Oreste,
Each SMPS300R can provide enough peak power to supply two UCD180 modules. however, if maximum performace is required, should use either two SMPS300R one for each UCD module, or one SMPS500R for both modules. these power supplies had regulated output voltage, not regulated current.
HxR modules add-on will allow you to get more detail than the current ones, if the cost isn't an issue, then it worth.
Each SMPS300R can provide enough peak power to supply two UCD180 modules. however, if maximum performace is required, should use either two SMPS300R one for each UCD module, or one SMPS500R for both modules. these power supplies had regulated output voltage, not regulated current.
HxR modules add-on will allow you to get more detail than the current ones, if the cost isn't an issue, then it worth.
Dear Cristi,
I think it could be helpful for your potential customers (like me) if we were better equipped to read the specs on your SMPS´s.
I don´t understand how 500W nominal (625 short term and 800W peak) relates to 4,5A nominal and 6A peak current capabilities at the 54V setting of your SMPS500R?
Please clarify this and how I and others should read the current capabilities of your SMPS´s in relation to amplifier demands.
E.g. If I have an class AB or D amp that can output 10A peak at say 50VDC - how do I choose the best SMPS to make best use of my amp?
500W SMPS sounds more than reasonable but 6A peak does not...
Best,
Hi,
this is general understanding of how a regulated (constant voltage) smps works.
500R +-54V can deliver
-nominal 4.5A. That is 108*4.5=486W.
-short term (for a few ms) 108*6=648W
-max before the overcurrent protection limits the power: 800W so about 7.4A peak
With the roundings, this is consistent with table page 3 of the 500R webpage.
does this help ?
I power a 2x200W in 4ohms classAB amp with a 500R +-48V.
On paper, doing the maths, this is way undersized.
In the real world, listening to music and not to a sinusoidal, at home and not for Public Address, I never reach the smps limits on 90dB speakers.
And I enjoy a damn kick when Frank Beard is on the drums
Al
I have several questions (newbee to SMPS supplies)..
My set-up will be this one.
One active sub basses enclosure, using a 500W Class D amp (cut à 100hz).
(May-be two 250W amps bridged.)
Two side enclosures. Each one is made that way:
- One 250W Class D amp (100Hz-1000Hz) powered with +-70 V (L20D Stero Power Amplifier Board IRAUDAMP7-200 IRS2092 en vente sur eBay.fr (fin le 05-mars-12 12:49:15 Paris) )
- One 145W Class AB amp (100HZ-3MHZ)with +-70/75 V
My questions:
1- Did a SMPS800R in +-70V in each enclosure enough ?
2- Did i have to use a separate SMPS for the class AB amp, or may i use the same one for the Class D amp and the AB one in the same enclosure ?
3- If i use only one SMPS for two amps, did-I have to add Caps near each amp to reject a little more power varaitions or crosstalk, and what would be their max values ?
4- Is-it possible to synchronize the clocks of two SMPS ?
Thanks in advance.
My set-up will be this one.
One active sub basses enclosure, using a 500W Class D amp (cut à 100hz).
(May-be two 250W amps bridged.)
Two side enclosures. Each one is made that way:
- One 250W Class D amp (100Hz-1000Hz) powered with +-70 V (L20D Stero Power Amplifier Board IRAUDAMP7-200 IRS2092 en vente sur eBay.fr (fin le 05-mars-12 12:49:15 Paris) )
- One 145W Class AB amp (100HZ-3MHZ)with +-70/75 V
My questions:
1- Did a SMPS800R in +-70V in each enclosure enough ?
2- Did i have to use a separate SMPS for the class AB amp, or may i use the same one for the Class D amp and the AB one in the same enclosure ?
3- If i use only one SMPS for two amps, did-I have to add Caps near each amp to reject a little more power varaitions or crosstalk, and what would be their max values ?
4- Is-it possible to synchronize the clocks of two SMPS ?
Thanks in advance.
Hi,
this is general understanding of how a regulated (constant voltage) smps works.
500R +-54V can deliver
-nominal 4.5A. That is 108*4.5=486W.
-short term (for a few ms) 108*6=648W
-max before the overcurrent protection limits the power: 800W so about 7.4A peak
With the roundings, this is consistent with table page 3 of the 500R webpage.
does this help ?
I power a 2x200W in 4ohms classAB amp with a 500R +-48V.
