I’d like to know about the best and safest way of using my PS-100 with my ZMACS.
My usage scenario is:
Amp 1&2 - 8 ohms
Cab 1&2 - 8 ohms (2 loadboxes)
Cab 3 - 16 ohms (real cab)
I’d like to attenuate the signal going to the real cab only.
My questions:
If I put the PS in the switchable attenuator loop, will it cause any problems if I turn the loop off and the PS stays in Operate instead of Bypass?
If I’m using the PS ONLY to attenuate either amp going to the real cab (which is 16 ohms so ZMACS will be set to Amp Z 8 ohms and Cab Z 16 ohms in this case), should I also be setting my PS similarly, meaning Amp In to 8 ohms and Speaker Out to 16 ohms?
Is there anything else that I should be wary of or need to do to be able to run the above scenario safely?
Hello, Welcome to the Fryette Support Forum! Here are the answers to your questions; Yes, run the PS-100 in the switchable attenuator loop of the ZMACS.
The PS-100 can stay in Operate mode safely when switching the attenuator loop in or out.
Set the ZMACS’s impedance selectors to match the amps and cabs, then set both of the PS-100 impedance selector switches to 8 ohms.
You can then switch the attenuator loop on along with the real cab selection and save that as your preset for that configuration.
This should take care of your concerns. Please let me know if I can assist you in any way. Cheers! Gil
Hi Gil,
Thank you very much.
The only thing I don’t undestand is why I would run the PS-100 at 8 ohms on the cab side if the cab connected to the ZMACS is rated at 16 ohms?
When the PS-100 is patched into the attenuator loop on the ZMACS, its impedance is irrelevant to the ZMACS’s Amp In and Speaker Out impedance settings so it’s essentially neutral in that signal path and the actual impedance that your amps see is set with the impedance selectors on the ZMACS.
Hope that answers your question. Gil
Hi, Gil. I just want to be sure that I’m not misunderstanding, because page 8 of the ZMACS Owners’ Manual seems to conflict directly with what you’ve just said here (under ATTENUATOR IMPEDANCE COMPENSATION):
To take advantage of this feature, first set the AMP and CAB impedance to match the selected amps and cabs. Next, engage BYPASS OVERRIDE MODEONLY IF THE SELECT HEAD AND CAB ARE THE SAME IMPEDANCE.
It goes on to say to set the AMP IN and SPEAKER OUT on the Power Station to 8 ohms, then says “If you are not surprised by what you hear, well, sometimes it’s OK to not be a total gear nerd.” I don’t know if this is in reference to the tone or what exactly, but it is a little confusing for me.
It’s not actually contradicting what I stated, the ZMACS’s internal impedance matching transformer automatically compensates for any mismatch between the attenuator’s impedance settings, when connected to the attenuator loop, and in the case of a Power Station, it simply states to set the impedance selectors to 8-ohms on both the amp in and cab out then the ZMACS does the rest. Please experiment and hopehully you’ll be pleased with the results. Gil
Okay I think that makes sense, thank you. I think I may have been confusing the impedance matching within the attenuator loop for the impedance matching between head and cab.
So, if I understand correctly, I can connect an 8 ohms head to Amp 1, put my PS-100 in the attenuator loop with both switches on the PS-100 set to 8 ohms, and a 16 ohm cab in Cab 1 - then I set the ZMACS for Amp 1 to 8 Ohms and Cab 1 to 16 Ohms. And I run the whole thing in Bypass Override Mode. And I don’t run into any of the risks associated with impedance mismatching?
