Hissssssssssssss

[Ricesnaps]

Just taken delivery of a Soundcraft Folio Notebook 10/2 mixer. Set up for a wet hire yesterday. All works fine, but there is a lot of white noise present which I wasn't expecting. The hire is for a fairly noisy dinner today and the venue are happy with the rig, but obviously I want to understand what's happening.

The Folio doesn't have balanced outputs - just two 1/4 inch jack sockets. Is that what the problem is and am I unlikely to get any better? I had thought Soundcraft a good make and the folio notebook has some great reviews, so is there actually something wrong with the mixer?

Currently set up as follows:

Beringer EP2500 powering my Mach M-Flex 15's
Folio connected to amp with jack to XLR leads
Mixer has two UHF radio mics, one lapel mic and a corded SM58 attached

Any thoughts?

[Paul James Promotions]

Does this happen with the mic channels turned down?

[Ricesnaps]

Does this happen with the mic channels turned down?

Yes - or at least I think so! Obviously not there at the moment!

[Paul James Promotions]

When you collect the equipment, have a play. Even though XLR is ideal, jacks shouldn't cause a hiss.

[TonyB]

I do believe the outputs are balanced. They use TRS jack plugs that look like stereo headphone ones, not mono jack plugs. But it is unlikely that it would cause the hiss.

I would guess that the most likely candidate is the radio mics. First I would try unplugging them to see if it still hisses.

Otherwise it could be that the gain structure isn't set up correctly. The master outs should not be full on. Without anything plugged into the mixer, turn the amp gain controls and master outs on the mixer to full then adjust the master outs until the background noise reduces, usually at 75% - 80%. Next attach an input source to the mixer such as a cd player and turn the gain controls on the amp fully down. Adjust the source input channel level to its max without clipping then turn up the amp gains until the clipping light just flickers then back off a bit so there is no clipping.

Its not so important setting up the gain structure when doing a disco as there is loud noise to drown out any background noise although it is good practice to do it correctly.

If none of that works, then I would contact Soundcraft support.

[Ricesnaps]

I do believe the outputs are balanced. They use TRS jack plugs that look like stereo headphone ones, not mono jack plugs. But it is unlikely that it would cause the hiss.

I would guess that the most likely candidate is the radio mics. First I would try unplugging them to see if it still hisses.

Otherwise it could be that the gain structure isn't set up correctly. The master outs should not be full on. Without anything plugged into the mixer, turn the amp gain controls and master outs on the mixer to full then adjust the master outs until the background noise reduces, usually at 75% - 80%. Next attach an input source to the mixer such as a cd player and turn the gain controls on the amp fully down. Adjust the source input channel level to its max without clipping then turn up the amp gains until the clipping light just flickers then back off a bit so there is no clipping.

Its not so important setting up the gain structure when doing a disco as there is loud noise to drown out any background noise although it is good practice to do it correctly.

If none of that works, then I would contact Soundcraft support.

WOW!

Thanks, what a comprehensive reply! I have some "stereo" to XLR adaptors and hadn't thought of trying them. Will do so when I collect the gear!

The amp gain controls are set to maximum, but the mixer output is already at about 75%, although I didn't try the set up exactly as you suggest, so that's worth doing. I have to say that the individual channel gains are quite high on the radio mics, but the channel volumes are around 0db or slightly higher. Not using a music source for this, just mics.

Lots to think about when i pick up, thanks for the advice

[sleah]

I have the same mixer. I find there is hiss when the gain controls (trim pots) are high. Try turning up the channel volumes and the trim pots down abit. If you can, tweak up the outputs from the radio mics so you don't need the mixer's gain so high.