amplifier class

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
I am just a beginner on this forum, but it is my impression that Class-D amplifiers are best suited to ESLs.

For example the Hypex (http://www.hypex.nl) modules use a 90V supply voltage, which means that in most cases a 1:50 audio transformer should be sufficient.
Also the output of a Class-D amplifier (see here: http://sound.westhost.com/articles/pwm.htm) needs a capacitor. So the ESL will be just an capacitor parallel to the internal capacitor of the amplifier.
 
Hi,
when Quad brought out their SS amp specifically designed to power their ELS they used ClassAB.

All their subsequent SS designs suit the ELS and ESL and still they are ClassAB, but with a funny feedback system called current dumping.
That must say something.
 
Hi,
Solid state ClassA get so hot you can tell it's not normal bias ClassAB.
There are a few high bias ClassAB around but these usually have heatsinks that get warm to hot due to their smaller size.
Tube/valve amps are difficult to tell apart.
But our tube experts could probably tell from the valve type and B+ voltage.
 
I too am looking for an amp for ESL's. My venerable B&K ST-140 amp, which I was using to drive my ESL's, died last week---at the same time that my DEQ2496 decided it was no longer interested in turning on. I haven't yet figured out what happened in this chain of events, but I find I'm in the market for another amp to drive my ESL panels. I'd rather stick to solid state and not spend a fortune. Have any class D modules been shown to be particularly cost effective and suitable for ESL service? Or as a more conventional (and less diy) alternative has anyone tried either the Behringer EP1500 or A500
amp? I've read some positive things about them, and the price is certainly right. I understand they can handle a low impedance load, but I haven't seen anything about their ability to drive a highly reactive load. Also, I have a feeling the Behringer DEQ2496 brought about the demise of my old amp so I'm a bit wary of Behringer at the moment.
 
Hi,

I can wholeheartedly recommend the HiFi-Akademie amps.

They are a stereo class-d pre-filter-feedback concept for DIY. So freq-response depends on the speakers impedance, but filter components can be easily tuned to suit Your demands.
Capacity (as ESL-manufacturer) recommends and uses them with his panels and they have proved to work exceptionally stable with my panels, which are a real proof with low impedance values and phase angles reaching more than 80°!!! B&Os Ice-Power-modules are for example not specified for the capacitive loads that typical ESLs represent and would start swinging with my panels (or ML-Panels)
I like that the H-As are built with a very straightforward simple signal-path and allow for higher currents than most other designs in their wattage-class. Price is similar to UCDs with Power-supply and You can purchase nice housings too.
Up till now their sonic performance in my setup was just topped by the enigmatic KR-Audio Kronzilla...at slightly elevated costs of course ;) Price/Performance-value is very good.
As an interesing feature it is equipped with a slot where You can put optional crossover modules in (analog as well as digital). So You can easily create a fully active 2way ESL-version.

jauu
Calvin
 
Thanks for the info Calvin. Now I just need to brush up on my German so I can read their site (it will actually take more than a brushing up...). I've emailed HiFi Akademie to ask if they have any information for those of us who are linguistically challenged. I've found the online language translations to be pretty cumbersome. I sure wish I had paid more attention in my German classes all those years ago!
 
OT Warning

Calvin, I read somewhere that H-A will also have a project with DSPs. Do you know anything about this?

<dreaming>

I would be overjoyed if H-A would do a class-D with integrated DSP.

I.e. digital in, EQ and Xover with DSP then feed digitally into a class-D.

</dreaming>
 
Hi Folks,

in germany its not a secret that Capaciti works together with HiFiAkademie.

I have some information about the upcoming (in November) DSP-modul:

1. 2 analog inputs, 2 analog outputs
2. The DSP is rather small since it got no own power supply.
3. The modul can only be used in combination with their Preamp or poweramp. You just stick it into an excisting slot, thats it
4. I have moduls in use in my company for testing. I need to say that the outstanding options of such moduls by far exceed the possible losses, which people mention when discussing about A/D - D/A conversion.
5. Using DSP for "standard" loudspeakers is fine, using it for ESL is the perfect match.
6. For example our "Element 160" which is a small Fullrange ESL shows a fundamental resonance between 35 -40 Hz. And as a principle of small baffle width and limited membrane area ii plays "lean" in the lower midrange. Using the Dsp you lift the lower midrange resulting in significant more volume and body. In addition you set a perfect notch to the resonance, which will increase max soundpressure significant.
7. You connect the modul to the parallel port of a PC and do the programming by software. It shows you anything and you can load excisting graphs of measurements.

