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Posts by raindog1975

Hello 13 cats,  Just peel off very gently the ear-pads ( they are glued to the baffle ) , and you will find 5 screws under a layer of "sticky stuff" ( glue ) . I suggest protecting the glue from dust and re-assembling the headphones only after all the modifications are complete ( I also replaced the cable with a diy one - braided 24 awg speaker cable and 1/4'' jack plug - ) .   
First you need to spray a primer ( after a thorough degrease of the parts - with alcohol - ). Look for a primer specifically made for plastics or at least an "universal" one. In my experience chrome paint ( the procedure you mentioned in correct , by the way ) should only be applied in a controlled environment ( no dust, low humidity etc ) otherwise the results can be pretty bad . As an alternative you could use silver paint and a clear-coat ( more "forgiving" than...
After some "googling" I came to the conclusion that balanced amps are used only in high frequency applications ( microwave band ) , the only thing similar, as far as audio signals are concerned, is the impedance balanced line used for connecting  microphones to preamps or mixers or connecting preamps/mixers to power amps over larger distances ( line level signal ) . 
What exactly do you mean by "balanced amplifier"? LM386 is not an opamp , it's a power amp and it is pretty much limited to what you can find in the data sheet ( a notable variation being the headbanger amp ).
Since you use the cmoy with a source that can drive ( poorly ) 32 ohm headphones it's possible to use even lower values for the pot ( like 1k or 4.7k ) , values higher than 10k are useful only if the source requires it . Commercial amps usually have an input impedance of around 50k because it's a "safe" value for most sources .
Most likely dried-up electrolytic capacitors ( given the age of the amp and the symptoms ). It would be a good idea to change all of them ( most electrolytic caps don't last more then 10-20 years ) , it's a pretty big job but well worth-it ( I did it with my Sanyo DCA20 and I could't be happier with the result ).
Nice work! It will probably last longer than any headphones you will ever own .
Finished yesterday : cmoy in a old PC ( Siemens ) PSU "improved" with wooden face and sides ( stained and oiled ) . Inside standard cmoy ( 6 gain , 10k pot , 0.47uF Wima input caps,  +/- 12 volts stabilized power supply ) ; for now it has a njm(jrc)4556 but it's socketed and I ordered opa2132pa ( but I have to wait two weeks for it  ) . Worked well at first try : no hiss , no hum , no oscillation ( checked with the oscilloscope ) and it sounds pretty good ( I expect...
As vintage as they get: circa 1940's 2000ohm ( each ) headphones - made in France , it says Pival on the headband(s) . Got them at the flea-market , cleaned them , re-cabled ( I kept the original plug ) I still use them on my crystal radios .
1) No idea  , just remove all the screws ( if any ) and make sure you don't force anything . 2) Try a paint stripper ( look for one that can be used on plastic ) and if sanding is necessary  use 600 grit minimum ( any coarser and it will leave deep grooves in the plastic ) and finish with 1200 grit ( or higher ) . Use a plastic primer ( general purpose primers don't work well on plastics ) and spray paint ( brushing leaves visible brush stokes no matter how fine the...
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