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  1. mono

    Magnets make life easier, so would putting a neo-magnet on the top of my headphones to stick to the wall cause any audio problems?

    Magnet field strength GREATLY decreases with distance, it's not going to affect sound quality.  The only real issue is what HC pointed out, they can wipe out the magnetic strip on credit /etc cards but even then you'd have to wipe it against them.   The main concern I'd have is how you're...
  2. mono

    cmoy upgrade(s)

    ^  Or a forum for people that can't stand when others offer a different opinion?   Suggesting something, spending the time to do so even if it doesn't agree with your ideal, tends to be the opposite of not giving a crap.  Is the ultimate goal to be an expert at op amps, or to end up with a good...
  3. mono

    Ear pad cushions alternative for Sennheiser HD515

    The most economized way to do it would be from scratch.  Find a piece of foam the density that you want, cut out a couple doughnut shapes and adjust their height to be suitable for the density of the foam, then buy at least a couple square feet of nice cloth from a fabric store and cover them.  ...
  4. mono

    cmoy upgrade(s)

    Is that a TL072 opamp?  If so, [EEK!] using something else with higher current or paralleling two of them like in an A47, or paralleling two of something else especially, is the next upgrade.  None of the old popular opamps for CMOYs do very good driving a load (cans), it's just sort of the...
  5. mono

    Is it possible to fix

    It is repairable, BUT you must get the pieces perfectly mated together or the coil will rub the magnet housing. Before trying to glue it, set the plastic in place, see if it fits well, and you might try passing an audio signal through it to see if it distorts unusually. If not, you should be...
  6. mono

    good/cheap heat press for DIY toner-transfer pcb's?

    1amigo, it's an old topic, Fred may not be monitoring it anymore.   I keep the iron moving but move it very slowly.  I'd assume the minimum length of time would depend on how thick your copper is and the total area you're covering... some small PCBs stay entirely under the iron during the...
  7. mono

    Bipolar Electrolytics Comparison

    Organic polymer caps have made good strides over recent years. Now they're becoming quite common on PC motherboards, video cards, in values like 16V/330uF. I think they're a bit overkill for an analog audio amp though, except if you're building something to give to the grandchildren some day...
  8. mono

    Working with lethal voltages?

    While I am also insisting you check voltages before handling circuits, there is also the option to build bleeder resistors into your design, or just add them across the caps on existing designs. Don't assume they did their job, but be glad you spent that 4 cents on resistors... you never know...
  9. mono

    Transformer secondary wire, not long enough?

    I find crimp connectors less reliable. If you twist the wires and aren't going to flex the joint, soldering them and covering with heatshrink tubing should be fine. Keep in mind this is assuming other proper design (regardless of how you connect them), chassis is grounded if metal and the supply...
  10. mono

    Premium Grade solder?

    Solder falls into the realm of voodoo science. Pick what works best for you, what you like the smell of or whatever, but if it costs more you're probably overpaying for aesthetic rather than important per function, reasons. Regular 60/40 and 63/37 low cost solder is not hard to use and most...
  11. mono

    Need help fixing an amp

    STK2125 being the output power amp IC, yes it seems there is a good chance that is the problem. I'd probably desolder and pull it off the PCB and measure supplyl voltage, and L/R signal strength at it's input (I mean the now empty spot on the powered PCB - being careful since there could be high...
  12. mono

    pwr. cables:plug end vs. iec end,sq.

    I find no difference whatsoever, unless it's an ancient cord where the wire was frayed and that is cut out, or the outlet seriously degraded and the new plug makes different contact. Usually an improvement with a different plug is only placebo effect, IMO.
  13. mono

    PCB extension leads

    You'll probably have to DIY, by noting the types of pins and sockets and ordering the appropriate individual parts from somewhere like Digikey, then soldering on the wires. If you don't have an iron or soldering skills this might be a good project to get your feet wet on that.
  14. mono

    IC: Group Buy Monofied Sijosae Buffer PCBs

    You can use many many complimentary pairs of transistors, but my general impression is if you use those with lower current rating you end up with a more harsh sound and less controlled bass. The BC327/337 happen to have high current for TO-92 size, but if your amp case has enough clearance you...
  15. mono

    Power Supply-->Crosstalk on my balanced a47?

    Quote: Originally Posted by Zaubertuba Seriously, your line of (very well thought-out) reasoning points me right back to a balanced JISBOS-with-gain that was suggested to me on another thread, or a balanced Pimeta like you're suggesting. Do you have any other reasons for suggesting the...
  16. mono

    Power Supply-->Crosstalk on my balanced a47?

    Quote: Originally Posted by Zaubertuba Responding to a post I made in the opamp thread about my "quest for greater soundstage," murrays pointed out the following: I realized my amp is already wired so L+ and L- utilize a set of opamps and R+ and R- use the other set, so there...
  17. mono

    IC: Group Buy Monofied Sijosae Buffer PCBs

    Seems like it's time for you to do a layout with a POT instead of a fixed resistance, then blind test it. I may be crazy but I think I hear a difference when bias goes up enough to heat the transistors. I mean they sound better before they warm up too much. Now that I wrote that someone is...
  18. mono

    IC: Group Buy Monofied Sijosae Buffer PCBs

    Higher bias increases clarity to my ears, the higher current transistor gives more controlled bass. I'm too lazy to do the math, but the optimal bias current to keep it in class A will depend on your volume level and the load (cans). 470 Ohm to 330 isn't a big change though, since 2N5486 is...
  19. mono

    Micro water pumps?

    I have a few potted vegetables outside right now, in 5 gallon pots they want about half a gallon of water each daily, but are still growing so later in the season they may need more. If you cover the soil around the stem with plastic it will reduce evaporation (except of course where the...
  20. mono

    DC power cables

    Regular copper wire will work fine.
  21. mono

    Micro water pumps?

    I don't think you will find a pump the size of two 9V batteries that has enough lift unless it were a very expensive piston pump with too high a power:water flow ratio. Probably a submerged pump is best in small sizes, to avoid priming issues. If you're only going to be gone a week, have you...
  22. mono

    Hakko 936-12 just arrived -- which tips should i get next?

    Don't base tip lifespan or performance upon anything radioshack offers, there is a world of difference. Best long-term solution is see what is on ebay, you can pick up a pack of assorted hakko tips for cheap if you're patient, then picking which one to use isn't based on what you have as much...
  23. mono

    Is there something wrong with this picture?

    There are different types of split-point bits, mine make very nearly if not actually flat holes, they look flat, close enough that tightening down a ring terminal would bend it to fit if it weren't actually flat. The flat top of a dremel would work too, but I think it would be harder to hold...
  24. mono

    Is there something wrong with this picture?

    That does not look at all like a zinc plated bolt. Zinc plated bolts are dull gray. The screws are probably nickel or stainless which aren't as significant. Also, even if they were zinc that would be opposite of ideal electrical conduction, it would only be better for structural non-corrosive...
  25. mono

    ls class-A really worth it (pimeta, etc) ?

    If someone wants to try biasing BUF634 to 120mA, I suggest the TO-220 part heatsunk, in a different amp not a Pimeta. Further, I suspect there is a point where very hot buffers degrade sound more than 100% class A operation improves it. Edit: Oops, sorry about reviving a dead topic.