Class D - diabolical

[BigRedX]

24 minutes ago, Chienmortbb said:

There are always exceptions to every rule. 

 

16 minutes ago, rhysyjob said:

Personally, I’ve found Ashdown very helpful.
TC Electronic, Line 6 we’re appealing (went in the bin) and Eden (about 9years ago) cost me a fair bit in petrol, phone calls and parts. 

 

I would have chalked it up to experience and forgotten about it, but then another Basschatter had exactly the same problem with the same model of Ashdown amp he had bought second hand and came on here raving about the great customer service he had received which IIRC essentially involved Ashdown fixing it for free. In my case when I had owned the amp from new, I got fobbed off, then quoted signifiant amounts of money to just look at the problem, and finally ignored. When I raised the problem with the Ashdown rep on here I got a nasty sarcastic response that didn't make me feel any better inclined towards the company.

[Mudpup]

39 minutes ago, Chienmortbb said:

I have to disagree, the main benefit is a valve amp is its inherent compression. 

No one mentioned valve amps..... 

 

Compression by definition limits dynamics and so do the class D amps that I have tried. They get squashier as you really crank them. My old Mesa's don't in my opinion (And the Ashdowns and EBS amps have I have used) They only have a valve preamp. But the power amp seems to make the difference. 

Edited May 2, 2022 by Mudpup

[ern500evo]

2 hours ago, BigRedX said:

 

Except when they don't. Myself and a couple of other people on here have been treated pretty badly by Ashdown's customer support. I'll never buy anything from them ever again.

Sorry to hear that. I’ve never dealt with them directly, but have seen a lot of people hear singing their praises. 

[lemmywinks]

1 hour ago, BigRedX said:

 

Except when they don't. Myself and a couple of other people on here have been treated pretty badly by Ashdown's customer support. I'll never buy anything from them ever again.

 

Same, both Superfly issues IIRC?

 

Although I would buy Ashdown if I liked the sound of them, almost pulled the trigger on one of the heavily discounted OR110 that were floating around recently before realising I didn't really need it. 

[Woodinblack]

4 hours ago, wateroftyne said:

Absolute marketing con, that. I hated that amp with a firey passion.

 

I was in two minds whether to sell it on, or ceremonially smash it to bits to get some sort of closure.

 

Send it to the lobster - I am sure he would have something to say about it!

[Woodinblack]

Ashdown are one of the few companies I found that had aftersales service.

[Phil Starr]

19 hours ago, orangepeelneil said:

My Mark Bass LM3 failed a few weeks ago, terminally = most likely a PSU PCB fault/failure.

The cost to fix it wasn’t worth it (was quoted £200) so I sold it to nice guy on FB Marketplace for £150, he was hoping to fix it, I hope he does.

For me this is the worst thing  about Class D amps.....😞

I've had the same experience with MB and there are many more than two of us .

 

It is increasingly difficult to repair any consumer electronics or even electrical goods and this is nothing to do with class D. It's to do with technological innovation and the way the consumer market works. Most amps now are built with surface mount components and multi level circuit boards. Those components are too small to handle by hand almost impossible to un-solder and re-solder but incredibly cheap and usually reliable. With a lot of things being done digitally you can get a lot of components that aren't always made after the end of a production run so spares are tricky/impossible to source. To keep costs down a lot of amps have everything on a single board so a single component going down stops anything else in the amp working.

 

How many of us repair and maintain our own cars now? 

 

However MB have decided not to release the circuit diagrams or make parts available and have contracted out the customer support to another company, Real Electronics. Effectively they are refusing a relationship with their UK customers post sale. Beyond the guarantee period you are on your own.

[lemmywinks]

With modern amp repair for micro heads you're probably out of the realm of traditional amp techs and would be better off taking it to someone who does laptop repairs or similar, people who work on far more complex boards (often without schematics) which are many times more delicate  and time consuming to disassemble than a bass head. You'll probably find a lot of these guys are a hell of a lot cheaper as well as having the relevant equipment such as microscopes and rework stations needed for board level repair, they will probably have a much quicker turnaround time too. There's a guy near me who will do board level repair on a Nintendo Switch and make it economically viable, he's invested a lot in his setup so I imagine a bass amp PCB would be easy work for him.

