What Power Amplifier Should I Buy?

After all this discussion of power, I bought a Bryston BP-17 cubed preamp. I'll get it next week. This discussion has convinced me that I have enough power from my power amp. So I decided to see if the much newer BP-17-3 can outperform the aged Levinson #38s. I hope so.

I'm not sure if anyone is still paying attention, but...

My time with the BP-17 has come to an end. I could not get rid of the sibilance that drives me crazy. The ergonomics are OK, but nothing like the Levinson 38s. I've listed it, but not on Audiogon yet.

Now I use my old, old Paragon System E as a line preamp and a phono preamp. I still use the 38s, but now it is relegated to volume control because it has a remote. The Paragon does not.

This is the best sound I have gotten so far. I have rebuilt the Paragon PSU, replacing all components except the transformer, so it should be good for a while.

The Paragon is a tube preamp with six 12AX7 tubes. I've got new tubes (JJ). It was sold in the late 70s through the mid 80s. I bought mine new.

I'm finished with this quest. Although I have not found the Grail, I am quite pleased with the relics that I have. I've firmly decided I don't need an amp with more power output.

Gotta go buy some records. My gear search has ended.

@kevemaher

Your Bryston 2.5B cubed specs show:

Power Output (per channel): 135W @ 8Ω | 180W @ 4Ω

However, Stereophile F208 review here suggests you need more current:

…. F208 will need to be driven by a good 4 ohm-rated amplifier…..

and that there was plenty of bass. Therefore a more powerful amp with adequate current is likely better than adding subs

Generally, a speaker rated at 8 ohms only hints at being average to easy to drive, while a 4 ohm is harder. But a further look into the frequency vs impedance/phase test/chart of the F208 reveals it needs more power

@kennyc 

Thanks for reminding me about this. I've seen the impedance plot on ASR. There is a dip to 3.7 ohms at about 100 Hz and 3 KHz.

I also measured the voltage into the speakers while I had the SPL at the listening position using pink noise. I found that I needed about 3 V, which is about 1 W for 8 ohms and 2W for 4 ohms.

I concluded that I have enough headroom to allow for a little higher SPL and for the low impedance at the above frequencies (100 Hz goes to my self-powered sub).

@kennyc 

Just looked at Bryston's published spec. It is rated at 180 W into 4 ohms. So it is rated at 4 ohms. However, I was cautioned that if the impedance was below 4 ohms for a large part of the spectrum, especially in the midrange, there could be problems.

I have never seen any of the overload lights turn red, although maybe that doesn't mean much.

I really haven't experienced anything audible or measured any parameter with REW that would indicate problems.

Am I thinking properly here?