On paper, doing the maths, this is way undersized.
In the real world, listening to music and not to a sinusoidal, at home and not for Public Address, I never reach the smps limits on 90dB speakers.
And I enjoy a damn kick when Frank Beard is on the drums
Al
Hi Alkasar,
Thanks for your explanation. I have never worked with SMPS tech before so highly appreciate your input.
The definition of taking the total voltage swing into account seems strange when trying to transfer it to amplifiers operational needs. Nevertheless it enables me to grasp what kind of peak capabilities to expect and that´s all I basically need as I too only listen to music where its the peak capabilities that typically limits the performance until accumulated heat may kicks in on prolonged loud listening sessions
7,4 A peak sounds rather good to me and is something that would probably not effectively limit my amps more than one dB or so. Neglectable really. If voltage is kept stiff within those boundaries the amp should sound very powerful indeed.
It seems that some have shown interest in adding extra capacitance to the SMPS´s. I guess that would mean after the regulation thus yielding more peak power capability with slight potential voltage drop under extreme conditions?
If this is generally thought of as an good idea, then are there any general guidelines for how much extra capacitance that can be added without causing problems for the SMPS?
Again thanks for any responses on my probably ill informed questions!
best,
Hi Cristi,
I ordered and received an SMPS800R late November/early December last year. This is for use with an SDS-470 from Class D Audio. I did a little bit of testing with it when I received it, and everything was OK. Then due to time constraints I haven't been able to work on this project until a couple weeks ago.
Now I have the amp fully built, and everything seems to work wonderfully, except the SMPS now makes a slight hissing/humming/static noise. The noise is usually fairly quiet, such that it can only be heard when I get my ear within a foot or so of the chassis. But every now and then it seems to be loud enough to be heard even within 10 feet or so of the chassis. Sometimes it is so quiet that I can only hear it with the cover off of the chassis and my ear right up next to it. I can't seem to discern any pattern to what makes this noise louder or softer, except that it seems it usually gets quieter after the whole unit has warmed up after running for a while.
The other thing I thought was weird: maybe this is related, or even expected, but the big capacitors on the input side of the unit have some potential on them. I didn't take a DMM reading, I discovered this the "hard" way when I happened to touch the capacitors and felt a little tingle. It wasn't a bad shock, just enough to startle me. (And I'm not sure if this is DC or AC, so don't know how to set my DMM to get a reading.)
These minor issues aside, my ears can't discern any audio quality difference between your SMPS800R and the linear PS from the kit. I was hoping the SMPS would be more efficient, but my rough readings (using a Kill-a-Watt) suggest that it is slightly worse than the linear one. With the same source material, same preamp setting, the amp with linear PS pulls about 22 Watts, and with the SMPS about 25 Watts. But the difference is so minor that I'm sticking with the SMPS in this build for its small size.
I posted some pictures of the completed build over on AudioCircle if you want to see how it's all hooked up.
Thanks,
Matt
I ordered and received an SMPS800R late November/early December last year. This is for use with an SDS-470 from Class D Audio. I did a little bit of testing with it when I received it, and everything was OK. Then due to time constraints I haven't been able to work on this project until a couple weeks ago.
Now I have the amp fully built, and everything seems to work wonderfully, except the SMPS now makes a slight hissing/humming/static noise. The noise is usually fairly quiet, such that it can only be heard when I get my ear within a foot or so of the chassis. But every now and then it seems to be loud enough to be heard even within 10 feet or so of the chassis. Sometimes it is so quiet that I can only hear it with the cover off of the chassis and my ear right up next to it. I can't seem to discern any pattern to what makes this noise louder or softer, except that it seems it usually gets quieter after the whole unit has warmed up after running for a while.
The other thing I thought was weird: maybe this is related, or even expected, but the big capacitors on the input side of the unit have some potential on them. I didn't take a DMM reading, I discovered this the "hard" way when I happened to touch the capacitors and felt a little tingle. It wasn't a bad shock, just enough to startle me. (And I'm not sure if this is DC or AC, so don't know how to set my DMM to get a reading.)
These minor issues aside, my ears can't discern any audio quality difference between your SMPS800R and the linear PS from the kit. I was hoping the SMPS would be more efficient, but my rough readings (using a Kill-a-Watt) suggest that it is slightly worse than the linear one. With the same source material, same preamp setting, the amp with linear PS pulls about 22 Watts, and with the SMPS about 25 Watts. But the difference is so minor that I'm sticking with the SMPS in this build for its small size.