 

[Chienmortbb]

6 hours ago, Mudpup said:

No one mentioned valve amps..... 

 

Compression by definition limits dynamics and so do the class D amps that I have tried. They get squashier as you really crank them. My old Mesa's don't in my opinion (And the Ashdowns and EBS amps have I have used) They only have a valve preamp. But the power amp seems to make the difference. 

Yes power amp compression in valve amps sometimes allied to power supply sag in earlier valve rectified models. It leads to a more pleasing sort of distortion (compression is distortion). With solid state amps (most Class A/B, G,H and D)  the amps keep getting louder until the start clipping which tends to sound harsher than from a valve amp. Some A/B amps use MOSFET outputs that distort/compress more like a valve amp, think Ashdown ABM and Trace Elliot SM. I suspect Handbox also use this topology.

[zranyard]

I had an issue with my previous amplifier which was mark bass and ran into the problem mentioned above, they don't release the circuit diagrams, meaning at the time the company who would fix it were in West London and I was in Bristol with no working amp and a gig the following day. I got lucky and a local chap managed to fix it for me, but I was really annoyed by it and replaced it 6 months or so later.

 

I do use a class D amp though (aguilar th) have had it for eight years and this one has never let me down and I love it! 

[rhysyjob]

It’s not just Class D, I had an Eden WT550 that plopped itself mid gig, nightmare! It then got worse as the uk tech couldn’t repair it had to send a new preamp board over from the US. Then a few months later the fan went and it overheated and cut out mid gig. I got it repaired and solid it, but I was an inch away from a Basil Fawlty Moment in the Car Park.

 

I loved the Eden sound, but the build quality of my particular unit was Friday pm at Longbridge in the 1970’s.

[wateroftyne]

52 minutes ago, rhysyjob said:

It’s not just Class D, I had an Eden WT550 that plopped itself mid gig, nightmare! It then got worse as the uk tech couldn’t repair it had to send a new preamp board over from the US. Then a few months later the fan went and it overheated and cut out mid gig. I got it repaired and solid it, but I was an inch away from a Basil Fawlty Moment in the Car Park.

 

I loved the Eden sound, but the build quality of my particular unit was Friday pm at Longbridge in the 1970’s.

I had one of them. Kept cutting out. Sent it back.

[agedhorse]

On 29/04/2022 at 13:22, 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 a viable topology for audio signals, not in any way.

 

ALL amps must have a power supply transformer in order to pass safety standards everywhere in the EU and just about everywhere else in the world as well.

[agedhorse]

On 30/04/2022 at 22:58, Waddycall said:

Could there be a difference between the quality of class d technology used in a large rack mount power amp and that squeezed into a tiny bass head?

In some cases they are identical. I have designed both bass amps and touring pro audio powered cabinets using the same modules.

Edited May 3, 2022 by agedhorse

[Woodinblack]

2 hours ago, agedhorse said:

Class C is not a viable topology for audio signals, not in any way.

 

As I mentioned in a previous post, that was a typo for class D

[Stofferson]

I whole heartily agree.

I went through several class D amps and all failed in some way, either over heating, poor volume or just plain rubbish.

ABM 600 now for the past 3/4 years doesn't weigh a ton and tone and power for days.

Horses for courses I know, and everyone of us has a different idea of what they need, but I need loud and reliable and that's what my amp gives me

[BassAdder60]

I too prefer my ABM600 head over the class D amps I’ve tried.

 

[EBS_freak]

Meh. Be done with it.

 

IEM and go through the PA. You'll be able to hear everything super clearly, not rag your ears... and your band will sound better for it too.

[lemmywinks]

3 minutes ago, EBS_freak said:

Meh. Be done with it.

