SMPS
The A and T SMPS looks good for a split supply SMPS for a class AB amplifier. Maybe even for several UcD400s.
However, the active filtersays it uses RC filtering, the R being the power transformer secondary and the resistance of the wiring.
This is like a car dealer saying to buy his car because it has wheels with skinny tires.
A high transformer internal impedance and lossy wiring is another way of saying the wire used in the transformer is too thin and they use skinny power supply wiring. What it really means there will be high source impedance, which will result in impaired impact in the low end. The caps will not be able to recover very well from strong bass notes.
With modern designs exceeding 80 db power supply rejection ratio, careful grounding is more important than high source impedance in power supply design.
I would recommend some series inductance except that the A and T power supply already includes this.
I suggest the A and T power supply be tried but the WN Audio active power supply NOT be combined with it. The WN Audio power supply should be confined to mid and high amplifiers, not full range units, at least not if you expect super tight bass.
As for the amp with 2 1000ASPs in it, the reason the people did it is that the 1000A is limited to 3 KHz. If you want 1000W per channel full range, you need 2 1000ASPs. I have been told, as of last October by the ICE Power people, that there were no plans at that time to extend the 1000A to full range as they have to many other interesting projects to work on and not enough talented people.
The A and T SMPS looks good for a split supply SMPS for a class AB amplifier. Maybe even for several UcD400s.
However, the active filtersays it uses RC filtering, the R being the power transformer secondary and the resistance of the wiring.
This is like a car dealer saying to buy his car because it has wheels with skinny tires.
A high transformer internal impedance and lossy wiring is another way of saying the wire used in the transformer is too thin and they use skinny power supply wiring. What it really means there will be high source impedance, which will result in impaired impact in the low end. The caps will not be able to recover very well from strong bass notes.
With modern designs exceeding 80 db power supply rejection ratio, careful grounding is more important than high source impedance in power supply design.
I would recommend some series inductance except that the A and T power supply already includes this.
I suggest the A and T power supply be tried but the WN Audio active power supply NOT be combined with it. The WN Audio power supply should be confined to mid and high amplifiers, not full range units, at least not if you expect super tight bass.
As for the amp with 2 1000ASPs in it, the reason the people did it is that the 1000A is limited to 3 KHz. If you want 1000W per channel full range, you need 2 1000ASPs. I have been told, as of last October by the ICE Power people, that there were no plans at that time to extend the 1000A to full range as they have to many other interesting projects to work on and not enough talented people.
Re: SMPS
Hi Dan,
That active power supply is a capacitance multiplier (although the web-site does not clearly say that), note that the web-site has a couple of power supplies.
The active one should have a very low output impedance as it is basically an emitter follower with the base voltage being an RC filtered version of the power supply voltage at the input (and a bit of voltage drop of course to create a bit of room for the emitter follower to do its work). This should give a very stable output voltage and very good noise suppression.
These active supplies work well when a relatively constant current is drawn, such as for class A amps. However, with Class D, where current consumption can vary over a wider range, they may get into problems (too fast voltage drop at the input). However, if that circuit is being fed by a regulated power supply, it should be able to work very well. That's why I want to combine the two.
Best regards
Gertjan
dmfraser said:
Hi Dan,
That active power supply is a capacitance multiplier (although the web-site does not clearly say that), note that the web-site has a couple of power supplies.
The active one should have a very low output impedance as it is basically an emitter follower with the base voltage being an RC filtered version of the power supply voltage at the input (and a bit of voltage drop of course to create a bit of room for the emitter follower to do its work). This should give a very stable output voltage and very good noise suppression.
These active supplies work well when a relatively constant current is drawn, such as for class A amps. However, with Class D, where current consumption can vary over a wider range, they may get into problems (too fast voltage drop at the input). However, if that circuit is being fed by a regulated power supply, it should be able to work very well. That's why I want to combine the two.
Best regards
Gertjan
1000A, etc.
The 1000ASP with one or two 500A modules for a bi/tri-amp system is fine. There is plenty of power for this in the setup.
The WM Audio power supply write up implied to me that the filter multiplier effect for the high power portion was an RC filter. The head capacitance multiplication is for the lower voltage supply. It doesn't really matter. If what they are doing is a true capacitance multiplier, that is active, all a capacitance multiplier is, is a regulated power supply that may have a relaxed regulation spec. When you are using an SMPS, that runs at high frequencies anyway, the normal capaciatnce would be 10 uFd. By using caps in the thousands, you have super capacitance already. As well, any ripple will be above the range of hearing.