Out of my experience there are DSP's which really compromise sound quality at all, but the HiFiAkadamie is close to just a wire connection of components!

It might appear that i "glorify" their components due to my business connection, but if you would read all the feedbacks in different german web-chats, you will know why.

Capaciti
 
Thanks Capacity,

Considering that a class-D amplifier is not really a D/A converter, having the DSP as a drop-in solution seems ok to me.
[Note: A feedback loop in the class-D would necessitate an A/D if it were to use a digital input]

A DSP in a class-D sounds great. I am looking for something like that but will wait for november :)
 
willyhoho said:
I am looking for a amp to drive my esl. I am confused when looking in this forum as to the class designation the amp should have. Can someone please clarify this? Do tube amps have different classes too?
Thanks


It appears that this thread has accumulated a great deal of speculation, but not much in the way of actual response to the original questions.
1) There's not a class that an amplifier "should" have in order to drive electrostatic speakers. Any of them can do the trick.
2) The most common classes are A, AB, B, and D. Yes, there are others, but those four cover 99.999% of the commercial amplifiers on the market. In case you were wondering, yes, there is a class C, but it's only of use for radio transmitters; it's not something you'd want to use as a high fidelity amplifier.
3) Tube amplifiers have classes, too. A, AB, and B. It's technically possible to have a class D tube amp, but why on Earth would you want to?
4) Class A is the best from all sonic points of view, but it runs much hotter, is larger and heavier, and costs more.
5) Class AB and class B each have their adherents, but they argue endlessly over the crossover distortion (when one set of devices hands the signal over to another set of devices and turns off) and other technical points that may or may not interest you. In general, it's better to have as much class A as you can get, so in a race between a class AB amp and a class B amp, I'd favor the class AB.
6) Class D? Well, let's see, they're lightweight, often cheaper, run cooler...and there we run out of benefits. Sound quality? If you put music in, sound will come out, but I don't know of a single critical listener who would take a class D over A, AB, or even B. The technology just isn't ready for prime time. On the other hand, if you're just looking for a lot of cheap watts so you can get loud, maybe they're the ticket. But if someone gave me one, I'd use it for background music in my shop, not in my audio system.
7) DSP is conceptually seductive, but not quite ready for high end use. The same thing can be accomplished with analog circuitry, albeit with a little more work on the part of the user.
8) Class D and DSP together? Shudder... I've got sandpaper in my shop. It would be cheaper and simpler to scrub my ears with 100 grit rather than go to all the trouble and expense to put those two together in a high fidelity system.

Grey
 
In case other non-German speaking audiophiles are considering the class-d Hi-Fi Akademie products to drive their ESLs I thought I'd pass on the response I received from them when inquiring about product information in English. Perhaps others with more experience with the amps can offer an opinion about whether they would be a reasonable option even without access to the information. Based on this response it doesn't sound promising.

I have all documentation in German only. Currently I have no plans to make an English version available. Whilst I could provide you with a price list and brief product information, this would probably not help much because you would also need the remaining information to actually build and operate the amps.

Thank you for your interest and apologies that I cannot help you further.
Best regards
Hubert Reith
 
Member
Joined 2004
Paid Member
If they made everything available in English, they would experience explosive growth in interest, and that would kill their reputation from the negative word-of-mouth due to the backlog. A fledging company needs very controlled expansion, so let's give them some time...

Or is there more behind their reasoning? (This goes for Capaciti-DIY also?)
 
Emails and postings are notoriously easy to misinterpret. In fact, I may be misinterpreting Tosh's. Just to be clear, it was not my intent to impugn the folks at Hi-Fi Akademie. They responded politely and promptly to my question and I'm sure they have good reasons for their policy. I was just passing on the message I received from them in the hope it might save someone else the trouble of emailing Hi-Fi Akademie---and save Hi-Fi Akademie the trouble of responding again.
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.