Mini 0r Micro Amps.... I Must Be Missing Something?

[KJung]

Your right they use a 250ASX2

But that amp still has 10% THD+N at around 100w instead of 60 on the 250asx2. I don't see how that amp is bridgeable to under 8 ohms given the information on the B&O site. It says the minimum load is 6 ohms; and that looks to be stereo.

I finally looked at that whole spec sheet. Mark is correct, you are posting 'each side'. So, the module starts to signficantly increase in distortion at around 100+ watts at 8ohms and 200+ watts at 4ohms... which is right at its published power spec per side.

Bridged, the significant rise in distortion starts at around 500 watts (as Mark stated.... at 4ohms or 8ohms doesn't really matter if the power is held to a maximum of 500 watts)

The correct spec does describe the TH500 quite well, but doesn't provide enough information on the Genz execution, since they have a lot of fancy stuff going on inside the 9.2 and 900 series that makes the performance quite amazing. Yes, it is not like the pure, open wump of the Puma900 or Glock, that uses 'no tricks' 1000 watt modules. But the 'tricks' Genz uses to make that module work at a higher power level are very impressive IMO and IME.

Well, wrong module and wrong chart. Now right module and wrong chart.

Third try should be golden

 

[Blankandson]

I'm leaning towards a compromise I love the sound of the GK fusion(4#), and the punch from the PJ speakers (40-50#). With the fusion in my gig bag I think I can deal with the PJ weight. In exchange, I get the sound I love and can cram into an orchestra pit beneath my chair.

 

[Saluki]

I posted this in another thread recently but may be relevant here. I currently have a Thunderfunk 750 and a SM9.2 and have compared them side by side with same cab using a/b switch. I just noted the SM9.2 has quite a bit more noise at the same volume levels. I can eq the SM9.2 to get close to the sound of the TF, but I can't get it quite as sweet nor as quiet. That said, the weight factor is a bigger issue for me and would rather take the SM9.2 where I can get in the same tone universe albeit with a bit more noise.

 

[joelb79]

Third try should be golden

I can't because they haven't publish that chart for it in bridge mode. They just state 10% THD+N @ 8 Ohms at the power spec. It's not charted. I would not think though that the performance of the bridge mode would be any more spectacular than stereo. Do we really need another try? Ever amp I've encountered has higher THD in bridged than in stereo.

This is fun though; popping the covers and seeing whats inside. And this discussion. It's not like we need to know this at a gig and pass out spec sheet as pointed out. But it's nice to know the inner-workings of amplifiers. It appeals to my inner geek.

 

[KJung]

I posted this in another thread recently but may be relevant here. I currently have a Thunderfunk 750 and a SM9.2 and have compared them side by side with same cab using a/b switch. I just noted the SM9.2 has quite a bit more noise at the same volume levels. I can eq the SM9.2 to get close to the sound of the TF, but I can't get it quite as sweet nor as quiet. That said, the weight factor is a bigger issue for me and would rather take the SM9.2 where I can get in the same tone universe albeit with a bit more noise.

Very different voicing between those two, and a LOT more upper treble extension (plus tubes) in the Streamliner, which would most likely account for bit more hiss through a tweeter at high frequencies IMO. I agree with what you hear (as usual!).

 

[KJung]

I can't because they haven't publish that chart for it in bridge mode. They just state 10% THD+N @ 8 Ohms at the power spec. It's not charted. I would not think though that the performance of the bridge mode would be any more spectacular than stereo. Do we really need another try? Ever amp I've encountered has higher THD in bridged than in stereo.

In bridged mode, they state 1%THD at 8ohms in the power spec. The charts you provide match the single channel power spec in the spec sheet. Again, it would be strange for a company as legit as B&O to market a 500 watt amp at 10%THD. Wouldn't really make sense.

You are quoting the 8 ohm power at each side. Bridge mode would represent the 4ohm power, combined from each side, with would be pretty close to their 8ohm bridged power spec of 500 watts bridged at 8ohms, or 230 watts, each side, running at 4ohms, 1% THD. Since the Aguilar is 'limited' to 500 watts at 4ohms, the spec should be about the same as the 8ohm bridge spec provided by B&O, and I believe is accurate in the Aguilar manual also.

