I am getting noise and popping when the Waza is plugged into the loop of the ZMACS. I’m using all 8 ohm heads plugged into the ZMACS with the ZMACS set on 8ohm and then from there out to my 16 ohm cabinet. The cabinet is set on 16ohm on the speaker out of the ZMACS. I’m using fractal FX8 effects in the loop of my Waza. When I unplug the effects from the Waza the noise goes away.
If the bypass the ZMACS loop and take the speaker out from the ZMACS and go directly into the Waza and use the Waza speaker out to the cabinet, everything works and sounds fine with no noise. Why isn’t the loop of the ZMACS noiseless with the original set up per the manual?
Because you mentioned FX, I am suspecting this is a ground loop issue. Probably if you isolate the FX loop with an audio isolator, these problems will go away. If the problem occurs without FX then it’s clearly something else, and we can help you debug that further.
You should be aware that the Waza TAE and Waza Core drive the speaker cab from a class D power amp. This type of power amp has a floating output ground that must not connected to system ground.
It’s probable that the Attenuator loop is getting ground from the FX in the loop of the Core. As Dan mentioned, you will most likely need to isolate your FX ground from ZMACS ground.
Try the Ground Lift switch on the rear of the ZMACS and see if that helps.
Here’s what I’d like to do if I can’t use the ZMACS loop due to the noise issue not going away. Is this Ok?
Can I use the ZMACS strictly as an amp selector with the ZMACS speaker output set to 8 Ω feeding the Waza Tube Amp Expander Core (8 Ω input), and then let the Waza drive my 16 Ω cabinet?
The ZMACS is designed to work with the PS-100 and PS-2 as well as most passive attenuators. The only ones that might have issues are those with SS power amps that have a floating output ground.
One last question, if I use your PS100 with my ZMACS and have all four tube heads set to 8ohm and my cabinet is 16ohm, do I set the back of the PS100 for 8ohm head and 16ohm cabinet just like the ZMACS being set for 8ohm and 16ohm cabinet?
I wasn’t sure about the PS100 in the ZMACS loop and how to set that to match the amps and cabinet.
I just got home from a trip and was able to try different things and came to the conclusion that the issue between the waza and the ZMACS is a fx loop feedback issue. When the waza is plugged in per the instructions in your manual, the fx loop on the waza won’t work without squealing. It’s definitely a feedback loop issue. If I unplug the effects from the waza loop then the squealing stops. If I turn on the internal effects in the waza without the loop activated, those effects work great but that’s not how I’m trying to run it. I’m trying to use my own external effects into the waza loop with the Waza plugged into the ZMACS per the manual.
The manual shows your PS100 plugged into the ZMACS with the loop of the PS100 having external effects plug in. How can that also not cause a feedback loop?
I’ve tried adjusting the volume inputs and exits of all my fx units to see if that would eliminate the issue with no luck. I’ve tried several sets of high end cables I have and that doesn’t work.
I read on chat gpt that the fx loop of the waza and the attenuator loop being used together is causing the feedback.
From what I understand, the “core” is just a reactive load, there is no Class-D power amp. So you could use it in the attenuator loop (always on) or as a silent speaker in one of the cab connections.
It won’t work in your attenuator loop. It causes a feedback loop. Waza is a class D amp. The waza is only squealing with effects plugged into the waza loop when being used in your loop.
From the Waza Core manual: A 30 W power amp is built into this unit. The input tolerance of your connected speaker should be at least 30 W.
Regarding your Gemini quote, that’s a pretty boiler plate explanation, but essentially true. As I mentioned above, the solution is to isolate the ground between the FX Loop ground and the Core speaker output ground. This can be done using an isolation box on the loop signal.
