Hi
Blackstar Artisan 412 A/B Extension Cabinet
...does this Artisan 412 amplifier use a switch mode power supply to supply it from the mains?
Blackstar Artisan 412 A/B Extension Cabinet
...does this Artisan 412 amplifier use a switch mode power supply to supply it from the mains?
Unless I am not reading correctly, what you have linked us to is a 4x12 speaker cabinet. No power supply in it at all. The data sheet refers to its 240 watts, but that means power handling ability. It doesn;t produce any power.
Just a question: if it were a power amp, why would the type of power supply matter?
Just a question: if it were a power amp, why would the type of power supply matter?
Oh Sorry...i meant this product instead........
Blackstar HT Stage 100 Head Guitar Amp Head
....Its juat that i feel that the SMPS powered ones will be more expensive.....so if its got an SMPS in it, then i will go elsewhere and look for the equivalent product with a simple 50/60Hz mains transformer and rectifier/capacitor bank.
Blackstar HT Stage 100 Head Guitar Amp Head
....Its juat that i feel that the SMPS powered ones will be more expensive.....so if its got an SMPS in it, then i will go elsewhere and look for the equivalent product with a simple 50/60Hz mains transformer and rectifier/capacitor bank.
Quite the opposite, SMPS's are cheaper, which is why they are becoming more popular, as well as smaller, lighter, much more efficient, and able to work over a wide voltage range.
toprepairman: - More complicated to repair, but by no means 'unfixable', engineers have been fixing SMPS's for over 40 years now.
yes but......an smps generally has to be rated for its peak power as if it was continuous...........wheras a 50Hz transformer based PSU, for audio use, can be significantly underrated, and handle the peak power with its overload capability.
So the mains transformer is cheaper, but granted you need the mains to be constant 230V or 115V, whatever.
So the mains transformer is cheaper, but granted you need the mains to be constant 230V or 115V, whatever.
You are taking one parameter out of the context of all the rest. An SMPS can be dsigned for any power needs you specify. I service 3000 watt professional amps with SMPS in them. Little tube guitar amos are starting to sport SMPS. The mains transformer is the single most expensive part in a guitar amp, getting rid of it is a large step in improving profitability of an amp. Even your under rated iron transformer will be more expensive than the SMPS alternative.
At 50Hz, the main filter cap has to hold up the power rail for 100ms. At 50kHz, the filter in that SMPS has to hold up the current demand for 0.1ms. Not only have we removed the big transformer, but we also can shrink the filter caps. And large filters are not cheap either.
And I agree with Nigel, SMPS are no less servicable than anything else. I have been repairing SMPS for at least 30 years now. They are however getting so inexpensive it is often cheaper to replace them than to spend the labor time fixing one. A shorted rectifier on the secondary side is fixed quickly with a 2 cent part.
At 50Hz, the main filter cap has to hold up the power rail for 100ms. At 50kHz, the filter in that SMPS has to hold up the current demand for 0.1ms. Not only have we removed the big transformer, but we also can shrink the filter caps. And large filters are not cheap either.
And I agree with Nigel, SMPS are no less servicable than anything else. I have been repairing SMPS for at least 30 years now. They are however getting so inexpensive it is often cheaper to replace them than to spend the labor time fixing one. A shorted rectifier on the secondary side is fixed quickly with a 2 cent part.
i'm sure you realise its 10ms , instead of 100ms......im sure that was a typo.....but granted, 10ms is a long time to hold up the rail.
...but electrolytics are cheaper and cheaper to assemble than all the paraphinalia associated with smps...........granted the 50Hz solution is likely bigger...but miniturization doesnt seem to have hit the guitar amp world.......it seems, the bigger the better is the attitiude
...but electrolytics are cheaper and cheaper to assemble than all the paraphinalia associated with smps...........granted the 50Hz solution is likely bigger...but miniturization doesnt seem to have hit the guitar amp world.......it seems, the bigger the better is the attitiude
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You're right, I wasn't thinking. 100Hz ripple means 10ms charging cycle. SO 50kHz switcher, 100kHz ripple, charging cycle 0.01ms? It requires a lot less cap to do that.
