Stereo HiFi amplifiers come in many different flavors. Class A, Class AB, and recently Class D has entered the fray.
You can do a Google search to understand Class A and Class AB…….
Class D is best described here: (From Wikipedia) https://en.wikipedia.org/wiki/Class-D_amplifier
A class-D amplifier or switching amplifier is an electronic amplifier in which the amplifying devices (transistors, usually MOSFETs) operate as electronic switches, and not as linear gain devices as in other amplifiers. They operate by rapidly switching back and forth between the supply rails, being fed by a modulator using pulse width, pulse density, or related techniques to encode the audio input into a pulse train. The audio escapes through a simple low-pass filter into the loudspeaker. The high-frequency pulses are blocked. Since the pairs of output transistors are never conducting at the same time, there is no other path for current flow apart from the low-pass filter/loudspeaker. For this reason, efficiency can exceed 90%.
I’ve built a number of amplifiers during this whole Covid lock down……A Tubes4HiFi Dynaco tube clone amplifier (60 watts/channel) and a s5Electronics K-12G four tube amplifier (8 watts/channel) and reconditioned a Pass Labs First Watt F5v2 (50 watts/channel) that someone else built.
You can read all about these HiFi adventures here:
But I didn’t have a really good Class D amplifier…..And I didn’t want to spend a lot of money on one.
Many many top of the line manufacturers are stating to use these exact same ICE POWER modules in their premium amplification products. https://icepower.dk/buy/asc-series/200asc/
There are two YouTube channels that feature these new Class D “ICE” amplifiers in a DIY format.
If you go to these YouTube channels they give you a very good idea of what is needed in your skill set to build one.
Here’s my story….
I decided to build the 200w/channel version and put it all in a premade cabinet that includes all the wires and hardware.
The amplifier boards were purchased from Parts Express. They offer a number of amplifier, preassembled boards with power rating of up to 1000 watts!
I decided on 200 w/channel as currently I’m not using any amplifiers over 100w/ch so 200 should be plenty.
You need two boards to build the amp I assembled
The main board “ICE POWER 200ASC” which contains the amplifier for one channel and the power supply for the whole amplifier.
And the second board is the “ICE POWER 200AC” which is a slave board for the second channel
For a cabinet and hardware, wire kit, etc, you need to go to China. Ghent Audio will set you up with a cabinet for whatever amplifier boards you decide to use. I bought the “200ASC+200AC Dual Mono DIY Case Kit”. (If you decide to order a cabinet, pay the $25+/- for expedited shipping, otherwise you could be waiting weeks if not months. I paid the extra and had the cabinet in 5 days)
Putting the kit together is really quite easy. But there are zero instructions included with either group of parts. The two YouTube channels above are really all you need.
The only soldering is on the balanced input jacks and a few wires need to be cut and soldered to gether. For the wires, you could use good crimp connectors. But the balanced jacks really need to be soldered. Otherwise, it is all plug and play.
I built my amp in 1.25 hours……And it worked perfectly on first start up.
A few things to be aware of. The color code of the included wires are all over the map. None of my wire colors matched any of the YouTubers wire colors. But just follow the directions “point to point” and you will be good to go. I had my laptop on my assembly bench and did a whole bunch of pausing and backing the video up to understand what wires when where.
The finished amplifier is quite small. And doesn’t weigh much. This aids in the assembly process.
Folks want to know the specs…https://icepower.dk/buy/asc-series/200asc/
|Output Power 1 % THD+N, 20 Hz – 20 kHz||230 W (4 ?)|
|Minimum load impedance||2 ?|
|Maximum amplifier efficiency||–|
|Maximum total amp+psu efficiency||79 %|
|Supply voltage input||85-264 VAC|
|Peak output current||12.5 A|
|Dynamic range||110 dB|
|Amplifier maximum output voltage per channel||43 V|
|Output referenced idle noise (A-weighted)||90 µV|
|THD+N 1W/1kHz||0.006 %|
So there you have it, for around $300 you can have an amplifier that rivals amplifiers costing a few THOUSAND dollars…..Do a search on YouTube for all the fantastic reviews these ICE Power amplifiers are getting…….
And….A very interesting morning…..At 9am FEDEX delivered my Ghent cabinet for an ICE amplifier build from China…..The amplifier boards showed up from Parts Express a few days ago. So I tear open the boxes and in 1.25 hours the amplifier is done. So simple to assemble, but no instructions. Using two YouTube videos I got it done. But it uses balanced inputs and I don’t have the adapters. I ordered them yesterday morning from Amazon……I plugged the amp in to just see it light up and as I did, like magic, my doorbell rang and the Amazon guy was handing me a package of balanced adapters!!!…….The amp works great. Lots of power and extremely quiet. Can’t hear a peep even with ear against speakers. Will be breaking it in and listening at length this evening…..
Be sure to check out my whole web page… http://rvbprecision.com/
Finally got around to some serious listening of the ICE Power Class D amplifier I built yesterday. I could easily live with this. Not fatiguing at all. Great low end response! Loads of power for the KEF LS50 Metas. Imaging and sound stage as good if not better than my other amps.(First Watt F5v2, VTA St120 Dynaco clone). A bit more sparkle in the highs compared to the other two. Not objectionable by any means, but in my very dead listening room, it might be welcomed. So far, all in all, a pretty nice $300 amplifier!
Back in school days getting a “D” was a bad thing. I had friends that got very good at changing a D to a B on their report cards! But I’m here to tell you that in this case, a “D” is a VERY GOOD thing. I’ve been in the HiFi retail business for near 50 years. I’ve had the luxury of being able to audition dozens if not hundreds of higher end HiFi components at home for extended periods of time. It always boiled down to “Length of Listening”….Some amplifiers and/or speakers were simply unlistenable for longer than 30 minutes or so. They were somehow fatiguing and I would simply shut them off and do something else. Many of these items were amazing on first few minutes of listening, but then grew very tiring and just not interesting to listen to the music any longer. Some components would put me into some kind of HiFi nirvanas and I’d be listening until the wee hours of the morning. I simply didn’t want the session to end.
Well, last night was one of those LONG nights! Using the ICE amp with a Zero Zone Conrad Johnson clone tube preamp and a Node2i/Gustard X-16 DAC playing Tidal direct, into my KEF LS50 Metas, I was smitten! And I didn’t hit the sack until well after midnight.
This amplifier defies all logic. $300, Kit Built, sparse parts, the size of a small box of cigars, doesn’t even get warm…….and it holds fort with my acclaimed Nelson Pass First Watt F5v2!…….But it has better bass!
Maybe it’s my near 70 year old hearing. Maybe I’m easily sonically pleased. But I don’t think so. During COVID, I’ve bought so many amplifiers and other HiFi gear and returned it because it sounded horrible. I can’t hear anything above 15Khz, but I can hear sound stage, imaging, air around the instruments, dynamics…..and I believe these things are more important to good HiFi that frequency response. And this ICE amplifier offers these attributes up in shovel fulls!
The question I now have to ask…..How much better does a $XXXXX.xx Jeff Rowland Class-D amplifier sound? Diminishing returns you say?
Yup, we got ourselves a VERY interesting hobby!