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!

 

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@lynn_olson 

I forget if I had posted previously that I am running a single 15" HSU sub right now, 800W plate amp. I xover at 120 Hz using a K231 from Sublime Acoustic. The two channels are combined in the sub.That value is higher than most recommendations. I chose 120 Hz because it helped to minimize a big null in the Revels at 80Hz.

So the load on the Bryston is significantly reduced. I'm not sure how much, but probably less than 50%, more than 25%. I'm thinking about adding a second sub.

I listened to and liked Coherent model 18 on the Montreal Audio show. These speakers are very sensitive and sound very easy and uncompressed (in the way like my Altec 604E) but with deeper bass and more smooth and extended high frequencies. They also have Model15 that should be very similar to model 18.

It is still more expensive than Klipsch Cornwall but IMHO it sounds better.

https://www.coherentspeakers.net/coherent-audio-gra-15-reference

Looks like quite a good loudspeaker, and surprisingly, fairly priced for what you get. Thanks for the link! Always good to see high efficiency speakers with quality drivers.

Definitely a solid alternative to the Tannoy and 604 Duplex loudspeakers.

Hi @lynn_olson ,

In the Montreal show were the Coherent speakers Model 18 (18" coaxial Radian driver with Neodymium magnet and aluminum diaphragm).

In 2022 they used a 300B Allnic Audio T-1500 300B SET stereo amplifier. This setup sounded the best. And in my opinion it was the best on this show.

In 2023 it was M-2500  Allnic 300B Push pull monoblocs. It sounded good too. But I liked the more warmish SET sound.

And in 2024 they use other speakers with 12" coaxial and 2x 15" woofers with transistor amplification. I didn't like this sound at all.