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progbuddy
05-09-2015, 08:35 AM
Thought I'd start posting a worklog on a side project I've been fairly busy with. It started out in life as a Lepai LP2020A+ stereo amplifier (pictured below), but now the amplifier has its guts spilling off to the sides. It needs a case. ;)

http://www.parts-express.com/Data/Default/Images/Catalog/Original/310-300_HR_0.jpg

I've added a relatively large hand-wound air core inductor to replace the relatively small stock air core that couldn't handle the additional amperage from the larger 12V5A aftermarket power supply. A 4700uF Nichicon Al-e capacitor in parallel with a small tantalum 1uF capacitor replaced the fairly pitiful stock 2200uF Al-e power filter/bulk capacitor. Eventually, I'm going to move on to replacing the no-name "Low-ESR" stock capacitors in the tone controls and on the input side with Elna SILMIC IIs to smooth out any mid-range grain.

Glad to be back in the creative mood.

d_stilgar
05-11-2015, 11:08 AM
I own that same amp. Love it! It's a great little amp for super low budget hi-fi. We definitely need pics of the modifications and of whatever case you build.

progbuddy
05-18-2015, 08:19 PM
I own that same amp. Love it! It's a great little amp for super low budget hi-fi. We definitely need pics of the modifications and of whatever case you build.

http://i.imgur.com/SHQ91yd.jpg

The modified power filtering backs things up when the load frequency or amplitude increases thanks to the larger bulk capacitor and 1uF tantalum cap in parallel. The air core was hand-wound with some wire that I had laying around, I'll have to do a better wind with better wire when I get the time and resources. Been hard at work planning out and building these tapered quarter wave pipe enclosures for the KEF 2-ways (with 3.8k crossover). Just have to upholster them, but here's what I have so far.


http://i.imgur.com/IbpzD8i.jpg

They're 48 inches in height, 7 inch width, 8.75 inch depth, with a useable overall horn length of about 80". They sound wonderful stuffed with a little Poly-fil.

http://i.imgur.com/KAMfqC0.jpg

Sealed everything up, just need that fabric/batting/finishing tacks for the real fun to start. I was thinking of making a matching Lepai case with venting for the added swankiness.

Need to work on getting together some cash for a toroidal transformer and an LM3886 amp setup though... So straightforward and gorgeous.