The key is, the charts you put up are not representing what you think they are measuring, and completely misrepresent the sound quality of this particular module run at 500 watts bridged. Trust me, it is IMPRESSIVE if you have gigged a TH500. That being said, as you heard in the clips, the TH500 preamp is ALL about the hair and growl, and that won't be liked by everyone.

 

[nostatic]

This is fun though; popping the covers and seeing whats inside. And this discussion. It's not like we need to know this at a gig and pass out spec sheet as pointed out. But it's nice to know the inner-workings of amplifiers. It appeals to my inner geek.

The problem is there is a difference between "know" and "guess" that gets blurred. I'm sure someone, somewhere, is now convinced that all micro amps have 10% THD because they saw a data plot on TB. Before you know it that will be the new conventional wisdom and a generation of kids will be spouting that as dogma.

If only we could figure out how to monetize it...

 

[KJung]

The problem is there is a difference between "know" and "guess" that gets blurred. I'm sure now someone, somewhere, is now convinced that all micro amps have 10% THD because they saw a data plot on TB. Before you know it that will be the new conventional wisdom and a generation of kids will be spouting that as dogma.

If only we could figure out how to monetize it...

+1 I'm hoping those charts get erased. They are not 'guesses', they are wrong. They don't represent the bridged output of that module.

+1 This is how the myth of 'power amp topology' goes on and on in the bass amp world, while it has been settled for years in the PA world.

 

[Saluki]

Very different voicing between those two, and a LOT more upper treble extension (plus tubes) in the Streamliner, which would most likely account for bit more hiss through a tweeter at high frequencies IMO. I agree with what you hear (as usual!).

Hey KJ on this one I was comparing the Shuttlemax 9.2 to the TF750. I posted about it in more detail in the Puma thread, which I will be ordering this week.

 

[KJung]

Hey KJ on this one I was comparing the Shuttlemax 9.2 to the TF750. I posted about it in more detail in the Puma thread, which I will be ordering this week.

Ah. Well, again, more treble extension in that head also. +1, not a lot of hiss coming out of the TF750a.... not that much going on way up high with that head to my ear.

That being said, the only amps that I've 'not bought' based on noise floor are some of the GK units, which of course have TONS of trelble sizzle, and a super hot gain structure. No free lunch...seems IME that the more goosing of gain and treble, the more inherent noise coming from a tweeter.

That being said, the Glock is WAY quiet!

 

[Passinwind]

+1 I'm hoping those charts get erased. They are not 'guesses', they are wrong. They don't represent the bridged output of that module.

Here is another published spec from the 250ASX2 spec sheet. It still doesn't represent any particular build up in a bass amp though.

Link Removed

 

[KJung]

Here is another published spec from the 250ASX2 spec sheet. It still doesn't represent any particular build up in a bass amp though.

Link Removed

+1 Lots going on inside all these executions. That is way over my head, but the amps again that I've played with this module bridged perform quite well, compared to 'heavier' executions with the same basic power specs.

 

[seamonkey]

I posted this in another thread recently but may be relevant here. I currently have a Thunderfunk 750 and a SM9.2 and have compared them side by side with same cab using a/b switch. I just noted the SM9.2 has quite a bit more noise at the same volume levels. I can eq the SM9.2 to get close to the sound of the TF, but I can't get it quite as sweet nor as quiet. That said, the weight factor is a bigger issue for me and would rather take the SM9.2 where I can get in the same tone universe albeit with a bit more noise.

For the noise, it may just be the pre-amp part of the head. You can plug the pre-amp out of one head into the amp in of the other, and I'll bet the noise stays with the pre-amp.

 

[joelb79]

In bridged mode, they state 1%THD at 8ohms in the power spec. The charts you provide match the single channel power spec in the spec sheet. Again, it would be strange for a company as legit as B&O to market a 500 watt amp at 10%THD. Wouldn't really make sense.