 

IEM and go through the PA. You'll be able to hear everything super clearly, not rag your ears... and your band will sound better for it too.

 

This all day long, there's no going back.

 

We're using a cheap PA (all Alto stuff) now that the RCF gear has gone and it's doing a great job for the pub/club circuit, so good in fact that it's a bit of a relief we don't have to upgrade in a hurry and it's much lighter as well. Even the single small sub kicks out some decent low end in a big room.

[EBS_freak]

For those interested in an IEM centric thread derailment - 

 

Otherwise, as you were.

[fretmeister]

1 hour ago, EBS_freak said:

Meh. Be done with it.

 

IEM and go through the PA. You'll be able to hear everything super clearly, not rag your ears... and your band will sound better for it too.

 

My big band doesn't have a PA!!

 

2 dozen brass and reeds is still smegging loud though.

[EBS_freak]

4 minutes ago, fretmeister said:

 

My big band doesn't have a PA!!

 

2 dozen brass and reeds is still smegging loud though.

 

No problem. Use ambient mics for monitoring (to keep volume down in your ears) and a PA speaker as your rig.

 

I set somebody up with an XR18, a RCF 735, a mic stand with a stereo condenser on. IEM feed from XR18. Job done.

Alternatively, IEMs an a Zoom field recorder work nice for monitoring.

 

[Lowend soldier]

1 hour ago, EBS_freak said:

Meh. Be done with it.

 

IEM and go through the PA. You'll be able to hear everything super clearly, not rag your ears... and your band will sound better for it too.

i couldnt ever be without the physicality and presence of the bass on the stage. I have too feel the colour of each note from its vibration. I cant hear with just my ears although my hearing is excellent. Caused much banging of heads over 20 years to be honest in night clubs, bigger venues with sound men, but we were always re booked. Recently been diagnosed with autism in my late 40,s which might explain that.

Thats exactly my gripe with all the class d amps i,ve had. You lose the outline of the bass note, it just goes boomy and the tone kicks in and over powers the low signal when volume is applied.

Fair too also add to this topic that apart from the gk mb800, all the other class d amps i have owned, had a coloured tone you cant dial out. Non more so than the tone hammer and rh750 i,ve sold over the week end. 

No doubt they work for many, out every week, but i think its a combination of reasons people opt for these. Not many have sighted sound alone above tbf 🤔.

None of these heads imo would stand up to a blind sound test comparison ie: a mesa subway against big block ect 

[EBS_freak]

26 minutes ago, Lowend soldier said:

i couldnt ever be without the physicality and presence of the bass on the stage. I have too feel the colour of each note from its vibration. I cant hear with just my ears although my hearing is excellent. Caused much banging of heads over 20 years to be honest in night clubs, bigger venues with sound men, but we were always re booked. Recently been diagnosed with autism in my late 40,s which might explain that.

Thats exactly my gripe with all the class d amps i,ve had. You lose the outline of the bass note, it just goes boomy and the tone kicks in and over powers the low signal when volume is applied.

Fair too also add to this topic that apart from the gk mb800, all the other class d amps i have owned, had a coloured tone you cant dial out. Non more so than the tone hammer and rh750 i,ve sold over the week end. 

No doubt they work for many, out every week, but i think its a combination of reasons people opt for these. Not many have sighted sound alone above tbf 🤔.

None of these heads imo would stand up to a blind sound test comparison ie: a mesa subway against big block ect 

Haptic feedback devices - woojer, backbeat - and boards, or buttkicker - all alleviate that perceived lack of feel you may have if you had no physical amp on stage. And they can pretty much can do more than the vibration you'd ever get from a cab.

Edited May 3, 2022 by EBS_freak

[Lowend soldier]

Just now, EBS_freak said:

Haptic feedback devices - woojer, backbeat - and boards, or buttkicker - all alleviate that perceived lack of feel you may have if you had no physical amp on stage. And they can pretty much can do do more than the vibration you'd ever get from a cab.

Thank you sir i will have a look into this witchcraft.....