H9 low hum noise issue

[nickrose]

The H9 should unbalance any balanced lead connected to it, so this is probably not the issue.

More likely, you have some kind of ground loop. This likely needs some skill and experience to diagnose, but you could try unplugging things one by one to see what makes a difference. If you have balanced lines, you could try disconnecting the ground (shield) at one end.

Make sure that everything is plugged into the same power outlet.

But, if all else fails you may need to find a technician to check over your setup. This is not something that can easily be done remotely.

 

[sillybat]

Im using my H9 as a send/return effects unit for my Xone96 mixer for live djing sessions. The mixer send/return connections are TRS and i am using sets of Oyaide TRS cables. My issue is that i am getting a light hum noise from the send/return channel even when i am not sending anything to the H9.

If i am not mistaken H9 has unbalanced connections. I was wondering if because the H9 uses unbalanced jacks and my cables are balanced TRS, connected to a balanced TRS or XLR connections on my mixer, I might have one side of my balanced line unterminated, which could cause the noise problem. I am not an engineer so i dont really know if this is an issue. 

Should i switch to TS cables? Or it would make no difference?

I have tried playing around with different gain levels on both the mixer and the H9 (H9 low and mixer high or the opposite) and i have also tried using different send/return connections of the mixer (it has 2 send/return channels) but i still get that light hum noise. 

Also in terms of power supply, i have my H9 plugged to the same multiplug as the rest of my gear (2 turntables and an amp, my speakers are passive and quite far away from the rest of my setup) and the multiplug is about 2m away from my gear. Dunno if this makes any difference but i though i mention it so you have an idea of my setup in terms of grounding. Also the noise is there even with the turntables off.

Is there a workaround or any idea what to try in order to eliminate this hum noise?

[joecozzi]

sillybat wrote:

Is there a workaround or any idea what to try in order to eliminate this hum noise?

Have you tried using another set of cables? Bad cables are notorious for causing hum issues in a DJ setup.

Have you tried using another device in the effects loop? Is the hum still there regardless? Just trying to narrow down where the hum is coming from, whether it’s your effects or it might me the mixer itself.

Disconnect the Xone’s outputs from your main speakers and simply monitor it in your headphones. Do you still hear the hum?

[joecozzi]

It is possible to suffer ground loop problems from USB ports, so I would also disconnect the USB cable to be sure.

[sillybat]

So with my limited knowledge.. The issue is not with any additional hardware i use. And since the H9 in some scenario (not the send/return usecase i am looking for but in the master insert) operates with no hum noise, i am left to believe it has to do with the cables and the send/return connectors of the mixer.

I find it hard to believe that they are faulty connectors since i have used all 4 return channels (the mixer gives the option for 2 normal channels and 2 aux return channels) and the hum issue is there. So the only thing left are the cables themselves. Again i am no sound engineer but it has to do with that since i have used the mixer send/returns via internal audio interface and a laptop running ableton with no hum noise so also the internal wiring seams to be working fine. 

[joecozzi]

I notice Send A has a Hi-Z switch. Have you tried using it with it on and off?

Have you tried connecting the H9 using Send B instead of A?

[bohan]

Have you tried relay bypass your H9?

[bohan]

There is no hum noise even when the pedal is in DSP bypass? That's weird. Do all algorithms have this noise? What if you turn the Mix to 0?

A couple of things you may try as well

1) Reinstall the firmware

2) Adjust the input gain in the Pedal Settings page in H9 Control

[sillybat]

joecozzi wrote:

Disconnect the Xone’s outputs from your main speakers and simply monitor it in your headphones. Do you still hear the hum?

Thank you for your reply. I have disconnected everything else from the mixer, (all outputs/inputs and even grounds from turntables) and only getting sound via usb and internal mixer audio interface. So the only connections in the mixer are the send/returns, the usb and the power cable. Unfortunately the hum is still there when monitoring via the headphones. I do not have a different pedal and no second pair of cables. So i guess i will have to get some different cables, this time unbalanced and hope for the best..

[sillybat]

nickrose wrote:

But, if all else fails you may need to find a technician to check over your setup. This is not something that can easily be done remotely.