I posted some pictures of the completed build over on AudioCircle if you want to see how it's all hooked up.
Thanks,
Matt
Matt, the buzzing noise comes when the smps works in burst mode or discontinuous mode. this is a pulse-skipping operation mode implemented to reduce power consumption at no load or very low load. it starts to operate normal as soon as the load reaches 50-70mA on each rail or ~3-5W power. that's below most of the amplifier quiescent current, but some amps could draw less than that if they are muted.
Every electrolytic capacitor can have the same potential (or very close) as the negative polarity terminal due to construction. these capacitors are NOT isolated like the large can AC capacitors used in power electronics circuits or motor starters. You should never touch the capacitors can (the top part which is exposed) as potentially lethal voltages are present. the capacitors are connected in series, each of them having half the bus voltage, so touching both caps in the same time you were feeling about 160V DC while operating or less after power off. do not do this again, to any electronic circuit, not only to this power supply, as it might be the last thing you do.
Every electrolytic capacitor can have the same potential (or very close) as the negative polarity terminal due to construction. these capacitors are NOT isolated like the large can AC capacitors used in power electronics circuits or motor starters. You should never touch the capacitors can (the top part which is exposed) as potentially lethal voltages are present. the capacitors are connected in series, each of them having half the bus voltage, so touching both caps in the same time you were feeling about 160V DC while operating or less after power off. do not do this again, to any electronic circuit, not only to this power supply, as it might be the last thing you do.
Hi, Cristi,
I would appreciate some answers to my questions,
http://www.diyaudio.com/forums/conn...hed-mode-power-supplies-smps.html#post2929066
as i need them to send my order.
I would appreciate some answers to my questions,
http://www.diyaudio.com/forums/conn...hed-mode-power-supplies-smps.html#post2929066
as i need them to send my order.
Jaques, i sent you the boards already, i will send you a mail with the tracking info.
Christophe, i will try to answer to your questions:
1. One SMPS800R is enough to supply one 250W class D amplifier module and one ~ 150W class AB amplifier. you can consider one SMPS500R but this might be at limit, as the class AB module draws more current than an equivalent power class D amplifier, roughly twice.
2. Separate SMPS might be a better choice, as the interractions between amps on the supply path are eliminated. just consider that the class D amplifier will experience pumping effect, since you will use it for low frequencies mostly. if the class AB amplifier does not have high PSRR it's performaces might be affected.
3. Adding capacitors is recommended if you want to reduce bus pumping or Hi-freq noise, if you also add some inductors in series with each supply rail. the total capacitance of the caps should not be double than the existing value of the caps from the smps or the smps might not start (enter in overcurrent protection mode during start-up, due to large inrush current)
4. The switching frequency of the resonant converters cannot be synchronized, as depends on the load, mains voltage and resonant tank characteristics. And is not even required. the switching frequency of the PWM power supplies or fixed frequency quasi-resonant type smps can be synchronized, but with additional hardware.
Christophe, i will try to answer to your questions:
1. One SMPS800R is enough to supply one 250W class D amplifier module and one ~ 150W class AB amplifier. you can consider one SMPS500R but this might be at limit, as the class AB module draws more current than an equivalent power class D amplifier, roughly twice.
2. Separate SMPS might be a better choice, as the interractions between amps on the supply path are eliminated. just consider that the class D amplifier will experience pumping effect, since you will use it for low frequencies mostly. if the class AB amplifier does not have high PSRR it's performaces might be affected.
3. Adding capacitors is recommended if you want to reduce bus pumping or Hi-freq noise, if you also add some inductors in series with each supply rail. the total capacitance of the caps should not be double than the existing value of the caps from the smps or the smps might not start (enter in overcurrent protection mode during start-up, due to large inrush current)
4. The switching frequency of the resonant converters cannot be synchronized, as depends on the load, mains voltage and resonant tank characteristics. And is not even required. the switching frequency of the PWM power supplies or fixed frequency quasi-resonant type smps can be synchronized, but with additional hardware.
It is the case: My class AB amp is a current feedback one (I.E. lowPSSR) with a 3Mhz power bandwitch.
www.esperado.fr - Le crescendo revisité
But i always prefer using a single Supply for harmonic dynamic coherency.between bass and treble during hight kick drums transients.
