA amp. Returned the bias resistors to 1M with the larger heatsinks. Running 20mA bias for the output sections.
  13. mwl168

    Technical Assistance/Advice Thread

    Good point. I should have mentioned that I mount the aluminum angle to the heat sink using M5 screws, which, in my experience, on top of having fewer holes to work with, is much easier to tap and far less likely to break the tapper. I drill the mounting halls on the angle slightly larger than the M5 screw diameter to provide some margin of error so I don't need to be as precise when I drill and tap the heat sink..
  14. mwl168

    Technical Assistance/Advice Thread

    You really have two options when it comes to mounting resistors to heat sinks: 1. mount the transistors directly to the heat sink which requires you to drill and tap the heatsink 2. mount the transistors to an aluminum angle then mount the angle to the heatsink Of the two options, I would opt for option 2 when possible. Drilling and tapping the heat sink is tricky and unforgiving. If you make a mistake like broken the tapper while tapping the heat sink, you may be forced to abandon that heat sink altogether. Drilling and tapping (optional) 3mm- thick aluminum angle (which I typically use) is much simpler and forgiving. Aluminum angle is also easier and cheaper to replace. I speak from personal experience.