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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!

 

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wsrrsw's avatar
wsrrsw
1,022 posts
 

This is a fantastic Pre. The Raven Preamplifier by Don Sachs and Lynn Olson. Lots more here on Agon. Yes I have one and it's rumored I'm a fan.

But Speakers are requirement one.

dr-boop
85 posts
 

Try crossing them lower, like much lower, say 60Hz. You're cutting the f208 above the knees by crossing them at 120Hz! I know these speakers well and realize they aren't bass monsters, but you can definitely let them play to 60 or even lower and flush out more punch.

iammessiach's avatar
iammessiach
2 posts
 

Based on your current setup, it sounds like you're already in a great place with your Bryston 2.5B cubed, but I understand the desire for more power. The 4B cubed would be a solid upgrade, delivering more headroom and dynamic range without sacrificing the Bryston sound you enjoy. Given your listening habits, it will likely provide that extra "oomph" you're seeking without risk of clipping, especially considering your Revel F208's sensitivity and your subwoofer crossover.

If you want to explore alternatives, consider amps like the Pass Labs X250.8 or used McIntosh MC452, both of which are known for high power, clarity, and reliability. Either should fit within your $5K budget used. However, the 4B cubed's synergy with your current system makes it an easy recommendation.

Good luck!

8th-note
409 posts
 

I have two suggestions.

1. If you haven't already, try running your Revels full range and let the subwoofer just handle the lowest frequencies. You will need to set its crossover low - around 40 Hz to achieve this and don't run your Revels run through the sub crossover. You may find that allowing the woofers in the Revels to handle lower frequencies improves the punch factor.

2. The 203's are a fairly difficult load for an amplifier. The Bryston is no slouch but it does not increase its power into lower impedances as well as some other amps (Pass, Krell, Martin Logan, etc.). You might want to look for an amp that is rated to 2 ohms or where the testing shows that power increases substantially into low impedances. These amps are heavy and expensive to build which is why most amps don't perform this way.

ghdprentice
6,982 posts
 

I cannot explain why two subwoofers over one increases the soundstage and can improve the imaging (through enlarging the soundstage)… it does. I have heard it, and others commented,  whenever disconnecting one of my two subwoofers when I used them.

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