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

[aborgman]

I don't think this is the case. If you are comparing say an MB-500 to TH-500 to a Shuttle 6.2, I would expect (and hope) that they sound different even though they are all based on the same class D platform. There are way too many significant differences in the preamp and power amp implimentations to ignore or to expect otherwise.

I'm not claiming they al sound the same.

Different mp3 encoding algorithms all sound different too.

... but there are certain artifacts that can be picked out of that difference which are common to all mp3's.

Now - I don't hear anything like that in class D implementations I have experience with, but I won't claim that such a thing isn't there for someone trained to hear it.

 

[KJung]

I'm not claiming they al sound the same.

Different mp3 encoding algorithms all sound different too.

... but there are certain artifacts that can be picked out of that difference which are common to all mp3's.

Now - I don't hear anything like that in class D implementations I have experience with, but I won't claim that such a thing isn't there for someone trained to hear it.

I guess the point would be (and I think the point Andy is making), if it is so subtle that you would need to be trained to hear/identify it, and also (I assume) that you could only hear something as subtle as that in pure 'power amp format', taking out the massive impact of preamp, etc., that primarily drives bass amp tonal/performance differences, then it is not really what we are talking about here.

+1 though... doesn't mean 'something' might be lurking in there that is 'systematic' if most probably trivial.

 

[joelb79]

Interesting! This again makes it clear that there is more to the execution and integration of the power stage than pure topology (or specific class D module used), and also (per Any's wonderful post) preamp voicing is a primary driver in tonal and even performance differences (hi passing, etc.).

Agreed.

 

[KJung]

Agreed.

This has been a fun thread, and continues to be a good one. I always learn something new from these types of threads

 

[Shane Carter]

Great that this thread could remain so civil and thanks for everyone who has contributed. I am impressed with the level of knowledge that users of this forum have. Interesting to learn that Class D amplifiers themselves could all sound different, rather than the difference just existing in their preamp section, although it makes perfect sense.

Sorry for the readers who might have thought I posted this as a "Bigger is Better" type post. The Crown XLS 1500 is a Class D power amp that weighs 8.6 lbs, 19 inches wide, 3.5 inches tall and 7.7 inches deep. I'm sure the 19 inches wide part is only so it can be rack mounted (in a small effects rack, not the standard depth rack. I also have a laptop case it would fit in.) The power, ohms and cabinet options it allows are impressive, combined with it's affordability and dependability made it a good option for me. I'm sure there a lot of other manufacturers making these power units and they will continue to shrink in size and grow in power.

Just maybe the future is separate small power amps, allowing you to customize your tone with playing-card size mini-preamps?

 

[Steve Dallman]

In my twenties, I gigged with an SVT head, a huge 2X15 Carvin folded horn cabinet, a 4X12 ARB cabinet with four coffee can EVSR0's or a West cabinet built with 1" particle board, and two coffee can EVSRO 15's. I hauled that heavy stuff up flights of stairs for years, and never thought twice about it. Today at 60, I'm thinking as compact and light as I can get. I now use a PF-500 and it does what the SVT did for me. I use two fairly compact 12" cabinets with 6 1/2" mids, and am thinking of making composite cabinets. Going lighter is just a necessary reality for me as I age, if I want to continue playing.

 

[agedhorse]

I guess the point would be (and I think the point Andy is making), if it is so subtle that you would need to be trained to hear/identify it, and also (I assume) that you could only hear something as subtle as that in pure 'power amp format', taking out the massive impact of preamp, etc., that primarily drives bass amp tonal/performance differences, then it is not really what we are talking about here.

+1 though... doesn't mean 'something' might be lurking in there that is 'systematic' if most probably trivial.

Correct "translation"

 

[vin*tone]

When people compare micros to lead sleds they often say that the older AB amps have more "heft", "girth", "weight" ....etc than their micro counterparts. eg Aguilar TH500 vs DB750, GK 700RB vs MB 500. What are we hearing feeling here? Is this an EQ thing? ... burst power thing?.... or a combination of both?

