Tubes with Infinity IRS Betas

Yeah, cheers George...

Not so much coin to put a Threshold into the mix
for grins.....

I have had a set of IRS Betas for just over 10 years now, and still have my original pair of Quantum 5s. In the past I have also had Kappa 8s, Kappa 9s and IRS Delta's.To power them properly & safely, I personally have had good results with the older vintage Threshold amps, S300 MKII, S350e & S500e.I have also had good results with modified Halfer amps as well, some moderately modified stereo DH200 and DH220s, and more recently a pair of extensively modded mono Hafler DH200s with custom driver boards.With the Betas I like to use the modded mono Haflers on the mid-high towers and the Threshold S350e on the bass towers, and that setup has power to spare and is the best sounding combination so far.Last year I picked up a pair of Doge Audio tube mono amps, and they do a a nice job on the mid high towers in class A mode. They do run very hot though, definitely need to make room for them to breathe.For the Haflers, I usually do not push the idle current, so they run warm but are not outrageous power consumers.The only thing I regret is not having a big enough room to do the Betas justice.Even so when people hear them for the first time they are blown away.

I like the RSIIa/bs, impressive sound and looks in a single tower configuration. Do you remember what you paid for them? I have a buddy right now who tracked down a good used pair of RS11s, they are nice but not the same without the emims like you had.A few years later (1987) is when I picked up my IRS Deltas, at the time they were $9500 Cdn, I traded in my Kappa 9s and had to sell off a car I was building to help pay for them. I still regret not hanging onto the Deltas, parted with them in 1990 when I moved to another province for work.