In the same spirit, i always prefer single power supply for the two channels for space image stability instead of separate ones. But, in my case, it is not possible (amps in the enclosures).
Well, using some air inductors, what would be the best values for the inductance ? What do you think about an other solution: adding a cap multiplier transistor and caps on each amps rails ?
www.esperado.fr - Alimentation Crescendo
I will lose some volts, but increase PSSR and HF filtering ?
And a last question. if i add a power resistance in serial in each rail during the starting time to reduce the inrush charging current, i suppose i can increase the total value of power capacitances with no issue for your SMPS ?
My system would be 3 SMPS800R.
For the sub, one SMPS, followed by a self and additional caps.
For the big satellites, one SMPS, each rail followed by a self and 2 cap multipliers (one for each amp) and several paralleled additional capacitances .
I cannot afford any hf noise, as my speakers are hight efficiency 98db/w units.
Did-you agree ?
I will publish an article of my final system on my site including your SMPS if it works great, with your permission.
Last edited:
Chistophe, Please wait few days, I just made a new SMPS300R version, which has LC filters on each output. On the actual version, there are 4 electrolytic caps on the secondary side, for each rail there are two caps connected in parallel, and for the single voltage version all 4 caps are connected in series. On the new SMPS300RE an CLC filter is implemented on each rail, the capacitors are not connected in parallel but an inductor is added on each rail between the caps, reducing the ripple even more.
I am not an adept of using air-core inductors, because they are bulky, and because they radiate a lot, requiring shielding or placing them far away from sensitive circuits. with the modern ferrite cores, can easy get at least the same performance of an air-core inductor or even better.
Adding a capacitance multiplier might be considered as last resort, if excesively low ripple is required, but take into account that there is power loss on the transistors, and complexity of short-circuit protection for that transistors. the overall efficiency will decrease. I find it odd using a high-efficiency power supply as a front end for a lossy circuit.
Adding a resistor in series is a bad idea, the output voltage regulation is lost in this way. you can add as much capacitance as you want (use good-sense limits) if the soft-start time is long enough to allow capacitors to charge with a limited current and without the smps entering in overcurrent protection mode.
I believe that the most important aspects to consider will be the correct placement of the boards into housing and correct wiring, a GND loop, wrong wiring, signal wires close to the SMPS transformers will harm more than you can save with expensive extra-circuits. Careful planning is required, and perhaps few wiring arrangements should be considered.
I am not an adept of using air-core inductors, because they are bulky, and because they radiate a lot, requiring shielding or placing them far away from sensitive circuits. with the modern ferrite cores, can easy get at least the same performance of an air-core inductor or even better.
Adding a capacitance multiplier might be considered as last resort, if excesively low ripple is required, but take into account that there is power loss on the transistors, and complexity of short-circuit protection for that transistors. the overall efficiency will decrease. I find it odd using a high-efficiency power supply as a front end for a lossy circuit.
Adding a resistor in series is a bad idea, the output voltage regulation is lost in this way. you can add as much capacitance as you want (use good-sense limits) if the soft-start time is long enough to allow capacitors to charge with a limited current and without the smps entering in overcurrent protection mode.
I believe that the most important aspects to consider will be the correct placement of the boards into housing and correct wiring, a GND loop, wrong wiring, signal wires close to the SMPS transformers will harm more than you can save with expensive extra-circuits. Careful planning is required, and perhaps few wiring arrangements should be considered.
It it just during the charging time of the additional secondary stage caps (with a delay). They will be short-circuited with a relay when caps arrive at 80/90% of the final V. That way, i can use big capacitance. But, if your SMPS is able to limit itself the current with no issue during long soft start (5sec), it will not be needed.
I don't care to lose 5v on 75V with a capacitance multiplier (don't forget your SMPS is still regulated, not so much more margin than the 0.7V+ ripple needed.). I will need-it with my AB amp witch need perfect power with no hf noise. And, if i care for weight (they will be in the enclosures) and price, i don't care too much about efficiency.
It will isolate the two amps from each other. I don't care neither for protection: a fuse is enough and i protect the amp outputs in a very secure and fast way.
I will wait for your new smps if they are available soon and able to give-me the + & - 75v i need.
If this modification is to enter the SMPS180 arena - I could have waited ordering my 180'.
Hi Cristi!
Interested in this version. How low is the ripple value(millivolt/microvolt) with this CLC filter in place?