 

[arai]

I would guess a lot of it is preconceived ideas and a bit of imagination

 

[fdeck]

I would guess a lot of it is preconceived ideas and a bit of imagination

There's also a negative side.

 

[agedhorse]

I would guess a lot of it is preconceived ideas and a bit of imagination

I suspect that this is representative of much of the difference, but also it should be remembered that preamp designs and goals have changed, advanced, evolved or whatever you wish to call it, in response to market demands.

Much the same as when Neo was introduced as a speaker's magnetic motor material, this opened up a new set of possibilities that transducer designers long wished for. The idea that ALL Neo speakers are brighter because the material sounds different is inaccurate because it's not the material but where designers could place the material and what that did to the motor geometry that allowed for a brighter design. Neo speakers do not have to be brighter, they can be however the designer chooses them to be. (Much of) The market itself had been seeking a brighter or more extended upper mid which transducer then took advantage of NEo to achieve this through better (or more desireable for THIS application) geometries. I can think of several Neo executions that are less bright than a similar ceramic counterpart... by design.

 

[KJung]

When people compare micros to lead sleds they often say that the older AB amps have more "heft", "girth", "weight" ....etc than their micro counterparts. eg Aguilar TH500 vs DB750, GK 700RB vs MB 500. What are we hearing feeling here? Is this an EQ thing? ... burst power thing?.... or a combination of both?

I have never experienced this myself (at least not in a systematic way across a large number of different heads of different designs). My guess is, it is due to comparing a very limited number of heads, and then attributing the difference of those heads to what they think is the cause of the difference (i.e., size, weight, big iron, whatever). IMO there.

Put another way, I have often experienced a larger, more traditional head bury a specific micro on many attributes. The key is, I've also experienced a micro absolutely crushing a 'full size head'. All heads sound different, and there is a different level of 'girth' across a wide range of bass heads, of all designs.

I also believe, to FDeck's point, that there is a little bit of 'listening with your eyes' sort of thing going on. We are all guilty of it, whether it be the impact of really good aesthetics, or heavy duty chassis material, or brand name, or price tag. Hard to not let that stuff influence your general feeling about what your are experiencing.

IMO and a lot of IME

 

[B String]

When people compare micros to lead sleds they often say that the older AB amps have more "heft", "girth", "weight" ....etc than their micro counterparts. eg Aguilar TH500 vs DB750, GK 700RB vs MB 500. What are we hearing feeling here? Is this an EQ thing? ... burst power thing?.... or a combination of both?

As I put in my former posting. For me its a feeling of heft and solidity in my right hand. After reading thread after thread about how power cables don't matter at all, but having every good tech I've ever known say otherwise, I realized that there are any number of things that effect how an amp sounds. Four class D amps will sound different with four different preamps, etc. However, as much as its been explained to me, I'm still not exactly sure why the amps with heavier transformers have more weight to the note or just feel more powerful under the my hand, but it just seems to be.

That being said, I don't think 99% of the audience could hear the difference. Its all about what the player needs to make them feel and hear the bass the way they need to, and I'm VERY happy with many of the micro or class D amps out there.

 

[B String]

IMO and a lot of IME

You and me both brother! Gonna miss you at NAMM. Maybe next year.

 

[KJung]

I suspect that this is representative of much of the difference, but also it should be remembered that preamp designs and goals have changed, advanced, evolved or whatever you wish to call it, in response to market demands.

Much the same as when Neo was introduced as a speaker's magnetic motor material, this opened up a new set of possibilities that transducer designers long wished for. The idea that ALL Neo speakers are brighter because the material sounds different is inaccurate because it's not the material but where designers could place the material and what that did to the motor geometry that allowed for a brighter design. Neo speakers do not have to be brighter, they can be however the designer chooses them to be. (Much of) The market itself had been seeking a brighter or more extended upper mid which transducer then took advantage of NEo to achieve this through better (or more desireable for THIS application) geometries. I can think of several Neo executions that are less bright than a similar ceramic counterpart... by design.

+1 Also, as you know much better than me, hi passing settings (and other low end sculpting by the designer) can result in one amp sounding very punchy and immediate and loud but not 'thundering down low, and another head with a similar power design and spec sound huge and fat and deep, etc.

