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Old 20th February 2013, 04:08 PM   #41
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Why on earth would you want to remove the output filter in a high power class D amplifier? Apart from being potentially hazardous to your loudspeakers the amplifier would then probably start violating a handful of EMI laws too. Not recommended.
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Old 20th February 2013, 04:13 PM   #42
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The big music stores often run 20% off specials to make margins. I got a 6000dsp for $399 last year over the phone.
The processing on this product is where the value is IMO...

And why on earth would you not put a near silent $10 fan in it? I have a Crown XLS that I use in the studio/workshop but with the fan swap you can have a quiet iNuke that won't thermal on you.

Last edited by mr. doom; 20th February 2013 at 04:20 PM.
 
Old 20th February 2013, 04:49 PM   #43
abcdmku is offline abcdmku  United States
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That's a little different than I was thinking it looked like Soldermizer, doesn't that scratch the top?

I got my iNuke3000DSP with a 50' Speakon to Speakon, 25' Speakon to 1/4", 20' 1/4" to 1/4", and a 10' Speakon to 1/4". All wires are Hosa, and the price was $399 with $14 shipping. Well worth it, it wasnt used, it was new. Sadly that deal is no longer on ebay. But there is one that includes:
iNuke3000DSP
1x "2U Shallow "X" Rack Case"
2x "Speakon to 1/4" Cables"

It doesn't say how long the wires are, but from the picture they look about 25'. Costs $399 and free shipping

Click the image to open in full size.
 
Old 20th February 2013, 09:50 PM   #44
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5th Element: " Why on earth would you want to remove the output filter in a high power class D amplifier?"

Because I like to experiment, thinking it might improve the sound. One of many of my failed experiments

some are successful (like the fan-ectomy on the NU3000), most probably have no perciptible change, some can be undone (or seemingly!), and some result in an instant "keep for spare parts" object !!!

"Apart from being potentially hazardous to your loudspeakers..."
You would mourn the death of a Bose 901 ????

"... the amplifier would then probably start violating a handful of EMI laws too. Not recommended." If I want to turn my amp into a radio transmitter, that is my perogative But seriously, you are right ... lesson learned the hard way.

Mr. Doom, you did very well if you got a 6000DSP for $400! Good on ya! Since my evil mods do not always work, I may grudingly try a near-quiet fan just for fun. Being a frequent ebay-er, I am somewhat the authority on prices of these and when I first got my NU3000(s) about a year ago, I probably would have gladly paid $500 for a NU6000. Yours must have been radioactive (it IS an "iNuke", after all )or have some other horrible hidden fault, at that good price

Abcdmku, yes a 30 lb (?) concrete block probably will scratch the top, but it's a f*****g* BEHRINGER, for crying out loud!!! A few scratches on it are not going to drop its value much when I sell it.

*I am not permitted to cuss apparently. You can probably figure out this one! But even w**** was bleeped, even though it is a perfectly good word for "prostitute" or as I intended it, more a client of such provider of services.
 
Old 21st February 2013, 04:43 AM   #45
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News flash! Additional soldermizing and the NU3000 has been resurrected...at least for now. I could not get a short across the inductor so I remote mounted it (two leads into the PCB). Now reading a short where I should...we have sound on Channel A. Now where to mount the loose inductor?

-- Soldermizer, turning well-designed electronics into breadboard-looking devices since 1972.
 
Old 21st February 2013, 05:30 PM   #46
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Quote:
Originally Posted by Soldermizer View Post
Cats are enjoying outside time right now. Besides, just got home and the masonary needs to warm up

Here is a photo. As you can see, a rodent is subbing for a cat. I doubt the cat would cause over-heat, however, the towel could restrict airflow if draped over the edges. The whole idea of this exercise was to allow the amp's waste heat to heat the concrete paver (approx. 20x20x2 inches).

I was listening to some "trance" music and got a thermal even at not apparently too loud volume. This is not the first time, and not unusual (although it was on the amp that I "experimented upon" and I sometimes worry that my half-assed resoldering is failing.)

I just got an incredibly simple evil idea worthy of the Grinch when he figures out his reindeer substitute
What if I put the fan back in the amp, and had a switch for it? If I need to blast music, I have the fan running. If I need quiet, turn off the fan. Experience has shown that the thermal protection works ok. Best of both worlds?

Seriously, you're going wreak the amps running them without a cooling fan. BAD IDEA. The paver is only inhibiting cooling further vs. just having air naturally circulating above them. Please, please, put a fan in. These are delicate amps that are not built with the intention that their components will be operated for any long period at above 50C or so:


Behringer inuke NU6000 vs KAM KXD7200 bench tested - Speakerplans.com Forums - Page 2

My friends already blew out a nu1000dsp in their rec room by running it in clipping (red lights on solid) for a while on several occasions and had to upgrade to a nu3000dsp. After a long talk with them and a second opinion, they are trying to keep the new one out of the red.
 
