Class D - diabolical

[rhysyjob]

The emergence of class D heads had me very excited! 800 watts in small box light box. No more lugging around huge transformers, great!

 

Except apart from the easy carry the rest of the story has been pretty erm stinky poo!!

 

Despite 8 years, five heads and every Eq patten under the sun. I simply cannot get on with the sound at volume. 😬

 

I”ve tried TC Electronics (BH 550) Aguilar (TH500) Tech 21 (VT) Markbass (Tube 800) and finally Mesa Boogie (D800) and no matter if you put a valve in front of them, a compressor before them, a neo or a ceramic speaker from them, or summon a religious cult behind them. They sound too direct at volume to my ears.

 

I tried, but I’m going back to my Class A/B happy place! 😊

Edited April 30, 2022 by rhysyjob

[BassAdder60]

Ashdown abm600 is the answer 

[MacDaddy]

Each to their own and all that, but my TecAmp Puma 500 sounds lovely and warm, and has suited any band situation I've been in.

Light and loud too 🙂

[Lozz196]

41 minutes ago, BassAdder27 said:

Ashdown abm600 is the answer 

Yep, the ideal compromise imo.

[rhysyjob]

20 minutes ago, MacDaddy said:

Each to their own and all that, but my TecAmp Puma 500 sounds lovely and warm, and has suited any band situation I've been in.

Light and loud too 🙂

Not knocking anyone else. The fact there are so many flavours means people like them. It’s just not for me personally. 😊✌️

[chris_b]

2 hours ago, rhysyjob said:

I tried, but I’m going back to my Class A/B happy place! 😊

 

Some good options in valve and solid state amps.

[la bam]

I'm pretty sure the next incarnation is solid state a/b amps in class d sized packages. I'm sure gk announced this then backtracked when they realised class d sales would plummet.

[Downunderwonder]

Diabolical is a pretty strong word.

 

Agedhorse was in the thick of it when class D was becoming a thing for bass amps. Genz Benz were getting pushback from ''the market'' along the lines of your critique. So they put the new preamp into a pair of boxes, one of each power stage, A/B and D. Nobody could tell a blind bit of difference.

[Jaybeevee]

Handbox R400 is a popular choice. Good reading in the Handbox thread.  I am currently awaiting reply to place an order for one myself. Any other shoutouts for decent class A/Bs one should be aware of?

[Woodinblack]

On 29/04/2022 at 20:50, la bam said:

I'm pretty sure the next incarnation is solid state a/b amps in class d sized packages.

well, don't pit your own money on that bet. 
a class B amp has to lose a lot of heat, class A more so. A class D doesn't have to lose anywhere near as much heat and doesn't need a transformer to get the voltage level down.

the smaller you are, the less heat you can lose, so unless you are at a very small output, an A/B is not going to be that small.

[gjones]

I own an old school Ashdown ABM 500 evo III. I rehearse in a place that has an Ashdown RM 800 as a bass amp. It sounds great through an Ashdown 410.

 

I decided to compare it to my old Ashdown head and frankly, the RM 800 sounded marginally better.

Edited April 29, 2022 by gjones

[Bleat]

My Marshall is class H. I won't pretend to know all the technical ins and outs but I understand  it utilizes a secondary power supply that kicks in to handle massive peaks. Either way it sounds awesome and definitely the best sounding amp I've owned by far.

[BassmanPaul]

1 hour ago, la bam said:

I'm pretty sure the next incarnation is solid state a/b amps in class d sized packages. I'm sure gk announced this then backtracked when they realised class d sales would plummet.

Problem with Class AB is the cooling required for the output devices. A large heavy heatsink is a necessity plus fans to increase the airflow over them.

[rhysyjob]

1 hour ago, Downunderwonder said:

Diabolical is a pretty strong word.

 

Agedhorse was in the thick of it when class D was becoming a thing for bass amps. Genz Benz were getting pushback from ''the market'' along the lines of your critique. So they put the new preamp into a pair of boxes, one of each power stage, A/B and D. Nobody could tell a blind bit of difference.

As I said it’s personal choice, I can tell the difference for sure and for ages I tried to tell myself I couldn’t. Ultimately it’s personal choice, but if work done or power is a function of area under the the output graph it feels like class D are steeper spikes and A/B are more sine waves with greater work done. This may explain the need to lose heat. I’m no expert but I trust my ears. 
 

No right or wrong just personal preference! 😉

[peteb]

4 hours ago, rhysyjob said:

The emergence of class D heads had me very excited! 800 watts in small box light box. No more lugging around huge transformers, great!

 

Except apart from the easy carry the rest of the story has been pretty erm stinky poo!!

 

Despite 8 years, five heads and every Eq patten under the sun. I simply cannot get on with the sound at volume. 😬

 

I”ve tried TC Electronics (BH 550) Tech 21 (VT) Markbass (Tube 800) and finally Mesa Boogie (D800) and no matter if you put a valve in front of them, a compressor before them, a neo or a ceramic speaker from them, or summon a religious cult behind them. They sound too direct at volume to my ears.

 

I tried, but I’m going back to my Class A/B happy place! 😊

 

Yes, I agree. Pretty much my experience. 

