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There's a new sheriff in town! Inuke DSP 12000 - Page 6

post #151 of 355
Looking at a previous post (#104)..is the "purple line" input current? From the link it appears so. If so...sorry, UGH! I haven't made a power supply that way since the late 90's. Is there a reason they aren't doing PFC with a a twinge of feed forward compensation? Maybe i'm off, but all my designs 100kW+ for power conversion. I just wouldn't do this. Even for my 100W supplies...I don't do this any more. I just got tired of the dealing with constant battle of inductor/capacitor balancing. I will say one thing about passive rectifiers....they are fast at transients which allows you to cheap out on the C. However, it sure jacks the hell out of the voltages in your house and what is present to your equipment.

post #152 of 355
If anyone has further questions on the inuke 12000 or other Behringer products this is a good thread at www.prosoundweb.com where Uli Behringer answers questions directly on a weekly basis. Here is the link: http://soundforums.net/varsity/4299-uli-behringer-music-group-q.html
post #153 of 355
"Is there a reason they aren't doing PFC..."

it is surprisingly uncommon among many pro amps...

i've actually never it tested either...

amp a with pfc vs. amp b without, same in all other respects.

would anybody notice the difference or is it all "academic"?
Edited by LTD02 - 10/4/13 at 5:03am
post #154 of 355
Quote:
Originally Posted by LTD02 View Post

"Is there a reason they aren't doing PFC..."

it is surprisingly uncommon among many pro amps...

i've actually never it tested either...

amp a with pfc vs. amp b without, same in all other respects.

would anybody notice the difference or is it all "academic"?

Definitely NOT academic. If you look at the input currents they are visibly different which can definitely affect peak currents drawn. Most breakers can handle whacks but remember their curves are not linear (usually a function I^2*t). Therefore the bigger the peak the lower overall power you can pull from a breaker.

Now, doing a PFC rectifier is easy. Any engineer with few years experience can do it. The same goes for a class D amp. However, to have the two work together is a more interesting exercise where you really want a guy with a controls background to deal with it and not a typical sparky. Are the issues insurmountable? NO! Will they bite you hard in the ass if you ignore them? Hell yes. Furthermore it does add a bit of cost.

Here is what I don't know. Are they doing PFC, but not to the letter of the "technical law" which is why they can't claim credit? That would be really interesting to know.
post #155 of 355
"If you look at the input currents they are visibly different which can definitely affect peak currents drawn. Most breakers can handle whacks but remember their curves are not linear (usually a function I^2*t). Therefore the bigger the peak the lower overall power you can pull from a breaker."

i get that, but breakers are designed for short duration overcurrent anyway. if folks were blowing breakers all over the place, we'd probably see more pfc. that is what I meant by academic. the theory is solid, it's just that maybe it doesn't matter in practice for the lower end pro amp class.
post #156 of 355
Quote:
Originally Posted by LTD02 View Post

"If you look at the input currents they are visibly different which can definitely affect peak currents drawn. Most breakers can handle whacks but remember their curves are not linear (usually a function I^2*t). Therefore the bigger the peak the lower overall power you can pull from a breaker."

i get that, but breakers are designed for short duration overcurrent anyway. if folks were blowing breakers all over the place, we'd probably see more pfc. that is what I meant by academic. the theory is solid, it's just that maybe it doesn't matter in practice for the lower end pro amp class.

I believe you are 100% correct but I don't think it is academic. My guess the reason we aren't seeing it is because most people probably never push their amps that hard anyways. You buy a 5kW amp..how often would the vast majority of people "get to that point"? However people like Pob and BTH who do "push their amps" have found out it was fairly easy to pop a breaker during a "spirited session". If PFC would have been in place, they may not have needed as many dedicated breakers or as high powered.

But at the end of the day, the only things that matters are "does it work" and "are you satisfied".
post #157 of 355
This coming from a guy with little amp knowledge, me, is it safe to say this isn't an issue for 99.9% of people that will rarely if ever drive their amps to full output capacity? I am going to go back through this thread and read it again to see if I am missing something. I don't have plans to buy the 12K, but if it is available and tested before I am ready to buy and will be a good fit I will add it to the list. smile.gif
post #158 of 355
Quote:
Originally Posted by Trepidati0n View Post

Quote:
Originally Posted by LTD02 View Post

"If you look at the input currents they are visibly different which can definitely affect peak currents drawn. Most breakers can handle whacks but remember their curves are not linear (usually a function I^2*t). Therefore the bigger the peak the lower overall power you can pull from a breaker."

i get that, but breakers are designed for short duration overcurrent anyway. if folks were blowing breakers all over the place, we'd probably see more pfc. that is what I meant by academic. the theory is solid, it's just that maybe it doesn't matter in practice for the lower end pro amp class.

