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About H713

  • Title
  • Birthday May 14, 1994

Profile Information

  • Location
  • Gender
  • Interests
    Audio equipment, analog electronics, vacuum tubes, DIY audio projects, Amateur Radio, sailboat racing, physics
  • Biography
    I'm an engineering physics student / intern who designs analog audio equipment for fun.

    Some of the audio equipment I've designed:
    -Elac 510 clone loudspeakers (crossover was my design)

    -Push-Pull 6L6 power amplifier

    -Push-Pull 1625 power amplifier

    -Discrete Class A balanced microphone preamplifier

    -A few discrete op-amp designs

    -Discrete balanced line stage with transformer balanced outputs

    -Op-amp line stage with MDAC attenuation and electronically balanced inputs and outputs (used in my lab)

    -Approximately 10-15 projects that have been 85-90% complete for at least 9 months.
  • Occupation
    Electrical Engineering


  • CPU
    Core i5 4460
  • Motherboard
    Asrock H97M
  • RAM
    16GB Crucial DDR3
  • GPU
    Quadro K2000
  • Case
    In-Win 303
  • Storage
    2x Samsung 250GB 850 EVO
  • PSU
    Antek HCG620
  • Display(s)
    Dell 27" 4K + 24" Acer auxiliary
  • Cooling
    Arctic Cooling Freezer 13 limited edition
  • Keyboard
    Corsair Strafe (Cherry MX blue)
  • Mouse
    Logitec G403
  • Sound
    Quested Q108 Active Studio Monitors (primary system)

    Elac 510 (my own clone) passive speakers + Quested AP700 amplifier (secondary system)

    Discrete Class A line stage with electronically balanced inputs and transformer balanced outputs (also my design)

    Lynx L22 Sound Card

    Crest XR20 mixer (mostly using it for the generally acceptable mic preamps and EQ)

    AKG SE300B microphone (for video conferencing).

    In the Shop:
    Sony MXP-2900 24 channel mixing console (under restoration / modification)- Has transformer balanced inputs and outputs and lots of useless Sony broadcast automation.

    BSS EPC780 power amplifier (under restoration)

    Crest Pro 3301 (lab amplifier- input op-amps upgraded to LM4562s)

    +around 15 less interesting projects that remain unfinished.
  • Operating System
    Begrudgingly switched back to Windows 10 from Linux when I started doing a lot of engineering work.
  • Laptop
    Mid-2012 Macbook Pro
  • Phone
    They're all turds, what difference does it make?

