Ideally, I'd like to have a 1000 W +-65 V unit so I can have 300 W into my 7 ohm speakers. I could do with an 800 W +-60 V unit as well, although the peak current at 7 ohm load will be 240 mA higher than the rated peak current for an 800 W SMPS (unless my calculations are failing me), which makes me think I'd need to come down to +-55 V for safety, which gives me a little less ouput power than I'd like.
qusp,
Both the 500 and 300 also have aux. but only the 800 comes with a regulated aux.
Like you, I will definitely wait for opc test results before committing to anything as general reputation of smps is not good. Hopefully, today's newer designs will test out. I would be waiting for opc to find time for these tests even if there had been no flooding in Thailand. It will be interesting to see what he discovers. I have a lot of confidence that nothing will get by him and his AP analyzer.
Both the 500 and 300 also have aux. but only the 800 comes with a regulated aux.
Like you, I will definitely wait for opc test results before committing to anything as general reputation of smps is not good. Hopefully, today's newer designs will test out. I would be waiting for opc to find time for these tests even if there had been no flooding in Thailand. It will be interesting to see what he discovers. I have a lot of confidence that nothing will get by him and his AP analyzer.
ahh IC, well it doesnt matter so much to me, i bought the linear supplies from Owen from the headamp as they plug right in, so unregulated aux is actually preferred for me, as i will regulate it after and the reg and local decoupling will then be more efficiently placed.
like i said though, Cristi has a modified design mostly ready for this amp project to suit.
yeah i also have a great deal of confidence in opc and his test gear and also that he will not just test objectively, giving a well rounded recommendation, that has been my experience before. as i was saying to Owen by email, since i only need about 100-150wpc max, the lower end of that at least initially, i'm tempted to lash together a linear fully regulated supply with 2-3 LT regs in parallel with current sharing ballast R's, or perhaps an LT reg with transistor power follower and call it a day
like i said though, Cristi has a modified design mostly ready for this amp project to suit.
yeah i also have a great deal of confidence in opc and his test gear and also that he will not just test objectively, giving a well rounded recommendation, that has been my experience before. as i was saying to Owen by email, since i only need about 100-150wpc max, the lower end of that at least initially, i'm tempted to lash together a linear fully regulated supply with 2-3 LT regs in parallel with current sharing ballast R's, or perhaps an LT reg with transistor power follower and call it a day
Jazzm:
There is no problem using a higher voltage device, but what you have there doesn't appear to be a lateral fet. If I'm reading the datasheet correctly, the Id increases with temperature, which means you will need a thermal compensation circuit to use these.
With lateral mosfets, the drain current will decrease as temperature increases which prevents thermal runaway and the need for thermal comp circuits.
Regards,
Owen
There is no problem using a higher voltage device, but what you have there doesn't appear to be a lateral fet. If I'm reading the datasheet correctly, the Id increases with temperature, which means you will need a thermal compensation circuit to use these.
With lateral mosfets, the drain current will decrease as temperature increases which prevents thermal runaway and the need for thermal comp circuits.
Regards,
Owen
qusp,
That seems a workable approach, especially since you already mentioned that you don't mind the electric bill and already have the parts on hand, but I'm still hoping to get the many advantages of SMPS as long as it doesn't cost much performance-wise. I sure don't want to throw away the Wire's performance by making a poor choice with PS .
That seems a workable approach, especially since you already mentioned that you don't mind the electric bill and already have the parts on hand, but I'm still hoping to get the many advantages of SMPS as long as it doesn't cost much performance-wise. I sure don't want to throw away the Wire's performance by making a poor choice with PS .
me too, but i'm not prepared for 1000 in SMPS for the AP2 solution for 4 channels and i'm unsure about Cristi's solution yet; suck it and see i guess. given the performance of the wire measured till this point was with a completely unregulated supply (even for the front end i think?) i think unless something truly dumb is done performance should be about equal or better.
the wire has such high PSRR i dont think there is a lot to worry about, but i'm with you, best get the best we can out of it. the linear regulated supply i mentioned wont be as inefficient as unregulated, but of course wont be 90% as some SMPS
the wire has such high PSRR i dont think there is a lot to worry about, but i'm with you, best get the best we can out of it. the linear regulated supply i mentioned wont be as inefficient as unregulated, but of course wont be 90% as some SMPS
Hi all,
I confirm for Monday upc collect package with deliver 2 days to Opc.