 

1 hour ago, Jaybeevee said:

Handbox R400 is a popular choice. Good reading in the Handbox thread.  I am currently awaiting reply to place an order for one myself.

 

 

That's the route that I eventually took. The R400 is a great amp that is an easy one hand carry in a compact box. Streets ahead of any Class D amp I tried / owned. 

 

[mattbass6]

4 hours ago, rhysyjob said:

The emergence of class D heads had me very excited! 800 watts in small box light box. No more lugging around huge transformers, great!

 

Except apart from the easy carry the rest of the story has been pretty erm stinky poo!!

 

Despite 8 years, five heads and every Eq patten under the sun. I simply cannot get on with the sound at volume. 😬

 

I”ve tried TC Electronics (BH 550) Tech 21 (VT) Markbass (Tube 800) and finally Mesa Boogie (D800) and no matter if you put a valve in front of them, a compressor before them, a neo or a ceramic speaker from them, or summon a religious cult behind them. They sound too direct at volume to my ears.

 

I tried, but I’m going back to my Class A/B happy place! 😊

I felt the same for a while, too. I’ve been through a load of them and one tried a full Ampeg SVT II rig. The difference was frightening, so was the size, and weight issues 😂 I took a punt on an Aguilar ToneHammer 500, and initial playing about left me cold, but some research, advice and persistence led me to believe that I may have found something that actually works. If this fails, which I don’t think it will, and go all our IEM because the prospect of going back to huge, heavy rigs is just not an option. 

[Sparky Mark]

My Markbass LM2 and LM3 heads are class AB output. They are no larger than the majority of 500/800 watt class D output stage heads. You can have a class AB head without the need for large heavy transformers.

Edited April 30, 2022 by Sparky Mark

[Nebadon2000]

2 hours ago, rhysyjob said:

As I said it’s personal choice, I can tell the difference for sure and for ages I tried to tell myself I couldn’t. Ultimately it’s personal choice, but if work done or power is a function of area under the the output graph it feels like class D are steeper spikes and A/B are more sine waves with greater work done. This may explain the need to lose heat. I’m no expert but I trust my ears. 
 

No right or wrong just personal preference! 😉

 

You also said at volume AKA loud; I tend to agree. At moderate levels [such as A/B test most likely] it may be harder to discern.

I have accepted well engineered Class D for its overall good sound and light weight for moderate loud [and power for loud gig's] Gig's I have been doing especially now at 67yrs old.

 

The loud gig's large clubs with less than stellar tone I can make through without much annoyance but those are few and far between last few years. 

[Newfoundfreedom]

I have the Bugera Veyron, which is probably the cheapest 'powerful' class D on the market. 

 

Press the low boost, and high boost buttons, dial in a little bit of the built in compressor, get the mids where you want them, leave everything else around 12 o'clock, and the thing sounds absolutely sublime! 

[funkydoug]

If the cabs are right any amp class can work very well. 
Look at any PA rig for proof.

Many class D bass rigs include compact cabs too, which soak up the big power rating of the head.

 

 

[wateroftyne]

Welcome to my world. I realised this years ago that consumer power modules are lacking (IMO) and nothing has changed my mind yet. It’s Diet Coke vs Full Fat Coke.

[King Tut]

1 hour ago, Newfoundfreedom said:

I have the Bugera Veyron, which is probably the cheapest 'powerful' class D on the market. 

 

Press the low boost, and high boost buttons, dial in a little bit of the built in compressor, get the mids where you want them, leave everything else around 12 o'clock, and the thing sounds absolutely sublime! 

I've got the valve version and gig it regularly. I'll cut the bass on mine and hoof the volume to bring the tops through. I've got a large valve amp and a couple of Trace heads which I do gig occasionally, but I find the difference in terms of audio is negligible and what difference there might be is compensated by the convenience factor. 

[Chienmortbb]

11 hours ago, Woodinblack said:

well, don't pit your own money on that bet. 
a class B amp has to lose a lot of heat, class A more so. A class c doesn't have to lose anywhere near as much heat and doesn't need a transformer to get the voltage level down.

the smaller you are, the less heat you can lose, so unless you are at a very small output, an A/B is not going to be that small.

Class C is not used in audio, it is designed for radio transmitters.

[MacDaddy]

15 minutes ago, wateroftyne said:

Welcome to my world. I realised this years ago that consumer power modules are lacking (IMO) and nothing has changed my mind yet. It’s Diet Coke vs Full Fat Coke.

 

Excessive use of class A/B amps can lead to tooth decay and diabetes? 😳

[rhysyjob]

25 minutes ago, funkydoug said:

If the cabs are right any amp class can work very well. 
Look at any PA rig for proof.

Many class D bass rigs include compact cabs too, which soak up the big power rating of the head.

 

 

I think it’s perfect for front of house where you want to have a completely uncoloured representation of the band (FRFR). However for an instrument amp, the preamp and power amp have historically added colour and character to the tone. FRFR lacks that colouration hence why Darkglass, Aguilar etc put pedal type preamps in front of them. 
 

I did have a Aguilar TH500 which wasn’t bad, but ultimately not for me. It’s all down to personal taste. 😊
 

 

 

Edited April 30, 2022 by rhysyjob