Digital amps

Rodrigo de Sá

Rodrigo de Sá

This club's crushing bore
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I am thinking of building a system not for music reproduction but for music making.

The idea is that you have a Mac, a few programs and a sound bank taken from real organs.

You link the thing to two midi keyboards and a pedalboard which feed an amplifier and speakers.

The amplifier should be powerful, go very deep and strongly so and be superlatively transparent. Of course, all this is very expensive.

But I've read something about digital amplification: it seems it is cheap, transparent and very powerful, with splendid bass.

I own a Lavardin IT coupled to a Proac panel tweeter pair of speakers (the truncated pyramids) and while this is good for home listening, it would be difficult to do justice to a large reverberating room (say 5 meters high, 6x4).

So, suggestions, opinions, everything, please.
 
Please be very careful with terminology...

Some people call any class D amplifier a "Digital" amplifier because the output (before the filter at least) is two-state. It is important to distinguish between digital input class D (eg sony s-master, TI, Apogee DDX, Zetex DDFA) and analogue-input class D (eg Hypex, UCD, ICEpower, Tripath, Zetex ZXCD).

In terms of what are you looking for comparison? The best digital input class D amplifiers can offer enormous power, high efficiency and performance better than linear amplifiers - either valve or SS. The worst class D amplifiers can be pretty dreadful.

You're looking for big, powerful bass.... This is a tricky area. Open-loop switching (class D) amplifiers have poor damping factors (ie high output impedance) - perhaps 40 into 8 ohms. Closed loop with post-inductor feedback can be superb (DF of several thousand) in this regard. However, there are difficulties in creating a closed-loop amplifier with a digital input.

Beyond that there isn't much I can say without possible accusations of bias or whatever...
 
I'd approach the problem from a slightly different perspective. To stand a chance of accurately emulating a large pipe organ you clearly need to shift a lot of air. This means big speakers. My personal choice for the task would be some very large and efficient horns such as Klipsch or 15" Tannoys or similarly big JBL monitors. It's not bass extension you need as such (though it is useful), it is the ability to push a really large quantity of air with ease and nothing but a really big speaker with big drivers can do this. The type of speakers I mention tend to be efficient and could do the job perfectly with very small amps of any type, though ultra-efficient speakers such as say Klipsch corner horns are far better served by small tube amps.

Tony.
 
Rodrigo de Sá said:
Ok, I'll rephrase:

How do digital amps fare against SS and valve?
Click to expand...

Different in one word.

Some like them, others hate them, so you do have to be careful.

Against SS amps they are very transparent, clear, pacy and do not have that sharp edge you can get with some SS amps.

Against valves they are clearer, sharper without that slow softness that can pervade some valve amps.

Downside: RF can be a problem. The tend to 'tell it like it is' which might not be what you want to hear. They can sound glassy and their timing can be off compared to SS amps.

If you want a clear, dynamic, detailed sound they could be for you. If you want a nice sound that doesn't grate (even on poor recordings) then you may not like them. See the threads on coloured/transparent sound---valves vs SS; which side of the fence are you should dictate if you want to hear them. If you like the sound you will love them as they have it in spades.
 
Tony's got it about right TBH. Massive (pref horn loaded) cabs are what you need.

I did a thread on 'living voice prototype' speakers here on ZG. They had 6ft x 6ft snail shell bass horns, all part of a 5 way system.

That would be my ultimate 'organ' repeating device.

http://www.pispeakers.com/catalog/product_info.php/products_id/107

i AM going to have these Pi 7 corner horns one day. I simply am.

15 or 18" woofer in a corner horn, 10" horn loaded mid-range, compression driver (horn loaded) for a tweeter.

They should give what you need.


Oh yeah, you'd be alright with a little amp - but they have the powerhandling if you want to go BIG!
 
im a real fan of the bel canto class D based amp... i find the ref1000's to be smooth, relatively forgiving of poorer recordings, yet open and detailed at the same time.

They are also capable of driving pretty much anything and will throw a genuine 1000watts into 4 ohms if need be.

A friend of mine has a pair running into focal 1047be speakers and such a system provides excellent air shifting capabilities with a very physical sound.