Eddy.
Christophe, i got it now, i haven't read carefully before. I thought that the resistors will be connected permanently. The soft-start time can be theoretically as long as you need but some modification is required, to allow the bias winding to supply voltage for the primary side section during start-up when the sw. freq is far from resonant freq. which allows secondary current limit. I have to try to be sure it can be done on the existing boards. with the current configuration, if very large capacitors are added, the smps will start, try to ramp-up the voltage in the preset start-up time, and if the current draw will exceed the maximum allowed the smps will enter in overcurrent protection mode, then after 1-2 seconds will try to restart. if the caps were not discharged in this interval, on the second-third try might start-up. overall it would take few seconds as well. but the current stress on the smps components is much higher, and could affect the proper operation and reliability if at each start-up will cycle few times through OC protection mode.
A 5V voltage drop from a 75V rail is indeed small, but heatsinks are required for the series regulators, and more important, an over-current circuit protection with fold-back characteristic. at that voltage, to limit the current at few amps would burn any TO220 transistor in less than one second. also, you have to make sure that the Vce of the transistor is higher than the smps output voltage. Although the SMPS300R has no heatsink, when operate near it's maximum output power or if supply class AB amplifiers, is recommended to be equipped with a heatsink, which can be fitted onto the case wall or heatsink. The board allows such heatsink to be mounted, and even more power can be obtained if the heatsink is used.
Jesper, If you want, i will check with the shipping company tomorrow what's the status of your package, if hasn't left china yet and can be replaced, i can change the order to another power supply. please contact me asap to tell me if you want.
Eddy, I haven't measured yet on the batch boards, but on the prototype and simulation was around 7-11 mV pk-pk for a +-45V version at 2A. the inductors and capacitors used have a great influence on the ripple value. Later, i will try to make some measurements using spectrum analizer to see all the noise spectrum at different current draws.
A 5V voltage drop from a 75V rail is indeed small, but heatsinks are required for the series regulators, and more important, an over-current circuit protection with fold-back characteristic. at that voltage, to limit the current at few amps would burn any TO220 transistor in less than one second. also, you have to make sure that the Vce of the transistor is higher than the smps output voltage. Although the SMPS300R has no heatsink, when operate near it's maximum output power or if supply class AB amplifiers, is recommended to be equipped with a heatsink, which can be fitted onto the case wall or heatsink. The board allows such heatsink to be mounted, and even more power can be obtained if the heatsink is used.
Jesper, If you want, i will check with the shipping company tomorrow what's the status of your package, if hasn't left china yet and can be replaced, i can change the order to another power supply. please contact me asap to tell me if you want.
Eddy, I haven't measured yet on the batch boards, but on the prototype and simulation was around 7-11 mV pk-pk for a +-45V version at 2A. the inductors and capacitors used have a great influence on the ripple value. Later, i will try to make some measurements using spectrum analizer to see all the noise spectrum at different current draws.
Thanks, Cristi, for all the time you gave. Do not worry, i was an electronic engineer during the 1970 decade in the research and development office of the most important hifi manufacturer at this time.
My questions where just about YOUR smps, as i'm not experienced with this technology,(i was dedicated in linear PSUs since now).
Everything is clear, now, with your nice answers.
I thing i will not wait for your new model, as i will work on my own filtering. So i will pass my order on your site this night or tomorrow.
About air inductances, (i have plenty of them) if i use them, i do not expect any issue, as they will be *after* your SMPS, so they will only have to deal with the very little remaining hf ripple. No saturation and low impedance (big wires diameter). And i know how to wire, shield (and cool ;-) all that stuff.
Thanks again.
My questions where just about YOUR smps, as i'm not experienced with this technology,(i was dedicated in linear PSUs since now).
Everything is clear, now, with your nice answers.
I thing i will not wait for your new model, as i will work on my own filtering. So i will pass my order on your site this night or tomorrow.
About air inductances, (i have plenty of them) if i use them, i do not expect any issue, as they will be *after* your SMPS, so they will only have to deal with the very little remaining hf ripple. No saturation and low impedance (big wires diameter). And i know how to wire, shield (and cool ;-) all that stuff.
Thanks again.
Using a "typical" value of 9 mV p2p, we get 4.5mV peak or 3.2mV RMS. That is .007% of 45V
Very close to a typical low voltage regulator spec of 0.003% ripple
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.