Regarding that 'girth' issue above, a good dose of lower mids and upper bass baked into the pre, with a relatively restricted deep low end in the preamp voicing, and there you go.

I have found (as I've learned more on this site, and actually took the time to understand what frequencies 'sound like what'), many players assume what they are hearing is about a full octave below what they actually are hearing when you put it on the scope, or add or remove it with a semi-parametric EQ. So, that 'girth and fullness' down low is much more upper bass and lower mid than 'huge deep bass' IMO. So, it often is not 'can the power amp deliver the big low end', but rather, is the preamp capable of sculpting a tight, full upper bass/lower mid response that sounds fat and, well, girthy

 

[KJung]

You and me both brother! Gonna miss you at NAMM. Maybe next year.

I know! I ended up feeling crappy enough toward the end of NAMM last year that we didn't really get to hang enough. Have fun. Maybe next year!

I want to hear what wonders Carey Nordstrand has in his booth this year.

And, will you just stop pussyfooting around and go to the TecAmp booth and get an endorsement deal for the Puma900 already!

 

[aborgman]

I guess the point would be (and I think the point Andy is making), if it is so subtle that you would need to be trained to hear/identify it, and also (I assume) that you could only hear something as subtle as that in pure 'power amp format', taking out the massive impact of preamp, etc., that primarily drives bass amp tonal/performance differences, then it is not really what we are talking about here.

Not necessarily. Everyone has different sensitivities... just because I (or most people) can't hear it without training, doesn't mean others can't.

See: smelling asparagus in urine

+1 though... doesn't mean 'something' might be lurking in there that is 'systemonatic' if most probably trivial.

I don't hear it, but that doesn't mean it isn't there.

 

[fdeck]

I suspect that this is representative of much of the difference, but also it should be remembered that preamp designs and goals have changed, advanced, evolved or whatever you wish to call it, in response to market demands.

If nothing else, the amount of space on the front panel for knobs dictates a different approach to preamp design. That's actually one thing I like about the micro heads: The designer really has to think about which controls will provide the most functionality and impact.

 

[agedhorse]

+1 Also, as you know much better than me, hi passing settings (and other low end sculpting by the designer) can result in one amp sounding very punchy and immediate and loud but not 'thundering down low, and another head with a similar power design and spec sound huge and fat and deep, etc.

Regarding that 'girth' issue above, a good dose of lower mids and upper bass baked into the pre, with a relatively restricted deep low end in the preamp voicing, and there you go.

I have found (as I've learned more on this site, and actually took the time to understand what frequencies 'sound like what'), many players assume what they are hearing is about a full octave below what they actually are hearing when you put it on the scope, or add or remove it with a semi-parametric EQ. So, that 'girth and fullness' down low is much more upper bass and lower mid than 'huge deep bass' IMO. So, it often is not 'can the power amp deliver the big low end', but rather, is the preamp capable of sculpting a tight, full upper bass/lower mid response that sounds fat and, well, girthy

Ken had the opportunity last year at NAMM to play around with a variety of our amps side by side, so he has a little bit of an unfair advantage here. 3 amps all with the same power amp section and they all sounded different. It certainly wasn't because of the power amp. Also, the same preamp with 2 different power amps and they sounded the same (within the limits of their respective power ratings of course).

Now Ken also mentioned something that I think deserves a little more discussion. It's assumed that the fundamental is responsible for the majority of the sound as well as the way the eq works. In fact, especially at lower frequencies there is more harmonics than there is fundamental, so the designer's choice of eq and voicing elements will sound different with different basses and with different notes depending on the realtive distribution of harmonics across the scale. This is one reason why one particular amp might be a better choice with a particular type of bass than another, just a happier mix of spices in the gumbo for a particular player or style.

 

[agedhorse]

If nothing else, the amount of space on the front panel for knobs dictates a different approach to preamp design. That's actually one thing I like about the micro heads: The designer really has to think about which controls will provide the most functionality and impact.

Absolutely true. There's nowhere near the margin for throwing things in there that there is in a bigger box.Form follows function.