Tell me about valve equipment

[Steve Toy]

I heard the ADM9s at the Bristol Show last year and I pressed Ashley at the time about the quality of the source material and how it was encoded. He stated that MP3 was fine and that higher resolution than that was irrelevant. He also refused to state how each of the recordings he was playing had been encoded/on which particular format.

I've heard his setup; it sounded dull, flat, strident and boring.

Oh, it was loud but very undynamic.

He also rubbished my findings having heard the Naim demonstration.

The guy is clearly a charismatic and yet disingenuous plonker.

[tfarney]

Marco, thanks for the welcome back. I've lurked from time to time, but found few discussions I thought would warm to my point of view . No, I'm not surprised that you disagree. And you won't be surprised, I'm sure, by my disagreement either. I understand the attraction to valve gear, but disagree with your characterization of it. I find good valve gear pleasant to listen to but far from "natural." I find the best, the most "natural" to be the least distinguishable from good solid state. No need to argue over it. It is simply two differing opinions.

It's OK that we disagree as it is a big world with a lot of choices. And I'm afraid we probably disagree even more now than we did when we last talked, because since then, I have acquired a pair of AVi ADM9.1s. They are, to my ears, precisely the kind of "boring," "dull," and "lifeless" that I love: Harsh recordings sound harsh. Clear recordings sound clear. Flat is flat and dynamic is dynamic (I completely disagree with Steve's characterization of their dynamic range, which is stunning for such a small speaker, on both a macro and micro level). They remind me of the best traits of the best active studio monitors I've worked with, without the flaws. Add the sub and I'm sure the scale would be more than enough for you, or anyone not living in a stadium, but you would still not be happy with them. I feed them lossless files, and they are a far cry from vinyl, valves and Tannoys. You wouldn't like them. That's OK. I'm the one who needs to like them. I'm the one who owns them.

Tim

[Marco]

LOL! What can I say, Tim?

It would indeed be a boring world if we were all the same! The cool thing is you're happy in your world and I'm happy in mine - sounds like a result to me

Don't be such a stranger in future, though. It's always nice chatting to you even though we rarely sing from the same song sheet.

All the best from this side of the pond

Marco.

[Marco]

Hi Vinnie,

Your enquiry has now been moved ot the D.I.Y section:

http://theartofsound.net/forum/showthread.php?t=3052

Marco.

[symon]

Sorry, asked a silly question. Please carry on.

[SPS]

I for one would like to know the ratio of speaker efficiency to amp. output (disregarding room size and personal volume preferences). I've never seen such a chart, so maybe there are just too many variables.

just having a quiet break and i dont think this has been explained

i'm not going to be very technical...

the ratio of watts to loudness starts with the speaker eff..

and as you double the watts from the amp you get +3dbs.. which is just nicely louder...

so an 85db at one watt speaker will give 88 db at 2 watts, 91 db at 4 watts 94db at8 watts... . so 105 db peaks need over 60 watts
thats sound easy...
but.. we are talking peak.. not rms values with a music signal,
so if the music your listening to is compressed to a 30db sound envelope

and your listening at 85 dbs average, parts of the music will be 15dbs louder and parts15 dbs quieter.

so, to listen at that level , and to play the peaks without distortion,
around 30watts is needed
around 85 to 90 dbs is my average listening levels
work that out how many watts is needed at 90 dbs average listening levels

most amps are not running is class A at that level,
and if the amp has a poor power supply, and the speakers them selves are being overdriven they will not play those peaks correctly.. resulting in distortion, or at best lack of life or scale,

now... work out how many watts are requred from 99 db speakers


most people think hi eff speaker just go louder... well they do....but

they go louder because they follow the musical sine wave signal much more.. the peaks in the signal are the volume, low eff speakers may only produce a small portion of that signal, and miss the finer details in the signal ...along with the volume that was in the source signal

i'm talking cone speakers
and the above is dependant on the basic quality of the drivers to start with being equal....regardless of eff.. there are good and bad in all.. but i'm sure hi eff gives the better sound, all being equal, but it is hard to achieve and sometimes expensive.

do realise that most (all?) powerful valve amps. are push-pull, and maybe you don't consider these to to have the same musical prowess as SETs, etc

well i dont know if you have had this answered
but my veiw..

audio valves generally come in two types triodes and pentodes/tetrodes

the triode is the basic valve and has one amplifing stage in it
it gives out a low output vs the current it uses
the pentode and tetrodes use extra grids, that give more amplification for the same amount of current used.,

with a triode you generally have a higher current to signal voltage ratio
which has its advantages. and much less distortion
but less volume...

its a bit like driving a car, 2nd gear is the triode, 4th is the pentode.. you can go faster( louder), but when you get a load it slows.. thats the effect on the valve from the signal.. a varying load (hills to the car).. you rarely get anything without some cost.. both types sound very good.. the triode should be a more accurate amplifer....


so triodes are generally used for low watt amps both push pull and single ended, and dont need feed back, and pentodes/ tetrodes can be used or higher powered p/p or single ended and generally use feedback.

push pull.. there are some very good push pull amps and some not so good

like most solid state amps there are two or more amplifing devices working together, matched valves are within 5% so not many valves are identical

so both give a very slightly different operational point, one side is pulling the speaker mostly back the other valve pushing mostly forwards, there is an overlap.
if the amp has been built very well, and the valves are very close, you can get near identical performace from both sides of the amp, and there are some very good p/p amps, but most are not like this, and you end up with each valves output being slightly different, so the push is different to the pull..

think of a photo through two projectors that are not quite focused on the same spot..

the slower parts of the signal will sound thickened up( bass) and the finer details will be masked,.. and the sharpness and transients suffer.. but there are good and bad in push pull of course..

now... many like the sound of a bad (and in betweens) push pull...
my veiw is because the speakers being used are not fast/accurate enough to reproduce what is actually going on, and our ears are easily fooled by the perceived extra depth, but slight lack of detail

cheers steve

[DSJR]

SET's are *supposedly* renowned for having loads of distortion. Their trick however, seems to be in the fact that this is added harmonics NOT smeared over time, so the sound is clearer and easier to follow.

An extreme example the other way was the Far Eastern amps from the mid seventies, designed with loads of global feedback to give very low THD, but smearing the distortion signal over the milli-seconds giving a dead and lifeless quality to the music processed through them. Just my view though..

It was said decades ago that what we need is 5W continuous with peaks of a KiloWatt or more. In practice we get nowhere near this ideal and currently, active speakers seem to come closest in terms of ultimate efficiency vs power. It's a real shame that AVI didn't play better produced material to show their speakers off - I understand they *can* do it for their size on a good, uncompressed recording.

Speakers are still the weakest part of the playback process and although the likes of Harbeth have worked extremely hard to get delicate and dynamic sounding speakers that also reproduce voice and acoustic instruments to a very high standard, leaving the soggy stodgy bass long behind.