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RA-1 and hissing?

post #1 of 10
Thread Starter 
My Grados, when plugged into my RA-1, when the power is on and no music is playing, there is a slight hissing, like electronic or something. My HPA-1 does it too, but i wouldn´t expect this from something that uses batteries as the power source...??? BTW, it does not get worse as you turn the volume up at all... it´s the same no matter what, i´m just wondering if this is normal. Thanks!
post #2 of 10
Maybe there's a Grado "rattler" inside the mahogany box. There's enough room in there for one to hide...
post #3 of 10
Too cool,
Try disconnecting source CDP and see if RA1 amp makes any hiss when turned on to normal level. If hiss disappears then CDP or interconnects are causing this. Because other headphones have same hiss you can eliminate headphones as source.

Also try moving location of RA1 especially if next to computer monitor or sitting on/near another components power supply.
post #4 of 10
Gradoistcool, I had a similar problem. Check out this thread for possible solutions and/or explanations:
post #5 of 10
get a couple of cheap radio shack RCA plugs and solder a 100 ohm metal film resistor from the hot to ground on each one.Plug them into the RA-1 and see if you still hear the noise.Even though resistors generate thier own noise 100 ohm should be low enough not to hear it but high enough to terminate the amp input with a load.
post #6 of 10
As the hiss does not increase as the volume control is turned up, I'd guess the problem is somewhere after the volume control, probably in the opamp.
post #7 of 10
unhook your amp , so that it all by itself. Now trun it on and listen with your headphones, do you still hear it? If not, then it's something else in your system.
post #8 of 10
Thread Starter 
ok, well, nothing helps, except trying the ground thing.... the hiss is so quiet, it´s almost inaudible, but i have very good ears. so... maybe i should just send it back to grado and see what they can do with it, it should be dead silent, not even a power hum, tscha! that´s why they ran it on batteries in the first place!!!
post #9 of 10
....it should be dead silent, not even a power hum, tscha! that´s why they ran it on batteries in the first place!!!
My sentiments exactly.........that's why I sent it back. They said they could find nothing wrong, but sent me a new one in its place. On my Grados, the hiss is not there at all. Still very slightly there on my Sonys.
post #10 of 10
I am not exactly sure where I read this but someone suggetred the volume control casing needed to be grounded.Of course for the amount of loot the RA-1 costs it should already have been done
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