Please let me explain what I intend for minimalism
I meant designs with low devices count
Let's take a line preamp
I have seen line preamps with one mosfet and other with 20 active devices per channel.
Quite a difference. And incidentally that one with one mosfet was the better sounding by a good margin.
This should mean something.
Or not ?
Is it reasonable to use 20 transistors for a line stage ?
Regards,
g
A well executed one mosfet may be better than a poor 20 mosfet, but a well executed 20 mosfet may be better than either. Or, one with a correct parts count for the design. Some seem to like non-buffered inputs and outputs with insufficient line level drive. I even did the passive line stage for a while, until I learned better. My low end Hafler FET preamp sounds better and my CA-5 Nak better still. I have never heard the Threshold, Halo or the Bolerby from Audio Amateur. They all have more than one FET, that's for sure. I am one of those wierdo's who actually prefers to have tone controls in my preamp and wish we still had loudness controls. Wide band amps with infra and ultra sonic filters are not a bad thing IMHO.
One way to look at it was a story I heard many years ago about Dynaco. Hafler told the designer to build it right, then start taking out parts until you heard a difference. Good story at least.
My general experience is that for most audio things, the majority of my BOM is around the edges anyway... Case, power supplies, RFI and transient protection, input and output buffering, holding bandwidth down to something sane, it all takes parts.
While you can build somethig that might work in a particular situation without much of that stuff, if you want a box that will just work reliably with random sources and loads hooked up, you need all that pain and it typically adds at least as many parts as the core circuit has.
I would concur about the value of engineering time Vs BOM cost for anything except consumer products.
There is something of a move among some audiophile to go for 'everything sould be as simple as possible..... AND THEN SOME', and it usually results in wince inducingly awful gear.
Regards, Dan.
While you can build somethig that might work in a particular situation without much of that stuff, if you want a box that will just work reliably with random sources and loads hooked up, you need all that pain and it typically adds at least as many parts as the core circuit has.
I would concur about the value of engineering time Vs BOM cost for anything except consumer products.
There is something of a move among some audiophile to go for 'everything sould be as simple as possible..... AND THEN SOME', and it usually results in wince inducingly awful gear.
Regards, Dan.
Hi ! it is one of my point.
Tube circuits are often pretty basic with low active devices count.
I do not understand that the same approach could work also with solid state, maybe not ? i ask because maybe it is not a viable approach with SS ...
But I have to say that looking at schematics from the 70s amps of that era looks more basic than current ones.
Not minimalist in the radical way like the generation of Aleph amps
But still simpler than the common today offering.
Like a trend to make things complicated.
Thanks a lot and regards,
bg
Yes, I am referring expecially to commercial products.
I gave a look at some power amps ... really really complicated.
I am pretty sure that very good simple projects already exist or are possible.
Why not keep things as simplest as possible ?
Not only.
I read a lot of very positive reviews about Aleph amps
And then the comment that they are "fussy" about speakers because of low power and high output impedance I think.
But if those amps give a spectacular sound why not first select the amp and then the right speaker to mate with it ?
Moreover with a little more complex schematics we can have also amps with more flexibility for different speakers (i.e. more power and lower output impedance).
Regards,
bg
Hi ! i think i understand your points
But I ask again ... if extremely good sound can be achieved with simple (let's not say minimalist) topologies why not dedicate more efforts to parts selection or circuit "fine tuning" ?
As an example I was referring to line preamps.
They have quite simple task: gain 2 o 3 and signal buffering
Or even just buffers: I see famous buffers with different level of complexity, from very basic ones (diamond buffers of 4 components) to extremely complex one
Are we sure that the extremely complex ones are the best sounding ?
maybe a 4 devices diamond buffer has a spectacular sound
Why go instead for buffer with 3 or 4 times the devices for the same purpose ?
Maybe there are reasons but ... they must be very robust ones.