I believe you are 100% correct but I don't think it is academic. My guess the reason we aren't seeing it is because most people probably never push their amps that hard anyways. You buy a 5kW amp..how often would the vast majority of people "get to that point"? However people like Pob and BTH who do "push their amps" have found out it was fairly easy to pop a breaker during a "spirited session". If PFC would have been in place, they may not have needed as many dedicated breakers or as high powered.

But at the end of the day, the only things that matters are "does it work" and "are you satisfied".

What a lot of people don't realize is the fact that audio power amps can't be driven to high average power levels with music being delivered to speakers as they can be with pure sine waves being delivered to resistive loads. The difference is an absolute minimum of 3 dB (half power), and can easily be 6-20 dB (quarter power to 1/100th power) or more. This presumes that you push the amp to just under clipping, which is yet another thing that happens rarely if ever. Lots of people have observed that a their big amps don't need their cooling fans in noarmal use, or that their amps with thermostatic fan controls never actually spin up their fans.
post #159 of 355
Quote:
Originally Posted by brian6751 View Post

I don't see how the 6000 needs a 25 amp circuit when Berry told me the ep4k only draws 5 amps with its old iron psw. I bet if you emailed them and asked it would be much less than a 25 amp circuit needed

I would suspect most people are running them on a 20A without problems and probably more than one on the same circuit.
post #160 of 355
"What a lot of people don't realize is the fact that audio power amps can't be driven to high average power levels with music being delivered to speakers as they can be with pure sine waves being delivered to resistive loads."

one caveat back is one that I've mentioned a few times...sealed subs do begin to go resistive as you head toward single digits and to a lesser extent ported cabs on their tuning frequency...can occasionally be hit with sine-wave-like max level computer generated effects.
post #161 of 355
"This coming from a guy with little amp knowledge, me, is it safe to say this isn't an issue for 99.9% of people that will rarely if ever drive their amps to full output capacity? I am going to go back through this thread and read it again to see if I am missing something."

voltage. all the time.

current, not so much.

power at the wall...hardly ever.

if you have a copy of winisd, model up any subwoofer and look at the apparent power tab. try to get a feel for what is going on on that page and a whole bunch of clarity will be achieved.
post #162 of 355
I will give it another shot. I have had no luck with the previous versions.
post #163 of 355
are you on windows 7, xp, or something else?
post #164 of 355
My old machine that I tried it on initially ran Vista. It has since died. The current OS is Windows7. I could enter new drivers just fine, but when I tried to move to a different tab the program froze and I had to use the Task Manager to kill it.
post #165 of 355
ah! problem solvable me thinks.

https://www.facebook.com/WinISD

the xp version blew up on me on windows 7 too. I liked that version more, but the windows 7 version works just fine and it is stable. you can copy the driver file too. no need to re-enter anything.
post #166 of 355
Quote:
Originally Posted by filtor1 View Post

My old machine that I tried it on initially ran Vista. It has since died. The current OS is Windows7. I could enter new drivers just fine, but when I tried to move to a different tab the program froze and I had to use the Task Manager to kill it.

Try running it compatibility mode, ala XP SP2.
post #167 of 355
Quote:
Originally Posted by LTD02 View Post

if you have a copy of winisd, model up any subwoofer and look at the apparent power tab. try to get a feel for what is going on on that page and a whole bunch of clarity will be achieved.

Not sure how on point that is, as it gives no insight into the effect of crest factor being discussed.
post #168 of 355
"Not sure how on point that is, as it gives no insight into the effect of crest factor being discussed."

maybe you don't know what the point is? :-)~ or maybe i wan't clear what my point was. :-(

in post 151, trep pointed out the high peak current from the behringer amp test. that is a resistive load test with sine waves. the conversation turned to "test power" vs. "actual power".

one thing that will reduce actual power is the crest factor, which was mentioned. typical music has a crest factor such that without a ton of clipping average power is about 1/8 to 1/4 of sine wave power.

another thing that will reduce actual power is the large difference between an actual speaker load where current varies by frequency and a purely resistive load which is what is used typically in amp testing. that effect can reduce power by even more than 1/8 to 1/4 of sine wave power into a test resistor depending on frequency.
post #169 of 355
Quote:
Originally Posted by LTD02 View Post

"What a lot of people don't realize is the fact that audio power amps can't be driven to high average power levels with music being delivered to speakers as they can be with pure sine waves being delivered to resistive loads."

one caveat back is one that I've mentioned a few times...sealed subs do begin to go resistive as you head toward single digits and to a lesser extent ported cabs on their tuning frequency...can occasionally be hit with sine-wave-like max level computer generated effects.

