John,
Thanks for asking George that question as I forgot and really very puzzled as to where he got that from.
Henry |
"The only negatives to class d is driving the exotic speakers,the ones that drop below 3ohms."
Kenny,
I believe it is all about system synergy and listener's preferences. I have class D driving the Apogee Scintillas just fine. The Scintillas's impedance is 0,8 ohms from 20Hz to about 2 KHz, and about 2ohms from there on up to 20KHz.
Henry
|
Hi Kenny,
Just to be clear so that there is no misunderstanding that I am not here to advertise my product. I am the manufacturer of the H2O AUDIO amps as some of you here know. But since you are asking, for over 10 years I have used the icepower modules, and specifically the 500A and 250A modules to drive my Apogee Scintillas. These are rated at 500W/4 and 250W/4 respectively. Recently, I have the implemented the NCore 400 modules just to see/hear what is the rave is all about. And it appears that the NCore 400 drives the Scintilllas just fine with one caveat. I have not really push it hard like I do with the icepower modules. And the NCore is still relatively new and is still being breaking in. As for SYNERGY. I really think it is very relevant in any discussion especially with any audio discussion. I will elaborate at a later time as this can take pages to get my point across.
Erik,
I use the icepower 500A and 250A modules. The 250A module which is rated at only 125W/8 but can drive the Scintillas with no problem. For those who are not familiar with Icepower, these modules do not come with the integrated SMPS. I design the H2O amps with my own home brew power supply using these amp modules. Biamp is always better with apogees which I have tried occasionally, but my system is currently configured as single amp with biwire.
Henry |
Hi Erik,
Well, It is not rated doesn’t mean it can not drive it. It is just that the designer didn’t test it with such a load. The same goes for the NCore. And to be fair, Apogee is no more for many many years and very few own the 1 ohm scintillas. So it is not a very popular speakers so there iI can see why there is no point in testing the amp with such a load. No worry about impedance, it is low enough, besides lower output impedance is not necessarily better or conversely, high output impedance is necessarily bad as you can have too much of a good thing knowhatImean :-)? I think you read a bit too much into spec at time. Don’t get me wrong. I am not saying that spec is not important It all depends on the system as I have alluded to. No I have not measured the Scintillas with these amps.
Kenny, Thanks for the good wishes. And yes I will keep you posted as long as no one here thinks that I am here to sell products :-). The H2O Special Edition uses the icepower modules 500A. has 1KW transformer and lots capacitance filtering reserves. I have implemented with many other goodies which is too long to list here. These are rated at 250Watts/8 and double that into 4 ohms. Don’t let the power fools you though. These will put the biggest boat anchors from Krell, Levinson and the likes into shame when it comes to liquidities, smoothness, extension, control subtleties, dynamic, composer when push hard :-). And should I go on? Oh even some class D too. LOL.
BTW, I spent 2 hours wrote about 3 pages long. Took a break and came back to continue and everything I wrote disappeared. This stupid computer. Not sure what happens.
Henry
|
Hi Erik,
I will elaborate at a later time since I lost all 3 pages which I wrote, seriously. But very briefly, I am not asking you to believe anything I say of course! until you hear it. In fact, I don't want anyone to take anything I say as gospel actually. I wish you can hear it in my system for yourself. Even then, you might still disagree with me after hearing it, but that is just fine as different people hear different things in the same system and more importantly each listener might consider different aspect of the sound as more or less important. This is what I have alluded to previously when conversing with Kenny. Just so you know.
Hi George,
"There is no way an Apogee Scintilla will sound anywhere near it's best driven by ANY class-d, and they could just switch off or blow up."