Thanks and kind regards,
gino
tubes are unreliable, large, expensive, power hungry and robust to transient V, power over their ratings
small signal transistors are reliable, small, cheap, and "fragile" in respect to over Voltage, Power
so it makes sense to "complicate" SS circuits with added protection, limiting
and to improve cirucit performance with compound transistors, buffering, added gain since you don't pay very much additional price - all of the "extra" the added Q for cascoding, ccs, buffers, even added gain stage like error correction parts in many audio power amps cost less than one added tube, the extra power less a single heater
and of course if the circuit function can be performed by monoithic op amps, they can beat discrete on many of the dimensions of design effort, board area, price, and measured performance
discrete can have an advantage in noise performane for phono preamps - just about the only place left in home audio reproduction where this is true
at line level from the output of our digital sources the input noise of properly selected op amps isn't a home audio listening limitation
small signal transistors are reliable, small, cheap, and "fragile" in respect to over Voltage, Power
so it makes sense to "complicate" SS circuits with added protection, limiting
and to improve cirucit performance with compound transistors, buffering, added gain since you don't pay very much additional price - all of the "extra" the added Q for cascoding, ccs, buffers, even added gain stage like error correction parts in many audio power amps cost less than one added tube, the extra power less a single heater
and of course if the circuit function can be performed by monoithic op amps, they can beat discrete on many of the dimensions of design effort, board area, price, and measured performance
discrete can have an advantage in noise performane for phono preamps - just about the only place left in home audio reproduction where this is true
at line level from the output of our digital sources the input noise of properly selected op amps isn't a home audio listening limitation
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Hi and thank you very much for your very interesting reply
I do not understand if you think that is not possible to achieve very good sound with simple topologies
I mentioned tubes beacuse they are used in very simple circuits
Maybe similar circuits can be built with transistors/mosfets ?
Thanks again and regards,
gino
I've lurked a bit in the Pass forums and find his design philosophy intriguing. Despite not having golden ears and unsure if I can tell the difference, I'll have try one of his design someday.
A 12AV6/50C5 audio stage works, even with wide component tolerances and they were made by the millions in "All American 5" AM broadcast radios. On the other hand I'm sure it doesn't have good distortion figures.
Nelson Pass' circuits are about as simple as those, but undoubtedly better. Part of that is surely the "fine tuning" and matching of components, something that makes the process more time consuming and less simple than it looks.
And this helps explain why most BJT circuits have so many transistors. Power amps look just like opamps with differential input stages, a voltage gain stage and current-gain output stage. Each one does its work without much change of Vbe - in fact, the circuitry tends to rely more on current gain, which is more (nearly) linear in BJT's, and to top it all off, the large voltage gain of the system is brought back down with a large amount of negative feedback. Because of this, the design is tolerant of component variation - each transistor can have markedly varying performance (as in current gain) from the next, yet each completed unit off the assembly line works pretty much the same as others without any component fine tuning.
One might argue that Pass' designs (and I presume other low-parts-count hifi designs) hide the complexity in the fine tuning of the components.
One might argue that some simple designs hide the distortion by a form of suggestion: tell the builder/buyer that he can't hear the distortion because it is 'nice' distortion and he may believe you. Once he has bought the item he may tell his friends too. I wonder whether there is any correlation between people who prefer simple designs, and people who are very open to hypnosis. Both require people to sincerely believe things which are not true.
The documented perceptual limits of distortion are pretty well known these days. I suggest the opposite, that these limits are ignored to achieve the lowest possible measured performance at the expense of added complication. For those of us who lived through the original brochure distortion races, buyers hypnotized to believe 0.001% is ten times nicer than 0.01% were a common experience. It wasn't true.
"minimalist" designs may have impressive low level linearity - reading Geddes, GedLee Metric it appers that the low level inearity is really dominant in listening tests
not a probelm for Class A output bias designs of any technology
30 yr old marketing wars really shouldn' be used to inform actual audio performance today
not a probelm for Class A output bias designs of any technology
30 yr old marketing wars really shouldn' be used to inform actual audio performance today
It depends what sort of music you listen to. Maybe a 15W SET thingy sounds lovely with a continuous loop of Dave Brubeck's Take Five (seemed to be all that was playing at an audio show I went to), but you might spot the distortion rising to 10% in some huge orchestral crescendo perhaps. I tend to like very dynamic music that gets loud in places. I think I need non-minimal design that can keep everything on an even keel over a wide dynamic range.
an amplifier using 400 parts does not mean it will sound better than one using 20 parts! it is all in the design, topology, parts used etc
an amplifier using 20 parts does not mean it will sound better than one using 400 parts! it is all in the design, topology, parts used etc
.
