Class D "digital" amps. Opinions on performance

[JimmyM]

Well one of the guys whom I've talked with about them in depth with is not a fan of heavy lifting and hates to move anything he doesn't have to move. He's also the best soundman I ever worked with, bar none. So if anything, he'd be more inclined to say, "Yeah, they're totally awesome and blow away those lead sleds in every way."

 

[R Baer]

What God help us. Virtually every major front of house system and top of the line DJ system is powered by class D/SMPS amps these days.

A lot of this has to do with the fact that these sound companies have to transport and install the gear. Heavier amps means more fuel in the truck and more labor at the sight. From the touring sound men I know, none of them has ever mentioned they use Class D because they prefer the sound. Not saying anything against the class D amps, it's just my opinion that touring companies find the other benefits are the driving force behind their decision to use them.

 

[xk49w]

From the touring sound men I know, none of them has ever mentioned they use Class D because they prefer the sound.

On the flip side, have you heard any of them say they don't use Class D because they dislike the sound?

 

[David Jayne]

Well one of the guys whom I've talked with about them in depth with is not a fan of heavy lifting .....

Ok but as you said, he's in the minority.

 

[KJung]

A lot of this has to do with the fact that these sound companies have to transport and install the gear. Heavier amps means more fuel in the truck and more labor at the sight. From the touring sound men I know, none of them has ever mentioned they use Class D because they prefer the sound. Not saying anything against the class D amps, it's just my opinion that touring companies find the other benefits are the driving force behind their decision to use them.

+1 in that no one in their right mind would carry a heavy power amp that has no sonic benefit over a lighter one. I don't think ANYONE would say a certain class of amp 'sounds better than another'. I've never heard that either. +1 Same performance, lighter weight... no brainer.

 

[KJung]

Well one of the guys whom I've talked with about them in depth with is not a fan of heavy lifting and hates to move anything he doesn't have to move. He's also the best soundman I ever worked with, bar none. So if anything, he'd be more inclined to say, "Yeah, they're totally awesome and blow away those lead sleds in every way."

Again, no one is saying class D amps, or class A/B amps driven by SMPS sound 'better'. Clean, transparent power is clean, transparent power, regardless of the topology.

 

[HolmeBass]

So if SMPS amps sound "the same" as amps with more traditional power supplies, then because they are lighter they are better, right?

 

[bryanspkr]

class d works great for bass as high end isn't critical. Theres a reason you don't see it a lot in hifi

HYPEX
B&O (Supplier to other companies too)
There are others.

 

[KJung]

So if SMPS amps sound "the same" as amps with more traditional power supplies, then because they are lighter they are better, right?

Exactly. That is why they dominate the market. There is a price premium, but that is even going away now. It is a wonderful world at the moment for bassists and front of house/PA users.

 

[fdeck]

So if SMPS amps sound "the same" as amps with more traditional power supplies, then because they are lighter they are better, right?

In a nutshell, yes. Because switchmode gear still tends to cost a bit more, there has to be a motivation to use it. That motivation could include one of:

1. It sounds just as good or better, and is more portable

2. It sounds almost as good but the weight reduction makes it worthwhile

One could decide on the sound quality issue in a couple of ways. For some of us, an expectation of equivalent audio quality based on knowing how amps work is good enough to go with. Others will prefer to conduct a careful listening test. Because a lot of things affect the perception of tone quality (including psychological bias), reports from listening tests will always be controversial. When it gets down to actual real-world bass gear, very little true apples-to-apples testing has ever occurred.

And the heavier gear will always remain on the market.

 

[bryanspkr]

I've talked to a lot of soundmen about them, and the majority seem to agree that they do work well and make roadwork a lot easier, but I hear the same thing out of a lot of them that I hear out of many bass players...if you're used to a certain amount of wattage in a lead sled, you will want to overbuy class D wattage to have that level of headroom. I've also heard from a handful of holdouts that they don't like the sound of class D power amps. With all due respect to Bob and the other folks who build power amps, these guys hear differences enough to hold onto their lead sleds and put up with the schlep. Granted, they're not doing arenas usually, and that would likely change their minds, but I think there's enough testimony out there from soundmen to believe there's something to it. Not a single one complains about neos, though

There is almost always a "what we already know and what we are used to bias" in confronting something different.
This is very common when someone is trying a new musical instrument. Change of habit and perception sometimes does not come easy, and makes us uncomfortable.

BTW, Neos are another story. Not a blanket one though.
Thats another thread maybe....

 

[bryanspkr]

A very succinct lecture and a very clear thinker. Enjoyable reading:
Invalid Link Removed

 

[JimmyM]

Again, no one is saying class D amps, or class A/B amps driven by SMPS sound 'better'. Clean, transparent power is clean, transparent power, regardless of the topology.

I'd be inclined to agree if this pesky business about the differences didn't keep cropping up.

 

[Bob Lee (QSC)]

A very succinct lecture and a very clear thinker. Enjoyable reading:
Invalid Link Removed

I remember that lecture was offered at the convention in Vienna. I wanted to attend that session but there was a committee meeting I had to attend. Thanks for posting the link!

 

[Bob Lee (QSC)]

Again, no one is saying class D amps, or class A/B amps driven by SMPS sound 'better'. Clean, transparent power is clean, transparent power, regardless of the topology.

+1012​

 

[bryanspkr]

My pleasure.

 

[bryanspkr]

I remember that lecture was offered at the convention in Vienna. I wanted to attend that session but there was a committee meeting I had to attend. Thanks for posting the link!

OOPS! forgot to quote.

My Pleasure!!

 

[HolmeBass]

Anecdotal experience: I used an Eden Metro for years. A very nice amp by most accounts, with a traditional A/B topology and a toroidal power supply (which was later discontinued). It sounds great.

I got the Eden WTX-260 and I like it's sound too, although the pre-amp has some circuit that "warms up" the input quite a bit. It's not quite a natural sound, but works very well, especially at lower volumes. It is a class D amp.

Then I bought a Genz Benz SM 9.2, also class D. This amp sounds every bit as good as the Eden Metro, perhaps even better. At moderately high volumes and louder the 3DPM (IIRC) power amp technology gives a tiny bit of the feel, give and bloom of an all tube amp. Just a hint of that, which I really like. It sounds pretty rotund in my opinion, and actually better than the Eden Metro!

 

[R Baer]

On the flip side, have you heard any of them say they don't use Class D because they dislike the sound?

I know plenty of engineers who claim class D doesn't sound as good ... I also know plenty that claim they do sound as good. What sounds better, a jazz bass or a P bass?

 

[David Jayne]

A P bass, obviously.