Class D Amps

[nottswarwick]

It's not just t he big all valve jobbies we are talking about though. It's the ones with big transformer based supplies that many of us favour too.

[4 Strings]

[quote name='ead' timestamp='1378243486' post='2197716']
A switched mode power supply is probably more reliable than something with valves in, more so when they are being lumped around. However there are books on Class A, A/B, D etc so probably not worth getting all hot and bothered about it on here (electronic degree here so some knowledge of the internal gubbins). Each to their own.
[/quote]

Valve radio equipment in crashed planes have still worked, whereas many a Class D amp has failed in normal use (SuperFlys etc). Unless you physically abuse the glass envelopes valves are generally very robust and tolerant to current surges etc.

Each to their own, definitely, although I wouldn't swap my Class D I love to see big amps when I go to gigs!

[discreet]

[quote name='4 Strings' timestamp='1378249197' post='2197821']
Each to their own, definitely, although I wouldn't swap my Class D I love to see big amps when I go to gigs!
[/quote]

So if you're just dabbling go with a class D... and if you're a pro go with a big valve amp..? [size=4] [/size]

[Beer of the Bass]

Although at your pro gigs, the big valve bass rig will be almost certainly be mic'd (if you're lucky or employing your own sound crew) into a PA comprised of Class-D power amps...

[Mr. Foxen]

I could get a class D valve amp made. That would highlight why they are pretty useless points of comparison.

[wateroftyne]

[quote name='Beer of the Bass' timestamp='1378254650' post='2197858']
Although at your pro gigs, the big valve bass rig will be almost certainly be mic'd (if you're lucky or employing your own sound crew) into a PA comprised of Class-D power amps...
[/quote]

As mentioned earlier, for me it's more to do with the feel than the sound.

And I don't think pro PAs powered by class D use the ICE Power module with clever processing to make the pro audio equivalent of 175w sound like 450w...

[xgsjx]

Pros have roadies to lug the gear. Me, I run into a venue with combo in one hand, pedalboard in the other & bass slung over my back & set up as quick as I can.
If it's just a straight does heavy sound better than light, then my Markbass combo sounds far better than the 8 ton 4x10 Trace Elliot combo I had & also far better than the Carlsberg, Peavey or Marshall things I had prior to that.

[LukeFRC]

[quote name='wateroftyne' timestamp='1378230463' post='2197448']
I've owned - for a decent chunk of time - an Acoustic Image Focus, TC RH450, Streamliner 900 and Ibanez Promethean... yep, they all sound different but just didn't cut it in the feel department in a similar sort of way. It's not immediate - it took me a while to realise with each that there was something missing (apart from the TC which I hated from the start. ha ha.).

Coinicidence? Maybe. Maybe not. At least three of those use the same power module.
[/quote] were you not quite positive in your reviews of the RH450 to begin with? I remember your review made me add it on my possibles list a few years back when I was looking for a new amp.
[quote name='wateroftyne' timestamp='1378271882' post='2197875']
As mentioned earlier, for me it's more to do with the feel than the sound.

And I don't think pro PAs powered by class D use the ICE Power module with clever processing to make the pro audio equivalent of 175w sound like 450w...
[/quote] I kinda know what you mean. I can't stand the sound of Markbass (one of the main class D amps I've played through) maybe it's just the amp but it feels like something's missing. My Tecamp puma 1000's got a different power modual (powersoft) and sounds very different. but.... never had to really push it so who knows.
I kinda miss my big heavy Hughes and Kettner Quantum 600 to be honest.

[wateroftyne]

[quote name='LukeFRC' timestamp='1378276532' post='2197909']
were you not quite positive in your reviews of the RH450 to begin with?
[/quote]

I was. For the first couple of weeks I was seduced by the flashing lights and buttons. The rot set in fairly quickly. Mind you, I stuck with it for a year..

Because of that and (to a much lesser extent) the Streamliner, I try not to say too much about new gear until the honeymoon period is over.

[nottswarwick]

Actually an interesting point was raised above about roadies. I'm all for convenient back saving gear, hence my light cab choice. However, I am curious to know what proportion of "big names" or "big bands" use the Class D stuff in preference to the heavier transformer or all valve stuff.

If they do, then maybe I have missed something in my experience with it. Or maybe it is just that rental companies wheel out Ampeg or Ashdown as it is what they have on hire most.

Oh, and don't misunderstand me, I'd happily set up in front of a Streamliner, lm3 etc if that was the situation, they are not BAD at all, in fact they are very good. But I'm happier with mine, that's all.

Edited September 4, 2013 by nottswarwick

[CyberBass]

I love my class d, amp, PF500. I love it's tone, it has great volume. However, the type of shows I play, it's always di'd into house PA, so how my sound is relayed to the audience depends very much on the room acoustics and what the engineer does through his equipment. On stage my pf500 and cab gives my monitoring along with stage monitors, so in my opinion in the environment that I play in, not many people in the audience would know whether I'm playing a class d amp or not. Either way, I am totally happy with my amp and cab :-)

[sk8]

LM2/3 are not class D. There are A/B and sound the better for it IMO. Side by side the LM 500 sounded far more organic than the 800 watt with the class D power module

[CamdenRob]

I've got a little GK MB200 dunno what class that is but it sounds great and weighs about as much as a calculator.

