HYPEX vs ICEPOWER

[agedhorse]

One could compare the same preamp with different power amps:

• Jule Amps M Series 700 watt bass amp (Hypex module)
• GSS Baby Sumo AmpXlite bass/guitar power amp (600 watt, most probably Ice module)
• Jad Freer Coda (700 watt, Jad Freer's class G power module)

We would hear if the power section makes a difference, or not. But it would be a very expensive experience

There can be additional processing elements in these types of power amps that integrate and modify the performance of the power amp circuit alone.

This is certainly true of my integrations of all power amps into my products. The raw power amp is only a portion of the bigger picture.

 

[John D Harris]

One could compare the same preamp with different power amps:

• Jule Amps M Series 700 watt bass amp (Hypex module)
• GSS Baby Sumo AmpXlite bass/guitar power amp (600 watt, most probably Ice module)
• Jad Freer Coda (700 watt, Jad Freer's class G power module)

We would hear if the power section makes a difference, or not. But it would be a very expensive experience

There is "confirmation bias" which points to needing a double-blind method of testing and for the ability to switch between two different units instantaneously to A/B them back and forth.
In your suggestion it would be A/B for a while, then A/C, then B/C to determine what, if any differences are detected.

 

[fdeck]

I got interested in Class-D amps at a pretty early stage, when the Hypex modules and their ilk had just become available. I bought a kit for a Class-D amp board that used one of the large Tripath IC's.

I came into this project with quite extensive electronics knowledge, and still learned some hard lessons. From this experience, I've arrived at the opinion that, assuming an amp module is competently engineered, chasing tone through module design is less important than the skill and knowledge of the designer who incorporates it into an actual bass amp. One issue is that Class-D amps really don't like to be driven into hard clipping, yet you also don't want to throttle the signal too much, lest you give up that paid-for power rating, or make the amp sound weak when played hard. It's not a trivial design problem. Getting the most out of these amps (or any sophisticated electronic device) also benefits from developing a relationship with the supplier's engineers.

 

[lug]

Beware of anything and everything suggested by the audiophile industry as being “true and accurate “.

That industry has a long and deep history of choreographed deceptions intended solely to separate their customers from their money. $1000+ designer power cables anyone?

Depends. My uranium depleted power cable makes my amp slam harder than a mere copper-based cable. My brother is am A10 Warthog machanic and he says depleted uranium slams harder than anything else on the market, you can take that to the bank! (also, don't trust banks, buy gold)

 

[Short4since64]

Very interesting. I'm French, so I'm scared to miss the subtilities of your beautiful phrasing, so if you don't mind I'm going to rephrase it in simpler words, just to check:

"If you want to get the "slam" of a tube amp with a class D amp, one solution is to use an overpowered class D amp, and use a compressor like a limiter (with super short attack/release)"

Is that correct?

It's super funny: I love my Quilter Bass Block, and I've always found that it has this "tube feel". The funny thing is that the Bass Block has a special limiter circuit in the gain stage, so it seems like if this amp was kind of using your trick, but internally… I wouldn't be surprised because Pat Quilter have always focused on making non-tube amps that sound like tube amps. Does it make sense?

From the BB800 documentation:

With any type of solid-state amplification, you always want to have considerably more power available than you need. Class-AB or H sounds terrible when clipping. Class-D doesn't actually clip, the conversion process of input to PCM is mathematical - comparison of the input against a radio frequency sawtooth wave so there must be a limiting means as the modulation cannot be less than zero or more than 100%. My personal combination to achieve that visceral stomach punch was 1-power 2-high efficiency large piston area cabs (like in street racing, there's no replacement for displacement) 3-playing right at the compression threshold. Too much compression, you have forever sustain but sound dull and lifeless. AND a real rackmount studio-grade compressor, not a pedal. I used a genuine DBX160, the one with the big VU meter and terminal screw connections, in the rack with a mono 31-band EQ and the power amp. Found I didn't need a preamp, with an active bass the EQ had enough gain, later went stereo with a Bass Rockman on my belt with inbuilt compression and chorus, into a two channel 31-band EQ. Crest 8001 power amp.
Alas, the good old days, eighties have been and gone with no path forward for a half-century+-old metal monster. Power trio, BC Rich active, Roto66s and loud.

