Need Advice on Amplifiers

About six months ago, I replaced my Benchmark AHB2 power amp with the Rogue Stereo 100 "Dark." While the Rogue is superb on the timbre and tonal qualities of the instruments, I seem to have lost some of the definition I had with the Benchmark.  My preamp is the Rogue RP-7, which was wonderful with the Benchmark, so I am not contemplating a replacement for it.  My Fine Audio F-702 floor standing speakers recommend amps up to 200 watts per channel, so I want to try something with more power--we do not listen at vey high levels, but I have found that the speakers "open up" at moderately loud levels. I have considered the Bel Canto eX1, the Brystonl 3B3, and the Van Alstine M225 mono blocs, but it then dawned on me that I was very pleased with the Benchmark, so why not try two of the AHB2's in a horizontal beam (passive) bi-amp mode to give me 200 wpc.  My preamp has four sets of variable gain outputs, two XLR and two single-ended,  So, comments would be appreciated on the named amplifiers and any suggestions as to alternatives I should consider in addition to these.  Also, should I seriously consider the bi-amp mode with two stereo amplifiers or should I stick with one more powerful stereo amplifier?  Thanks, in advance for your comments and suggestions.

In other developments, I added the Lounge Audio LCR III Gold phono preamp to my system--with the Thorens TD 126 MKII and an Audio Technica MM cartridge, and I am simply stunned by the dynamics, clarity, instrument placement, tonality, and "organic" nature of the resultant sound from a couple of my 1980s audiophile discs, including a Sheffield Lab recording of Lincoln Mayorga and an M&K 45 rpm LP of the Phrisco Phunction.  Time to seek out more LPs!


At any price point, Audionet.  Best of Solid State with definition and clarity, while also having great midrange  and bass and not fatiguing

Sounds like you’re not totally happy with either.  I don’t think adding another Benchmark amp makes a whole lotta sense because it clearly doesn’t give you the soul of the music you get with the Rogue, so why double down on that?  More Watts won’t fix that.  This upgraded McCormack amp may well give you the best of both worlds while giving you the power you’re looking for.  Plus, if you like what it does you could send it back to SMcAudio and do further upgrades by the original designer if you want and get even more.  I do also like your thought of Van Alstine as well.  I’d think you’d be thrilled with either given what you’re looking for.  Great preamp BTW, and best of luck.

This is very common when purchasing components at about the same investment level. If you want a substantial upgrade, typically you need to double your investment. Then all aspects improve instead of trading one set of strengths and weaknesses for another.

Your systems page has a lot of nice components, can you post pics of your room? Did you ever measure the FR? 

FWIW your reference to speakers opening up at moderate loud volume is a very common complaint, one that I’ve also experienced using both high quality electrostatics and some box speakers. In my quest I never found that higher power amps helped, but quality ones did I think because the quality of the amps was such that I didn’t mind so much the higher volume. My best amp the was a 50wt Class A and I was driving speakers with an 86dba. Your quest for improvement by increasing the power may be nothing more than an attractive fantasy.

I looked at the specs on your speaker and frankly I think that a similar amp would/should be more that adequate. Your manufacturer recommends up to 200 wts but consider, volume wise that is not much more than a 6db increase in volume. A 50wt amp would drive your speakers up to about 106db, that’s loud!

@mike4597 I had the original ST100 and am not familiar with the Dark version. I can tell you that I’ve not experienced lack of definition with that amp, driving it with Rogue RP1, RP5 and Pass XP12. Indud upgrade the tubes in the Rogue preamps as well as the 12AU7 and 12AX7 in the amp. I also had pretty good cables on all my components. If you’re using stock JJ tubes, probably worth experimenting with tube rolling before you give up on this amp. The Gold Lion tubes were very nice in the ST100 and the Rogue pre if you don’t want to invest in NOS. 

Also, are you using balanced interconnects? If not, you should give that a try. 

Going from one of the best measuring solid state amps to a tube amp, I am not surprised that you have lost some definition. Given that you have a tube preamp, it might make sense to go back to solid state with your power amp. Your speakers are fairly sensitive at 92 dB, so I am not sure that adding more wattage is going to get you anywhere. I would suggest looking at solid state amps that provide a fair amount of Class A watts and have high current designs. I listen at low levels as well, and my Coda #8 has 18 w of Class A, guessing I rarely if ever venture into A/B.