Pre/Post Routing Noise Issue

[ill_clinton]

I have seen this asked on the forum but there wasn’t a solution so I am asking again.

I’m hoping someone can help me with this and it’s a simple fix. 

I am trying to run my H9 in pre/post but the noise level is unbearable. When I only hook up one side of it the noise level drops to where you would expect it to be.  But every time I hook up both the pre and post side the noise level jumps to an unreasonable level. 

 

So far I have tried:

Using the supplied power adapter.

Plugging the supplied power adapter into a plug on a different circuit at my house.

Plugging the supplied power adapter into a plug on a different circuit at a studio.

Testing each audio cable.

Simplifying the chain so it is only Gtr > H9 > One Stompbox > H9 > Amp

Nothing has made a difference. What else can I try?

 

 

 

 

 

[bohan]

ill_clinton wrote:

I am trying to run my H9 in pre/post but the noise level is unbearable. When I only hook up one side of it the noise level drops to where you would expect it to be. But every time I hook up both the pre and post side the noise level jumps to an unreasonable level.

Simplifying the chain so it is only Gtr > H9 > One Stompbox > H9 > Amp. Nothing has made a difference. What else can I try?

If you

1. set your H9 to Pre/Post mode

2. connect your Guitar to H9's Input 1

3. connect H9's Output 1 to Input 2

4. connect H9's Output 2 to your amp

Does it make any difference when you change the mode of your current preset from PRE to POST?

[ill_clinton]

Thank you for the reply.

I connected the H9’s the way you suggested and the noise was at a reasonable level and did not change when I toggled between PRE and POST. 

 

[bohan]

ill_clinton wrote:

Thank you for the reply.

I connected the H9's the way you suggested and the noise was at a reasonable level and did not change when I toggled between PRE and POST. 

Then I guess it might be your external stompbox's problem? What if you insert that stompbox into the Pre/Post loop? (Output 1 -> Stompbox -> Input 2)

[ill_clinton]

 

[/quote]

Then I guess it might be your external stompbox’s problem? What if you insert that stompbox into the Pre/Post loop? (Output 1 -> Stompbox -> Input 2)

[/quote]

Thank you for the response.

I initially thought it had something to do with the other boxes as well. I have tried what you suggested and when I insert any of them, (Output 1 > Stompbox > Input 2 > Output 2 > Amp) the noise is there. But if I go straight to the amp, (Output 1 > Stompbox >Amp) there is no noise.

I’ve swapped pedals, cables, power sources. I’m stumped.

 

 

[bohan]

ill_clinton wrote:

I've swapped pedals, cables, power sources. I'm stumped.

When you insert your stompbox into H9's Pre/Post loop, does toggling Pre/Post affect the noise? What if you bypass the stompbox while toggling Pre/Post? 

I don't know…If H9 works fine on its own in either Pre or Post, I don't think it's H9's problem.

[ill_clinton]

bohan wrote:

ill_clinton wrote:

I’ve swapped pedals, cables, power sources. I’m stumped.

When you insert your stompbox into H9’s Pre/Post loop, does toggling Pre/Post affect the noise? What if you bypass the stompbox while toggling Pre/Post? 

I don’t know…If H9 works fine on its own in either Pre or Post, I don’t think it’s H9’s problem.

 

Again, I appreciate the help.

When I insert any stompbox (OD or Delay or Tuner) into the H9’s Pre/Post loop I get the hum regardless of if that stompbox is bypassed or not. Switching between pre and post doesn’t change the level of the noise.

Yes, the H9 works fine when I connect just the pre or just the post side. But the noise consistently happens when I connect both sides of the H9 regardless of what cords, stompbox, and power supply I use in the loop.  The noise always goes away once I take the second instance of H9 out of the chain.

[bohan]

ill_clinton wrote:

Yes, the H9 works fine when I connect just the pre or just the post side. But the noise consistently happens when I connect both sides of the H9 regardless of what cords, stompbox, and power supply I use in the loop.  The noise always goes away once I take the second instance of H9 out of the chain.

I'm a bit confused. What do you mean by connecting both sides of the H9? If you connect both sides of the H9 (like what I suggested in my first reply. What I meant was using a cord connecting H9's OUTPUT 1 and INPUT 2 as a "pedal in bypass") it does make noise?

By toggling Pre/Post I meant toggling that in H9 Control's preset screen, with connected cables unchanged. Please find the attachment. You may also do that on your phone.

By doing so you may find out which i/o ports have problems.

[jnorris]

I am experiencing a much higher noise floor using pre/post mode. I am trying to use my amps effects loop with this and have even tried putting a gigrig humdinger in every spot to mitigate with no luck. Any assistance?

[pjmaclean]

I have a similar issue with pre/post.  I used an RJM Mastermind PBC MIDI controller.  It has loops for up to 10 pedals that can be assigned as 1-6 in front of the amp and 7-9 for the loop.  I ran the H9 input/output 1 into loop 6 (in front of the amp.  and input/output 2 into loop 9 (FX Loop) I assigned my presets appropriately so that the pitch based effects are pre (in front of the amp) and delay and reverb are post (in the loop).  Previously, I just had the H9 in the FX loop and dealt with it that way for years.  Actually, I don’t think pre/post was even an option back when I bought it.  I had read that you can split the signal using pre/post for the purpose of running the pitch based effects in front, where they like to be and then running the time based effects in the loop – where I like them.  I’m actually not writing this post for a solution, because I don’t believe there is one, but maybe I’m wrong.  For some people this works fine, but depending on what you have going on, noise does occur.  It’s too bad though because the H9 sounds fantastic like this (except for the noise).  

[nickrose]

Because of the nature of pre/post, it is very prone to ground loops and feedback (which can present as increased noise level).

Since every setup is different, we can't give much advice, except keep cables as short as possible, and make sure you have a single common main ground connection.

 

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