 

[Short4since64]

I got interested in Class-D amps at a pretty early stage, when the Hypex modules and their ilk had just become available. I bought a kit for a Class-D amp board that used one of the large Tripath IC's.

I came into this project with quite extensive electronics knowledge, and still learned some hard lessons. From this experience, I've arrived at the opinion that, assuming an amp module is competently engineered, chasing tone through module design is less important than the skill and knowledge of the designer who incorporates it into an actual bass amp. One issue is that Class-D amps really don't like to be driven into hard clipping, yet you also don't want to throttle the signal too much, lest you give up that paid-for power rating, or make the amp sound weak when played hard. It's not a trivial design problem. Getting the most out of these amps (or any sophisticated electronic device) also benefits from developing a relationship with the supplier's engineers.

AND consider the manufacturer's conservative ratings. Don't expect a module to perform well at it's absolute max ratings. It's a sophisticated design, not a rude barking bank of 6550s.

 

[agedhorse]

AND consider the manufacturer's conservative ratings. Don't expect a module to perform well at it's absolute max ratings. It's a sophisticated design, not a rude barking bank of 6550s.

Understanding what the specs actually mean and how they are derived is critical, there are undocumented aspects of performance that can be exploited by an experienced engineer, or crippled by lack of experience and/or knowledge.

 

[paulraphael]

Purify modules perform best according to tests at audiosciencereview.com. But they're testing with an eye toward hifi amplification, not musical instruments. I don't know if they make modules that would make sense for a bass amp, or if the lower noise / lower distortion qualities would make a meaningful difference.

My ToneHammer amp (IcePower) can put out its maximum rated power for hours (which is amazing for abuse-by-musician) but does so at 10% THD (which would be considered obscenely bad in a hi fi amp).

 

[juledude]

You could compare any standalone preamp and standalone power amp, just as people have done for years with pre/power rack setups. My point was specific to the Trickfish amps in the prior quote where the difference to the end user and on paper may be just down to the power amp, but what goes on at the interface of the two, which is not known to the end user remains an uncontrolled variable in the comparison.

Yes. That interface is usually forgotten; it can make or break the quality of the experience. Now that I think about it, I've found that I can screw things up just about anywhere in the signal chain.

 

[fdeck]

Purify modules perform best according to tests at audiosciencereview.com. But they're testing with an eye toward hifi amplification, not musical instruments. I don't know if they make modules that would make sense for a bass amp, or if the lower noise / lower distortion qualities would make a meaningful difference.

My ToneHammer amp (IcePower) can put out its maximum rated power for hours (which is amazing for abuse-by-musician) but does so at 10% THD (which would be considered obscenely bad in a hi fi amp).

Here's a THD graph from a datasheet for the little IcePower module that's probably close enough to what's in my bass amp. The caption is missing, but this graph is for a 4-Ohm load, running on 120 V, 60 Hz.

Every power amp spec sheet that I've seen, including IC's and modules, has a similar graph. The rapidly rising THD above a certain threshold is simply indicative of the onset of hard clipping. The same amp could have a different distortion / power rating if desired. The "banner spec" at the top of the spec sheet says 170 Watts. But in a bass amp, it could be rated in the ballpark of 200 Watts at 10% THD.

Both the hi-fi and musical instrument worlds face the same paradox, which is: What's good enough?

 

[agedhorse]

Purify modules perform best according to tests at audiosciencereview.com. But they're testing with an eye toward hifi amplification, not musical instruments. I don't know if they make modules that would make sense for a bass amp, or if the lower noise / lower distortion qualities would make a meaningful difference.

My ToneHammer amp (IcePower) can put out its maximum rated power for hours (which is amazing for abuse-by-musician) but does so at 10% THD (which would be considered obscenely bad in a hi fi amp).

I think you are misunderstanding the entire THD specification and how it's derived.

First, if you take just the raw power module, that particular part delivers 500 watts RMS at less the 0.1% THD so I'm not sure where you got your number from. I have the real numbers since I used that part on some of my previous designs.