I include 2 smps (regulated/unregulated).
I sure that Opc try well and show measure of amplifiers with this smps,specially fft and thd Vs. frequency on amp. also fft at vcc output of smps with 100mA and 500mA.
Measures in this way, say all .
unregulated: dimension 100x100mmx36 (include active ripple power filter).
this last smps, support up to 2x10.000uF/63V at output.
Regards
I confirm for Monday upc collect package with deliver 2 days to Opc.
I include 2 smps (regulated/unregulated).
I sure that Opc try well and show measure of amplifiers with this smps,specially fft and thd Vs. frequency on amp. also fft at vcc output of smps with 100mA and 500mA.
Measures in this way, say all .
unregulated: dimension 100x100mmx36 (include active ripple power filter).
this last smps, support up to 2x10.000uF/63V at output.
Regards
You guys are a bit on the worried over nothing side of the power supplies. None of the SMPS that have been discussed have very high ripple or very high EMI. Remember that even normal power supplies can generate EMI. The diodes can act as nice little radio transmitters if they are chosen incorrectly.
And in an amplifier there have been various studies that seriously question the facility of regulated output on a power amp supply. Anecdotal evidence is there in leaps and bounds. But when you set things up in an intelligent fashion, provide enough supply reserve for current peaks you are not in any way shape or form running into trouble.
I have always liked amps that are true voltage sources. As in doubling the power in each halving of the load. There are limits to this in practice with the numbers of output devices provided. Hence the reasoning behind me asking for more output devices. ( Please! ) Current reserve is by far more important to keeping things linear when actually driving a dynamic load. Power supply fluctuation is directly related to the amount of current available. Remember that this amplifier is a voltage source. To keep the voltage constant you need current variation.
So sizing in my little world would be a 800 watt power supply for a 10 to 150 watt per channel amp. That will allow me headroom of nearly 3 db and power reserve for current peaks when the impedance drops. Drops are present in many speaker systems. All kinds of voodo is used in crossovers to extract extra oomph. I know a bit about this stuff. I consult part time for driver design and design speaker systems. This amp will be set up as a badly needed reference. Not really available in any commercial format costing less than a decent used automobile. I'm very happy to wait. Gives me time to finish up some projects and make the enclosures. I have a four channel almost done and I am planning the big boy enclosure.
I also have found a cannibalised enclosure for the wire pre-amp. Should be interesting!
And in an amplifier there have been various studies that seriously question the facility of regulated output on a power amp supply. Anecdotal evidence is there in leaps and bounds. But when you set things up in an intelligent fashion, provide enough supply reserve for current peaks you are not in any way shape or form running into trouble.
I have always liked amps that are true voltage sources. As in doubling the power in each halving of the load. There are limits to this in practice with the numbers of output devices provided. Hence the reasoning behind me asking for more output devices. ( Please! ) Current reserve is by far more important to keeping things linear when actually driving a dynamic load. Power supply fluctuation is directly related to the amount of current available. Remember that this amplifier is a voltage source. To keep the voltage constant you need current variation.
So sizing in my little world would be a 800 watt power supply for a 10 to 150 watt per channel amp. That will allow me headroom of nearly 3 db and power reserve for current peaks when the impedance drops. Drops are present in many speaker systems. All kinds of voodo is used in crossovers to extract extra oomph. I know a bit about this stuff. I consult part time for driver design and design speaker systems. This amp will be set up as a badly needed reference. Not really available in any commercial format costing less than a decent used automobile. I'm very happy to wait. Gives me time to finish up some projects and make the enclosures. I have a four channel almost done and I am planning the big boy enclosure.
I also have found a cannibalised enclosure for the wire pre-amp. Should be interesting!
well it seems we have the perfect test of your theory, as there are regulated and unregulated SMPS from AP2 on the way to opc. with 2 from the same manufacturer this should be good indication. Owen himself seems to believe that regulated will make a difference to the output and we've seen from the little power amp how good it can get with a regulated supply, so i guess we'll see.
my concern with having a switching frequency that is actually within the active bandwidth of my equipment should be obvious. you would have to be pretty irresponsible to get meaningful back EMF from the diodes in a linear supply, so i dont think thats particularly relevant here; possible? yes, likely? no not really
i'm watching with interest and if my concerns are proven to be misplaced, then i'll be a happy man, as long as it doesnt mean i'm lusting after a 4 channel psu that sets me back a grand
my concern with having a switching frequency that is actually within the active bandwidth of my equipment should be obvious. you would have to be pretty irresponsible to get meaningful back EMF from the diodes in a linear supply, so i dont think thats particularly relevant here; possible? yes, likely? no not really
i'm watching with interest and if my concerns are proven to be misplaced, then i'll be a happy man, as long as it doesnt mean i'm lusting after a 4 channel psu that sets me back a grand
I for one think this Mosfet delay could be useful as it will give Cristi a chance to have a new version of SMPS800R and AP2's Power supply the tested against a toroid.