.. + dangerous to users health if broken
not talking only about mercury rectifiers.. barium flash getter, mildly radioactive thorium-wolfram (direct heater), broken glass bleed hazard, oxide mixtures cathodes (strontium,calcium,barium)
but there is a pixiedust-like experience, where one cannot understand "OH DEAR GOD WHY DIFFERENCE?"
If USB DAC heaphone output paired with 250ohm phones should play full , but pulling additional 20W from wall by tubeamp makes audible difference
call me insane tube zombie
old joke says: luxury wines are in glass bottles, not plastic; so are the electrons
"Our snake oil is better than theirs"
whole industry circus where are involved manufacturers and reviewers, one can imagine the cash flow sometimes
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I realise this may come as a shock to some people, but simple circuits with impressive low level distortion performance came first. Then people complicated them in order to improve them, so that lower distortion and better sound were available at higher power too. Of course, human nature being what it is, some then got distracted into specmanship. At least their specs could be measured.
Nowadays some seem to hanker for a golden age of simplicity. They still pursue specmanship, except that the new specs can't be measured or expressed in numbers and (often) can only be heard in conjunction with sight of the equipment or its price tag.
Nowadays some seem to hanker for a golden age of simplicity. They still pursue specmanship, except that the new specs can't be measured or expressed in numbers and (often) can only be heard in conjunction with sight of the equipment or its price tag.
From my perspective minimalism should really be replaced by 'engineering elegance', but the definition wouldn't be quite the same. Basically this would mean using the simplest/cheapest/cleverest solution in order to get the required performance out of the design.
In my way of thinking, there's little to be gained by adopting the minimalist ethos simply for the sake of minimalism. In other words, you're designing an amplifier and adding in a handful of small signal related components would result in a significant improvement in amplifier linearity. It would only represent less than 1% of the end total amplifier cost too, but you choose to omit said components because less is more.
On the flip side one can over do things, both in terms of component count and the type used. You often see people going with certain types of parts based off of promotional marketing and audiophile hearsay. Often parts are picked without much, if any, attention being paid to the actual specs of said part, where good solid engineering would show that you can achieve the same performance for less, or actually get better performance for less. And that two is definitely better than three, but going to four is rather pointless.
One area where true engineering elegance can be appreciated is in passive loudspeaker design. 99.9% of the time minimalist designs in this field fail from an engineering point of view, but it is also easy to get carried away and end up with a crossover that is far more complex than it needs to be. A good design will include enough components to get the job done, but no more and no less. The same goes for component quality too, where the best solution is the one that only uses more costly parts in areas where it matters.
Over engineering on the other hand is a different thing entirely in my opinion, where one could argue that, for example, the 7 channel, 100 watt per channel, HT amplifier equipped with a 500VA transformer makes logical marketing sense. From a strictly engineering point of view, if you want the amplifier to perform to it's maximum potential regardless of the program material, then the 500VA traffo ain't gonna cut it.
The same can be said for other areas of DIY, where we would add in an additional pair of output transistors, just to be safe and set the protection scheme up so it runs things less to the wire than a commercial design would. We are not constrained by profit margins, so can go slightly further than is strictly necessary to ensure good reliability and this is one area that we should take advantage of.
In my way of thinking, there's little to be gained by adopting the minimalist ethos simply for the sake of minimalism. In other words, you're designing an amplifier and adding in a handful of small signal related components would result in a significant improvement in amplifier linearity. It would only represent less than 1% of the end total amplifier cost too, but you choose to omit said components because less is more.
On the flip side one can over do things, both in terms of component count and the type used. You often see people going with certain types of parts based off of promotional marketing and audiophile hearsay. Often parts are picked without much, if any, attention being paid to the actual specs of said part, where good solid engineering would show that you can achieve the same performance for less, or actually get better performance for less. And that two is definitely better than three, but going to four is rather pointless.
