Class D Amps

[JimmyM]

Everyone knew exactly what I meant when I said "topology." Aborgman's post was the equivalent of poking me with a stick.

 

[Bob Lee (QSC)]

Probably just better to not think about topology at all. Doesn't matter. Every amp is different. If you prefer an SVT and I prefer a Glockenklang Blue Soul, who cares why.

The important point is for people not to eliminate entire classes of equipment based on oversimplistic reason (i.e., I will only consider a heavy amp, I will only consider a hybrid, I will only consider all solid state, I will only consider all tube, etc., etc.).

Decide on the features you want and try to play or at least read about every amp that is a possibility. Then, pick the one you dig. If it happens to weigh 100 pounds, cool (kind of), if it happens to weight 3 pounds, cool.

It is a bad mistake IMO for a potential buyer to eliminate a piece of equipment based on one feature that may or may not explain the tonality of that piece of gear (neck through versus bolt on, ash versus alder, tubes versus solid state, hybrid versus pure solid state, all tube versus not all tube, etc., etc.

Well said!

 

[wcriley]

I don't have the experience with equipment others have. And I don't have golden ears. That said...

I used a G-K 1001RB-II for several years. Didn't know it was class G until after I bought it. I bought it for the features/power/price.
I recently replaced it with a Genz-Benz Shuttlemax 9.2. Same price as the G-K (both bought new). Roughly equivalent power. Completely different feature set, which is why I bought it. The "class" didn't enter into my decision. No difference in "sound" or "response" that I can attribute strictly to the type of power supply or output device/class.

I've had a QSC PLX 1600 in my PA rack for several years. Again didn't know (or care) about it being class G. Bought for the features/power/price.
Added a Peavey IPR 1600 to the rack a couple years ago. Same price (both bought used). Same rated power. Completely different feature set. The weight was a main part of my buying decision. No difference in "sound" or "response" that I can attribute to the type of power supply or output device/class.

It's possible that I don't find any difference because I don't make a habit of pushing any of the above gear to its limits.

 

[aborgman]

OK, so all amps have output tubes and an output transformer?

Ummm... amp topology/class has nothing at all to do with the output device.

You can build a class A, class AB, or class D amp using tubes.

You can build a class A, class AB, or class D amp using solid state.


Here is the patent for the first class D amplifier - using 12AT7. 12AU7, and a pair of 6293 power tubes. Not a solid state device in it.

http://www.google.com/patents/US3011025

Boy, way to get hung up on words.

If you're going to argue that amplifier class/topology is a defining characteristic - it helps if you're actually talking about amplifier class/topology.

 

[Bob Lee (QSC)]

I've had a QSC PLX 1600 in my PA rack for several years. Again didn't know (or care) about it being class G.

If you mean PLX1602, that's a class AB amp. Not that it really matters!

 

[wcriley]

Yep. I meant to type "1602".
I always thought it was class G. Shows how much I know...or care.

 

[Mr. Foxen]

What was class G? I'm sure the Crate Power block used to be described as class G, but now it says D.

 

[Chef]

I've had amps of many types.
I've liked some.
I've not liked others.

I'll never understand why any discussion/point of view here is important enough to anyone to feel like it's worth having a crummy attitude over.

If you can't make your points politely, you can permanently dodge irritating users with the ignore feature; or, you can go find many thousands of other threads to go poke around in.

 

[DrumsAndBass]

Probably just better to not think about topology at all. Doesn't matter. Every amp is different. If you prefer an SVT and I prefer a Glockenklang Blue Soul, who cares why.

The important point is for people not to eliminate entire classes of equipment based on oversimplistic reason (i.e., I will only consider a heavy amp, I will only consider a hybrid, I will only consider all solid state, I will only consider all tube, etc., etc.).

Decide on the features you want and try to play or at least read about every amp that is a possibility. Then, pick the one you dig. If it happens to weigh 100 pounds, cool (kind of), if it happens to weight 3 pounds, cool.

