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alexa3020

Do all class D heads really lose their thud at volume?

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I have been trying to put a good lightweight rig together for the past few months (you may have seen previous posts from me asking for advice).

The cab is sorted, so it’s now time to look at the head.

My current lightweight head is a Tc bq500, which is ok, but at high volume it didn’t seem to have the same presence in the mix and the sustain on the notes seemed unnaturally long. After a bit of research and some advice it turns out these heads scoop some of the lows and compress at volume.

Is this true of all class D heads? Will it be more prevalent on cheap heads like the TC & can anyone advise any class D heads that don’t do this?

Im coming back round to the idea of going A/B instead and maybe getting an ABM evo 4 or similar instead.

any advice here would be most welcome.

 

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Just now, alexa3020 said:

I’m guessing this has been done to death with no general consensus then

Yeah, pretty much. Everyone hears differently I guess, and the amp manufacturers want to market & sell what people want to buy (i.e. featherweight).

FWIW, I've been back in A/B-land for years now, and unless someone comes out with a genuine game-changer, rather than the same old in a new frock, I can't see myself moving back any time soon.*

*Other opinions are available

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I have a tc450 and a Ashdown CTM (also another ashdown A/b in a case I have only played live once).

The CTM sounds better for rock stuff, but as a 100w amp it is hard to make a clean sound at volume. If you like the tubey compressed sound it would certainly be a winner. It also is very heavy and until I changed car recently it was too much of a faff getting it into a car and into a pub, so the 450 does most gigs with me and all practices. Also the full time tuner on it is handy for giving the guitarist a clue as to what key we are in :D

If I was prepared to carry more, or didn't have to carry the PA, or had some bandmates who were prepared to actually help with stuff, then maybe I would use the CTM more. And bigger speakers of course, Its too wide to go frontwards across a 12" speaker cab!

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If you have an amp that runs out of steam at higher volumes, don't blame the amp, just get a more powerful one, or maybe some better speakers so you don't have to push the amp so hard.

I've played my Aguilar AG700 at ear bleeding volumes and the louder you go, the better it gets.

 

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OK, I'll start the punch up!

I've not experienced anything to suggest to me that the design of a solid state power amp has any bearing on how it sounds or feels within its operating range. If anything, the one I have pushed hard to the point of losing it is an A/B LMII.

It shouldn't be an issue of class, but of headroom. Any power amp turned up enough to saturate the signal path with lose something of the dynamics, and the further it is pushed, the more noticeable it will become. Valve amps tend to do it in a pleasing way, depending on requirements, and solid state amp tend only to exhibit negative effects when overloaded. If you can't turn the amp up loud enough for what you need, you either need higher wattage, or more likely more, or more sensitive speakers. Headroom- as in the abililty of the amp to reproduce the signal without clipping is what makes the difference. Running any class of amp beyond its capabilities will result in distortion of the signal in some form.

*chris_b posted as I was typing!*

Edited by Jus Lukin
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8 minutes ago, chris_b said:

If you have an amp that runs out of steam at higher volumes, don't blame the amp, just get a more powerful one, or maybe some better speakers so you don't have to push the amp so hard.

Im not blaming the amp, it is just a 100w amp, and the reason people say about 'valve watts' is that once a valve amp runs out of steam it compresses and distorts with even harmonics which are musically pleasant, so people are happy with that. a transistor based solid state A/B type will distort with odd harmoncs which aren't musically pleasant so people don't do it, so you get this idea of valves being louder, just that valves are more 'musical' when overdriven.

A class D will run out of power supply capability before anything else, so yes, the low end will go first because it is the bit which requires most power.

If I was going to use the CTM for pub gigs without PA support and wanting to not overdrive, I could go for a CTM300, but that would involve having someone to carry it for me, and I suspect that isn't going to happen!

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1 hour ago, alexa3020 said:

I’m guessing this has been done to death with no general consensus then

It has, I guess I'm one of the techy nerds here so I'll give you the bullet points.

You can't trust the specs on promotional material

Having said that there are no magic watts, class D watts are the same as class A/B watts. The PA you hear at most big gigs is almost certainly class D.

Amps of all classes often cut corners on the power supply. That will mean they can only provide power downhill with the wind behind them.

The tendency in the past was to design and test on sound. Amps and speakers were often highly coloured and most of us like that. Modern amps tend to be cleaner out of the box. So long as they have plenty of headroom you can usually eq something decent.

Only buy an amp you've had a chance to play and listen to at volume, don't worry about the class, that's for the designer to sort and if they haven't, don't buy it. 

I've moved from an old Hartke 3500 which sounded great to am MB Tube which was okay and much more reliable but a bit meh until I dropped it off the stack and I bought a really cheap Peavey MIniMax as a temporary replacement. It's great, really solid sound out of the box. One all to each.

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I don’t think my issue is anything to do with headroom. The TC is loud - I don’t think ive had it past 12oclock on the master and I’m not clipping the preamp. It just seems to lose the thud in the mix at gigs.

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7 minutes ago, alexa3020 said:

I don’t think my issue is anything to do with headroom. The TC is loud - I don’t think ive had it past 12oclock on the master and I’m not clipping the preamp. It just seems to lose the thud in the mix at gigs.

This is the sticking point in the discussion, I think. Some notice this, others don’t.

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1 hour ago, wateroftyne said:

Yeah, pretty much. Everyone hears differently I guess, and the amp manufacturers want to market & sell what people want to buy (i.e. featherweight).

FWIW, I've been back in A/B-land for years now, and unless someone comes out with a genuine game-changer, rather than the same old in a new frock, I can't see myself moving back any time soon.*

*Other opinions are available

Have you tried the Bugera Veyron BV1001T? It’s pretty hot! 