As for capacitance multipliers, I had one on my very first amp, in 1968 because the crappy single ended designs of the day had poor supply rejection, a problem we had solved by 1975 in the amp design. Hum and noise are not your problem. And as far as an electronic curcuit giving you more oomph in the bass, the best way to do this is to either use bigger caps or increase the power frequency, something you are doing by a factor of 1000 by getting the SMPS. Remember that if you increase the frequency, theoretically, a given amount of capacitance will be 1000 times as effective. In practice, maybe 50 times but more than a capacitor multiplier will do for you.
However, you can't hurt anything besides your wallet by doing both.
The 1000ASP with one or two 500A modules for a bi/tri-amp system is fine. There is plenty of power for this in the setup.
The WM Audio power supply write up implied to me that the filter multiplier effect for the high power portion was an RC filter. The head capacitance multiplication is for the lower voltage supply. It doesn't really matter. If what they are doing is a true capacitance multiplier, that is active, all a capacitance multiplier is, is a regulated power supply that may have a relaxed regulation spec. When you are using an SMPS, that runs at high frequencies anyway, the normal capaciatnce would be 10 uFd. By using caps in the thousands, you have super capacitance already. As well, any ripple will be above the range of hearing.
As for capacitance multipliers, I had one on my very first amp, in 1968 because the crappy single ended designs of the day had poor supply rejection, a problem we had solved by 1975 in the amp design. Hum and noise are not your problem. And as far as an electronic curcuit giving you more oomph in the bass, the best way to do this is to either use bigger caps or increase the power frequency, something you are doing by a factor of 1000 by getting the SMPS. Remember that if you increase the frequency, theoretically, a given amount of capacitance will be 1000 times as effective. In practice, maybe 50 times but more than a capacitor multiplier will do for you.
However, you can't hurt anything besides your wallet by doing both.
Re: 1000A, etc.
Hi Dan,
Thanks for the additional comments. The reason why I'm thinking of using the capacitance multiplier is to remove the 75kHz switching frequency ripple of that SMPS since that ripple will depend on the power I draw and on the quality of the caps at the output of the SMPS. Besides that, I don't know how well the SMPS is regulated, so I wanted to improve the power supply decoupling between the amps for the woofers (directly fed from SMPS) and the amps for mid and high that would be fed from the active supply.
Of course, this stuff with the active suplies after the SMPS may very well be overkill, just want to try it. I plan to do measurements (using a scope) on that SMPS and active supply, first without amps. What would be a good load? I was thinking of just connecting a few 100W 100V lightbulbs between the + and - rail of the supply to get a load of a few 100 Watt. This is cheap and 100V lightbulbs are easy to get here, besides that, you have immediate visual feedback
. Of course can only simulate a steady state load that way but that is good enough for a start. Later when connecting the amps, I may load the amps with lightbulbs as well, has anyone tried this before. Much cheaper than huge dummy load resistors and if the frequency is not too high, it may work pretty well.
Best regards
Gertjan
dmfraser said:
Hi Dan,
Thanks for the additional comments. The reason why I'm thinking of using the capacitance multiplier is to remove the 75kHz switching frequency ripple of that SMPS since that ripple will depend on the power I draw and on the quality of the caps at the output of the SMPS. Besides that, I don't know how well the SMPS is regulated, so I wanted to improve the power supply decoupling between the amps for the woofers (directly fed from SMPS) and the amps for mid and high that would be fed from the active supply.
Of course, this stuff with the active suplies after the SMPS may very well be overkill, just want to try it. I plan to do measurements (using a scope) on that SMPS and active supply, first without amps. What would be a good load? I was thinking of just connecting a few 100W 100V lightbulbs between the + and - rail of the supply to get a load of a few 100 Watt. This is cheap and 100V lightbulbs are easy to get here, besides that, you have immediate visual feedback
. Of course can only simulate a steady state load that way but that is good enough for a start. Later when connecting the amps, I may load the amps with lightbulbs as well, has anyone tried this before. Much cheaper than huge dummy load resistors and if the frequency is not too high, it may work pretty well.Best regards
Gertjan
Hi, this discussion took a fun turn.
How about some small series resistance with the lights to limit their inrush, I don't know what their impedance would be when cold, but it will certainly draw a surge.
No doubt it is overkill, but if you want to try it, I'm eager to hear of your results
Of course you know, all the added complexity significantly increases the odds of something going wrong with it, I hope you get to test it to your satisfaction without anything like that happening.
Regards.
How about some small series resistance with the lights to limit their inrush, I don't know what their impedance would be when cold, but it will certainly draw a surge.
No doubt it is overkill, but if you want to try it, I'm eager to hear of your results
Of course you know, all the added complexity significantly increases the odds of something going wrong with it, I hope you get to test it to your satisfaction without anything like that happening.
Regards.
classd4sure said:Hi, this discussion took a fun turn.
How about some small series resistance with the lights to limit their inrush, I don't know what their impedance would be when cold, but it will certainly draw a surge.
