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Class D Amps?

#61
pfschim said:
Andy, let me also add my thanks and appreciation for your clear statements on these amp technology questions. Even non-techies like me can at least get a basic understanding of the technology in play as things evolve in the bass amp market. As an "old school" (and an old) player who has a certain tube bias, but also a great appreciation for lighter weight gear options, I struggle with this in practical terms all the time.

For example, when I auditioned the original Shuttle 6.0 12T combo against my (admittedly beloved) Mesa Walkabout 12, I definitely felt that the 600w (@4ohms) Shuttle 12T combo did not present the same kind of useable (not tech bench specs) volume as the 300w (@4ohm) Walkabout 12 combo, and neither did the very experienced, well respected, bass guy at a local Bay Area music store. Different format, different controls, different driver and cab, of course, but to my ears - I could not make the Shuttle reach the same clean volume levels as the Walkabout - again - To My Ears. Part of it is that the two amps are not voiced the same of course, but I walked away attributing the rest of the difference to the fact that the Shuttle was SMPS and the Mesa had a more traditional toroidal transformer.

I have heavy iron amps (Fender Studio), and I have hybrid amps (Mesa Walkabout) that I can use for gigs as appropriate, but I am currently also deep into a search for a higher wattage amp (600-1kw) for certain applications. I find that, outside of pre/power rack systems, my choices come down to hybrid designs with traditional transformers (4pro, 6pro, MPulse600, LH1000 and the like) or SMPS designs (7pro, Streamliner, Tecamp 900 etc). I'd like to lower my weight profile, but do wonder if I can get similar performance from the SMPS/Class D players as I know I can from the more traditional designs.

keep the clarity coming.

oh, I and I hope you are up to good things with the guys in Petaluma.
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I had the same impression of the 6.0 years ago. In hindsight I'd be willing to bet I'd get different results with one based on my use of my Shuttle 9.0.

The "problem" was me. Prior to figuring that out I wasn't initially blown away by my 9.0 either because I treated it like one of my other amps. I've been blown away ever since.
:D
 
#62
I just played with one of my older bands that I haven't played with in a while. It's heavy music and I forgot how load they play. My ampeg pro 4 could barely keep up with volume. I have had the chance to try out the carvin or genz Benz, etc... I'm guessing from what I read none of these will be load enough if I continue with this band?
 
#65
The Regulator said:
That's a 1200 watt amp and it barely keeps up? :eek:
Maybe you need to swap the 115 for another 410.
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Perhaps the tone profile is causing the bass to get lost without so much volume... I would look at the position of the cabinets relative to the player, and what's going on in the mids and low mids relative to the overall low end.
 
#66
bayondai said:
I just played with one of my older bands that I haven't played with in a while. It's heavy music and I forgot how load they play. My ampeg pro 4 could barely keep up with volume. I have had the chance to try out the carvin or genz Benz, etc... I'm guessing from what I read none of these will be load enough if I continue with this band?
Click to expand...

You need to upgrade your cabs, or fix some gain staging, or rework your eq first.
 
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#67
Just figured out the problem. Ha ha my battery was dead in my g&l Anyways when the battery is good I usually can keep up with the volume and usually have the master on 1/2 to 3/4 of the way up. The guitar player uses a 5152 head and like I said earlier he plays loud.
By adding another 410 instead of the 115 will be louder?
Here is my head now

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#70
bayondai said:
Just figured out the problem. Ha ha my battery was dead in my g&l Anyways when the battery is good I usually can keep up with the volume and usually have the master on 1/2 to 3/4 of the way up. The guitar player uses a 5152 head and like I said earlier he plays loud.
By adding another 410 instead of the 115 will be louder?
Here is my head now

Invalid Link Removed
Click to expand...

And here is my head now:

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#71
The Regulator said:
I mentioned swapping the 115 for a 410 because of the imbalance of wattage between the cabs. Your 410 is 800 watts and your 115 is 400 watts.
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Not a problem, the power balance is pretty good in this case considering each cabinet will be powered at 600 watts, so that's 1.3x the power handling of the 15" and .75x the power handling of the 410. Well within a couple dB power-balance wise. There may or may not be an efficiency or bandwidth tradeoff, that's hard to tell as it can be different on a case by case basis. Off hand, without knowing more details, I wouldn't automatically say it's a bad idea.
 
#73
Assuming he stays with the same GK cabs he has already, I think it's accurate to say another 410 will be decently louder if he replaces the 115 with a 410. Certainly does vary with bandwidth and construction, though, no doubt about it, but I guess I don't have to tell you that ;)
 
#74
Agedhorse mentioned in passing, if I understood the point he was making, that many modern micro amps are capable of extended low-end response (compared to tube amps of equivalent rated output power) that does not necessarily translate into perceptible increases in volume.

Looking at that another way, perhaps it partly explains the apparently greater volume produced by tube heads at a given output power rating: if they begin to roll off the low bass as the tubes approach saturation, that means that they produce only the low mids and above, i.e., the frequency range that requires comparatively little power for the perception of high volume. In addition, the resultant distortion from the overdriven output tubes contributes to the perception of high volume.

Example: live recordings of Mountain, with Felix Pappalardi playing his mudbucker-equipped Gibson through dimed Marshalls or Sunns: there's almost no low end there, but the low mids and the distortion make it obvious that the perceived volume, a.k.a. din, must have been incredible.

I would guess that the "drive" control on my Ampeg PF-500 and PF-800 does add a bit of distortion but that the degree of distortion is not proportional to the volume control settings. Wonder whether any micro amps are designed to progressively roll off the low end and add distortion as the volume is turned up?
 
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