What tube amp for Harbeth 40.1

A few reminders may be necessary before making the jump to tubes.

1 Alan Shaw himself is unlikely to recommend a tube amp.

@paulfolbrecht asked earlier,

'Have you seen the video where and where A. Shaw demonstrates that the big Harbeths easily pull 500W on transients?'

In that video Shaw himself was shocked at just how much current his M40 speakers were drawing on  certain transients. Yes, a peak of 750 watts!

[Not recommended viewing for anyone with low power tube and low efficiency speakers].

How Much Amplifier Power Do I Really Need?

https://youtu.be/Y3WpRY-EtX8



2 No tube amp is likely to have the same dramatic bass punch as a powerful SS amp will. That's not why people buy tube amps.


Having got that out of the way, if you still want a tube amp then I'd also suggest the Leben CS600. 

There are many accounts of satisfied owners using them with Harbeth speakers. See the Harbeth forum for more details.

Furthermore, the Leben amp is such a gorgeous work of art in itself that it should always bring you pleasure before you even switch it on.

@aj523,

M40.2 Anniversaries?

Well, that’s certainly one impression of the current state of the art in loudspeaker design!

To be fair Alan Shaw has always stated that despite their seemingly low efficiency, Harbeth speakers do not present a difficult load to drive for any amplifier.


@gte357s,

Yes, keep us posted on how you get on.

The McIntosh MC 275 seems like another solid choice with first rate build quality.

A little more power can never be a bad thing.

@gte357s ,

’I don’t think the speakers draw power, but it is the amp pushing power, right?’


The speaker / amp relationship is pretty murky, at least to me, but the important thing to remember is that to get the same volume from the M40s a lesser powered amp might be forced into clipping, even if it’s for mere milliseconds.

Clipping happens when an amplifier runs out of power a bit like a car with a tiny engine going up a very steep hill. If there isn’t any protection built in to the amp, clipping can be disastrous for the loudspeaker.

With a more sensitive loudspeaker you certainly wouldn’t want to keep the volume knob in the same position unless you wanted to use it outdoors or in a much larger room.

This is assuming that it was capable of being played much louder in the first place. Not all more sensitive speakers are, but size is a good indicator.

It’s also worth remembering that loudspeakers are horribly inefficient devices. Hence the temperatures inside the voice coil can reach hundreds of degrees.

Much like car engines, most of the power going in is converted into heat. not sound (or in the case of the car engine, power). Overheating is a common enemy of both.

For those who like to play loud, thankfully before we are able to destroy our speakers by overheating, we should get a warning by experiencing a compression (and likely much distortion) in the sound.

It might simply not be worth going beyond a certain point of the amp volume dial as the speaker will tend to only get hotter, not louder.

https://en.m.wikipedia.org/wiki/Power_compression