I'm not surprised. Looks like it's way underbiased stock. One Vbe multiplier with 606 / 360 ohms for 4 BE junctions (1x CFP pair, 1 EF pair) seems hardly luxurious to say the least. You can probably guess what this means for crossover distortion.
XLS 402 | Crown Audio - Professional Power Amplifiers
Not totally surprising for portable PA gear though, where less power consumption and heatsink weight would be desirable. Maybe it'll accept somewhat higher bias without blowing up, one would have to look at the real thing to tell.
XLS 402 | Crown Audio - Professional Power Amplifiers
Not totally surprising for portable PA gear though, where less power consumption and heatsink weight would be desirable. Maybe it'll accept somewhat higher bias without blowing up, one would have to look at the real thing to tell.
No I reckon the power supply gives up long before that happens (seen the insides) wimpy power is a form of protection.
Crossover distortion is the least of worries for typical setups this thing sees. LOL
It is what it is, even the THD specs don't hide it. higher bias means the fans will be going full tilt at all times.
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Not even all of that...that series of Crowns are just gritty/nasty sounding...the specs, especially IMD reinforces that.
Dan.
For anybody playing along at home - I ended up grabbing those eBay boards. I wired everything up and initially got some very strange results on one of them - signal on the ground, 3db difference between the hot and cold outputs, etc. After sending all the test information back to the supplier they gave me a complete refund and let me keep the boards.
This afternoon I thought I'd take a stab at fixing the dodgy one by comparing voltages/signal at different points....and everything magically started working while I was testing it. I have NO idea what I did; I thought there may have been a bad solder joint somewhere but I can't see anything. I shook the board around a bit and retested and everything works still, which is...good?
If anybody grabs them in the future, they have a gain of 3db (although that's possibly what "Amplification: 1 is meant to mean) and a SLIGHT inbalance between hot/cold channels (~80mv). Aside from a difference in output levels, there is very little signal noise even in a plastic housing on a bench surrounded by fluoro lights, multiple AC power feeds and all sorts of stuff running nearby (3D printers, etc).
Very happy with my zero cost purchase!
This afternoon I thought I'd take a stab at fixing the dodgy one by comparing voltages/signal at different points....and everything magically started working while I was testing it. I have NO idea what I did; I thought there may have been a bad solder joint somewhere but I can't see anything. I shook the board around a bit and retested and everything works still, which is...good?
If anybody grabs them in the future, they have a gain of 3db (although that's possibly what "Amplification: 1 is meant to mean) and a SLIGHT inbalance between hot/cold channels (~80mv). Aside from a difference in output levels, there is very little signal noise even in a plastic housing on a bench surrounded by fluoro lights, multiple AC power feeds and all sorts of stuff running nearby (3D printers, etc).
Very happy with my zero cost purchase!
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