You are quoting the 8 ohm power at each side. Bridge mode would represent the 4ohm power, combined from each side, with would be pretty close to their 8ohm bridged power spec of 500 watts bridged at 8ohms, or 230 watts, each side, running at 4ohms, 1% THD. Since the Aguilar is 'limited' to 500 watts at 4ohms, the spec should be about the same as the 8ohm bridge spec provided by B&O, and I believe is accurate in the Aguilar manual also.

The key is, the charts you put up are not representing what you think they are measuring, and completely misrepresent the sound quality of this particular module run at 500 watts bridged. Trust me, it is IMPRESSIVE if you have gigged a TH500. That being said, as you heard in the clips, the TH500 preamp is ALL about the hair and growl, and that won't be liked by everyone.

They do list this:

Output power @ 10%THD+N 20Hz < f < 20kHz (AES17 measurement filter) with a RL = 8&#937; . Then the spec differs from voltage at the mains, for 230Vac / 50Hz 630 Watts (Typical) and at 115Vac /50Hz 510 Watts.

Link Removed

At 1% those numbers drop to 500w at 230Vac and 420w at 115Vac respectively.


Those charts are very confusing. Why are there so many conflicting specifications? I would assume that depends on the implementation.

Please; Please! nobody think that this means all Class-D amps perform at 10% THD. Each amplifier needs to be measured in its implementation for THD before that could become a fact. It should have been made clear from a few posts in this thread that the way the amp is implemented means more than the bare amplifier specifications; as each manufacturer has the choice to limit or not limit the output power (there are many ways to do this) so the amplifier might not be capable of getting to the 10% point at all.

But to deny that the amp goes into 10% given the ICEPOWER spec sheets would be a wrong assumption as well. It certainly will; and I feel those spec sheets have so many different specs in order for a designer to plan their implementation accordingly.

As I said before the ASP series seem more solid than the ASX versions, and ICEPOWER have many different amp series available with different power supplies, output sections, DSP ect. Impressive lineup really, I can see why people like Demeter would be slapping them into the bare space inside their preamps; and I can see why GK would use them as well in the MB series.

I'm just in agreement with the OP about the micro thing is not worth the effort, IMO. For me, I'm still doing 2 trip load ins with a micro now. I'd much rather carry some bigger iron on that 2nd trip using my hand cart instead of strapping a 25lb gig bag plus a bass gig bag onto my body and walking in half-cocked sideways. Shoot, I'd even do 3 trips if it made sense.

 

[Saluki]

For the noise, it may just be the pre-amp part of the head. You can plug the pre-amp out of one head into the amp in of the other, and I'll bet the noise stays with the pre-amp.

Good point. I could check that.

 

[fdeck]

Those charts are very confusing. Why are there so many conflicting specifications? I would assume that depends on the implementation.

Those charts are intended for somebody with a technical background to determine how the power amp module will behave in its intended use. There is nothing confusing about the THD graphs.

Please; Please! nobody think that this means all Class-D amps perform at 10% THD.

They don't. How are you interpreting those graphs? FYI a typical mainstream Class-AB power amp will have a similar graph.

 

[mwig]

Own both. It's lugging the cab(s) not the head that's a pain the pain in ass anyways. I will say that micro heads I've played and owned sound very good at low to moderate volumes, but seem to struggle in higher volume situations, but then again who puts a micro head on a 810? Every type of head has its place...

 

[Jim C]

I always find these micro posts entertaining with the usual disagreement between specifications, reliability, and tonal descriptions.
What I find more interesting than anything in this thread is the fact that most of the big manufacturers continue to make conventional amps and that some are even bringing out new heavy amps (OK usually tube). Many of the amps that are being discontinued are being replaced with like units.

For that matter many of the amps from the 50's, 60's, etc. were pretty well made and that components can be sourced for repairs for a very long time.

Can't say the above for 95% of other consumer electronics.

 

[Dave W]

but then again who puts a micro head on a 810? Every type of head has its place...

I put one on a 4X12. Although not quite the same as an 810, it's definitely in the same ball park. No issues with it whatsoever. It absolutely pounds.

 

[fdeck]

I always find these micro posts entertaining with the usual disagreement between specifications, reliability, and tonal descriptions.

Even as a micro amp fanboi, I think the discussion is largely healthy. "The new kid on the block" always comes under the most scrutiny.