One area where true engineering elegance can be appreciated is in passive loudspeaker design. 99.9% of the time minimalist designs in this field fail from an engineering point of view, but it is also easy to get carried away and end up with a crossover that is far more complex than it needs to be. A good design will include enough components to get the job done, but no more and no less. The same goes for component quality too, where the best solution is the one that only uses more costly parts in areas where it matters.
Over engineering on the other hand is a different thing entirely in my opinion, where one could argue that, for example, the 7 channel, 100 watt per channel, HT amplifier equipped with a 500VA transformer makes logical marketing sense. From a strictly engineering point of view, if you want the amplifier to perform to it's maximum potential regardless of the program material, then the 500VA traffo ain't gonna cut it.
The same can be said for other areas of DIY, where we would add in an additional pair of output transistors, just to be safe and set the protection scheme up so it runs things less to the wire than a commercial design would. We are not constrained by profit margins, so can go slightly further than is strictly necessary to ensure good reliability and this is one area that we should take advantage of.
That is funny, and it may well be true. Unfortunately, a glass bottle is not a guarantee of a good wine, and a tube amp is not a guarantee of good sound, and especially not under all circumstances (for example, power levels, load impedance, etc).
There is, perhaps, a meme that says that any particular circuit/configuration/system can be made to work perfectly if a golden combination of component values can be found. An earlier post hinted at this, suggesting that amplifiers only need more parts because it's not possible to hand tune them in mass production; that the single MOSFET and two resistors can be given high power, low distortion, wide bandwidth, load non-fickleness, stability, high power supply rejection, temperature-independence, self-protection, load-protection and 'musicality' if only an artisan would approach it, lay his hands on it, feel its energy, then delicately file small slivers off the resistors while listening to opera music through it.
You have to remember that all commercial products have to be fairly universal in order to sell in volume . In order to achieve this they have to be little over-designed and foolproof.
There was a period in late 80's of simple square black boxes (shoe box audio) but it didn't last as we entered a "decadent" era of thick faceplates and blue LED's . Simple requires quite complicated and expensive auxiliary components . Like my 1.5W 45 amp needs $$$$$ full horn speaker to develop some convincing sound. Also all simple PASS amplifiers need almost equally elaborate read big and expensive speaker systems for serious orchestral works . Actually I'd say that no matter what amp you have if big orchestral works are concerned the speakers are going to be serious. I think it's a cultural thing. Since traditionally Asia is listening to solos on single string , simple yellow 5" driver will do and you see the popularity of yellow drivers and tiny electronics oversimplifying since the biggest horn systems and Tannoy behemoths are also there partially due to I think extreme herd behavior and cult of "Old things" . Because western culture developed big orchestral works we have a tendency to bigger more complicated system - Germanic people with lots of marching BASS and treble (Americans are following closely along with Russians , you'd be surprised how similar tastes and imperial mentality is Brits with their tarnished past and small, small apartments and small and usually simple systems and the rest of Europe somehow in between . I already forgot what I'm talking about so please excuse me,...
There was a period in late 80's of simple square black boxes (shoe box audio) but it didn't last as we entered a "decadent" era of thick faceplates and blue LED's . Simple requires quite complicated and expensive auxiliary components . Like my 1.5W 45 amp needs $$$$$ full horn speaker to develop some convincing sound. Also all simple PASS amplifiers need almost equally elaborate read big and expensive speaker systems for serious orchestral works . Actually I'd say that no matter what amp you have if big orchestral works are concerned the speakers are going to be serious. I think it's a cultural thing. Since traditionally Asia is listening to solos on single string , simple yellow 5" driver will do and you see the popularity of yellow drivers and tiny electronics oversimplifying since the biggest horn systems and Tannoy behemoths are also there partially due to I think extreme herd behavior and cult of "Old things" . Because western culture developed big orchestral works we have a tendency to bigger more complicated system - Germanic people with lots of marching BASS and treble (Americans are following closely along with Russians , you'd be surprised how similar tastes and imperial mentality is
Brits with their tarnished past and small, small apartments and small and usually simple systems and the rest of Europe somehow in between . I already forgot what I'm talking about so please excuse me,...- Status
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