BillFitzmaurice.info

Bill Fitzmaurice wrote:

Charles Jenkinson wrote:'Eva' from diyaudio had this to say. Boy did I laugh.:

New class D amplifiers without heat-sinks are the most evolved (and evil) form of programmed obsolescence that I know. They are designed to fail after a few years (just out of warranty) due to thermal cycling, dust build up and corrosion. A fair engineer would never throw air directly at a PCB. This is easy money for a few ones today and lots of garbage and ruin for the planet and us tomorrow.

I recall much the same said 40 years ago, when transistors began to replace tubes. Google 'Luddite'.

I don’t fear modern technology, even though I’m convinced that Skynet will soon deploy Terminators to destroy the human race. I do however, fear modern manufacturer's marketing specifications.

Why won’t my XTI1000 drive a 250w driver at 8 ohms full range with the input signal correct and the attenuator open without clipping? My Com-techs and CTSs will.

Why does the Drive rack tell me to set attenuators at 55 percent when the XTI is selected without knowing my gain structure?

Why are there no engineering specs for any of the class D amps?

Why do amps with engineering specs cost 4 times as much?

Why did speaker manufactures invent a program power spec which is conveniently twice continuous and recommend an amp that matched program? (Please don’t quote manufacturers, I’ve read that)

I AM NOT bashing class D technology, I would just like to know what to expect when I buy one. If I can achieve a limiter voltage, I would like to be able to achieve it under load. I’m not too likely to leave my input signal at 1khz and say “sounds good doesn’t it?”

netwerks wrote: Yes you are correct? Any idea what max voltage swing is on a NU3000?

I get about 52V with 'no' limiting and 50V with -0.5dB limiting. I say no limiting as the limiter is set to 0dB, but from what I have seen, I think that the limiter does still engage when set to 0dB to protect the electronics... I may be wrong and I use the -0.5dB setting anyway just to be certain but from what I have seen the limit light still illuminates at the same point when on 0dB compared to -0.5dB. This is just my experience and may be totally wrong, but I thought I'd mention it.

There is an independent test of the amp at http://www.behringerdownload.de/_pdf/To ... _Rev.0.pdf which should tell you pretty well much what you need to know... They measured the amp at 50.33V but have a read of that article as it's very interesting for anyone considering class d.

escapemcp wrote:

netwerks wrote: Yes you are correct? Any idea what max voltage swing is on a NU3000?

There is an independent test of the amp atwhich should tell you pretty well much what you need to know...

They measured the amp at 50.33V but have a read of that article as it's very interesting for anyone considering class d.

http://www.behringerdownload.de/_pdf/To ... _Rev.0.pdf

Great article thank you for passing this along! Would be interested if anyone has run these for several hours "somewhat hard" @ 2 ohms for real world use.

netwerks wrote:Great article thank you for passing this along!

Thanks, not a problem... it's nice to add something to the great BFM knowledge pool, as I have been extracting from it for a while now!

Picked up an IPR3000 last week - ran my 4 Otop 12's on it (2 per side) plenty of headroom, clean sounding.
The Otop's gen so much volume with so little power that I cannot imagine pushing an IPR3000 into limiting.
(I would not want to be in the same county with something that loud)
Have not tried my 4 T39's on it though, but I'm not afraid to, perhaps next weekend- I've another outdoor gig.
I love the weight - or lack thereof. By this time next year I plan to have NO heavy amps in my racks.
As for switching mode Amps being less reliable, I don't buy that - there are a LOT of switching mode amps out there pushing ten+ years of daily operation.

Having tried several of the digital switchers, I have settled on Ashly. Became a dealer, although they're not on the site yet. They're a hybrid. They just sound better. I'm not a big one on hearing differences between amplifiers, but there's no doubt that they're just better. That little dab of old iron they left in there just gives them balls that the pure digitals don't seem to have.

Any particular models and price suggestions Leland? (for the US guys)

They're looking a bit rare and pricey in the UK at the mo.,(pricier than Matrix even!) without more digging.

I have to quote MAP publicly.
KLR2000 $599
KLR3200 $799
KLR4000 $1299
KLR5000 $1599

No, they aren't cheap. But they just sneer at 2 ohm loads. Running all out they never get warm. Most of the rest of Ashly's line is designed for commercial applications, running 24 hrs a day. Networked, all kinds of crazy amplifier configurations. That industrial design has obviously filtered into their prosound amps.

The KLR2000 has a list price of £660 in the UK. I already 'cheaped out' on an amp for the jacks by going Synq over Matrix. Now I'm in the market for a sub amp I can't see me going premium when a QSC GX5 is half the price. It's a lovely problem to have.

All this chat about the new amps made me so curious I had to go and get one. Found an ipr1600dsp on ebay that I offered $275 for.
Dropped the XTi2000 as my backup, and the XTi1000 is now up for sale

The DSP is certainly more limited, but it will do everything that I need it to do. I don't notice anything musically different running a single OT12 and T39 WOT, but the 10-pound drop is noticeable in the rack.

Seeing that my iNuke amp is still pretty new, I will be running it in a few weeks into a 2ohm load (4xlab12s in tubas) for about 12 hours and using a 2.6KVa (continuous) generator to power it. If it survives that then I'm happy... If it doesn't, I still got my warranty . Best to test whilst I still have my get out of jail free card that is the guarantee! The only issue with this test is that I won't have channel 2 loaded with much, so only half of the amp will really be tested and I won't be putting a massive load on the PSU. :/

So how did it perform?