ELAC Alchemy Collection DPA-2 energy amplifier
Once upon a time, in the early days of Class D amplification, the idea that the ELAC (ELectroACoustic) Alchemy DPA-2 stereo / mono power amplifier ($ 1,495 each) used a Class D output stage , caused some readers to turn the page (footnote 1). But as Class-D amplifiers established their pedigree as true hi-fi components, audiophiles began to embrace the idea of a lightweight, cool-running amplifier that doesn’t dramatically increase the electricity bill and is perfectly possible when properly performed in a musical.
Others, however, may still oppose the suggestion that this thin, 14-pound Class D device from the American division of ELAC Germany, auditioned here in a bridged monoblock configuration, can bring the heart of music to listeners . Perhaps the realization that the DPA-2 was designed by Peter Madnick, who also oversaw the design team for Constellation Audio and expressed all of its products, will encourage them to explore further.
Peter Madnick on the DPA-2
When developing the DPA-2, which combines a Hypex UCD Class D output module with a Class AB input stage, Madnick worked with ELAC’s power supply developer to prepare the switching power supply that will deliver the juice to the Class D module . With experience developing nearly 400 products, including 20 or 30 amplifiers for multiple companies, he and his team designed everything but the case. Cosmetics were left to another ELAC team.
“We didn’t spend a lot of money on design aesthetics,” Madnick admitted during an iPhone chat. “It is not a beautifully ground jewelry.” Even inside, “these amps are very simple. I don’t want to make them any more than they really are. There’s nothing like this product and Constellation.
“My goals were broad market attractiveness and good value for money. I’ve always been very good at value engineering? I’ve decided where to spend the money and where I shouldn’t. We wanted to make it easy and simple . ” To take with you and install, and able to walk without emitting a lot of heat or consuming a lot of electricity when it’s on. I wanted as high a performance as I could cram into a unit height chassis that is the standard 1¾ “Vertical Distance Between Holes on a Pro-Rack.”
Sonically, Madnick’s conclusion was that the DPA-2 had to sound like live music. His inspiration came from four decades of regular participation in symphonic performances, often with season tickets, which currently brings him seven rows back to the middle section, where the combination of direct and reflected sound has maximum impact.
“I wanted to offer the kind of transparency and clarity in real life that you wouldn’t expect at the price, plus an overall balance sheet that would make you say, ‘Wow, this thing is really good for the money.’ My goals included dynamics, clarity, and the opposite of the bad reputation that Class-D had (although we all know good-sounding Class-D amps exist) I’ve played with all sorts of Class-D designs When they came out, they all sounded “digital.” To me that means harsh, unmusical, irritating, incoherent and sewn together from low to high. This is what early D / A converters sounded like, and some still sound that way. It was a Sound I couldn’t have. Until we did I was able to find modules and techniques to make sure they didn’t sound like that. I didn’t want to introduce a class D amplifier. ”
Madnick had numerous amplifiers on hand – his own designs – for comparison. He also checked with ELAC speaker designer Andrew Jones if he was satisfied with the sound. Madnick listened with multiple speakers from different brands and asked his speaker pals to rate his prototypes to make sure they would work with their models.
The input stage of the DPA-2 is a fully discrete JFET design that accepts both single-ended and balanced inputs. It also converts single-ended to balanced, so that the class D modules are controlled with a symmetrical signal. The amplifier is fully DC-coupled: no capacitors in the signal path. The potential for a DC offset is eliminated through the use of servo technology. According to Madnick, the input stage generates a very clean, low-distortion, symmetrical signal that drives the Hypex modules without feedback. He also noted that the DPA-2s don’t get particularly hot – nowhere near hot enough to warm your hands after shoveling snow – and are about 93% efficient when you play them loudly. “The louder you play them, the more efficient they become,” he said. “400 watts on the output jacks mean that you are using approximately 430 watts.”
The DPA-2 can function either as a stereo amplifier or as a monoblock. Madnick says you can’t damage it if you accidentally switch it to mono while playing in stereo. The DPA-2 is bridged in mono: the left channel generates the positive phase of the signal and the right channel generates the negative phase. Madnick says the DPA-2 could run into “any” impedance and should work fine with my reference Wilson Audio Alexia 2s.
Some of Madnick’s choices piqued my curiosity. After he called the amp a “hybrid” I asked why. Because it “connects a traditional JFET analog input stage powered by a linear power supply to a class D PWM output stage that uses a switched-mode power supply,” he replied. “I made a mistake early on when I named the amplifier with the initials DPA [for digital power amplifier]because these amplifiers are not digital. Class D is a PWM [pulse width modulation] Technology that is more analogue than digital (footnote 2). But I kept the bug in order to maintain consistency between the DPA-2 and its predecessor, the Alchemy DPA-1. ”
Given the linear power supply he’d used for the DPA-2’s sensitive input stage switching, why did Madnick choose a louder switching power supply for the Class D modules? “Through years of experiments I have found that switching power supplies in Class D modules is okay. Noise is not a problem with them.”
Why did he use an older Class D module? “I’ve been listening to the newer Hypex NCore modules … Honestly, I don’t care that they measure better; they have to sound better and, to me, not. I know that for a large part of the world, Class D module- Market, specifications are a really, really important, critical criterion. But we all know that things measure great and don’t sound good and vice versa. ”
I’ve known Madnick for a decade and a half and I’ve taken the liberty of asking if there’s anything in retrospect about the design that he might have done differently. “If I could have done it again it might have cost more money, but it could have produced up to 700 Wpc in mono,” he admitted. “The specs may have been more impressive, but the specs aren’t what I’m selling.”
Outside, inside and on the rack
Hallelujah: The DPA-2 comes with a manual – actually two, one in each monoblock box. The manual is also available online. In my recent experience, newer and more expensive components are less likely to have a manual.
Setup was a breeze for 14 pound amps which, if they had dog friendly handles, could have easily dragged one of our 21 pound terriers across the floor. In fact, dogs, babies, and even adults could easily knock the amplifiers off their shelves or equipment racks if they are not careful (footnote 3).
Footnote 1: In the comments that followed my first stereophile review of the Dynaudio Focus 200 XD active speaker, “georgehifi” stated, “There are many of us who ignore Class D.”
Footnote 2: Read Bruno Putzeys’ opinion on this topic here.
Footnote 3: I’ve used stiff, heavy-duty power cords that could likely pull a 14 pound amplifier off the shelf, or at least throw it off balance. But then probably not many DPA-2 buyers will be using power cords that cost many times the cost of the amplifier like Jason does