At the slightly cheaper end the S300 is also excellent, but is perhaps less happy with difficult speakers, offering slightly less weight to the lowest end. It does however, sound incredibly musical within its limitations.

If you fancy a look at class D analogue input amps on the cheaper end, look at acoustic reality's website. They have the same 1000w module as in the ref 1000's in an amp called the 1001-ref. Its not quite built as well as the bel canto, but should in theory sound all but identical, for considerably less money.

If you fancy solid state, im also a big fan of the cyrus monoX, its a fantastically linear amp that extends cleanly to the very lowest end of bass with no overhang. It is capable of driving pretty much anything, and has plenty of current on tap.
 
George Sallit said:
Different in one word.

Some like them, others hate them, so you do have to be careful.

Against SS amps they are very transparent, clear, pacy and do not have that sharp edge you can get with some SS amps.

Against valves they are clearer, sharper without that slow softness that can pervade some valve amps.

.....

If you want a clear, dynamic, detailed sound they could be for you.
Click to expand...


IME George is spot on (I've owned quite a few Class D amps - and I love their sound).
 
Thank you for all the answers.

There are two or three bits of information I should perhaps have given.

I do not have a huge amount of money ;)... I read that the best solution would be to have several small speakers (but then this ought to need a different kind of amplification) of the monitor kind plus a powerful sub. Of course the Klipsh really are waht I'd like to have, but, as I said, I am not rich...

About my sonic tastes. When I was searching for a system, I thought I would go into valves because all SS were horribly spitting. There is a liquid quality in valves that I greatly enjoyed. But then valves do get a little blurred in the bass and transparency is not their forte. I call this the resolution ability of an amp, as with cga, vga, super vga, and later.

My choice finally fell in the Lavardin precisely because it was rather transparent but not whispy. That said, while it is rather good in the treble and can be quite realistic with harpsichord, guitar, and voices, a big organ or orchestra do sound compressed and I think a little spitty (all is relative: truth is, I found nothing best).

I bought the yellow banded Meridien CDP (the white banded one was too aggressive in the treble even if it was more expensive) and I spent almost a year searching for speakers - the proac futures did the trick because of their silky treble.

What I still find about every system is that the natural resonance of the real instruments is lacking. Take a guitar and just pluck the lowest note: it is deep, warm but dry and very resonant. I never listened to that in any system, even the extremely expensive ones.

My hearing is, of course, getting worse, but I am still quite capable of listening to bats... I have never had a good hear for really low basses (under 25 Hz). But what I think I have above usual people is the capacity to unravel timbres and to listen for distortion - that truly horrifies me and that is why I always listen to music rather softly.

For those who wish to delve into the thing I'm after, look here
 
The Pi 7's are really an updated version of the Klipsch horn, improved upon if you like.

The K.Horn was one of the designers favourite speakers, and a starting point for the 7 corner horns.

If you're skilled at DIY I'd consider buying the plans (available) and the drive units. You could build them for about £1k.
 
The objective is to play at home, but in a setting as close to a small chapel as possible. Indeed, the house is in project, and I am planning a music room in which to house my harpsichord and, at another level, the organ. The room cannot be very large, but it can be high.

I plan to play for myself and occasionally for some selected friends, but I would like it to be very realistic. I am extremely reluctant to buy an electronic organ: I had two and both sucked. It seems the Hauptwerk system is rather good and, anyway, I cannot afford a real organ - even a small one will fetch about €15000, and it is boring to play on just two or three stops.

Thank you for the link, I will investigate it.
 
Rodrigo de Sá said:
The objective is to play at home, but in a setting as close to a small chapel as possible. Indeed, the house is in project, and I am planning a music room in which to house my harpsichord and, at another level, the organ. The room cannot be very large, but it can be high.

I plan to play for myself and occasionally for some selected friends, but I would like it to be very realistic. I am extremely reluctant to buy an electronic organ: I had two and both sucked. It seems the Hauptwerk system is rather good and, anyway, I cannot afford a real organ - even a small one will fetch about €15000, and it is boring to play on just two or three stops.

Thank you for the link, I will investigate it.
Click to expand...


Am I missing something here? Dosn't the Organ have an Amp inside. If the purpose is to have a device to play the organ for you why would you want to mess it up with electronics?


rollo
 

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