No doubt it is overkill, but if you want to try it, I'm eager to hear of your results
Of course you know, all the added complexity significantly increases the odds of something going wrong with it, I hope you get to test it to your satisfaction without anything like that happening.
Regards.
I'll keep you updated, will of course first only use the SMPS.
The Inrush current of the bulb would be interesting
This is nice actually, can check the transient response of the regulation loop of the SMPS that way By the way, has anybody ever investigated the impedance of a light bulb as a function of frequency? I guess it has a bit of series inductance. Yes, this really becomes a fun project.
Gertjan
ghemink said:
New on this forum, but very interested in Class-D and SMPS. I experimented with Class-D in the 70's (small HF transistors, 8 Watts output, not a nice sound ......
I wonder if an SMPS can handle the low load of a Class-D amplifier during the silence periods and does not switch off. If an artificial load is neccessary in normal musical operation it would be really a pity.
Anyhow, I will follow this thread with high interest!
Success,
Art
marconist said:
New on this forum, but very interested in Class-D and SMPS. I experimented with Class-D in the 70's (small HF transistors, 8 Watts output, not a nice sound ......
I wonder if an SMPS can handle the low load of a Class-D amplifier during the silence periods and does not switch off. If an artificial load is neccessary in normal musical operation it would be really a pity.
Anyhow, I will follow this thread with high interest!
Success,
Art
Still waiting for the kit to arrive
Gertjan
unclemonty said:
Dear Sir,
please excuse me if I got back this extremely interesting information.
I understand that also Rotel has jumped on the ICE wagon.
If the price you mention is real they have an amazing mark-up on their latest amps.
Are you referring at the ASP version with the embedded switching power supply?
This is unbelievable.
A ASP module with just some cable anc connectors is a ready to use high quality power amp !
I think that in the next future we will see an huge growth of hi-fi and pro amps based on these modules, if the price stay this low.
Thank you very much again for the information.
Kind regards,
bg
Nice forum, lot of interesting and funny information! First of all, I want to make a comment about zobel circuit. A zobel should be always over the audio bandwidht, in that way, it only serve for stability and do not dissipate lot of power or blow in continuous hight frequency measurement. Please everybody learn this!!!
Second. Power measurement. A good way I think to rate amplifier is to rate the VA, not the watts. And best is maximum continuous (30 minute for our power amp) at 0.5% distortion. After this, we design heat sink to handle 50% of maximum power for 8 hours. If you whant to rate your amplifier at maximum power just before it blow, it's your right, but because of this, a lot of good product with real spec can be sold.
Least, about switching power supply. I think their is no rule here. I have try some competitor amplifier, and some did not work very well with our power supply, especialy the ICE module. Our switching power supply can provide over 6.5Kw of peak power, with 4 Kw continuous capacity, and always blow with ICE modula at near 600W continuous. But with our power amp, a 4 Kw continuouscan be measured continuous. We never understand what happen with the ICE module, protection in the power supply never trigh. Lot of analog amplifier sound better too with a switching power supply, but lot too sound very bad. I think that is no rule for this, just experimentation.
My comment now about the ICE with a 1.5Kw transformer. It sound very good in the mid and hight frequency, that's impressive. Maybe better than our D-Amp amplifier. But the lack of power and bass sustain make it unemployable for PA.
I dont agree with a lot of statement in this tread, lot of people will not agree with me too, but that's the purpose of this forum!
Fredos
www.d-amp.com
Second. Power measurement. A good way I think to rate amplifier is to rate the VA, not the watts. And best is maximum continuous (30 minute for our power amp) at 0.5% distortion. After this, we design heat sink to handle 50% of maximum power for 8 hours. If you whant to rate your amplifier at maximum power just before it blow, it's your right, but because of this, a lot of good product with real spec can be sold.
Least, about switching power supply. I think their is no rule here. I have try some competitor amplifier, and some did not work very well with our power supply, especialy the ICE module. Our switching power supply can provide over 6.5Kw of peak power, with 4 Kw continuous capacity, and always blow with ICE modula at near 600W continuous. But with our power amp, a 4 Kw continuouscan be measured continuous. We never understand what happen with the ICE module, protection in the power supply never trigh. Lot of analog amplifier sound better too with a switching power supply, but lot too sound very bad. I think that is no rule for this, just experimentation.
My comment now about the ICE with a 1.5Kw transformer. It sound very good in the mid and hight frequency, that's impressive. Maybe better than our D-Amp amplifier. But the lack of power and bass sustain make it unemployable for PA.
I dont agree with a lot of statement in this tread, lot of people will not agree with me too, but that's the purpose of this forum!
Fredos
www.d-amp.com
Hi Fredos,
Do you have any hypothesis as to why it might sound thin in the bass, something with the topology(feedback) perhaps?
You'd heard a UCD I presume...thin bass has been observed by many with that too, any correlation there in your view?
