I have a new prepro and seems to be suffering from this. The hiss is nothing like ground loop hum I have heard in the past; it does not vary at all with volume, remains completely consistent in tone and volume and does not change with input selection. The hiss starts as soon as a relay clicks quite late in the prepro boot process. Any idea what this could be? Is it a faulty prepro?
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Soft hiss audible at 2-4ft from speaker
- Thread starter Krobar
- Start date
I have 2 pre/pros, 1 REALLY OLD Sony TAE 9000es, and an old Integra DHC 80.3. Both of them are dead silent regardless of volume or input. If you put your ear right up to the tweeter you hear a VERY slight hiss, and nothing from more than a couple inches away. Something's got to be wrong...Are you running dedicated power amps?
What'a "prepro"?
"pre/pro = preamplifier+processor" Basically, it is an AVR without amplifiers.
I see. This device is generating noise in the output path, then, especially if the hiss starts when a relay (probably an output protection relay) closes.
I've had serious idle hiss problems with cheap powered studio monitors. Even my decent-quality Yamaha HS8 has a bit of idle hiss. If you can hear hiss from beyond a couple of inches then there's a problem.
If you get this problem with your new prepro then it's your prepro.
I have L/C/R on external monoblocks and have slightest hiss on tweeters at 3" - 4" from the tweeter. Woofers are completely silent. Same goes for my surrounds which are run off the Denon AVR.
I hooked up 3 DIY 15" subs to 3 channels of Crown XLS 2502 and initially there was hiss - perhaps because of the mismatch in the gain structure. I set up a LPF in the crown and the hiss went away and the 3 subs are stone cold silent.
I hooked up 3 DIY 15" subs to 3 channels of Crown XLS 2502 and initially there was hiss - perhaps because of the mismatch in the gain structure. I set up a LPF in the crown and the hiss went away and the 3 subs are stone cold silent.
- Thread Starter
- #7
Thanks for the responses all. I 'm really not sure what to do, my Denon AVP-A1 is utterly silent to the point I can put my ear on the speaker grill with a running HDMI input at min volume and only hear the whisper of the soundtrack with no hiss or buzz at all.
Have now tried an Arcam AV40 and Datasat and they both hiss constantly out of all speakers and I can hear it about 2 feet from the speaker if in line with the tweeters. This applies even with only the poweramp and prepro connected so I know its not ground loop or source device related. The Hypex based power amp is dead silent on it own too.
Is the noise floor on modern prepros just crappy no matter what? Would appreciate your input @Kal Rubinson since I guess you have listened to quite a few.
Have now tried an Arcam AV40 and Datasat and they both hiss constantly out of all speakers and I can hear it about 2 feet from the speaker if in line with the tweeters. This applies even with only the poweramp and prepro connected so I know its not ground loop or source device related. The Hypex based power amp is dead silent on it own too.
Is the noise floor on modern prepros just crappy no matter what? Would appreciate your input @Kal Rubinson since I guess you have listened to quite a few.
I have not noticed this. I say "noticed" because putting my ear up to the speakers to listen for it is not something I normally do. Unless I hear some noise from a distance (as your observation of noise from 2-4' away), I would have no reason to try. None of the prepros I have tried have been that noisy.
That said, my beloved AR MP1 is noisy and, with normal setup, I can hear it nearly 2' from the tweeter. I have mitigated the problem by using reduced gain in the power amps
That said, my beloved AR MP1 is noisy and, with normal setup, I can hear it nearly 2' from the tweeter. I have mitigated the problem by using reduced gain in the power amps
- Thread Starter
- #9
Thanks Kal. With todays firmware update the AV40 is down to about 18 inches distance for audible hiss for me so at least no longer encroaches on the listening position. Some of it seems to depend on hearing condition, my father cannot hear it at all, kids can hear it easily.
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Can't help you, but I've noticed this before as well when trying RCA -> RCA vs RCA -> XLR
Is there any signal processing going on? If you have a surround effect enable that could add noise. Try turning any of that off and see if it goes away.
I agree that RCA to XLR is likely just lowering the level due to using 1/2 the signal level. If you have an SPL meter, play pink noise or some reference tones and make sure the sound out of the speakers is playing at the same level from each connection, then check again to rule that out.
I agree that RCA to XLR is likely just lowering the level due to using 1/2 the signal level. If you have an SPL meter, play pink noise or some reference tones and make sure the sound out of the speakers is playing at the same level from each connection, then check again to rule that out.
- Thread Starter
- #14
Thank you for the replies.
I do have a sound meter which I used to calibrate the levels. The difference between XLR to XLR and RCA to XLR was higher than I thought; RCA is about 6-7dB lower. However boosting the channel I connected via RCA by 7dB does not increase noise at all, it retains the lower noise floor.
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