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What Power Amplifier Should I Buy?

I am looking to increase my system power. I currently am using a Bryston 2.5B cubed, which is specified at 135 Watts/CH. I am using Revel f208 speakers crossed over at 120 Hz to a 15" HSU sub. The f208 speakers have 88.5 dB sensitivity (Amir measured 88-89dB SPL at 1W into 8 ohms). I sit about 7.5 feet away from the speakers and listen up to 92 dB SPL, but mostly stay between 80-90 dB SPL at my listenin g location.

I have not had power issues. I've never seen a clipping light. I just want more oomph. I've never had a power amp with more power than the 2.5B cubed.

My budget is about $5K. I have been looking at some used 4b cubed amps.

My preamp is a vintage ML No. 38s. Digital from Bryston BDP-3/BDA-3 combo. Analog using Koetsu RS and Shelter 901 cartridges into an SUT (20x) followed by a very vintage Paragon System E used as a phono preamp (I have fully repaired this preamp, particularly the power supply).

I like the sound of the 2.5B cubed. I had a Cary 120 tube amp for some time, but grew tired of the heat and the continuous maintenance, including the insane prices for tubes. I did not experince that great "tube sound" that others rave about. I sold the Cary and went back to the 2.5B cubed.

Will the 4B cubed disappoint?

What other amps should I consifder, new or used?

Thanks for your help!

 

kevemaher

Showing 2 responses by kennyc

kennyc
1,781 posts
 

@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
1,781 posts
 

Both Stereophile and ASR test show plenty of bass down to 30hz. Your 14x19x8h room looks fine, but the other impedance show the F208 is harder than average to drive. Conclusion is that you don’t have enough power. Also, if one defines “average” needed power to run most speakers, seems to be in the 150-300watt at 8ohms range, somewhat doubling down to 4ohms.

If you love your amp, I suppose you could try to fill in the missing bass, but my preference would be to get the bass from the speaker since it’s matched to the other transducers (mid treble).

Maybe you can test by borrowing a more powerful 4ohm amp?

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