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cmoy amp hissing

E

ericlikeseatin

Limp Gawd
Joined
Jan 5, 2005
Messages
314
hi guys,

i recently found a good deal on a used cmoy amp and when i plugged everything in today, i heard this background hiss that is pretty audible during quiet parts of music. even when i mute my output, i hear the hiss. i am using an audigy 1 as my source, a monster cable interconnect to a cmoy camp using an op2227pa chip, which SR60's are plugged into. ive tried adjusting the volume on my computer and everything, but all combinations still give a hiss. does anyone have any ideas? :confused:
 
plug that same setup into a discman while it's next to the PC, then while it's somewhere nowhere near the PC, but on a different electrical plug-in.

If you don't hear noise while its next to the PC, it's prolly the soundcard picking up noise.

If you don't hear it on a different outlet, find out what's on that line that's making that noise and relocate it....if you can't relocate it, get a noise filter for your line.


also take off the interconnectes, and turn it up dry...do you hear a hiss now that there is no input whatsoever?
 
mustang_steve said:
plug that same setup into a discman while it's next to the PC, then while it's somewhere nowhere near the PC, but on a different electrical plug-in.

If you don't hear noise while its next to the PC, it's prolly the soundcard picking up noise.

If you don't hear it on a different outlet, find out what's on that line that's making that noise and relocate it....if you can't relocate it, get a noise filter for your line.


also take off the interconnectes, and turn it up dry...do you hear a hiss now that there is no input whatsoever?
Click to expand...

the location of the setup doesnt seem to affect the hissing. however, when i take off the interconnects, i no longer hear a hiss. when i leave the interconnect plugged into the amp but not connected a source, the hiss is even louder! does that mean i have a bad wire?
 
http://headwize.com/projects/showfile.php?file=cmoy2_prj.htm

The first step in troubleshooting noise is to make sure it is coming from the amplifier itself, and not from the audio source. Disconnect the audio source and listen to the pocket amp for any background hiss, static, RF (radio frequency) or EM (electromagnetic) interference. If the headphones are low impedance types (such as the 32 ohm Grados), the amp will function better with the load resistor R5 installed (see figure 1). The load resistor can be added either inside or outside the opamp feedback loop (figure A1). Inside the feedback loop is the preferred method because it keeps the output impedace of the amplifier very low, but some DIYers have reported better performance with the resistor outside the loop.

If the noise is primarily RF or EM interference and is not coming from the audio source, it is probably due to long interconnects and headphone cords, which can act as antennas that channel RF signals into the headphone amplifier. The easiest way to block RF noise is to place one or more clip-on ferrite noise suppressors on the audio cables. They should be located on the end of a cable as close as possible to the input or output of the headphone amplifier. The clip-ons can be removed if the interference is temporary and subsides. See A Quick Guide to Headphone Accessories for more information on ferrite clip-ons.
Click to expand...
 
after some more testing, i found out that the hissing was indeed coming from the source. thanks guys for all your help!

now....i was thinking of replacing my audigy with a chaintech av-710 that i would mod using the JP3 jumper trick. any input anyone?
 
What Audigy?
Audigy?
Audigy2?
Audigy2ZS?

If it is a plain ole Audigy mute all of the inputs including the CD and the hisss should become tolerable
 
ahh...it was my audigy. with my new chaintech av710, i get pure silence when nothing is playing. i am using the high res mode with digital output to the un amped line out. beautiful! :D
 
I know about that guide. I link to it as well.

My point is that that's an analog connection described there.
 
hmm, i see what youre saying. i was going more by this screenshot:

2.png
 
If you are not using the optical output..... all of that means nothing. ;)
 
i am getting the superior 24/96 Wolfson DAC if i output from speakers 7-8 into stereo mode right? it sure sounds good! (i dont want my world to come crashing down upon me)
hey question mister x: how much better is the optical out?
 
not willing to spend anymore on a DAC, i am very content with my setup right now, its adequate for my listening pleasure. i have to stop visiting head-fi.org though...haha!
i have to re-rip many of my CD's now though...what a pain.
 
ericlikeseatin said:
i have to re-rip many of my CD's now though...what a pain.
Click to expand...

Secure rip to FLAC format using EAC. Read the proto-FAQ for a guide. Also, use Foobar with kernel streaming, resampling to be compatible with the high-sample requirements.
 
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