Recent Profile Visitors

1,130 profile views
  1. Keep in mind that even if it does still "work", that doesn't mean you haven't damaged it. In an externally polarized condenser microphone, the diaphragm is usually some sort of metalized mylar film, and is quite thin. It is also *very* close to the the other electrode. Suffice it to say, the diaphragm itself (and the electrical attachment points) are quite fragile. Blasting it with compressed air, be it from a compressor or a can, could potentially be sufficient to tear the diaphragm, or even just enough to permanently deform it. You may not stop the microphone from wo
  2. Probably a semi-custom part designed to work with the AM4 socket, which is also (as far as I know) a custom part that AMD developed in-house. You're not going to be able to do much with them anyway though. It's been a while since I've messed with these sockets, but aren't the pins welded (rather than soldered) to the CPU board?
  3. Listen to the people telling you to avoid this. YOU CAN DO DAMAGE WITH COMPRESSED AIR. I've seen it happen many times, damaging things a whole lot less fragile than a microphone diaphragm. I'd suggest that you don't try to clean the inside of the microphone yourself.
  4. Of greatest concern is that you've most likely damaged the board. Hard to tell from the pics, but there's a good chance you've damaged some traces. Now, I wouldn't worry too much about what's inside the chip. There may be trace amounts of heavy metals, so don't eat it, and you should also make sure to dispose of it properly (that is, send it to an E-waste recycler if you can). I wouldn't be too worried though. It's not like a magnetron (beryllium ceramic) or an ignitron (considerable pool of mercury in the bottom) or some old HV capacitor with half a gallon of PCB oil
  5. This is the kind of switch I was talking about. Never bought from this supplier, but I was too lazy to dig through the DK parametric search: https://lovemyswitches.com/spst-momentary-foot-switch-normally-closed-vampire-fangs/ Also, there is one advantage to the Arduino Nano over the Uno, and that's that it conveniently plugs into a breadboard, or a socket on a PCB. I prefer prototyping this way rather than jumpering a bunch of wires from the Uno over to a breadboard. Of course, if you want to use a shield on the Uno, As for debouncing, if you're implementing it su
  6. Here's a few ideas: 1) The push-button switches used for guitar pedals (I guess they call them "toe switches" or "stomp switches") are very robust, and some of them have a very beastly snap-action to them. I like using them for the "manual trigger" button on pulse generator boxes, since it gets heavily abused and there is no questioning whether it activated or not. You might like them for this application. 2) You also might consider a rotary switch for selecting times. I tend to use Lorlin / C&K switches when I need something cheap but serviceable, or Grayhill / Ele
  7. Do it in the analog domain. If they're both running off the same analog source, the time difference should be negligible.
  8. A few points... 1) Below 0.02% is really easy. Below 0.005% is a lot harder. It is highly unlikely that you'd be able to hear the difference. Yes, by AudioScienceReview's standards, 0.02% is lousy for a power amplifier, but they have (in many ways) gone off the deep end chasing numbers that are so far below the audible threshold it almost couldn't matter less. ASR's standards for "inaudible" means "under the worst conditions I can notch out the fundamental and put my ear up against the speaker cone without hearing anything when playing a test tone". 2) Power level is e
  9. If you're doing SMD desoldering, wick is the way to go and works fantastically. It is also the way to go for single-sided through-hole boards that don't use plated through-holes (PTH). Pumps are useful for removing big globs of solder from big through-hole parts, connectors, point-to-point wiring terminals, etc. IMO, that's about all they're good for. The right way to do through-hole desoldering, particularly on boards with PTHs, is a vacuum desoldering station. The Hakko FR301 (I think that's the model) is pretty good. The Metcal DS1 is better, but requires compressed
  10. Yes it's feasible, but you're using a power supply capable of delivering something like 40 A to power something that probably needs less than 100 mA. Not practical at all.
  11. Probably depends on what you consider "high voltage". There are a lot of people that wouldn't call anything under 1000 volts "high voltage". For the sake of this post, I'm going to consider anything above 100 V to be "high voltage", since most people rarely encounter DC voltages that high in their projects. Almost any blu-ray player is going to use a switching power supply. In order to improve efficiency and save space, the transformer is run at a relatively high frequency (probably about 100 kHz). This allows for a much smaller core section, and it allows the use of easily-produce
  12. It's not particularly clear what the OP is asking for. If anyone else had better luck deciphering that first paragraph / run-on sentence, let me know. Here's the response to what I think is being asked. All of this depends on what you need the DAC to do. For 95% of things, it doesn't matter. Keep in mind that DACs are very likely the most ideal part of the audio chain. Seriously, modern DACs can handle anything from about 20 Hz to about 90 kHz, with distortion and noise better than 100 dB below the fundamental. No other part of the audio chain is that ideal.
  13. H713


    Yeah, I use a #1 and #2 phillips, and one size of slot for 80% of what I do. The rest is mostly just hex / torx, or pozi-drive if I'm doing work on Quested / Turbosound / BSS equipment.
  14. H713


    I use the Felo wood-handle screwdrivers for most of the big stuff, and they're pretty good. For all the little stuff, I really like Wera. I've got one of those toolkit type sets (similar to the iFixit), and although it's useful to have a wide range of bits, I really prefer to have dedicated, fixed drivers. As much as I believe in buying good tools, I really can't bring myself to spend $50 on a Snap-On screwdriver. I used to have some Wera stainless-steel screwdrivers (along with some stainless pliers and wrenches) that I kept on my MC scow, since they don