Which 300B SET amp's work well with Usher Be-718 speakers ?
default -- Thu, 09/18/2008 - 14:45
Hi Folks,
I am wondering if there would be a good or better match for a 300B SET amplifier (mono blocks or integrated) for use with the Usher Be-718 speakers at 87 dB (or even lower at 85 dB as reviewed at times).
It would be at very low to low volume levels in the evening in dedicated listening sessions in a properly set up and treated room. It is not about loudness or tactile sensations for us as it is about being there right in front of the musicians and emotional connection with the music.
Blues, jazz, some rock, some gospel .. again, all very soft to soft
I refuse to even consider Cary and Cayin due to several very unpleasant experiences with the people who make or import / distribute them respectively.
I do not want to do push pull but will gladly do parallel 300B's per side for higher wattage.
Border Patrol ? Manley ? Air Tight ? Sophia Electric ? VAC ? Unison Research ? Others ?
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I wrote to Border Patrol about this ...
"Hello. What amplifier(s) would you recommend with the Usher Be-718 speakers please ?"
I got this reply from Border Patrol's rep. ...
On 9/19/2008 11:28 AM, BorderPatrol wrote:
That's a tough one. The 85dB sensitivity will be problematic to most 300B amplifiers and Single- Ended amps in particular. A typical 9W single ended 300B amp will really struggle into that load. It may be surprisingly loud but it will have no headroom and the sound will be compressed.
If you listen very quietly then you might have a chance with a 20W/channel parallel single ended such as the BorderPatrol S20.
If that give no joy then I think you have purchased the wrong speakers for SE amplification. To get the best from Single-Ended amps you usually need speaker efficiency >90dB/watt and often a lot higher depending on the amp.
Best Regards,
Gary Dews
We have not purchased the Ushers yet, but will. Perhaps an SET-like sounding push-pull amplifier in (ultralinear mode or triode mode) will be a good match. I understand that triode mode sounds more like an SET overall.
A second reply from Border Patrol ...
I suppose I could have written back and said Border Patrol amps are all
things to all men and they can drive anything but that would not have been very constructive.
When buying loudspeakers and amplifiers it is very important to consider them together. Unlike high power transistor amps which can drive anything - but sound more like machines than music - tube amps need more sympathetic partners and this is particularly true with low powered single-ended designs. You are correct to target an SE amp. SE's are the most natural sounding amplifiers and good ones will definitely get you in the room with the musicians but the laws of physics are still the laws of physics.
An increase in sound pressure level of 3dB requires a doubling of amplifier power. If the speaker is 85dB/W then the max SPL with a 9W amp is about 94dB and with 20W amp approx 98dB which is hardly loud. Bear in mind these are the levels that can be achieved on dynamic peaks which generally take much more power (think bass drums, crescendos, opera singers) and the majority of the music will be much quieter than this.
With a 90dB/W speaker the max SPL from 9W is approx 100dB which is 4 times louder and the 20W will give an extra 3dB again but more important is the extra headroom afforded by the higher efficiency and the 20W will have more current on tap too. It means the amp can produce the music without strain and dynamic limitation which is vitally important if you are to feel relaxed in front of the system. There is no enjoyment to be had from listening to an amplifier running up against clipping or sounding strained and emasculated regardless of how pure the midrange might sound on simple music pieces at very low level.
The BorderPatrol S20 costs $14250 without Western Electric 300B's. I would love to sell you one if it falls within your budget and it may do the job you want. You said you listen very quietly so there is a good chance it will provide the beauty, purity and 'being there' experience that you are looking for but my gut feeling is that if you want to enjoy the naturalness and vitality of a good single-ended tube design you need to think about more sympathetic partners otherwise you are painting yourself into a corner and like many others, will then embark up on quest to find the mythical solid state amp which sounds like a single-ended tube amp and believe me, there aren't any.
If you want to try the S20 please let me know and we can work something out, or if you have any further questions about assembling a good SE based system please fire away.
Best Regards,
Gary Dews
You might consider one of the new Pass XA .5-series of amplifiers on the Usher Be-718. They have much of the midrange magic of 300B-based amplifiers without the power limitations.
I would be very hesitant about driving the Be-718 with a 300B amplifier.