Search:

Type: Posts; User: nickb; Keyword(s):

Page 1 of 18 1 2 3 4

Search: Search took 0.04 seconds.

  1. Replies
    106
    Views
    1,816

    These are for over current protection. The...

    These are for over current protection. The collectors are a maximum of +/-15V. You'd want them to sink all the current that the drivers Q206/ Q207 can provide under over current conditions, so say...
  2. Replies
    106
    Views
    1,816

    It does make it confusing. In the BOM the 7204...

    It does make it confusing. In the BOM the 7204 is called out as "70467204 SDS-7204". The cross ref matches SDS-7024 with Peavey p/n 70407204. The substitutes are 2N6557, MPS-U10 and later on...
  3. Replies
    106
    Views
    1,816

    The Peavey cross ref gives 2N6557 for the SD7204....

    The Peavey cross ref gives 2N6557 for the SD7204. Here is the data sheet for it showing the package and the power rating.
    56030

    Thye more I look at I the less sure i am about the max CE voltage...
  4. Replies
    106
    Views
    1,816

    The "300V 10mA" seems to be a typo on...

    The "300V 10mA" seems to be a typo on amplifiedparts. It's actually a 300V 500mA 10W ( 2W free air) part. It has a metal heatsink tab TO202 package.

    The 10mA and 115V average for this circuit...
  5. Replies
    106
    Views
    1,816

    Ah! In that case you've solved that problem at...

    Ah! In that case you've solved that problem at least!
  6. Replies
    106
    Views
    1,816

    I fear those uniwatt packages will overheat and...

    I fear those uniwatt packages will overheat and die in short order. The original is 2W in free air, 10W on a large heatsink. The MPSW42 is 1 watt, 2.5 if you can keep the case at 25C or less.

    Is...
  7. Replies
    106
    Views
    1,816

    It doesn't, but it 's the best I could find for...

    It doesn't, but it 's the best I could find for the moment that would not evaporate.
  8. Replies
    106
    Views
    1,816

    No, that will fry. The best I came up with was...

    No, that will fry. The best I came up with was an MJE340 but the pinout is wrong and it's a bit slow. Might work at a push.
  9. Replies
    106
    Views
    1,816

    No I didn't mean that but I see what happened. I...

    No I didn't mean that but I see what happened. I searched for the required part and it brought up the wrong one (nearest lexical match- how dumb is that?) and didn't spot it. Well spotted - thanks....
  10. Replies
    106
    Views
    1,816

    Dang - wrong part - deleted :(

    Dang - wrong part - deleted :(
  11. Thread: Cleaning PCB

    by nickb
    Replies
    11
    Views
    326

    It depends on the flux. Rosin: scrub with lots...

    It depends on the flux.
    Rosin: scrub with lots of isopropyl alcohol (IPA), dab dry with kitchen towel.
    Water based: water with a little non foaming detergent ( i.e floor cleaner). Flush then dry...
  12. Replies
    106
    Views
    1,816

    To be honest, I'm not sure what happened here. ...

    To be honest, I'm not sure what happened here. You connected live to chassis (nasty!) , neutral and earth to power transformer, right? In that case the amp would not have been energized so no risk...
  13. Replies
    12
    Views
    473

    Just to add to this. I got (a lot) of white LED...

    Just to add to this. I got (a lot) of white LED strips off flea bay. Worked great for about three months then started to fade and go yellow. Moral: don't even think about using cheap substitutes!
  14. Replies
    15
    Views
    453

    It's odd that they don't thave the same ESD...

    It's odd that they don't thave the same ESD protection on that signal as they do on the input. After all, both are exposed to the outside world. Maybe as simple as a 100k in series would do it.
  15. Replies
    5
    Views
    256

    Well, no... If the joints are bad they will be...

    Well, no... If the joints are bad they will be high resistance. That means with preamp connected it will read low and when disconnected it will read higher.

    The way to check is to measure the...
  16. Replies
    5
    Views
    256

    and adding...The resistors R101 and R102 run...

    and adding...The resistors R101 and R102 run quite hot and the solder joints can fail. Look at them closely, remove the old solder, clean and resolder.
  17. Replies
    15
    Views
    453

    ..and the all important pin 14 of the processor...

    ..and the all important pin 14 of the processor does what with the jack in/out? Should go between 3.3v and 0v.
  18. Replies
    15
    Views
    453

    What is the voltage on D15 pin 3 ( BIAS_ON sigal...

    What is the voltage on D15 pin 3 ( BIAS_ON sigal sheet 3 bottom right quadrant)? it should about -1.3V when in play mode with a input plugged in. Check that changes when you unplug the input. That...
  19. Replies
    11
    Views
    350

    I wonder who were the subjects to gather the data...

    I wonder who were the subjects to gather the data on shock currents? Arts students perhaps?
  20. Replies
    2
    Views
    173

    You're only hope is to trace it out. I don't...

    You're only hope is to trace it out. I don't think even G4M have the schematic but just a spec that they are made to by yet another Chinese factory. At the prices they pay these are throwaways.
  21. Replies
    26
    Views
    656

    Oh there's more.. let's apply the rules of occult...

    Oh there's more.. let's apply the rules of occult numerology (adding adjacent pairs)
    1733 -> 1+7, 7+3, 3+3 -> 8, 10, 6 -> 18, 6. Now 18 is THREE SIXES!!! The spare 6 goes with the KT66 to give...
  22. Replies
    80
    Views
    2,024

    The circuit is a commonly found arrangement dual...

    The circuit is a commonly found arrangement dual voltage SMPS front ends.
  23. Replies
    50
    Views
    981

    I see big bottles and... a barrel of beer. Amp...

    I see big bottles and... a barrel of beer. Amp welcoming party maybe?
  24. Replies
    80
    Views
    2,024

    I guess it's a matter of definition. Getting...

    I guess it's a matter of definition. Getting double the voltage out qualifies it as doubling to me. The figure on the right is actually a quadrupler.
  25. Replies
    80
    Views
    2,024

    What Chuck drew is a doubler. It has a 12V...

    What Chuck drew is a doubler. It has a 12V winding and nominally 24V out ( actually more like 30V). A split supply has a center-tapped transformer.
  26. Replies
    80
    Views
    2,024

    An 18V transformer would be easier as no doubler...

    An 18V transformer would be easier as no doubler required. Or even easier a 24VDC wall wart.
  27. Replies
    31
    Views
    707

    Indeed. I'm starting to think the result is not...

    Indeed. I'm starting to think the result is not real.

    I went back to my simulation and carefully tweaked things for better precision. There is now a small 0.2mW difference in power dissipated in...
  28. Replies
    31
    Views
    707

    The difference is quite small for this particular...

    The difference is quite small for this particular case, but in point or fact, due to the waveform distortion the version with the diodes will use about 2 -3 % more power than the purely resistive...
Results 1 to 28 of 500
Page 1 of 18 1 2 3 4