Any downside to Digital power sections?

[Mykk]

I have a cheap class D poweramp I use in my rig, so far it's proven worthy. Powerful, sounds good, lightweight. If there were to be a downside it would just be the inexpensive overseas manufacturing with cheap components that may make for a shortened lifespan/reliability. However, that is not unique to just this product.

I feed it with either the pre-amp out from my Mesa M-2000 or an Eden WTDI. Sounds great either way.

[SactoBass]

Originally Posted by JimmyM

That all depends on the execution of the tube. In stuff like the SVT 7 Pro and Streamliner amps, a lot. In the case of others where the tube is wired in a starved plate design, it has a little impact but it's less important to the sound.

+1

The only tube preamps that ever sounded good to me are high plate voltage. Examples are: Kern IP777, Alembic F-1X, BBE B-Max-T, etc.

I knew that the Streamliner has a high voltage preamp, but I didn't know that the SVT-7 Pro had that. Thanks Jimmy for educating me on that! That's probably why the SVT-7 Pro sounds so good (for a hybrid).

[JimmyM]

Ampeg's never been big on putting in glory tubes. They usually make the tubes work. I don't know what voltage the tube runs at in the 7 Pro, but you can hear differences when you swap tubes out, and that's usually a sign of the tube getting some good voltage. I'm not a tech, and I sometimes end up getting corrected on this type of stuff, but I'm pretty sure that differences in tubes won't be nearly as apparent in starved plate designs.

[wmheilma]

Class D is a great way to go if you are a busy player and need a loud, light, flexible rig. It does not have the character of an all tube head or a standard solid state Class A/B power section. It's different, but very very effective.

I still cannot believe I have not blown up my Genz-Benz! It sounds great, is very loud, gets lots of different tones, and weighs almost nothing. So surely it has to blow up on me sooner or later, right? Two years steady gigs and still going strong! GB makes great gear.

[Jerrold Tiers]

Some of the early small amps around 100w really had ZERO heatsink.... just a small pad of copper. With the parts then available, that was good enough if not pushed..... but if pushed they died hard.

With modern parts, you can get 10x the power with the same small heatsink area, so long as you have a fairly big fan pointed at them (Peavey as an example).

people tend to cut more corners with small amps.... but in general that unreliability is old news, small class-D is all single chip solutions now, with very decent reliability. The biggest problem is taking home stereo parts and trying to use them to MI limits..... They were just good enough for home stereo, MI is too much of a strain, and there can be problems if the chip limits are not respected.

For the techie ultra-literal definitions and meanings dweebs..........

About "digital"..... PWM is NOT "1s and 0s"..... Amplitude is transformed into pulse width, both analog values..... it's generally a very linear transformation, but digital it is not....

Truly "digital" should mean transforming analog amplitudes into binary numeric values.... but that whole thing has gotten so conflated that it is worthless to even argue the point.

[arai]

Originally Posted by bubbastain

-the sales person advised against some of the small lightweight Class D heads. He mentioned something about playing loud for extended periods would overheat it or something like that. Any truth to this?

Many times my class d head has been the back line for multiple band gigs (4hours+) and I am always surprised how cool the head is at the end of the gig.

[JimmyM]

I've never played a micro that ever felt hot, and I've had mine on and working as long as 8 hours at a time. Slightly warmer than room temperature at the most.

[Duke21]

There is one major "flaw" with these class D amps, they are too light, an amp such as the MB500 is so light, you might pull it off the cab if you walk away from it with a too shorts guitar cord...

And here is btw my HiFi class D hybrid amp

[bubbastain]

Originally Posted by Duke21

There is one major "flaw" with these class D amps, they are too light, an amp such as the MB500 is so light, you might pull it off the cab if you walk away from it with a too shorts guitar cord...

If I get one, I'll just velcro it to the cab. One less thing to carry.

[Doug Parent]

Originally Posted by fdeck

I've gotten over the hangup about calling these amps "digital." I've got a Class-D head for those occasions when lugging my other Class-D head is impractical.

[chienmort]

There is no crossover distortion as with solid state class B or A/B. However there is the chance on badly designed ones for some HF spikes to come through. In most cases these will be inaudible.

ironically having started in Electronics at the crossover from Thermionic Valves/Vacuum Tubes to Transistors, I have the same fondness for a good A/B amp as some have for tubes/valves.

The reality is that PWM amps (incorrectly called class D) are smaller, lighter and should be more reliable as even at full power, they are not being used near the SOAR (safe operating area) of the output devices. So they do not get too hot and should, if built and designed to the same standards, be more reliable.

With regards to tube amplifiers, you should consider them as space heaters with the side issue of being able to put out some good sounds.

[Aeko]

As said before, the only think to be worry about is if someday something inside get broken. Sure it's hard to repair. But, for the expensive price of repairs and for the cheap these D amps are, buying a new one with 2 years warranty is always a good option.

[amimbari]

I used tube amps for years until the weight was just unbearable.
The A/B power amps came into play and was a "little" better as I went to a amp/pre/rack setup and used a Mackie 1400i, but still too heavy and I struggled for a while. Bought a Crown XTI and was like YEA BOY, then the XLS series came out. I waited 2 years to see who had issues, didn't see any and retired the XTI to my house PA and have been using an XLS1500 ever since.
I have the same similar story about the amp being cooler than the other items in the rack is also so true.

70lbsto35to15to8...won't ever go back.

[chadds]

Originally Posted by Duke21

There is one major "flaw" with these class D amps, they are too light, an amp such as the MB500 is so light, you might pull it off the cab if you walk away from it with a too shorts guitar cord...

And here is btw my HiFi class D hybrid amp

You said it right there. Put it in your shorts.

[mattbass6945]

put it in your shorts.......where's the like button?

[fdeck]

My view about repairing Class-D is that entire circuit modules will eventually cost less than some of the bigger parts inside a Class-AB amp such as the transformers, especially when shipping cost is taken into account.

Repairability is already becoming relegated to an issue for just a few of us geeks who do our own repairs because of skills that we bring from other fields. With the rapid extinction of good amp techs, repairability will take a back seat to being able to pop a micro bass head in the mail for a few bucks. We already read stories of bassists who have a Class-AB amp that is effectively unrepairable because some component is hard to find (power transformers), or there are no techs in their area and they have to contemplate the cost of shipping a huge amp.

The compactness of the micro heads lets you think about some things that would have seemed pretty audacious in the past, like having an entire head shipped to you by a fellow TB'er just to throw in the back seat of the car as a spare.

These amps won't become icons like the classic tube amps, but I think it's just because we're living in a different age. There will be no "MB200 vintage re-issue" 20 years from now.

[username1]

My svt 7 pro has more power than i will ever use and is always cold to the touch even after a long workout. I also had a gk mbfusion that i lost in a fire and was very impressed with that amp as well. I've been so impressed by class d amps that all of our power amps in our rack have been replaced with these and it makes a huge difference in the weight of the rack and they also perform very well.

[georgestrings]

Originally Posted by Handyman

The only practical downside to class D amps is that they're significantly more complex than plain old class AB, and you won't be able to drop them off to any old repair shop should the need arise.

That said, I use a Genz Benz Streamliner, and don't see a reason to go back to the old stuff.

Yeah, I did a fairly demanding gig with my Streamliner 900 last weekend - thumped the crap outta the place for 4 hours against 2 Triple Rec halfstacks and a loud drummer - and it wasn't even warm to the touch... I'm not getting rid of my M-pulse 600 just yet, but I'm very confident of the Streamliner's capabilities after that...


- georgestrings