Solid state preamp grain compared to valves

[anthonyTD]

Hi Marco,
I think It may be better to first get others points of view on this, I just feel sometimes I am banging my head mate, we can all refer back to the text books, and quote how things should work, but there seems to be few of us here these days who are willing to think outside of the box, and look at other aspects that could posibly have an affect, rather than taking the stance, if you cant measure it, its not happening, and therefore; those who experience these affects, are somehow deluded, or fooling themselves, I try very hard not to do that, which is why I usualy keep my explanations as non technical as posible, once you start spouting equations, and textbook speel, you lose the attention of posibly 90% of your intended audience!

Understood, Anthony. I'm just wondering though, ultimately which effect will be more audible (although of course it may vary from system to system): the former, as you describe, or the limiting factor of the interconnects, in terms of a passive's inability to 'drive' them as efficiently?

After all, when all said and done, the signal his to pass through those cables to the next stage of the amplification chain (the partnering power amp), and so any bottleneck present there is bound to have an influential effect.

If HF frequency response, as Alan says, is being curtailed to any notable degree, it'll always be heard on a good system

Marco.

[Marco]

Yeah, mate, I get that and agree. However, you have a way of putting technical points across that any layman of reasonable intelligence can understand and appreciate, as I do (mostly), so I'm sure that also applies to other folks here

Ultimately though, there's a limit to the amount of people who are interested enough in this particular subject, to go into it in such detail. Most just want to discuss how stuff sounds, rather than why. However, I think it's good having these types of discussions, because as you say, thinking outside of the box, with any aspect of audio, is the only way you learn and make progress!

Marco.

[anthonyTD]

Yeah, mate, I get that and agree. However, you have a way of putting technical points across that any layman of reasonable intelligence can understand and appreciate, as I do (mostly), so I'm sure that also applies to other folks here

Ultimately though, there's a limit to the amount of people who are interested enough in this particular subject, to go into it in such detail. Most just want to discuss how stuff sounds, rather than why. However, I think it's good having these types of discussions, because as you say, thinking outside of the box, with any aspect of audio, is the only way you learn and make progress!

Marco.

[Firebottle]

Just to reiterate I was hypothesising that the change in the phase response could be what makes the sound appear 'soft', if we stick with that word.

In any system that has a decreasing frequency response there will be an associated phase response change, however small.
Here is a plot to show a typical change in phase with gain (aka loss at higher frequencies) :



The human hearing is incredibly sensitive to small changes in phase, that is how we hear the direction of a possible threat.
What I am suggesting is that with a small phase change say on the percussive parts of music, the impact of such may be interpreted as 'soft' possibly.

Just trying to think of associated effects, rather than the obvious (and readily heard/measured) curtailment of frequency response.

[Macca]

I thought the opposite was true and that we are not very good at picking up on phase errors?

Also that any phase error would only exist over a very narrow frequency band and therefore be unlikely to be audible?

[Firebottle]

I thought the opposite was true and that we are not very good at picking up on phase errors?

I think that is the point, that we can't put our collective fingers on what the difference is caused by phase errors.

[Macca]

I think that is the point, that we can't put our collective fingers on what the difference is caused by phase errors.

Both sides of argument well presented here http://www.silcom.com/~aludwig/Phase_audibility.htm

Another question is, that assuming the loudspeakers have phase errors, and most do, would this not swamp any phase error from the passive pre-amp? And therefore the issue would be the same with any type of pre-amplifier unless using speakers with perfect phase.

[Primalsea]

I wonder if gain structure has a lot to do with it. If you considered the circuits of the source, preamp and power amp as one large compound circuit and then broke down where gain and attenuation occurred along with how much of each in this one compound theoretical circuit, I wonder if there will be some correlation between perceived grain and the gain structure?

[Pharos]

Loudspeakers have comparatively poor phase, and the best are referred to as 'liner phase' which actually is a misnomer, 'constant phase' being more accurate.

The top loss above may affect transient perception.

[mikmas]

I wonder if gain structure has a lot to do with it. If you considered the circuits of the source, preamp and power amp as one large compound circuit and then broke down where gain and attenuation occurred along with how much of each in this one compound theoretical circuit, I wonder if there will be some correlation between perceived grain and the gain structure?

I've been musing about exactly that every time I dip into this thread.

I currently have an integrated DAC/amp but up 'til a year ago used a Quad 405-2 with a passive 'pot in a box' and found the sound absolutely spiffing. This came about following suggestions I came across here and on other forums and was based on the notion that an active pre was pretty much superfluous given the sensitivity of the Quad (0.5v) and the high output of contemporary sources ... such as the Q-Dac I was using and RPi/IQaudio combo.

Plenty of drive and vitality - no 'softness' - and no 'grain' that I was aware of (whatever that nebulous word means....)