Second, the numbers of the raw module doesn't even matter since many of these designs incorporate the addition of distortion components by the various stages of the preamp itself, which once added can't be extracted numerically. This is why you often see higher distortion numbers in MI products, because they are intentionally added to benefit the texture and feel in addition to the tone.

Also, don't believe everything you read in the audiophile world... just sayin'.

 

[DJ Bebop]

Beware of anything and everything suggested by the audiophile industry as being “true and accurate “.

That industry has a long and deep history of choreographed deceptions intended solely to separate their customers from their money. $1000+ designer power cables anyone?

Audiophile crystals and rocks

 

[Clark Westfield]

Jim Bergantino uses ICEPower, so to me that’s a win!

 

[paulraphael]

I think you are misunderstanding the entire THD specification and how it's derived.

First, if you take just the raw power module, that particular part delivers 500 watts RMS at less the 0.1% THD so I'm not sure where you got your number from.

From Aguilar's published spec.

I have the real numbers since I used that part on some of my previous designs.

Second, the numbers of the raw module doesn't even matter since many of these designs incorporate the addition of distortion components by the various stages of the preamp itself, which once added can't be extracted numerically. This is why you often see higher distortion numbers in MI products, because they are intentionally added to benefit the texture and feel in addition to the tone.

I understand this. And I've seen the same IcePower module used in hifi amps with much lower distortion specs (and lower power specs). I'm just saying that these rather extreme numbers (10% THD) suggest design goals for the bass amp that are quite different from what you'd see in a hifi amp.

So I'm leaving at as an open question if Purifi would be an interesting option for bass.

Also, don't believe everything you read in the audiophile world... just sayin'.

Audiosciencereview isn't the audiophile world. Check it out. Amir is an engineer like you. He's got an Audio Precision analyzer and a Klippel Near-Field scanner in his basement.

 

[John D Harris]

... "rather extreme numbers (10% THD)" ...

Apparently you do not understand what agedhorse was getting at, otherwise why would you use this phrase.
What is extreme in the world of hifi music reproduction, is completely different from what agedhorse is getting at - which is adding the kind of pleasing distortion and harmonic excitement that enhances and adds richness to the sound of bass guitars.

Feel free to design and build your own equipment in whatever way you see fit, but he answered your prompting and yet you want to continue to push the issue with him.

 

[agedhorse]

From Aguilar's published spec.

I understand this. And I've seen the same IcePower module used in hifi amps with much lower distortion specs (and lower power specs). I'm just saying that these rather extreme numbers (10% THD) suggest design goals for the bass amp that are quite different from what you'd see in a hifi amp.

So I'm leaving at as an open question if Purifi would be an interesting option for bass.


Audiosciencereview isn't the audiophile world. Check it out. Amir is an engineer like you. He's got an Audio Precision analyzer and a Klippel Near-Field scanner in his basement.

If Aguilar is specifying this number, then the THD is (as I suspect) intentionally generated within the preamp and power amp interface circuitry. It’s a common approach, which is why chasing power amp specs is a “fool’s errand”.

 

[DJ Bebop]

Audiosciencereview isn't the audiophile world. Check it out. Amir is an engineer like you. He's got an Audio Precision analyzer and a Klippel Near-Field scanner in his basement.

Unfortunately, even though he has some expensive test gear, I find his analysis of the data they provide a bit skewed and unimpressive because of that. Snake oil in a nicer bottle, imho.

 

[paulraphael]

Unfortunately, even though he has some expensive test gear, I find his analysis of the data they provide a bit skewed and unimpressive because of that. Snake oil in a nicer bottle, imho.

Can you show one example? Where does he even say anything that could be mistaken for snake oil? He spends a lot of time debunking audiophile myths.

I don't think Agedhorse and I are even disagreeing on anything fundamental. If he says that the 10% THD spec is from intentionally generated distortion in the preamp, this makes perfect sense and would explain a lot.

My original points were only that 1) Purifi modules measure better than the others, in a hifi context, and 2) I don't know if this would be relevant in any way to bassists, but it would interesting to know.

 

[agedhorse]

I don’t believe the Purifi modules measure better and it doesn’t matter one bit for bass applications anyway.

 

[fdeck]

Hmmm... maybe a nearfield scanner needs to be my next DIY project.