You SEEM to be knowledgeable about audio but I am truly surprise at some of the statements you just made. Actually, I have seen your same statement being made at some other discussion as well. You seem to be all about theoretical stuffs. So with your statement which I quoted above... So let me be a bit blunt here. Have you ever own the 1 ohm Apogee Scintillas in the past? Do you currently own them? Have you designed an amp of your own design to drive them? Have you heard a class D amp driving the 1 ohm Scintillas? Have you personally heard an H2O amp driving the 1 ohm Scintillas? and if you did, did the amp blow up? I have the scintillas for about 20+years now. and Yes I have designed amps specifically to drive them. Conventional discrete transistors pure class A design that is. Since you mentioned about the big krells, so how about 80watts pure class A amps dissipated 1000watts idle weight 200 pounds with over 1 Farad of capacitance reserve. Two 1KVA transformers for the output and twin 250 VA transformers for the front end and makes most Krell and Levinson amp look small. I wish I can post some pictures right here just to show you. Now I am not all about mine is bigger than yours but since you mentioned the Krell Master Reference amp. Well, I am sure it can hack the 1 ohm Scintillas without sweat. Krell amps are pretty good in my opinion and many still love them to this day. But then suggesting only those big Krell can drive the Scintillas properly and sound good? Can drive it! I agree totally no questions! Sounding good? Well that is just a matter of opinion and that is your opinion which is perfect fine. And the same goes for my opinion. And here is my opinion. The H2O icepower based amps can put all these big krell and Levinson boat anchors and the likes into shame across the whole audio frequency spectrum. Talk about dynamic, transparency, extension, Bass power and control, not sterile and one note or bloated bass mind you, midrange liquidity, imaging, staging, composure at loud listening level, subtleties and should I go on??? But remember this is only one man opinion which is mine. Actually, I know a few Scintillas owners happen to agree. But still, that is still not the majority. And as for class D blowing up while driving the 1 ohm Scintillas, Well all I can say is NOPE!!! Not here at least for the 13 years or so while some the big SS boat anchors either blow up and/or going into thermal shutdowns.
Henry
|
Kenny,
Unfortunately, I am not very well equipped with instruments to perform such tasks.
Henry |
Erik,
There is no misunderstanding at all and I apologize for my writing not being very clear at times. I understood completely what you asked, and that is you want to see is the real frequency response plot of the amp while driving such a load and also to determine what the 3 dB points are for both frequency extremes. Again, the answer is NO. I have not done the measurement. Because of the output filter of the icepower, and most of class D amp, I would speculate that there will be some high frequency attenuation at very high frequency due to the impedance raise of the inductor.
What I meant by lowest output impedance of the amp, especially completely flat up to the extreme treble region, is not necessarily always good is that it depend on the system. IMHO and IME, extreme low output impedance amp does not sound very good when mating to a highly damped loudspeakers. This is the very reason why tubeohiles really object to solid state amps, especially those with lots and lots negative feedback, to lower output impedance and distortion. The end result of such mating results in a sterile and one note bass and everything is too tightly control. Therefore, there is not much left in terms of air around instruments, much smaller soundstage, Closed-in midrange,
harsh and sterile treble etc... I am speaking strictly in terms of conventional discrete transistor design. I have designed, built, test, tried this and tried that for as long as I can remember. I agree with you about experience. There is no substitute for that. Also, Absolutely! Apogee did put Krell on the map for sure.
Henry
|
John,
It is very rare to find a Scintillas owner. Are you located in Texas?
Henry |
Erik,
Just to add a bit about the Scintillas. Sure, they are closer to a short over the entire audio frequency spectrum than any other speakers to date. It is not that hard to design a conventional linear class A amp to deal with that which I have done. But what compounding to the low impedance problem is their efficiency, and if I remember correctly, Stereophile’s measurement came up with was in the mid 70 dB or so. And Here is where it is an equally challenging task to deliver substantial power into such low impedance and inefficient load.
Henry |
Thank you Erik for starting this thread. Since I am a manufacturer and of Class D at that. Therefore, I am obviously biased. So I think my comments isn’t worth much and rightly so I suppose. Anyway, I won’t get into endless debate on the technical mumbo jumbo, rather to say that class D CAN (and this is the key word) sound extraordinary. Then again, the same can be said for tube, conventional class A and class AB design.
Henry |
Hi John,
Thanks very much for the tip on the microphone and the software. I will check it out. Sorry you have to give back the Scintillas.
Erik, Agreed. The room plays a big part as well and among other things.
Kenny, Looking forward to your review, especially the difference compared to the Ncore.
If anyone here interested in hearing the H2O, I am willing to send it for you to test drive in your system. No string attached of course. I would be very interested to read your review on the differences, especially compared to the Ncore and other icepower amps that you have. Please remember though, the H2O has 8 kohm input impedance so you should have an appropriate preamp to drive it properly.
Henry |
