SD Powerstage 170. How loud?

tbm

I've only just become aware of these, but they could potentially solve a problem or me. 

I have a new, heavier project going, and thus far have been using rehearsal room amps. Some good (Orange CR120) but some shite (Marshall AVT50), so I'd like a bit of consistancy. I had been thinking about picking up the one of the Orange's, or a Jet city JCA50 but I really don't have room for another proper amp, and anyway, it's a loud heavy band. My main concern is being heard, not the sound of the guitar in isolation.

My question for anybody who's tried these, or know stuff generally about amps (@ICBM) is, how loud is 170watt class D? The other guitar player is loud (cranked 50 watt head), the drummer is loud, and the bass player owns an SVT. I need to be heard and I'm not overly concerned with warmth and tone, my main thing is to find a spot in the mix. And I have the pedals for that if I can be loud enough.

Thoughts?

ecc83

I can only give you 'the numbers' . They are rather coy about the exact specification vis a vis load and 'proper watts' but assuming a genuine 170 watts into say a 4Ohm V30 loaded 4x12? 122dB SPL at a metre and that is pretty loud.

But, into 8Ohms, maybe 100 watts and probably no more than 60W into 16R and that drops us to 117dB SPL, still loud but not such a killer! This ALL assumes of course that SD are not telling technical porkies!

If it helps, it is said that 'our' 1D60 class D amps ARE as loud as SOME 50/60W valve amps but NOT all 50/60W valve amps!

All that said, these sort of power 'trips' really benefit no one and certainly NOT your hearing!

Dave.

ICBM

Purely based on experience and not science, the power supply is important as well as the power amp type - this will have a switch-mode power supply rather than a transformer. I would say that a Class D/SMPS amp is about as perceptively loud as a Class AB/transformer amp of half the power rating, and as loud as a valve amp of about a quarter of the rating, all other factors such as speakers etc being equal. It seems to be that (ironically) the poorer regulation of a transformer-based power supply produces more perceived volume.

ie a 170W Class D/SMPS amp is not going to be as loud as a cranked 50W valve amp, but it will probably be not far off in the same ballpark.

Some people are going to dispute that based on the science! But just for once I will politely disagree.

I also know that Blackstar cheat with their ID series, and the amps are actually capable of double the claimed power… (Dave may correct that for detail, but I know it's in that range.) I did A/B an ID60 against a 50W valve Marshall, and it was certainly close to as loud, although the Marshall still had the edge for 'presence'.

Either of them would need earplugs for sustained use though.

ecc83

"Purely based on experience and not science," Your comments are just as 'scientific' as mine IC! I could find no hard data on the SD amplifier other than the minimum load was given as 4 Ohms and thus I made the assumption that the 170W was at that Z. There is no qualification of the power, i.e. 'peak' or the nonsensical 'rms' so I had to assume honest, continuous sine ?

It is of course fruitless to try to pin down the power output of a valve amp. The only really valid measure is rms volts across a given resistance for a specified total level of harmonic distortion.  Some '50 W' amps will hit 10% THD* at maybe 55W another might manage 75, even  80W.  The comment about 'presence' is well taken. Subjective loudness is very dependant on 'spectral content' or 'voicing'.

*A fair figure for a guitar amplifier I would humbly submit?

Dave. 

tbm

Thanks gents. Very interesting. I think that given a 4 Ohm cab isn't readily available to me that this might not be the problem solver i was hoping.