Agreed with the caveat that I prefer systems that have a huge roll off right below their designed-in bass extension limit.
post #170 of 355
"Agreed with the caveat that I prefer systems that have a huge roll off right below their designed-in bass extension limit."

where would you put that point for a highly capable sealed subwoofer system?
post #171 of 355
Quote:
Originally Posted by LTD02 View Post

"This coming from a guy with little amp knowledge, me, is it safe to say this isn't an issue for 99.9% of people that will rarely if ever drive their amps to full output capacity? I am going to go back through this thread and read it again to see if I am missing something."

voltage. all the time.

current, not so much.

power at the wall...hardly ever.

if you have a copy of winisd, model up any subwoofer and look at the apparent power tab. try to get a feel for what is going on on that page and a whole bunch of clarity will be achieved.

+1
post #172 of 355
Quote:
Originally Posted by LTD02 View Post

"Agreed with the caveat that I prefer systems that have a huge roll off right below their designed-in bass extension limit."

where would you put that point for a highly capable sealed subwoofer system?

Below the design frequency. My approach is to pick a number from this list:

I think that systems that systems that are nice and smooth but only go down to 120 Hz can be nice for casual listening, in an office for example. Speakers like the NHT Superzero have many fans for this reason.

60 Hz is where something like IMO high fidelity begins.

(Approximate numbers)

43 Hz is the lowest string on a 4 string bass guitar.

32 Hz is the lowest string on a 5 string bass, and most large but not huge pipe organs. This is about as far as even really large floorstanding speakers go.

20 Hz is usually given as the lower limit of the audio band

16 Hz is the lowest pipe on the largest pipe organs

below that you are into EFX.

and then design a system to match the given cut-off with the big roll off just below the system design frequency.
post #173 of 355
"below that you are into EFX."

that's the thing...most folks around here want those efx.
post #174 of 355
Quote:
Originally Posted by LTD02 View Post

"Not sure how on point that is, as it gives no insight into the effect of crest factor being discussed."

maybe you don't know what the point is? :-)~ or maybe i wan't clear what my point was. :-(

He said "This coming from a guy with little amp knowledge, me, is it safe to say this isn't an issue for 99.9% of people that will rarely if ever drive their amps to full output capacity?"

IMO crest factor is 90% of the answer to his question, with apparent power a much less important modifier.
post #175 of 355
Thanks for the link, most interesting.

I have to say my opinion of Behringer is much higher now.
Quote:
Originally Posted by Swolephile View Post

If anyone has further questions on the inuke 12000 or other Behringer products this is a good thread at www.prosoundweb.com where Uli Behringer answers questions directly on a weekly basis. Here is the link: http://soundforums.net/varsity/4299-uli-behringer-music-group-q.html
post #176 of 355
"IMO crest factor is 90% of the answer to his question, with apparent power a much less important modifier."

that's fine. however, depending on the content, apparent power can reduce current demand by 50-75%, so both effects are large and significant.

"I have to say my opinion of Behringer is much higher now."

+1. goes a long way to explaining how in a relatively short period of time behringer has become such a force with such large market share.
post #177 of 355
Quote:
Originally Posted by LTD02 View Post

however, depending on the content, apparent power can reduce current demand by 50-75%, so both effects are large and significant."

That's only 3 - 6 dB; I've seen many mentions of crest factors of 24 dB - 64X more power than 6 dB.

"I have to say my opinion of Behringer is much higher now."
Quote:
Originally Posted by LTD02 View Post

+1. goes a long way to explaining how in a relatively short period of time behringer has become such a force with such large market share.

I've been reading more of it; contrary to my assumption that they copied Peavey's ipr technology, they went their own way after buying patents for other class D technology.
post #178 of 355
i was trying to be polite (well as least argumentative as i can be :-)), if you hit it around the impedance peak it can be 8-10db and a lot of electronic bass hits that push the limit can have crest factors of less than 6db, so it really depends how you want to construe it.
post #179 of 355
the impedance peak results in lower power requirement
post #180 of 355
Quote:
Originally Posted by LTD02 View Post

"below that you are into EFX."

that's the thing...most folks around here want those efx.

Not knocknig EFX, just calling a spade a spade.

Since EFX generally have no real world sonic equivalent, they are what they are.
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