Noisy unit

[stevegreenberg]

Hello,

I received the Wahoo from Peterson in the US. Overall, it seems well built and the basic sounds of the unit is fantastic. However, the overall signal is quite noisy and what is of the most concern is that it produces noise even when in bypass. I have switched out the audio cables multiple times with no effect. It is being powered by a commercial 9 volt power supply from ISPOT. I have removed all other pedals from the power system and from the audio signal path and the noise persists.

Although I dont have another unit to compare it to, it also seems that the overall signal level is lower than is should be, the noise floor is really quite high.

Regards,

Steve

[stevegreenberg]

Just did some more testing and the noise was there in bypass. I then pulled the 9v power supply and the noise went away. it turns out that I did have another pedal connect to the power supply, a Rivera Shaman Compressor. It seems whenever that is attached to the power circuit the Wahoo makes noise, whenever I remove it, the noise goes away. I am now connecting it to my computer to upgrade the firmware to see if it makes any differnce at all

Steve

[stevegreenberg]

Behaves the same way after the firmware update. May also try batteries and/or a separate power supply to the Rivera pedal

[james]

A firmware update shouldn't fix this, because it sounds like it may be a ground loop problem -- signals from the PSU ground is coupling into the audio ground. You can get similar problems with some USB power supplies where digital USB noise can couple into the audio signal.

When the Wahoo is bypassed, the signal is completely disconnected from the pedal, but the ground is still connected (via some EMC components).

Does it seem ok when the compressor is not connected?

[stevegreenberg]

Yes, exactly. When physically disconnecting the compressor from the power signal, the Wahoo noise drops way down. So obviously they need to be isolated, but notable that no other pedals have any noise induced in them by the compressor, including a Soundblox Multiwave, which is pure diigital device. Does that indicate that the Wahoo power supply is not well isolated?

[james]

Actually, I think the problem is the other way around. The Wahoo PSU is isolated from the signal ground, but the other pedals have power and signal ground connected, so when everything is connected together there can be problems.

Currently, the best solution is to use separate power supplies. But we'll investigate possible other solutions.

[stevegreenberg]

Hi James,

Just to be clear, in this scnenario the Rivera compressor was removed from the audio signal chain but still connected to the power line. I will repeat that test to be absolutely certain, but I think the noise is being induced solely through the power connection. I will verify that to be sure. I agree that separate power supplies will be necessary. Annoying but not that big a deal and no indictment of the Wahoo!

[james]

Hi Steve,

Yes, please check and let us know. It's hard for us to test every conceivable combination of things. I suspect that the "any polarity" feature of the Wahoo power may make it less tolerant of some setups. So maybe there is a trade off of one convenience for another. Your feedback is very valuable to us!

James

[stevegreenberg]

Will do, I am away for the weekend, but will test it all again and report back

Steve

[stevegreenberg]

Had a chance to re-test and pay close attention to what exactly is connected. As you suggested, the Rivera compressor induces noise into the Wahoo only when connected to both the power source and the audio signal path. This surprised me because the Rivera is after a Radial SwitchBone AB-Y box which I thought was transformer isolated. However, it does not seem to separate the ground signal.

So next step is to try a dedicated power supply for either the Rivera or the Wahoo.

Steve