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I know it's cheating a bit, but Sure Electronics do some fairly well regarded class D amp modules, so I just bought one of those:



www.ebay.co.uk/itm/350542134444?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649







Then I needed a power supply. Ideally I wanted 36v (the max that the module can take) but I settled for 24v, with this:



www.ebay.co.uk/itm/110820555032?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2648







Then I needed a case, so I took the measured dimensions and stuff and decided I could cram everything in this, and it would fit on top of a speaker nicely.



www.ebay.co.uk/itm/110908324070?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649#ht_1044wt_1163





And obviously I'd need a volume control, so while searching through a load of expensive potentiometers, I found an interesting digital volume thingy again from sure electronics, so I ordered that:



www.ebay.co.uk/itm/230646999349?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2648#ht_5163wt_957







I had the binding posts, capacitors etc etc in stock cos I'm super cool like that. They were all cheap chinese stuff, but they were all pretty good.



Anyway, a couple of weeks later all my loot had arrives, so I set it all up on the bench and noticed one of the inductors in the power supply was wobbly, so I cracked the thing open to find it had completely come adrift - resoldered it, turned the power supply on and it worked GR8 for about ten minutes, when one of the AC capacitors on the input decided to set on fire. On top of that, it didn't actually fit inside the case on account of it being 10mm larger in all directions than specified.





So, my power supply ended up being an even more cheap universal laptop power supply (for now) along with a load of capacitance to beef it up. This has the advantage that it'll also work off a 12v feed, but I've never tested it. This was also ordered off chinese ebay a few months ago but none of the supplied tips fitted my laptop. I've already cracked it open and repaired it (it turned up completely DOA due to the voltage switch being full of gunk)



Anyway so here's the amp in all it's "glory":















It seems to work great - By ear, it seems to be more powerful than my Denon 55wpc amp , and with normal music the power supply can keep up, too (it only dips by about half a volt according to my cheapo scope) but I'll probably end up replacing it at some point. With a tone generator doing 40hz I can suck the supply dry after a couple of seconds. As for sound quality, I'm not good at articulating what I hear unless the SQ is particularly poor. I can comfortably listen to this amp at high volume all day, whereas many much more expensive systems have been tiring to listen to.



Ignore the solid core wire as the speaker outputs - I'm not some audiophile plonker who thinks it'll make a jot of difference, but I just thought it would be neater than using stranded flex, and I had some of it to hand.



The little fan on the amp seems a bit overkill, but it's totally silent when sealed in the ally case. It's a bit silly enclosing a fan in a sealed case, but the air circulates around inside and the whole thing stays fairly cool because the alu case is good and conducting heat.



So overall, other than the PSU setting on fire (the seller has already dispatched another one) everything arrived in under a fortnight and was just as described.



As for ebay chinese sellers, sureelectronics seem to be pretty good (I've used them dozens of times and never had an issue) so I can 100% recommend them. The case guy seemed good, and we'll see if the power supply guy sends a replacement like the promised. I'll just have to use the replacement 24v supply as a bench supply or whatever when it turns up.

I'd been tempted to build an amp for ages, and I wanted something with a bit of power. After a few beers I decided to build one entirely out of bits ordered off chinese eBay, just to see how it would turn out.I know it's cheating a bit, but Sure Electronics do some fairly well regarded class D amp modules, so I just bought one of those:Then I needed a power supply. Ideally I wanted 36v (the max that the module can take) but I settled for 24v, with this:Then I needed a case, so I took the measured dimensions and stuff and decided I could cram everything in this, and it would fit on top of a speaker nicely.And obviously I'd need a volume control, so while searching through a load of expensive potentiometers, I found an interesting digital volume thingy again from sure electronics, so I ordered that:I had the binding posts, capacitors etc etc in stock cos I'm super cool like that. They were all cheap chinese stuff, but they were all pretty good.Anyway, a couple of weeks later all my loot had arrives, so I set it all up on the bench and noticed one of the inductors in the power supply was wobbly, so I cracked the thing open to find it had completely come adrift - resoldered it, turned the power supply on and it worked GR8 for about ten minutes, when one of the AC capacitors on the input decided to set on fire. On top of that, it didn't actually fit inside the case on account of it being 10mm larger in all directions than specified.So, my power supply ended up being an even more cheap universal laptop power supply (for now) along with a load of capacitance to beef it up. This has the advantage that it'll also work off a 12v feed, but I've never tested it. This was also ordered off chinese ebay a few months ago but none of the supplied tips fitted my laptop. I've already cracked it open and repaired it (it turned up completely DOA due to the voltage switch being full of gunk)Anyway so here's the amp in all it's "glory":It seems to work great - By ear, it seems to be more powerful than my Denon 55wpc amp , and with normal music the power supply can keep up, too (it only dips by about half a volt according to my cheapo scope) but I'll probably end up replacing it at some point. With a tone generator doing 40hz I can suck the supply dry after a couple of seconds. As for sound quality, I'm not good at articulating what I hear unless the SQ is particularly poor. I can comfortably listen to this amp at high volume all day, whereas many much more expensive systems have been tiring to listen to.Ignore the solid core wire as the speaker outputs - I'm not some audiophile plonker who thinks it'll make a jot of difference, but I just thought it would be neater than using stranded flex, and I had some of it to hand.The little fan on the amp seems a bit overkill, but it's totally silent when sealed in the ally case. It's a bit silly enclosing a fan in a sealed case, but the air circulates around inside and the whole thing stays fairly cool because the alu case is good and conducting heat.So overall, other than the PSU setting on fire (the seller has already dispatched another one) everything arrived in under a fortnight and was just as described.As for ebay chinese sellers, sureelectronics seem to be pretty good (I've used them dozens of times and never had an issue) so I can 100% recommend them. The case guy seemed good, and we'll see if the power supply guy sends a replacement like the promised. I'll just have to use the replacement 24v supply as a bench supply or whatever when it turns up.