Can anyone confirm if the Naim NAP 135 mono block Amps are fully differential please?
Out of interest, what does that mean and why might it matter?
I Googled it and it sounds like something to do with ‘Balanced’ output but then my brain started hurting so I came back here.
Do you mean fully regulated?
Good thinking Batman. If that is the question, the answer is yes.
just tried Grok 
“Yes, the Naim NAP 135 is a true differential amplifier design (fully balanced from input to output)”
But still not sure what this means TBH
Martin
The NAP135s are not balanced but they are something much rarer, a fully regulated amp.
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It matters in my particular setup as it determines how my two subs can be connected to 135 mono blocks.
The question remains as to what you mean by differential.
Anyway, do not connect subs to the 135s. Instead, take the signal from the rear of the speakers.
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Differential was the term bandied about on the sub manufacturer’s web site saying it would need a different connection to the subs if the amps were differential in design. I am wary about connecting the subs in any way that conflicts with the information given by their manufacturer. What benefit would there be connecting the subs to the speaker terminals?
The benefit is that the amplifier doesn’t see the subwoofer, so it’s as though it’s just driving the speakers. If you connect the sub to the amplifier, it changes the load and can negatively affect the amplifier. I’m sure that if you do a search you can find a more technical explanation but that’s basically it.
Have you used subs before? I suspect you’ll gain more bass output but lose the exciting sound that you’re currently used to.
Personally I would try to figure out other ways to increase bass output. I.e isolation, positioning
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I’ve used subs for many years but have never heard or seen advised them being connected to the loudspeaker terminals.
That makes sense. Thank you.
Connecting to the speakers rather than the power amp is very much specific to Naim amps, and certainly worth bearing in mind with your 135s.
An alternative would be a low level connection to the preamp. Naim and some sub manufacturers tend to prefer the high level connection, but this can still work well.
Probably referring to a bridged design - a la the NAP500 - where subwoofer connection is not recommended.
Kinda disagree with your statement….when carefully setup they are fabulous particularly with smaller speakers. It not only improves extension but improves the mids and sence of depth and air… However…if you turn up the wick up on the sub which is tempting..then it does no favors. You also need a fast powerful sub..
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Fair enough. I’d love to hear a system that has great integration with subs. Personally I e tried it many times and always failed. I have an affinity with stand mount speakers so bass is always something my system lacked yet I was never convinced by the sub integration.
I’ve tried a bunch of brands. Chief among them was the REL subs with high output. Tried the larger models. Then I tried smaller ones. I tried two and now with the class D amplification but they always sounded slower than the speakers.
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I agree,always lack of timing with subwoofers.
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A differential amplifier is an amplifier where op amps are used.
I’m pretty sure a 135 doesn’t have any.
Maybe a real Naim engineer will come along and confirm.