Old 21st February 2013, 06:17 PM   #47
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I've had a nu6000dsp for about 3 months now, haven't used it that much but have had it up to about 50% output and it seems to be solid.

Have recently been trying to figure out the real power supply requirements, it is fused for 24A per the manual, is nominally a ~650w draw at 1/8th power, and draws big current spikes per the review linked above. I think what it comes down to is if you were to run some test tones at on both channels at about 2x1200w rms or greater, you would probably blow the fuse in short order, but not trip a typical 15a breaker, due to the trip characteristics of a breaker:

(x-scale is multiples of rated current)

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Old 21st February 2013, 09:41 PM   #48
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Default heat rises, s##t floats, coincidence?

Turbodawg: your concern is welcome. However, I willingly took the risk to run fanless. Originally I ran my "mod" with out the top on, with the idea like you, that it would give maximum convection. Later (partly for safety reasons) i put the cover back on. The amp seemed just as happy. Note that air can enter from the front as well as the fan hole in the rear. Warm air does what? It rises, and heats the cover. I see no difference if I have a concrete block on top of amp(s) ... the cool air still enters at the bottom (unobstructed) and still rises. Unless the laws of physics have changed, I see no problem with my "cat warmer." It may shorten the life of components, but my NU3000 has suffered most from my unwise mods beyond just removing the fan.
 
Old 21st February 2013, 10:14 PM   #49
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Originally Posted by Soldermizer View Post
Turbodawg: your concern is welcome. However, I willingly took the risk to run fanless. Originally I ran my "mod" with out the top on, with the idea like you, that it would give maximum convection. Later (partly for safety reasons) i put the cover back on. The amp seemed just as happy. Note that air can enter from the front as well as the fan hole in the rear. Warm air does what? It rises, and heats the cover. I see no difference if I have a concrete block on top of amp(s) ... the cool air still enters at the bottom (unobstructed) and still rises. Unless the laws of physics have changed, I see no problem with my "cat warmer." It may shorten the life of components, but my NU3000 has suffered most from my unwise mods beyond just removing the fan.
The concrete will act as an insulator, preventing normal air convection outside the unit against the top cover, having a large block on top of the amp will absorb that heat and is much less effective. If you want to put that block to good use, place it on top of your subs.

Have you every taken any courses in thermodynamics or heat transfer, or have any real world training?

The best way to cool this without a fan is tip it on end so there is air flow from bottom to top.

But just so everyone is clear: SOLDERMIZER'S MOD'S ARE A BAD IDEA OR A TROLL.

Last edited by turbodawg; 21st February 2013 at 10:19 PM.
 
Old 22nd February 2013, 12:48 AM   #50
gmarsh is online now gmarsh  Canada
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Speaking both as an amateur radio operator, and as someone that has designed radio broadcast transmitters and worked extensively with RF engineering and EMI compliance...

DO NOT REMOVE THE OUTPUT FILTER FROM A CLASS D AMPLIFIER. EVER.

Class D amps have fast edge rates coming out of their output stage - the frequency content of these signals have harmonics that go well up past 10MHz. Now feed them into a speaker cable which could be tens of feet long and could potentially make a great antenna. Boom, you've just created a radio transmitter.

What's it broadcasting over? Probably lots of things. NDB radio beacons that aircraft use to find airports, HF radio communication channels used by long range aircraft to communicate with radio traffic controllers, ham radio operators using the HF band, maritime mobile, and others. Go download the radio frequency allocation chart for your country and read it up to 20MHz, you'll probably find there's a dozen or more things you could interfere with.

And when companies/agencies get interfered with, they call the FCC or its equivalent in your country. Industry Canada here have fantastic radio location gear and a lot of well trained people. If a navigational band gets interfered with, they can potentially be at your house within hours, and I imagine most other governments have equally capable agencies. You'll get your equipment seized, and potentially several thousand dollars worth of fines. That's standard. But in a post 9/11 world, if you manage to interfere with an aircraft transmission and homeland security gets involved... things could be much worse.

In conclusion, DO NOT REMOVE THE OUTPUT FILTER FROM A CLASS D AMPLIFIER. EVER.

"but filterless amps exist, it can't be that bad!"

Yeah, and you'll find out that they stop at the tens of watts, use class BD or sigma delta switching, have slower edge rates and lower efficiency as a result, still require ferrites, and tell you not to use speaker wire lengths over a few inches. Thinking that an iNuke or similar amplifier falls in the same category is utter lunacy.

"But it sounds better!"

Throw out the old output filter inductors, and wind new inductors with litz wire on decent inductor cores. Maybe even replace the output capacitors with good film caps. It might make things sound just as good. If it doesn't, buy a better amp.

End of rant. Thanks.
 

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