H9 Pre/Post Signal Issue – Weak Left Channel, Overmodulating, Hum

[VN]

Hey guys,

Just bought a H9 MAX. Super excited, there are some amazing effects in that box. The sping reverb is phenomenal, beats easily everything else I have heard.

The pedal is brand new – my first Eventide stomp box. Trying to set it up using the 4 cable method with my Friedman Pink Taco. Ran into a weird issue. The Left channel (Input 1 -> Output 1) is very weak – see the attached screenshot. The signal coming from the amp’s effects loop (Input 2 -> Output 2) is much stronger – see the screenshot below. When I turn the gain up it gets overmodulated, starts generating hum and other crazy noises.

Double-checked the wiring, everything seems to be in good shape in that department. All software is up to date. If I hook up the pedal only in the EFX loop of the amp, the problem disappears. Same when the pedal is entirely in front of the amp. Same when I am using only Input 2/Output 2. The issue appears ONLY when 4 cables are used.

I’d love to use my H9 both Pre and Post. What is it that am I doing wrong? Any suggestions would be highly appreciated. Many thanks in advance!

[nickrose]

A number of amps seem to have a lot of gain on the effects loops – would this explain what you are seeing ? This means that you are sending a low level guitar signal to the pre, and a high level effects loop signal to the post.

 

If you are not using pre-post, you will presumably use a single mono jack for both in and out, meaning that the levels on each channel will be the same. The level would be less when using the guitar.

[VN]

nickrose wrote:

A number of amps seem to have a lot of gain on the effects loops – would this explain what you are seeing ? This means that you are sending a low level guitar signal to the pre, and a high level effects loop signal to the post.

I’d expect that with any amp out there the situation would be the same – Hi-Z signal from the guitar, and once that hits the preamp, the signal in the effects loop after the preamp would be much stronger. The manual says that H9 should detect those differences in signal levels, and will adjust itself automatically. 

I also have a Strymon Mobius. Using it in the same situation – 4CM. Never had any problems with it.

What can I do to solve this? Any ideas would be much appreciated.

Many thanks in advance!

 

[nickrose]

VN wrote:

The manual says that H9 should detect those differences in signal levels, and will adjust itself automatically. 

I don't see this in the manual. The only automatic gain change comes where it reduces the output to offset an increased input.

You can adjust the input gain, but not on a channel by channel basis. You could try cranking up the input gain a little, especially if you can reduce the level of your effects send.

Beyond that, not sure what to tell you. What you see on the meter represents the actual signal level you are giving it. Pre/post setups are prone to ground loops, so this may be worth looking at it you are getting hum.

 

 

 

 

[VN]

Your answer doesn’t give me the information I am looking for. 

Naturally, from my perspective, when you sell a pedal, designed to be hooked with 4 cables in a Pre/Post configuration, the first thing that comes to mind is potential ground loops and signal level issues. I can’t comprehend how something so simple can be a problem for you guys. Strymon does not have this problem at all with their Mobius. How come you do!?

I was super excited when I got this thing. It would have solved all my modulation, reverb, delay and octave divider needs. It turns out this pedal is not what it is advertised to be. I feel I am left with no help at all. Thank you anyway for all your efforts.

The pedal will receive the due reviews on Amazon, where I got, and videos on Youtube with a clear demo so that people know.

[gkellum]

VN wrote:

Naturally, from my perspective, when you sell a pedal, designed to be hooked with 4 cables in a Pre/Post configuration, the first thing that comes to mind is potential ground loops and signal level issues. I can't comprehend how something so simple can be a problem for you guys. Strymon does not have this problem at all with their Mobius. How come you do!?

Strymon does have this problem with their Mobius.  We talked about whether it was even a good idea to add pre / post given the fact that this was going to lead to ground loops for some people long before we started working on this feature, because we knew from the feedback of Mobius users that this was going to lead to ground loops.

We decided to do it anyway b/c (1) not everyone was going to have that problem (2) there are products on the market for addressing ground loops (3) you don't have to use it in the effects loop of an amp in the first place.  It's useful just moving your H9s position in your signal chain to before or after other pedals.

With regards to your guitar signal coming in weaker than your amps signal, a fair number of people have gain control on their amps effect loop.  If you don't, you can buy a boost pedal for your guitar on amazon for as little as $30.  If you have a weak signal coming in from your guitar, boosting the signal will also lead to things sounding better overall, because the H9 will have a better representation of your guitar's signal before it goes through A/D conversion.

 

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