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As Phil says the amp topology is not the problem. TC were notorious for exaggerating their power output in a subtle way.They named the model after their “algorithm” that estimated the equivalent output power with their magic processing. Firstly it was not magic and secondly it was cheating in the same way as  say the sister brand Bugera “estimated” their class D amps at 2000 watts. 

Despite  this amps were not bad per se and I have one of the Bugera’s. 2000 watts it ain’t but it is bloody loud and probably outputting  700-800 watts. 
 

Secondly the position of the volume control is no indication of power output. Depending on the  output level of the bass, maximum output could be at 12 o’clock or even before.

The “ magic” in TC heads is a form of compression and the TC 500 is actually around 300-350 watts into 4 ohms if I remember correctly. 

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So far I’ve tried

ashdown rm evo2

Little mark 3

ampeg pf350

orange terror

aguilar th 700

The only one I didn’t like was the orange - didn’t really like the way it distorted.

the tonehammer initially sounded best to me, but I think that’s because I played it through an Aguilar cab. Yesterday I tried the ashdown and rootmaster in the same cabs & I probably preferred the ashdown. Could certainly do more with the eq anyway.

however till I get to the band environment, I’m not gonna know.

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15 minutes ago, alexa3020 said:

I don’t think my issue is anything to do with headroom. The TC is loud - I don’t think ive had it past 12oclock on the master and I’m not clipping the preamp. It just seems to lose the thud in the mix at gigs.

But that doesn't add up!

It's either has enough headroom, in that you can get to the volume you need without the signal being altered, or or it isn't, in that by the time it is loud enough it is altering the signal. The point on the dial is irrelevant- so many factors in how a rig as a system can be topped out, could be the power section, could be the speaker/s, could even be the room.

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4 minutes ago, Chienmortbb said:

 

The “ magic” in TC heads is a form of compression and the TC 500 is actually around 300-350 watts into 4 ohms if I remember correctly. 

Would this account for the unusually long sustain on the notes do you think?

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I think it may have more to do with the fact that we tend to use lightweight, compact cabs with class D heads. Many of those (there are honourable exceptions - BF, et al) don't shift the air the way big, old skool cabs do at high volumes. I had an old Ashdown 1x15 - the enormous one. The driver blew, so I replaced it. Sounded huge with my AG700. I sold it because it was so large and I live in a first and second floor flat with narrow stairs, but it certainly had no lack of heft or oomph..

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Class D amps i have tried in loud band scenarios and subsequently sold on mainly because i felt they lost the whoomph when pushed - 

Genz Shuttle 9.2 (900w)
Gallien MB Fusion (500w)
MarkBass Evo1 (500w)
Genzler Magellan 800 (800w) (much better than the previous 3 though - maybe because of newer power module design?)
Mesa Boogie Subway D800 (800w) (as above....)

Class D amps i have tried in loud band scenarios, still own and use regularly because they retain 90% of the whoomph when pushed - 

Quilter Bass Block 800 (800w) (doesn't use an off the shelf power module like the above ones to my knowledge)

Class D amps i have yet to use in a band scenario - 

Darkglass M900 (900w) (last chance saloon for class D for me - if that doesn't do it for me then nothing will)

All used with the same old cabs (Barefaced BB2 Gen3) for all of them. Same band. Same hairy ended drummer. And mostly the same venues.

Class A/B amps that i currently use as first choice or would cheerfully have again (for reference) -

Gallien Krueger 700RBii
EBS TD650
Ashdown ABM600 evo4
Handbox R400 (not used in anger yet but it's looking promising)

Make of that what you will....I'm assuming it's a type of power supply thing or headroom thing as the higher power ones or the amps without the generic power supplies are closer to my liking.

 

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3 minutes ago, Dan Dare said:

I think it may have more to do with the fact that we tend to use lightweight, compact cabs with class D heads. Many of those (there are honourable exceptions - BF, et al) don't shift the air the way big, old skool cabs do at high volumes. I had an old Ashdown 1x15 - the enormous one. The driver blew, so I replaced it. Sounded huge with my AG700. I sold it because it was so large and I live in a first and second floor flat with narrow stairs, but it certainly had no lack of heft or oomph..

That’s not my experience.

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6 minutes ago, Mudpup said:

Class D amps i have tried in loud band scenarios and subsequently Quilter Bass Block 800 (800w) (doesn't use an off the shelf power module like the above ones to my knowledge)

 

I’ve heard this a few times, and the bit in brackets is in line with what I suspect is at the root of this.

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9 minutes ago, Jus Lukin said:

But that doesn't add up!

It's either has enough headroom, in that you can get to the volume you need without the signal being altered, or or it isn't, in that by the time it is loud enough it is altering the signal. The point on the dial is irrelevant- so many factors in how a rig as a system can be topped out, could be the power section, could be the speaker/s, could even be the room.

You may have to forgive my ignorance on this subject.

for me, when it’s loud I struggle to hear the detail in tone quite as well. This is true of all amps I have tried.

What I can tell is how the bass cuts through in the mix and it just doesn’t feel the same up at higher volumes - perhaps it is a headroom thing - I’m not sure, but I don’t feel like I’m really pushing the head too hard.

take your point about the room. Strangely, I’ve always thought it sounded better in larger rooms.

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10 minutes ago, Dan Dare said:

As I said, there are exceptions.

Yeah, but over the years I’ve generally used old-school cabs, not BF etc.

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My Glockenklang Blue Rock (1000w) stayed true all the way up. My Bergantino  Forte HP (1300w) has not been tested yet but at ear testing levels in my study suggest it should also be okay. 😀

Both via a BF Big Twin II. 

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