Kits built and working
So... It took me a while longer than I thought to get it all up and working. I ran into some problems that, I believe probably had nothing to do with the actual kit. Here's the story:
I built the first board and went to test it. Unfortunately, none of the LEDs came on but one of the capacitors did bulge on me. I thought to myself, crap I did something wrong. The power supply made some weird noises, which I figured was probably due to the board I had just built having a problem. Ok onto build the second kit.
I put the second kit together and gave it some power. No lights, but my PS was still making some odd noises. And then, the PS gave out all together. I figured I had put two boards together and they had both managed to kill the PS. Bad news. I was on the verge of giving up.
Pause for a few weeks, a buddy of mine comes over and we have some beers. I showed him my boards: I was proud how awesome they look despite not working still. We both agreed that the CAP was certainly toast on the first board, but he asked me a simple question "Well did you try to hook some speakers up to the second board and see if it works?" "No, the PS died, and I don't want to risk my toroid/PS to testing anymore." "Come on, let's give it a try." Ok, sure beer and electricity sounds like a great idea. ;-)
We wire it all up, power it on - no lights still - but now there's a speaker hooked up and an audio source. I hit play. Wow. Awesome. It works. Turns out there is nothing wrong with the second board, except that I installed the LEDs backwards. Pulled the LEDs, swapped polarity and boom its all perfect.
So today, I replaced the cap on the first board, and also reversed the LEDs and boom its working perfect.
I'm left to wonder - did a bad cap on the first board kill my PS, or did my PS kill my board, or maybe I just had a bad cap and a bad PS. Who knows? It all works.
So here's my impressions:
1) Build - this build was actually quite easy. My first soldering project was an elenco am radio kit, which was really for kids. This was my second project. The documentation is quite good, and the kit was complete except one resistor. The resistor, R43, was apparently added as a revision and is not in the BOM in the docs, but was in the foot notes. At this point there's only one thing I'm unsure of on these boards and that's the thermistor: should it be touching the heatsink or just free standing near the heatsink? I don't know, and I believe it only really matters if I plan to run this thing at extreme power levels without adequate ventilation.
2) Support - I emailed Cristi a ton. In fact, a massive amount of emails went back and fourth between he and I. I'd say that the support was fantastic - better than can be expected for a $30 board+components. It's hard to debug things from the other side of the planet, but her certainly did invest a lot of effort in trying to help.
3) Sound - sounds fantastic. I have a CDA254 and 50ASX2 to compare to. To my ears sound quality is way up there. I found one thing weird, or great, or something I'm not sure. I'm driving it from my PC using a Tascam US-122MKII. The other boards, when I drive it with the volume all the way up get very loud but will distort at a point. I can drive this at 100% volume without noticing distortion, but it doesn't get as loud as I expected. I'm not sure if this is an impedance matching thing, or it's expecting a higher voltage source? Either way, it gets plenty loud driven from that source - louder than I'd realistically subject my ears or speakers to anyways.
In conclusion, I was able to build this with what is really the bare minimum of experience and it worked out for me. I suspect this is a project most people with some soldering experience could take on. Given the tight spaces one would probably want a decent soldering iron with proper tips. I am satisfied with the end result, and though I know for around the same money I could have bought a prebuilt unit, I have the satisfaction of having built an awesome sounding amplifier myself. To me that's pretty cool.
So... It took me a while longer than I thought to get it all up and working. I ran into some problems that, I believe probably had nothing to do with the actual kit. Here's the story:
I built the first board and went to test it. Unfortunately, none of the LEDs came on but one of the capacitors did bulge on me. I thought to myself, crap I did something wrong. The power supply made some weird noises, which I figured was probably due to the board I had just built having a problem. Ok onto build the second kit.
I put the second kit together and gave it some power. No lights, but my PS was still making some odd noises. And then, the PS gave out all together. I figured I had put two boards together and they had both managed to kill the PS. Bad news. I was on the verge of giving up.
