Where does hiss come from in a mixer?

Snarl 12/8 · Post by **Snarl 12/8** » Sat Apr 18, 2009 8:32 pm

Hey People,

I'm starting to notice hiss that I never noticed before. I don't know if it was always there, or if it's getting worse. As a general question, where does hiss come from? Would I minimize it by improving the power supply? Caps? Knobs? Shielding?

Analog stuff has hiss, where does it originate? How do you mitigate?

Can this be asked as a general question, or do you need the schemo. In case it matters, I'm still talking about my Ashly MM-508 mixer.

Thanks,

JWL · Post by **JWL** » Sat Apr 18, 2009 8:35 pm

The most hiss I can get out of my Mackie Onyx 1620 is when the mic pres are cranked.

Snarl 12/8 · Post by **Snarl 12/8** » Sat Apr 18, 2009 9:44 pm

Yeah, me too. I guess gain circuits add hiss? Or do they just amplify hiss that's brought into the circuit by other means?

I plugged some headphones into my Ashly with nothing else plugged in. When I turn up the headphone out I hear a little hiss. Then if I bring up a channel's main "fader" I hear a bit more, then I turn up the mic gain and I hear more. As I do this on more and more channels it gets louder still. What should be done to minimize this or is it intrinsic to the circuit/circuit design.

I guess I'm asking if recapping, swapping opamps, transistors, power supplies would effect this. And if so, what's the most bang for my buck/time.

Thanks,

klangtone · Post by **klangtone** » Sat Apr 18, 2009 10:21 pm

All circuits have noise, my friends. Even a resistor just sitting there can be a source of noise (although very very small). Any gain stage is going to have a noise floor associated with it. And noise that exists at the input of the gain stage will be amplified more and more as you turn the gain up.

So if you have a mixer that has multiple mic pres all summing together to the stereo buss, you get all kinds of noise adding up at the output.

You're never going to totally get rid of noise and I wouldn't bother messing with it unless it really becomes a problem. Then recapping and better opamps and all that can help.

Roy

apropos of nothing · Post by **apropos of nothing** » Sun Apr 19, 2009 5:57 am

This is why the shortest signal chain from source to capture is the most desirable; minimized component=minimized hiss.

I find that the monitor section of my mixer is really noisy. So when I'm recording, I usually bypass that and monitor out the recorder's outputs.

kayagum · Post by **kayagum** » Mon Apr 20, 2009 2:06 pm

Snarl 12/8 wrote:what's the most bang for my buck/time.

Proper gain staging.

ott0bot · Post by **ott0bot** » Mon Apr 20, 2009 3:01 pm

A wild cobra probably snuck into one or your tape returns. I'd buy a snake charming flute and start playing near the main ouputs. Have a burlap sack and some anti-venom on hand.

Top_Shelf · Post by **Top_Shelf** » Thu May 07, 2009 5:00 pm

I had a good reply when i came in here, but that hasslehoff graphic you have just blinded me...

Snarl 12/8 · Post by **Snarl 12/8** » Thu May 07, 2009 6:13 pm

Top_Shelf wrote:I had a good reply when i came in here, but that hasslehoff graphic you have just blinded me...

If you're in Firefox you can just right click on it to block it.

wkrbee · Post by **wkrbee** » Fri May 08, 2009 9:02 am

I had an answer too,but that icon is just toooooooooo creepy

RefD · Post by **RefD** » Fri May 08, 2009 9:15 am

Snarl 12/8 wrote:
Top_Shelf wrote:I had a good reply when i came in here, but that hasslehoff graphic you have just blinded me...
If you're in Firefox you can just right click on it to block it.

the most disturbing aspect for me is how he appears to emerge from his own stunted boy bits.

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Where does hiss come from in a mixer?

Where does hiss come from in a mixer?

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