It seems I need to clarify something here. My comment above referred to **all** tube amps, not just Atma-Sphere (and FWIW, our MA-2 is quite comfortable driving four ohm loads).
However- what everyone in audio (and thats a lot) need to realize that there is a trade-off between sound and impedance. **FOR ALL AMPLIFIERS**
I highlighted that but I don't intend to be yelling... the point is, that even transistor amplifiers sound better on higher impedance speakers than they do on low impedance.
Steve McCormick is well-known for making rugged transistor amplifiers- has for years. In a recent email to Paul Speltz, who makes the ZERO autoformer, Steve reported that his amplifiers sound better driving 4 ohms *through the ZERO* than they do direct. In this case, the ZERO was loading the transistor amp at 16 ohms.
On hearing this, I asked several transistor amplifier manufacturers at CES what was up. Universally, they all responded, to paraphrase: 'Just because the amplifier is comfortable on 4 ohms does not mean that they sound best there- they sound better when you run less current through them. Yes, they do sound better into higher impedances'.
What this tells me is that 4 ohms is to get power as a tradeoff against sound quality. Everyone take note!
So I am amending my statement made some months ago above:
'If you are investing in an audio amplifier (tube or transistor), your investment dollar will be best served if the speaker used is at least 8 ohms or more (all other things being equal), if sound quality is your goal.'
To me, high end audio is **only** about sound quality.
While your amplifier might sound great on a given 4 ohm speaker (for example Magnaplanar tells me all the time that their speakers 'never sounded better' than on our MA-2), it will sound smoother and more detailed if you could magically change the impedance upwards without changing anything else.
Right now the closest we are to that is to use a set of ZEROs.
Interesting huh?
However- what everyone in audio (and thats a lot) need to realize that there is a trade-off between sound and impedance. **FOR ALL AMPLIFIERS**
I highlighted that but I don't intend to be yelling... the point is, that even transistor amplifiers sound better on higher impedance speakers than they do on low impedance.
Steve McCormick is well-known for making rugged transistor amplifiers- has for years. In a recent email to Paul Speltz, who makes the ZERO autoformer, Steve reported that his amplifiers sound better driving 4 ohms *through the ZERO* than they do direct. In this case, the ZERO was loading the transistor amp at 16 ohms.
On hearing this, I asked several transistor amplifier manufacturers at CES what was up. Universally, they all responded, to paraphrase: 'Just because the amplifier is comfortable on 4 ohms does not mean that they sound best there- they sound better when you run less current through them. Yes, they do sound better into higher impedances'.
What this tells me is that 4 ohms is to get power as a tradeoff against sound quality. Everyone take note!
So I am amending my statement made some months ago above:
'If you are investing in an audio amplifier (tube or transistor), your investment dollar will be best served if the speaker used is at least 8 ohms or more (all other things being equal), if sound quality is your goal.'
To me, high end audio is **only** about sound quality.
While your amplifier might sound great on a given 4 ohm speaker (for example Magnaplanar tells me all the time that their speakers 'never sounded better' than on our MA-2), it will sound smoother and more detailed if you could magically change the impedance upwards without changing anything else.
Right now the closest we are to that is to use a set of ZEROs.
Interesting huh?