Beats the HH Bass Baby combo I bought second hand when I first started out... Weighed about as much as Eric Pickles and sounded like it has a pillow stuffed in the speaker cone.

Rob

[stingrayPete1977]

Do they make valve in ear monitors?

[Lord Sausage]

[quote name='Lord Sausage' timestamp='1378226533' post='2197348']
Tonight, for the first time, i will be using Harley benton 500w head thru a GK mbe 212 and a zoom b9 1ut. Will let you know how it goes!
[/quote]
To be honest it sounded awesome. I just tried the different amp models on the zoom i.e, GK, Aguilar, Hartke, Sansamp etc. Left the eq flat on amp bit had the gain on about 75%.

[discreet]

[quote name='stingrayPete1977' timestamp='1378284189' post='2197994']
Do they make valve in ear monitors?
[/quote]

Yes - here they are in action.

[Dood]

[quote name='Marvin' timestamp='1378221075' post='2197242']
An electronics engineer (an authorised service engineer for the likes of Yamaha and Ampeg) explained to me the difference between digital, solid state and valve...and it made complete sense why people say class D is good but just lacks something. Suffice to say I won't be buying one in a hurry.

He also explained why they can be unreliable.

Just to add, I'm probably one of the weediest, skinniest blokes on earth and I've also got a bad back due to work. However, I don't have any problems moving my Ampeg cab around, it weighs over 35kg. COME ON YOU LOT, MAN UP!!!!!
[/quote]

The reason that some D Class amps have been less reliable is that manufacturers have been answering requests for gear to not only be lightweight, but also as small as possible too. Therein lies the problem. Taking away all the space from inside the amplifier means in an overload situation the amp components get hotter faster and not being able to cool enough leads to component failure.

Which leads to another interesting foible of the small amplifier revolution. In order to keep these high power amps in small boxes cool, smaller faster fans are used. Some have been noted to be a bit more 'obvious' when they kick up to full speed!

The only other major reliability issue that i've seen so far is using really cheap far eastern machining - but this isn't limited to just D Class kit.

I'm a little reluctant to take 100% opinion from an electronics engineer who calls D Class a 'digital amplifier'

[Count Bassy]

[quote name='dood' timestamp='1378284729' post='2198005']
The reason that some D Class amps have been less reliable is that manufacturers have been answering requests for gear to not only be lightweight, but also as small as possible too. Therein lies the problem. Taking away all the space from inside the amplifier means in an overload situation the amp components get hotter faster and not being able to cool enough leads to component failure.

Which leads to another interesting foible of the small amplifier revolution. In order to keep these high power amps in small boxes cool, smaller faster fans are used. Some have been noted to be a bit more 'obvious' when they kick up to full speed!

The only other major reliability issue that i've seen so far is using really cheap far eastern machining - but this isn't limited to just D Class kit.

I'm a little reluctant to take 100% opinion from an electronics engineer who calls D Class a 'digital amplifier'
[/quote]

Well a class D amplifier is digital in that its output devices are either ON or OFF, much like a digital computer. (Same as a switch mode power supply)

That's the whole point. When off there is voltage across the output device but no current (hence 0 watts dissipated in the output device). When on there is a high current but (ideally) no volts across the device (hence 0 watts again). Hence the low heat generation.

[ead]

[quote name='Count Bassy' timestamp='1378290819' post='2198118']
Well a class D amplifier is digital in that its output devices are either ON or OFF, much like a digital computer. (Same as a switch mode power supply)

That's the whole point. When off there is voltage across the output device but no current (hence 0 watts dissipated in the output device). When on there is a high current but (ideally) no volts across the device (hence 0 watts again). Hence the low heat generation.
[/quote]

There is much to disagree with in those two paragraphs.

[clauster]

In reading this I've found the only class D head I've used isn't actually class D. Didn't particularly like it anyway.

[neepheid]

I don't care. I've never cared that much about amps. Give me an amp that is loud enough and got enough EQ smarts to be heard amongst the sonic chaos that is live music then I'm a happy bunny.

[ead]

Good call neepheid.

[discreet]

[quote name='neepheid' timestamp='1378294665' post='2198187']
Give me an amp that is loud enough and got enough EQ smarts to be heard amongst the sonic chaos that is live music then I'm a happy bunny.
[/quote]

Yes, that's the bottom line, really. Though I do like some big boxes behind me just for the look of the thing.

[sk8]

[quote name='clauster' timestamp='1378294262' post='2198175']
In reading this I've found the only class D head I've used isn't actually class D. Didn't particularly like it anyway.
[/quote]

[Count Bassy]

[quote name='ead' timestamp='1378293965' post='2198169']
There is much to disagree with in those two paragraphs.
[/quote]
Go on then.

Edited September 4, 2013 by Count Bassy