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Hafler effect setup - any concerns for a "ParasoundZonemaster2350" p-amp (or in general)

I have recently come across information on the web about the "Hafler effect" for creating a "studio" or "live venue" sound from a 2 channel system (such as most of us have). Basically it is implementing a third speaker located behind and centre of listening position with one speaker cable connected to + (red) of front left and one speaker cable connected to + (red) of front right going to the rear centre speaker + (red) and - (black). (** at least this is my interpretation/understanding of it **).

My question is, is this a dangerous set-up for my "Parasound Zonemaster2350" power amp? I have read that it can be catastrophic for bridged amp's and, my limited knowledge of bridged setups (which is none), I'm not sure if this would be safe to attempt. I have reached out to "Parasound" for their advice but pretty sure they will blanket statement recommend against so as not to take any responsibility, but who knows, maybe not.

Thanks in advance to all who reply,
much appreciated

Rob
tunehead

Showing 2 responses by pch300

pch300
56 posts
 
This "Hafler" setup was sold earlier as the Dynaco Quadaptor, of Hafler design of course. Some Dynaco amps have this circuit built-in.

https://en.wikipedia.org/wiki/Dynaquad
https://www.hifiengine.com/manual_library/dynaco/qd-1.shtml

The amplifier must safely permit both front channels to be connected in this fashion or else you can damage the amp. Also, this lowers the equivalent impedance that the speakers presents to the amp. Some amps don't like low impedances. Verify that the amp will be safe with this circuit attached before going ahead.
pch300
56 posts
 
I recall using the Quadaptor with Dynaco amps. It worked fine. After I upgraded to a more powerful amp that cautioned against going below 4 ohms load, I had to disconnect the Quadaptor. My speakers were 4 ohms and adding the Quadaptor with rear speakers would lower the impedance below 4 ohms. The sound was more enveloping while it lasted.
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