About measuring amps in VA instead of watts. As far as I know, watts=VA, volts times amps. What you rate your amps for "reactive power" would seem to imply VAR, volts amps reactive, but that's not true power delivered to the load given the angle by which the volts and current are out of phase with one another, producing no real power.
Please do correct me if I'm wrong.
Regards,
Chris
Do you have any hypothesis as to why it might sound thin in the bass, something with the topology(feedback) perhaps?
You'd heard a UCD I presume...thin bass has been observed by many with that too, any correlation there in your view?
About measuring amps in VA instead of watts. As far as I know, watts=VA, volts times amps. What you rate your amps for "reactive power" would seem to imply VAR, volts amps reactive, but that's not true power delivered to the load given the angle by which the volts and current are out of phase with one another, producing no real power.
Please do correct me if I'm wrong.
Regards,
Chris
Fredos,
Sorry I posted too fast and confused a few things, like watts doesn't =VA in the sense which you obviously used it, which was that of "apparent power" and not "reactive power" as I'd implied.
Obviously I confused myself there.
Still, I maintain my point, although slight reformatted, VA would seem to artificially inflate the rating, since it doesn't take phase into account. True power (watts) is what the load is actually using, I'd think it preferred to continue rating amps for true power, anything less would seem to be kin to such things as PMPO, hate to say it though.
Regards,
Chris
Sorry I posted too fast and confused a few things, like watts doesn't =VA in the sense which you obviously used it, which was that of "apparent power" and not "reactive power" as I'd implied.
Obviously I confused myself there.
Still, I maintain my point, although slight reformatted, VA would seem to artificially inflate the rating, since it doesn't take phase into account. True power (watts) is what the load is actually using, I'd think it preferred to continue rating amps for true power, anything less would seem to be kin to such things as PMPO, hate to say it though.
Regards,
Chris
VA is the real power delivred to the load, including inductive, reactive and resistive power. VA is more when you measure power dissipated in a load, but less when you measure from a source! So that's why people won't believe the power of our power amp! When you put a QSC of 1500Watts again a D-Amp of 1500Watts (VA), the D-Amp is always louder (a lot!)!
About the tinny bass sound of competitor, I cannot say why, but I suspect more the PSU than the amplifier itself. Or it's just maybe the damping factor of the amplifier...If feedback cannot compensate for the resistive component of the output filter (and maybe power supply), the bass will by tinny or with no control..That's the reason why all the power stage of my amplifier have only X12 (X24 for my HVI serie) gain. I give the voltage gain before the class d amplifier with a class a voltage amplifier...So in this way, I have a real control over the output.
Fredos
www.d-amp.com
About the tinny bass sound of competitor, I cannot say why, but I suspect more the PSU than the amplifier itself. Or it's just maybe the damping factor of the amplifier...If feedback cannot compensate for the resistive component of the output filter (and maybe power supply), the bass will by tinny or with no control..That's the reason why all the power stage of my amplifier have only X12 (X24 for my HVI serie) gain. I give the voltage gain before the class d amplifier with a class a voltage amplifier...So in this way, I have a real control over the output.
Fredos
www.d-amp.com
crashed cap.
Hi. I managed to place my hands on a pair of used 500asp modules thanks to trading posts on this forum. I have however a small problem with them. During transportation one of the capacitors was crashed. This is the cap connected straight to the transformer. It is Vishay`s BC Components RVI136 series: 680uF 100V capacitor - practically unavailable online.
Because I can`t get BCC cap I am experimenting with other brands` caps. I used Panasonic FC series cap but the sound lost its tubey character and became too bright. Caps were replaced after few days with Nichicon PF (M) series. This time there is sufficient amount of lower frequencies but the bass is soft and uniformed. I bought some ELNA RJH series on ebay but they are still in hands of transportation company.
What do you think guys, which capacitors can be closest to RVI136 Vishay`s series?
If somebody has this capacitor in his/her drawer I would really appreciate contact. Regards.
Hi. I managed to place my hands on a pair of used 500asp modules thanks to trading posts on this forum. I have however a small problem with them. During transportation one of the capacitors was crashed. This is the cap connected straight to the transformer. It is Vishay`s BC Components RVI136 series: 680uF 100V capacitor - practically unavailable online.
Because I can`t get BCC cap I am experimenting with other brands` caps. I used Panasonic FC series cap but the sound lost its tubey character and became too bright. Caps were replaced after few days with Nichicon PF (M) series. This time there is sufficient amount of lower frequencies but the bass is soft and uniformed. I bought some ELNA RJH series on ebay but they are still in hands of transportation company.
What do you think guys, which capacitors can be closest to RVI136 Vishay`s series?
If somebody has this capacitor in his/her drawer I would really appreciate contact. Regards.
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