Sound Quality Vs. Measurements

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Jan, the schematic you supplied is, I beleive, actually a hybrid design, as it also uses BJTs, most importantly in its VAS stage. The poor, old VAS always gets to do the most of the heavy lifting.

The BJT is not really the VAS. But you would have to read the whole article.
Plus his previous article on low power implementations that were a bit less complex.
One circuit topology he included is his BestPentode circuit which has the BJT but still works as a pentode. Another L|A article ;)

Jan
 
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Demian, just one thing I'd like to clear up: in your first paragraph, you connect clipping with NFB. Does this connection vary with the amount of global NFB, and does it have anything to do with full power open loop bandwidth?

Let me describe what happens a little better, and this is true if its an amp or a servo speaker-
When the amp hits a limit, clipping or whatever the feedback tells the gain to increase to push the output to the target level. In a design that this was not addressed the internal circuit can saturate at the rail in the direction of the clipping. Recovery can take a long time as the internals come out of saturation. The simple fix on an amp usually is Baker clamps limiting the saturation of the BJT's doing the amplification. In larger systems it can be worse. Ask anyone who has clipped an amp tied to a cutter head with feedback. . .

Its pretty independent of open loop gain, bandwidth etc. Usually clipping the amp and looking at the "sticking" as it recovers highlights the issue. In some cases you can see the output reverse during overdrive. The amp should be checked with reactive loads since the loop gain in clipping is very different and it could even oscillate while clipping.
 
Sometimes, when some audio product sounds extra good, it does not need much extra promotion. However, you have to believe that that are real differences between audio electronics, to make sense of this. Almost all manufacturers 'promote' 'market' or 'advertise' their products in order to get more sales than just 'word of mouth. Two exceptions were the CTC Blowtorch and the Vendetta Research SCP-2 which supported no advertising throughout the life of the product. We did show at CES a few times, but that was it, yet they acquired an excellent reputation by how they sounded, although they measured better than many tube products, they did not 'measure' as well as some audio op amp designs.
 
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Outputs reversing:

I would hope a modern design would avoid this but opamp datasheets still talk about it and I suspect if not explicitly discussed in the datasheet an opamp might just reverse on overload. Internally, where I work, we take an old salt and modify it thus: How can you tell when an IC sales rep is lying? His lips are moving. . .
 
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I don't know why LAMM is so expensive. Perhaps, because they can get the price, but it did sound very, very good. Best of show that year.
One reason: some images, closeups of the internals show beautiful execution; every lead is carefully dressed to follow a precise route to its end connections, the designer definitely understands the significance of the "small stuff", and fully carries it through.
 
One thing that keeps me 'on my toes' so to speak is the listening QUALITY of a number of tube playback systems. It just doesn't 'hurt my ears', it sounds in some ways, more musical, and yet, often, not quite as 'accurate' as the best solid state.
The "answer" obviously is to combine the two attributes: "musical", and "accurate". This is certainly achievable, I have zero patience for listening if it's not musical, the Off button gets pushed, quick smart; it's not so much 'hurting', it's disturbing, unsettling, irritating. Then one gets the accuracy to climb on board by making sure there is enough effective grunt to get the sound done, which is achieving realistic sound levels without audible or obvious artifacts.

Interestingly, the PC sounds like sh!t at the moment, :D!! I've reorganised the house electricals to give the music keyboard the best environment for clean sound, and the PC has been shoved into a back corner, quality wise, at the moment ... and is suffering! It sounded so awful, gave away listening quick smart - a clear demonstration of the need to spend time and effort to extract the best from any system, not matter how lowly ...
 
diyAudio Senior Member
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Hi,

From what I've seen so far those are just plain vanilla, classic valve circuits on a PCB.

Top quality valve circuit should use P2P wiring built in such a way that it does not even require solder to work.
At the asking prices they should be able to afford the extra labour, no after sales service to speak off anyway.

Ciao, ;)
 
Why nonsense? "Musicality" is simply the absence of excess, disturbing distortion - get rid of the latter, and the sound is "musical"; most people here know a "musical" system when they hear one ...

Our Yamaha keyboard does a pretty good acoustic grand simulation, but it very quickly develops an unpleasant edge, becomes "un-musical", annoying to listen to, if the electrical environment around it is not optimised. And the same goes for audio systems in general ...
 
Average rms level of both files is within 0.1dB order. The nature of lossy compression (both dynamic and frequency) does not allow for precise amplitude matching. There is no exact point for matching. Nevertheless, you can hear what lossy compression subtracts. The difference is a garbage of the worst kind.
Sorry, I meant to comment earlier. I went through an exercise a while back where I was attempting to optimise the null, I was using attenuations with numbers like 0.00137dB, to get the best match - the slightest change in numbers changes everything; so, what is the 'right' difference? To my mind the optimum null should give one a difference which sounds like total nonsense, which gives no clues as to what the original music was - it should in fact sound like "garbage", but at a very low level ...
 
Jimmy Hendrix made beautiful noise.
When an artist wants to explain pain he may use unpleasant distortion.
We are not living in paradise and i think that is fine.
OK, the HiFi should not change that message.
A good example. I have a live track of Hendrix, with excellent pickup of the sense of the crowd - you can hear comments, noises in the audience, way off in the distance; drums are beautifully captured, cymbals are excellently rendered; his voice is soft, layback, casual, nice 'n' easy, 'cool' to the max; but his Marshall kicks and shudders, growls, spits at you, a tortured beast, the hiss and hum goes up and down as he uses his pedals, etc. All this happens in a beautifully laid out soundscape - you're there, experiencing the moment...
 
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