Pause for a few weeks, a buddy of mine comes over and we have some beers. I showed him my boards: I was proud how awesome they look despite not working still. We both agreed that the CAP was certainly toast on the first board, but he asked me a simple question "Well did you try to hook some speakers up to the second board and see if it works?" "No, the PS died, and I don't want to risk my toroid/PS to testing anymore." "Come on, let's give it a try." Ok, sure beer and electricity sounds like a great idea. ;-)
We wire it all up, power it on - no lights still - but now there's a speaker hooked up and an audio source. I hit play. Wow. Awesome. It works. Turns out there is nothing wrong with the second board, except that I installed the LEDs backwards. Pulled the LEDs, swapped polarity and boom its all perfect.
So today, I replaced the cap on the first board, and also reversed the LEDs and boom its working perfect.
I'm left to wonder - did a bad cap on the first board kill my PS, or did my PS kill my board, or maybe I just had a bad cap and a bad PS. Who knows? It all works.
So here's my impressions:
1) Build - this build was actually quite easy. My first soldering project was an elenco am radio kit, which was really for kids. This was my second project. The documentation is quite good, and the kit was complete except one resistor. The resistor, R43, was apparently added as a revision and is not in the BOM in the docs, but was in the foot notes. At this point there's only one thing I'm unsure of on these boards and that's the thermistor: should it be touching the heatsink or just free standing near the heatsink? I don't know, and I believe it only really matters if I plan to run this thing at extreme power levels without adequate ventilation.
2) Support - I emailed Cristi a ton. In fact, a massive amount of emails went back and fourth between he and I. I'd say that the support was fantastic - better than can be expected for a $30 board+components. It's hard to debug things from the other side of the planet, but her certainly did invest a lot of effort in trying to help.
3) Sound - sounds fantastic. I have a CDA254 and 50ASX2 to compare to. To my ears sound quality is way up there. I found one thing weird, or great, or something I'm not sure. I'm driving it from my PC using a Tascam US-122MKII. The other boards, when I drive it with the volume all the way up get very loud but will distort at a point. I can drive this at 100% volume without noticing distortion, but it doesn't get as loud as I expected. I'm not sure if this is an impedance matching thing, or it's expecting a higher voltage source? Either way, it gets plenty loud driven from that source - louder than I'd realistically subject my ears or speakers to anyways.
In conclusion, I was able to build this with what is really the bare minimum of experience and it worked out for me. I suspect this is a project most people with some soldering experience could take on. Given the tight spaces one would probably want a decent soldering iron with proper tips. I am satisfied with the end result, and though I know for around the same money I could have bought a prebuilt unit, I have the satisfaction of having built an awesome sounding amplifier myself. To me that's pretty cool.
Video of two kits running
Before clicking you may want to turn your volume down.
https://www.youtube.com/watch?v=ulS1taTAmOY
I've had time to listen to these in stereo. I'm still happy with the way they sound. One of the boards may look a little odd. I lost or broke some parts, so to finish the last board I had to source some parts locally. Specifically, the cap at C5 is the same value, but taller and with a smaller diameter. Some of the disc capacitors I couldn't find locally (102k) as discs, but were available as mlc in the same ohm / volt rating. I built 3 of these kits total - the second one went up in smoke after I accidentally plugged the power in wrong.. -50v, +50v, ground instead of -50v, ground, +50v). I'll probably just give up on the broken board, I saw smoke coming from the area around the irs2092s chip - and who knows what's destroyed and what's not. It'll make a nice conversation piece on my desk at work.
Before clicking you may want to turn your volume down.
https://www.youtube.com/watch?v=ulS1taTAmOY
I've had time to listen to these in stereo. I'm still happy with the way they sound. One of the boards may look a little odd. I lost or broke some parts, so to finish the last board I had to source some parts locally. Specifically, the cap at C5 is the same value, but taller and with a smaller diameter. Some of the disc capacitors I couldn't find locally (102k) as discs, but were available as mlc in the same ohm / volt rating. I built 3 of these kits total - the second one went up in smoke after I accidentally plugged the power in wrong.. -50v, +50v, ground instead of -50v, ground, +50v). I'll probably just give up on the broken board, I saw smoke coming from the area around the irs2092s chip - and who knows what's destroyed and what's not. It'll make a nice conversation piece on my desk at work.
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