03-24-15: Ptss
Bombay(hope it's ok for short-otherwise I could use Walla?).
I try to address everyone by their chosen moniker without abbreviating as a mark of respect to that person. doesn't cost me anything - i use ctrl-C & ctrl-V to accomplish that rather than typing the moniker. Saves time & makes the other person happy that i addressed them as they want to be.
but if you are averse to typing, sure.
Appreciate your comments. I think we can never overlook that in todays world there's an unavoidable intense pressure on manufacturers to create "newer", faster and "cheaper".
true. but in audio, it's all about the sound quality even when manuf use cheap components because even those cheap component audio manuf know that the human ear is very sensitive to distortion & if their gear doesn't meet the min requirements of the human ear not hearing distortion, their gear is not going to sell.
So, it's not like an automobile that uses cheap components that break in 1-2-3 years vs. 10 years because in such a case (autos) you can still sell the product & not have the consumer come back for a long while. OTOH, in audio, if you have unacceptable distortion, one listen & the consumer will be out of the door looking for something else & the audio manuf will have a zero sale.
so, yeah, audio manuf are pressured to make things newer, smaller, cheaper but distortion has to be kept below the average-Joe's hearing level.
Also, just to point out - the "newer" fad is very much an American/USA thing. In other parts of the world, "newer" is not always better & once people are satisfied with the performance of whatever piece of equipment they have, they don't necessarily get an itch to switch it out with something newer. In the USA they seem to have this itch pretty badly. Different culture.....
Which power supply is less expensive?
Loaded question. ;-)
The correct answer is "depends".
Linear power supplies have been around for a long time so their hardware has been in production for a long time as well. Plus a lot of the hardware for a linear power supply is also used in industrial applications thereby giving it the economies of scale from a pricing stand-point. To make a low AC ripple, high current, fast transient response linear power supply is not an easy task. It requires some careful design, careful layout esp. of the grounds & some expensive components.
To take it further, some audio manuf are using a regulated linear power supply. And, this is an even tougher job esp. when the bandwidth of the regulated power supply is to be large (> 100KHz). There are some audio manuf who have a 1MHz regulated power supply but it's relatively low current (3-5A) & used with front-end components. You'll be asking why 3-5A when front end components often using 1A or less? It's the dynamic headroom required when you have large signal variations in the program material that suddenly draws a lot of current from the power supply. This momentary current draw can be very high & the power supply needs to support it otherwise the music loses its sparkle.
The linear power supply can be made cheap & you see this in a lot of power amps in the market where you have high wattage but with very little current delivery to support those watts meaning that such high wattage amps cannot be used with difficult speaker loads. Cheap linear power supplies will also squash the dynamics in front-end components sucking out the life of the music.
Linear power supplies can be made very expensive like the ones you see in high wattage, high current power amps that weigh a ton. You see expensive linear power supplies in 2-box or multi-box preamp units.
A linear power supply is expensive from a power dissipation perspective - you have to design its max voltage for the max peak voltage of the program material but in normal operation the linear power supply operates mostly at the average voltage of the program material. The difference in the peak & average voltage is dissipated as heat. Of course, you don't know what the max voltage of the program material is so you have to over-design further leading to more heat dissipation.
SMPS power supplies have been around since the 1960s but used extensively in places other than audio. All power supplies in airplanes are SMPS - efficient & light-weight (compared to a linear power supply) where weight is a big issue. Their harmonic distortion performance for audio probably sucks but who cares in that application. So, it can be made cheap - there are hundreds of planes manuf each year & each plane uses many, many SMPS power supplies.
For audio applications, harmonic distortion is paramount so the SMPS output spectrum has be cleaned up so that you have vanishing low (something like -120dBc) distortion. That takes a lot of effort - good design, careful layout especially separating the analog & power/switching grounds and some expensive components that have low ESR/DCR such that the output ripple is low.
So, a SMPS is a complicated circuit that had a lot of failures initially for the audio application because people just didn't understand how it worked & how to reduce its output distortion. That has changed for the better & continues to evolve. 1st you used to see class-D amps with linear power supplies. Now you are seeing class-D power amps with SMPS. These are not necessarily cheap & the best are very expensive. It takes some good amount of engineering to keep the SMPS (located in the same chassis as the amplifier stage) from spraying high freq noise into the amplifier. You will now say " the noise is high freq so it's out-of-band w.r.t. to the audio so why should i care?" The answer is that all electronic components have some non-linearity (nothing is linear from DC - infinite frequency) & this non-linearity will respond to the hi-freq spurious emitted by the SMPS & will mix it down into the audio bandwidth. Once that happens the distortion looks just like an audio/program material signal & is impossible to separate. When this happens, the life of the music is simply sucked out. To avoid this, takes some concerted effort.
So, a SMPS can be made cheap & it is also expensive to make.
Now you know why the answer is "depends"!! ;-)
hope this helps......
