Subwoofer Amplifier Guidance

Present Equipment.

Audio Research Classic 60 Amp.

Audio Research LS5 MK III (Running Unbalanced).

ProAc Response 2.5 Speakers.

Two REL Storm III Subs.

Turntable and Primarily Vinyl Playback.

Room is ASC Tube Trap Treated per ASC recommendations.

I was very close to buying a Rythmik F12 (12" Sealed) to run solely since one of my REL Storm III Subs is malfunctioning. My intent was if the Rythmik F12 was satisfactory to me then I would add a second F12. Connection would be from the ARC Classic 60 Amp Speaker Taps to the Rythmic F12 Speaker Level Inputs (High Level Input).

Unfortunately, I was stopped cold when I read this on the Rythmik Website and then talked to Brian the Owner of Rythmik who does not recommend that I proceed. Brian went so far as to say that I should repair the REL Storm III;

" Tube power amplifier issue. If your power amplifier is tube-based, then speaker level input method has one additional drawback. Tube power amplifiers are known to have low damping factor (DF). Low DF means the frequency response from tube power amp is highly load dependent. If one connects to 5 different speakers, it gives you five different frequency response curves at the power amplifier output (whereas solid state power amps produces same power amp output regardless speaker impedance). Sonically bass has always been the weakness of tube power amps with bass often perceived as sloppy and under-controlled. Stereophile has been publishing deviation of FR using their pseudo speaker load when reviewing tube power amplifiers. The plots show wavy frequency response. If one uses the tube power amp output to drive subwoofer inputs, the same sloppy/ill-controlled bass from the front speakers will transfer to subwoofer and also make subwoofers sound sloppy and under-controlled. That certainly is not the best way to achieve good bass.

5) Can lead to damage when connecting to a fully complementary class-D power amplifier. Our speaker level inputs are designed with single-ended power amplifier outputs in mind. "Single-ended" means the red speaker terminal (+) carrys hot signal and black terminal (-) is true ground. Accidentally touching the black terminals from both channels will not lead to amplifier damage. Some class-D power amplifiers are single-ended while the majority are fully complementary which means the black terminals at the back of power amplifiers are not true ground. Instead, the black or (-) terminal has an opposite polarity of the red or (+) terminal. Accidentally touching the black terminals from both channels can lead to amplifier damage ".

I have been happy with the REL Storm III’s since new and I do not expect perfection but rather like the bottom end boost.

They are tucked in behind the ProAc Speakers and my thought was to try a different location with the sole Rythmik F12 using the Speaker Level Inputs on the Rythmic from the Amp.

I have been so far removed from what is out there that I am looking for Options and if it is feasible to use 1 of my 2 Pre Outs to run a Solid State Amp for the Rythmik F12 Sub solely.

I am not getting rid of the Amp and the appearance of the present REL Subwoofers is a little off-putting to me with the High Glass & REL Emblazed everywhere. I would much rather order some Subs from BK Electronics in the UK versus the present REL finishes.

Any thoughts would be appreciated.

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