As Mark says conventional power supplies are not immune to interference if not internally then externally via the toroidal transformer, input filtering is always required to stop refrigerator clicks and the like.
On the subject of the mosfet delay I have received an email from Farnell giving the expected delivery date of P ch mosfets W/C 2nd April 2012 this ties up with dates given to Owen.
John
As Mark says conventional power supplies are not immune to interference if not internally then externally via the toroidal transformer, input filtering is always required to stop refrigerator clicks and the like.
On the subject of the mosfet delay I have received an email from Farnell giving the expected delivery date of P ch mosfets W/C 2nd April 2012 this ties up with dates given to Owen.
John
not so much with balanced systems =)
but of course input filtering is needed, but my point is; what competent designer would leave it off?, the point is kinda moot as we arent fools here. there are caveats with both ways, but better the devil you know. i need to see results, very high frequency is not so simple to stop, but i will be actually very happy to try it out if given reason to
anyway enough of this back and forth about it, you are not going to convince me, or likely any other person waiting on the results with words. i will also have other very wide band DC coupled amplifiers nearby that might it cause problems for.
actually on that note opc: do you think you could test the output of the LPUHP placed nearby when you are doing this testing?
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Generally my systems are interconnected using un-balanced.
Generally I never hear any interference coming out of my speakers.
The one I have not tested is what happens when I use an arc welder in the attached workshop while the stereo is on.
I don't do anything special to achieve this silent state. Unless you count NOT using wireless anywhere in the house, except for my phone.
Generally I never hear any interference coming out of my speakers.
The one I have not tested is what happens when I use an arc welder in the attached workshop while the stereo is on.
I don't do anything special to achieve this silent state. Unless you count NOT using wireless anywhere in the house, except for my phone.
where do you live that not using wifi in the house means theres no wifi in the house?
Hey opc: has the AP2 switcher arrived yet? keen to check it out, even just pics
Hey opc: has the AP2 switcher arrived yet? keen to check it out, even just pics
I got a shipping confirmation from AP2 on Monday with a UPS number! Unfortunately, I don't think they will make it in time for this weekend's Ottawa audio show, so you guys might have to trust my judgment on this one 🙂
I'll let you guys know when the supplies arrive, and I'll post pictures right away. I'm really looking forward to testing these!
Cheers,
Owen
I'll let you guys know when the supplies arrive, and I'll post pictures right away. I'm really looking forward to testing these!
Cheers,
Owen
ok i'm camping right here.....
wow do you guys have a diy contingent at the ottowa audio fest? i misunderstood your diy meet thread as being completely non commercial
wow do you guys have a diy contingent at the ottowa audio fest? i misunderstood your diy meet thread as being completely non commercial
It is completely non-commercial... and I suppose the word "show" probably isn't the correct term. It's more of a DIY gathering.
Cheers,
Owen
Cheers,
Owen
Ah IC, thats actually much cooler anyway imo, i wish we could get something worth mentioning going here, we only have tiny gatherings or just show up with the 'masses' at the regional head-fi or audio meets with DIY gear.
ive been trying to encourage a more organized event here on a national level for a while, but it never seems to pick up. strange because we have such a strong showing here on DIYA for the size of the population. the same could be said of Canada i guess and you guys are similarly spread out across a large country.
have a great day, i'll pop in to check out the thread anyway, keen to hear some listening impressions of the LPUHP
ive been trying to encourage a more organized event here on a national level for a while, but it never seems to pick up. strange because we have such a strong showing here on DIYA for the size of the population. the same could be said of Canada i guess and you guys are similarly spread out across a large country.
have a great day, i'll pop in to check out the thread anyway, keen to hear some listening impressions of the LPUHP
It started with eleven guys. Last time we had close to three dozen. See what happens this weekend.