are SMPS created equal? choosing the best

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noviygera

noviygera

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Joined 2009
#1
I want to convert my Technics 1200mk2 to SMPS, like the new models, replacing the linear transformer with smps.
What is the best 20-30w SMPS?
Are there really good ones that emit the lowest noise? Brands, models. etc? TRACO?
Does it matter?
 
#2
Why do you want to change it?
Short and sweet advice : Don't, they create all sorts of problems in circuits not designed for one.

Meanwell is well regarded here in India, best quality components inside on those I checked.
Japanese capacitors, TI switching controllers (TL494 family), good quality PCB, fan, transistors, diodes and so on. Higher than expected component ratings. Quite reasonably priced as well.
 
#5
Moving to SMPS is usually for cost, not performance. Transformers are expensive.
You can dip a transformer (I have used a pressure/vacuum cycle pot) , put it remote, or buy a better transformer.
How much overhead and all those little things on an SMPS I do not know as well as a linear. I know some throw off copious RF, some outputs not very clean, and some must be great as amplifiers like the Benchmark, many class D are vanishingly clean. I am not sure I would want a switcher near the phono leads though. Maybe fine, maybe a rabbit hole. Watts and volts are not enough to chose wisely.
 
#7
tvrgeek said:
Moving to SMPS is usually for cost, not performance. Transformers are expensive.
Click to expand...
Or EMC compliance. Some transformers are also so lossy that the finished product can't meet standby energy specs.

There's no reason a well-designed SMPS can't deliver good performance. I've measured excellent performance with an SMPS - in some cases better than the performance I would get with a traditional supply. The key is "well-designed" or at least designed for low noise. Your standard laptop charger is not likely to work very well as a power source for an audio amp for example.

Tom
 
#11
A well timed question - I'm about to build a new power supply for one of my SP10mk2's and was looking at Meanwell. I've just looked at the XP Power units and will go this way.

I like well engineered SMPS and all 8ch of my Modulus power amps use Meanwell SMPS and the performance is better than when they powered by LPS. This may be because of where I live and our house is connected to the grid by a pole transformer. (living in farming area).
 
#12
What about replacing that humming/straying transformer for a better one? There are various aftermarket transformers either molded/dipped toroid with shield or EI with shield designed exclusively for Technics 1200. So on a small chassis with rubber feet etc. They won't bring as much issues as the average SMPS which are really only chosen for low cost and avoidance of liability. Apparently the fact that SMPS are sold most is a key factor in deciding to also use one?!

The measured performance is what counts whether people like this or that and their numbers are often appallingly bad with free pollution of the mains voltage as a bonus. As always many will defend SMPS (WHY?) but then mention the upper class ones with spectacular specifications while the average person buys an average SMPS. That average SMPS is no competition for the average LPS. The SMPS that is better than the average LPS is way more expensive 🙂

Anyway if you decide on SMPS the advice is to use mains filtering and shielding as good as possible as you will need it. The fight against HF/RF is a difficult battle compared to the 50/60Hz battle.
 
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#13
As jean-paul says, SMPS are done for cheapness. When it comes to low noise, an old-fashioned EI transformer with E/S screen, traditional rectification/smoothing, plus 317 regulator wins hands down. And if the transformer has an unacceptable leakage field, put it a bit further away.
 
#14
SMPS use is often to reduce size and weight as well as cost (copper is not cheap these days). You remember how heavy microwave ovens used to be? The modern ones feel feather-light by comparison (and more efficient too). [ In the microwave oven world they wrongly use the word "inverter" when they mean SMPS, I notice. ] Virtually noone wants to pay more for something that's heavier and bulkier and less efficient!!
 
#15
Working with industrial high power SMPS for many years now and they’re quite good when done right. The market demands low losses/high efficiency, low heat, small size, low weight etc. and things count quickly in higher power devices. One can calculate what having 80% efficiency or 96% efficiency makes of a difference in annual energy costs with for instance a 1 MW installation working 24/7.

In a few VA consuming analog turntable with mV sensitivity it makes no sense to use an SMPS straying HF/RF. It makes more sense to use a molded/dipped toroid and pay attention to vibration.
 
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#17
A seasoned analog aficionado would make the same choice (having coped with hum, AM radio etc. already in the past). I have built a few phono preamplifiers for turntable guys and these are sensitive devices picking up pollution etc.

Personal thing but I really can not imagine turntables with SMPS and phono preamplifiers with SMPS to be a benefit for playing LP records.
 
#18
 
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