Building a Hypex UcD700-based power amp
Over the past couple of years, Hypex electronics have been gathering an increasing
reputation for their class D amplifier modules. A flick through diyaudio.com
reveals many pages devoted to just this company's products. Latterly,
HiFi World magazine have reviewed some comercial
designs employing these modules and have been very impressed - Noel Keywood, in particular, noting that they measure better
than other class D designs he's so far come across.
Of course, even a year ago, I'd never heard of these amps. It was a friend who came across them. To cut a long story short he was looking for something that would drive a pair of 1 ohm (or less) speakers. The number of speakers with that kind of load can probably be counted on the fingers of one hand. To save you guessing, we're talking about a pair of Apogees, the Scintillas, in particular. At first, likely candidates encompassed the usual Krells, assorted American esoterica to less obvious fayre like a number of highly regarded Japanese domestic-market-only class-A monsters. Either way, we agreed that his current Naim 250 might struggle just a bit...
For various reasons all of the above came to nought. This is where my friend came across, first, the B&O 'ICE' amp module and then the Hypex stuff. It was then that a plan was hatched...
Of course, even a year ago, I'd never heard of these amps. It was a friend who came across them. To cut a long story short he was looking for something that would drive a pair of 1 ohm (or less) speakers. The number of speakers with that kind of load can probably be counted on the fingers of one hand. To save you guessing, we're talking about a pair of Apogees, the Scintillas, in particular. At first, likely candidates encompassed the usual Krells, assorted American esoterica to less obvious fayre like a number of highly regarded Japanese domestic-market-only class-A monsters. Either way, we agreed that his current Naim 250 might struggle just a bit...
For various reasons all of the above came to nought. This is where my friend came across, first, the B&O 'ICE' amp module and then the Hypex stuff. It was then that a plan was hatched...
This is one big amp. Aside from the actual Hypex UcD700 amp module (which is small), the case had to accommodate a 2000VA transformer and 8 33,000uf smoothing capacitors. These components are probably far in excess of the size they need to be - things did get a bit out of hand at the component ordering stage. There are plenty of warnings about over-sizing things like transformers and smoothing capacitors. I guess we'll find out later...
My friend sourced the major components as well as the case. The latter, I believe, comes from Taiwan. It's 19" wide by 24" deep and about 7" tall:
Despite the enormous size, the side rails (drilled for a few hundred T03 devices) and heatsinks steal a lot of room. This actually made space at something of a premium, as we'll see later:
The above pics show the aluminium base-plate to which the capacitor bank will be fixed and the power-amp brackets. The latter are short lengths of 3"x3"x1/8" cut to suit. There's also the front-end power supply board and soft-start module of which more later.
