Class D: Turns Out it Does Suck!

[Panelhead]

  I would guess the top waveform is from a Class D amp. Also the modulator runs at 400Khz in that amplifier. 

  Hope I am wrong.

[Panelhead]

2 hours ago, pawsman said:

I picked up a Crown XLS 2500 on closeout for $299; it's the best buy I've ever made in my many years in this Hobby.

I drive a pair of Selah Audio ported Veritas (5 ohm/83db sensitivity) and have no problem achieving SPLs as loud and dynamic as I'd ever want to hear (with mainly classical music). At a weight of 10.5 Lbs., it puts out  440/775/1200 wpc into 8/4/2 ohms; it's has almost unbelievable power for such a small amplifier. The highs ARE slightly different than other (Class A/B) amps that I've owned; I'd describe the highs as better damped and more accurate that the other amps, but still with plenty of extension and air. Many Class A/B amplifiers I've heard have a slight sheen/resonance/brightness  in the highs (crossover distortion?) that I don't hear with the Crown-

 

pawsman

  I read several posts where people bragged on the XLS. When I found a XLS-1500 for less than 200.00 with shipping I pounced on it. 

  Did a little more reading and it seemed the sweet spot in the product line was considered to be the XLS-2000. Paralleled output devices, twice the filter capacitance. Like the 2500, just lower voltage rails. 

  Was using either a MP Evolution Full or MP Evolution Rev A to drive anything from a B&W 801 to Lowthers. 

  The sound was a little thin with the 1500, better with the 2000. Did a little work on the linear power supply in both. This cleaned up the presentation some. 

  What have noticed is the lack of sonic signature. Poor recordings sound poor. Good recordings sound better. 

  Small changes in playback, whether upsampling red book to 88.2, 96, 176.4, or 192k are clearly audible now. Same with converting ISO files to 88.2 or 96k. 

  This should not occur, I think the DriveCore operates at 48k. But it is transparent enough to hear differences in higher sampling and the filtering used.

  I am very happy with my two XLS amps. One tip, only use the balanced inputs. The complaints about noise level and turning the input attenuators to 11 - 1 o'clock to reduce noise all come from users with single ended sources. 

  I think the amp puts out a lot of noise that single ended cabling picks up. Using balanced cabling rejects this noise.

  I purchased the first one because I had sold all my amps with balanced inputs. Every Dac/pre I own has balanced outputs.

  Are these the best amps I have heard, no. Best amps I own, no. Best two amps purchased for 500.00 delivered with warranties. YES. Better than I can build myself with 500.00 in parts, easily.

  Being a switching amp with a linear supply does not limit the sonics. Class D does not suck, just different. Tripath does suck.

  I think Crown could do better if they built at a higher price point.

[Panelhead]

21 minutes ago, GUTB said:

Since you guys are talking about these Crown amps, let's take a look inside:

 

 

Compared to an NC1200:

 

 

It's widely accepted that nCore is at the top of the class D game. If even nCore modules are unable to impress at the high end, how much can we really expect out of a $300 amp using a generic / unknown class D circuit?

  I am biased. Own a Crown, never built one of Bruno's designs. But to compare the two take a picture side by side. 

  The pictures make the 8.6 lb XLS-1500 look like a toy. But it is twice as large as the nCore amplifier. The pic makes the two metal oxide power resistors look huge in the nCore amp. 

  I would like to hear Bruno's latest work. Convinced it is top notch.