Thank you for your reply. Unfortunately with the corona situation it is rather difficult to get anyone to assist me with this. I have tried removing everything except the pedal and a usb cable from the mixer but i am still getting that hum noise. I will get some different cables and have my fingers crossed. 

[sillybat]

joecozzi wrote:

It is possible to suffer ground loop problems from USB ports, so I would also disconnect the USB cable to be sure.

I actually removed also the usb so no actual signal is being sent to the H9 and the hum noise is this there. 

The other thing i tried is use the pedal not as send/return but as a master insert. Here the noise is gone! Even if then add the usb back so there is signal send to the H9, there is no hum noise.

 

The connectors for the master insert however have different specs.

 

MASTER INSERT SND / RTN

Provides INSERT points for the MST1 outputs to connect hardware dynamics processors such as a limiter, compressor, or graphic equaliser. Or when connecting effects hardware in-line with the (MST1) LR MIX output for external MASTER INSERT FX. Insert devices do not affect MIC A/B inputs. INSERT SND: Balanced (TRS) 1⁄4“Jack, wired; Tip=Hot [+], Ring=Cold [-], Sleeve=Ground. INSERT RTN: Unbalanced (MONO) 1⁄4”Jack, wired; Tip=Hot [+], Sleeve=Ground.

 

while the Send/Return 1&2 i used previously

 

SND 1 / SND 2, LINE Outputs

Connect your external FX inputs to SND 1 or SND 2 outputs and use SEND 1 / SEND 2 controls to send Channel audio to the FX unit. Connect MONO devices via L/M. Switchable SND 1 input and RTN A output impedance for external FX between LN, or Hi-Z suitable for guitar FX pedals or legacy hardware.

Balanced (TRS) 1⁄4“Jack, wired; Tip=Hot [+], Ring=Cold [-], Sleeve=Ground.

 

and

 

RTN A / RTN B, LINE Inputs

Connect auxiliary LINE level music sources, or external effects device outputs to RTN A and RTN B LINE inputs to route to CH A and CH B. Use L/M sockets when connecting MONO and Hi-Z devices. Balanced (TRS) 1⁄4“Jack, wired; Tip=Hot [+], Ring=Cold [-], Sleeve=Ground.

[sillybat]

joecozzi wrote:

I notice Send A has a Hi-Z switch. Have you tried using it with it on and off? Have you tried connecting the H9 using Send B instead of A?

Yes i have tried using both Send 1 and 2 and Return A, B, C, D. I have also tried switching Hi-Z on and off. There is a difference in output level and when compensating via the gain the hum noise is still there. Even if I run the gain level very low and again with no signal the hum noise is there, quieter but still noticeable.

[sillybat]

bohan wrote:

Have you tried relay bypass your H9?

I have no issue in bypass mode. All 3 modes have no hum noise when activated.

However in my usecase i need to have the H9 active and only engage via the send knobs for each channel i want to run my effect on my mixer which in turn send that channel’s signal to the pedal which then returns it to the return channel of the mixer. This is the standard way most djs utilize pedals for effects in their live acts.

So I need to have the H9 active all the time. But when no signal is passing, since my send knobs are off, there is this hum noise coming from the return channel.

[sillybat]

bohan wrote:

There is no hum noise even when the pedal is in DSP bypass?

bohan wrote:

Do all algorithms have this noise?

Yeap in all 3 bypass modes when H9 is not active i hear no noise.

 

It is not in all algorithms. At least i cannot hear it since its a light hum which is mostly audible in distortion effects like PitchFuzz Schnapps and other similar ones. I have tried adjusting the input gain but the noise is not audible only in levels where my effects are too low to be utlized in my mix. 

bohan wrote:

 What if you turn the Mix to 0?

This happens in many effects that dont have mix and the only control that makes a difference and eliminates the noise is out level which i guess its the same as lowering the input gain in general.

bohan wrote:

1) Reinstall the firmware

2) Adjust the input gain in the Pedal Settings page in H9 Control

 

I will try reinstalling. As far as input gain it makes no difference. No matter if H9 is low and channel gain in mixer high or the opposite. At the overall level which is needed in order for the effect to actually mix well if I have no signal sent i hear the hum.

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