It is a bad mistake IMO for a potential buyer to eliminate a piece of equipment based on one feature that may or may not explain the tonality of that piece of gear (neck through versus bolt on, ash versus alder, tubes versus solid state, hybrid versus pure solid state, all tube versus not all tube, etc., etc.

+1

 

[arai]

Ummm... amp topology/class has nothing at all to do with the output device.

You can build a class A, class AB, or class D amp using tubes.

You can build a class A, class AB, or class D amp using solid state.


Here is the patent for the first class D amplifier - using 12AT7. 12AU7, and a pair of 6293 power tubes. Not a solid state device in it.

http://www.google.com/patents/US3011025





If you're going to argue that amplifier class/topology is a defining characteristic - it helps if you're actually talking about amplifier class/topology.

You know what they say about a little bit of knowledge

 

[bongomania]

{copying SVT tone with solid state components} would be a fruitlessly pointless and expensive engineering exercise...and even if a new unit is cheaper, more powerful and identical sounding, the universe will cry.. "but its not an SVT" and any bassist that wants an SVT will go buy one regardless, and everyone else wont buy it cos they didnt want an SVT in the first place .,,hence it would be doomed to commercial failure.

...Tech21 seems to have had quite a lot of commercial success and acclaim doing exactly that. Even if we agree their products don't sound 100% perfectly identical to an SVT, consumers still clamor for those products.

Same could be said for TCE. Even if they are not trying to copy an SVT necessarily, they have made a successful commercial go of that "fruitless and pointless" engineering.

 

[scotch]

Technical jargon, engineering theory and selection bias issues aside- I'll say this as a full-time working musician who puts tone and reliability ahead of weight savings:

I finally started finding smps amp heads that I felt sounded good last year. Not before. To my ears & performance expectations, the latest crop of bass heads with smps power sections are way better than the products of just a couple years back. I now feel comfortable taking them on tour.

I can't tell you the mathematical equation why or what has changed, simply that the tone and output potential (without cutting off) are finally at a point where I can trust them to help put groceries on my table + I can enjoy the tone. I happened to go with an Aguilar Tone Hammer but the newer Genz amps also sounded 'right' to me (the Aggie just had a more familiar sound for an old-school tube amp guy like me).

I still tour with my tube amps, but my Tone Hammer is there if something breaks, I just want a change that night or when I fly. I'm a former "nay-sayer" that kept a cautiously open mind & finally became impressed!

 

[wateroftyne]

I finally started finding smps amp heads that I felt sounded good last year. Not before. To my ears & performance expectations, the latest crop of bass heads with smps power sections are way better than the products of just a couple years back. I now feel comfortable taking them on tour.

I don't understand the jargon, really - I'm of the opinion that they're getting better, but they're not quite there yet.

 

[seamonkey]

It may be people need to get use to not hearing artifacts they are use to hearing. Happened going from LP and Cassette to CD. And way back in history when Vinyl replaced Wax.

In this case, class-ab amps, the well designed ones, really don't have artifacts audible to humans. Class-d doesn't either. FOH has totally migrated to class-d and not because it sounds better or worst. It's mainly due to features, not sound.

 

[wateroftyne]

It may be people need to get use to not hearing artifacts they are use to hearing. Happened going from LP and Cassette to CD. And way back in history when Vinyl replaced Wax.

In this case, class-ab amps, the well designed ones, really don't have artifacts audible to humans. Class-d doesn't either. FOH has totally migrated to class-d and not because it sounds better or worst. It's mainly due to features, not sound.

It was 100% sound for me, and how the amps performed at gig volume.

 

[Bob Lee (QSC)]

It may be people need to get use to not hearing artifacts they are use to hearing. Happened going from LP and Cassette to CD. And way back in history when Vinyl replaced Wax.

In this case, class-ab amps, the well designed ones, really don't have artifacts audible to humans. Class-d doesn't either. FOH has totally migrated to class-d and not because it sounds better or worst. It's mainly due to features, not sound.

+1

 

[Gabriel51]

Some interesting reading here, thanks.