And no, they are not cheaper. Price a 20,000uf 80v cap and compare it to a 200uf 80v cap. You are saving with smaller caps. Price a large 200 watt power transformer, compare to a whole 200 watt SMPS. But keeping in the spirit of the discussion, compare it to the small SMPS transformer. Rectifier diodes will be about the same. The SMPS will have a couple switching transistors and a small cheap control IC. Plus the mains rectifiers and filters. All of those together do not cost as much as that linear transformer alone, let alone with the large filter caps.
Ther are arguments against SMPS, but cost is not one of them.
And no, they are not cheaper. Price a 20,000uf 80v cap and compare it to a 200uf 80v cap. You are saving with smaller caps. Price a large 200 watt power transformer, compare to a whole 200 watt SMPS. But keeping in the spirit of the discussion, compare it to the small SMPS transformer. Rectifier diodes will be about the same. The SMPS will have a couple switching transistors and a small cheap control IC. Plus the mains rectifiers and filters. All of those together do not cost as much as that linear transformer alone, let alone with the large filter caps.
Ther are arguments against SMPS, but cost is not one of them.
Linear transformers very rarely go wrong, SMPS's always do.
A dead diode in a tx type supply might be a 1N4007, replacement cost 10 pence, for a SMPS, some exotic very fast Shottky likely to cost 50 times as much. The switching transistors are generally FETs, which by the time you need them are osolete and difficult/expensive to find. And that cheap chip?, yea sure it's cheap when fitted originally, but, like the FETS it's obsolete when you need it and then it's expensive, add postage, small order charge, tax etc and your cheap chip becomes 10 to 20 quid.
Then when you switch it back on it all goes back up in a puff of smoke! (I'm much more careful then that, current limiting resistors, variac and all that, but the point is the same)
A dead diode in a tx type supply might be a 1N4007, replacement cost 10 pence, for a SMPS, some exotic very fast Shottky likely to cost 50 times as much. The switching transistors are generally FETs, which by the time you need them are osolete and difficult/expensive to find. And that cheap chip?, yea sure it's cheap when fitted originally, but, like the FETS it's obsolete when you need it and then it's expensive, add postage, small order charge, tax etc and your cheap chip becomes 10 to 20 quid.
Then when you switch it back on it all goes back up in a puff of smoke! (I'm much more careful then that, current limiting resistors, variac and all that, but the point is the same)
You can't carry on living in the 1960's
Switch-mode is the way it's going, and it's only going to get more so.
Nigel you are absolutely correct, and sadly these things tend to be customer led, ie., they want it as cheap as possible.
That's Ok with telly's and the like, when most people will happily just buy a new one, but tell the guy with his Newfandango200 guitar amp that's only 15 years old that the parts required are simply no longer available. The we'll be shoehorning in linear 50Hz transformer based power supplies into his much loved box.
That's Ok with telly's and the like, when most people will happily just buy a new one, but tell the guy with his Newfandango200 guitar amp that's only 15 years old that the parts required are simply no longer available. The we'll be shoehorning in linear 50Hz transformer based power supplies into his much loved box.
Except the cost of doing so, along with caps and recifiers, is probably not cost effective.
And, with a linear power supply, that big transformer's isolating you from the mains just about everywhere. No shorting something that turns out to be live with the scope lead, much lower probability of electric shocks (even on 450 volt tube supplies).
But yes, anyone who's ever transported a couple of kilowatts of traditional power amp knows why switch mode is taking over.
But yes, anyone who's ever transported a couple of kilowatts of traditional power amp knows why switch mode is taking over.
I understood that even if a 450V tube supply exists........
Then it is produced from a flyback step-up converter, which appears after the isolation stage......whether that isolation stage comprises a 50Hz transformer, or a high-frequency switch mode power supply transformer.
......i dont think 50Hz transformers exist with 450V secondaries?
By the way, in a 350W amp, does anyone know what power would be drawn by the tube supply.......presumably 350W?...(-minus the bit for the tube filament heater?)
Then it is produced from a flyback step-up converter, which appears after the isolation stage......whether that isolation stage comprises a 50Hz transformer, or a high-frequency switch mode power supply transformer.
......i dont think 50Hz transformers exist with 450V secondaries?
By the way, in a 350W amp, does anyone know what power would be drawn by the tube supply.......presumably 350W?...(-minus the bit for the tube filament heater?)
It's simple to make transformers with any winding you want, valve transformers were common and easily available back in the valve days.
Now a days they are still fairly easily available, but pretty pricey.
Probably around 750W or more - valve amps are EXTREMELY inefficient - their theoretical maximum is only 50%.
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