There's so many to choose from.
This one worth a $hit? http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=251530917669&ssPageName=ADME:X:RTQ:US:1123
This one worth a $hit? http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=251530917669&ssPageName=ADME:X:RTQ:US:1123
There exists a thread on this forum about the L12 amp. Use the search function.
So you want us to choose one for you?
How do you define worth? Resale value? Maybe buy raw Copper instead then from a metal dealer, or find some in a junkyard, much better economic return.
Amongst several Ebay amplifiers that seem more focused on maximum output power per $ than overall quality, L12-2 is a good amp. with some great quality components. I've heard a few out-of-the-box and kitform builds of this one and they make surprisingly good sounding, efficient and tidy amps when you add the other 90% of a finished amplifier with a decent transformer, power supply and protection circuits.
Best value IMO, is the already built up version on its own little heatsink.
Like Esgigt suggests, search the L12-2 thread and see what the designer and other builders had to say.
Best value IMO, is the already built up version on its own little heatsink.
Like Esgigt suggests, search the L12-2 thread and see what the designer and other builders had to say.
Thanks Ian. I hadn't specifically searched "L12-2" so I'll try that. It's always easier to just ask then spend days searching (which I had) and still not find anything. We're mortal after all.
Yes, searches can be difficult without the right keywords but I just used Google instead. I only typed L12-2 and in less than 10 secs had 5 lines and one of those was for DIY audio:
Here: http://www.diyaudio.com/forums/solid-state/196089-l12-2-cfp-output-amp-120w-2-8r.html
good reading
Here: http://www.diyaudio.com/forums/solid-state/196089-l12-2-cfp-output-amp-120w-2-8r.html
good reading
All the offers I've seen are for the same and only boards available AFAIK. The problem talked about "between the lines" on that thread is that neither the designer (OP) nor the seller want's us or their competition to copy them too easily and bypass their kits, so the schematic doesn't have errors, so much as it has been deliberately sabotaged - get it?
The schematic I posted was for an earlier (L12) version which is much the same apart from output stage emitter resistor values. Otherwise, it fills in most of the details that have been obscured in the L12-2 schematic. Just forget you ever saw the 12-2 schematic, right? That probably really irked LJM-LJM too.
If you are unconvinced, look at finished and working examples on their small but useable heatsinks (this is a CFP design, so they don't run hot). Friends and I have bought from 3 other suppliers as just parts, finished boards and also with heatsinks fitted and all were the same goods being supplied. I'm looking at complete modules from Along1986090 and Doukmall as I type - can't see any difference. Note though, not all sellers offer all options all the time. Sometimes you have to buy them separate. The sinks though, are predrilled and tapped, which is great so long as you have the washers too.
2pcs Mono L12 2 Power Amplifier Board Amp Assembled 2 CH 120W 55V w Heatsink | eBay
L12 2 Assembled Stereo Audio Power Amplifier Board 2pcs DIY Kit 2 0 Channel AB | eBay
At the end of the day, others are just going about using these kits without problems so unless you hear otherwise, I wouldn't worry too much schematic "errors". I don't even think building it from parts is worth the hassle anyway. All seem to work fine set with about 25-40 mA current as they come. There are no adjustments to make, so prebuilt is fine.
The schematic I posted was for an earlier (L12) version which is much the same apart from output stage emitter resistor values. Otherwise, it fills in most of the details that have been obscured in the L12-2 schematic. Just forget you ever saw the 12-2 schematic, right? That probably really irked LJM-LJM too.
If you are unconvinced, look at finished and working examples on their small but useable heatsinks (this is a CFP design, so they don't run hot). Friends and I have bought from 3 other suppliers as just parts, finished boards and also with heatsinks fitted and all were the same goods being supplied. I'm looking at complete modules from Along1986090 and Doukmall as I type - can't see any difference. Note though, not all sellers offer all options all the time. Sometimes you have to buy them separate. The sinks though, are predrilled and tapped, which is great so long as you have the washers too.
2pcs Mono L12 2 Power Amplifier Board Amp Assembled 2 CH 120W 55V w Heatsink | eBay
L12 2 Assembled Stereo Audio Power Amplifier Board 2pcs DIY Kit 2 0 Channel AB | eBay
At the end of the day, others are just going about using these kits without problems so unless you hear otherwise, I wouldn't worry too much schematic "errors". I don't even think building it from parts is worth the hassle anyway. All seem to work fine set with about 25-40 mA current as they come. There are no adjustments to make, so prebuilt is fine.
I need 4x100w into 4 ohms. 4 of the modules would be mounted to a large heatsink that's about 16 x 10" with 1.5" fin. An SMPS is also needed since this is for 12v operation. The narrow 12-2 boards would lay out nicely on one end with 2 SMPS's on the other end. It may improve stereo separation by having one SMPS powering the right 2 channels and another SMPS powering the left 2 channels.
If it works well, I'll take another heatsink and build a monoblock AB for the subwoofer and bolt them together for an all-in-one 5ch amp.
If it works well, I'll take another heatsink and build a monoblock AB for the subwoofer and bolt them together for an all-in-one 5ch amp.
I have one of these -
Tung Yung TA 802 PCB for 80WX2 Power Amplifier with Schematics | eBay
And I am impressed. But of course ... I didn't build it or even pay for it really, it turned up a few days ago when someone I traded stuff with had to get some space emptied in the car ... so out this one went, right into my garage.
Mine was put together with a toroidal transformer and a damn decent chassis too ... missing a top, but decent otherwise.
Cool.
Srinath.
Tung Yung TA 802 PCB for 80WX2 Power Amplifier with Schematics | eBay
And I am impressed. But of course ... I didn't build it or even pay for it really, it turned up a few days ago when someone I traded stuff with had to get some space emptied in the car ... so out this one went, right into my garage.
Mine was put together with a toroidal transformer and a damn decent chassis too ... missing a top, but decent otherwise.
Cool.
Srinath.
This board is an LJM design. This guy is a great amplifier designer. The quality of his products is superb.
Just be careful whom you buy from. These boards (believe it or not) are vastly pirated.
Why don't you try to contact him at MR. 刘 <ljm_ljm@foxmail.com>;
He always answer. He is also a member of DIYAudio. Some of his designs are reviewd here. Once he offered me to sell me directly.
RGDS
PEMO
Hi,
I use these amps since years and remain impressed about their drive capability into difficult, complex loads and their sonic qualities.
Mostly ordered from Along's ebay shop.
Unfortunately LJM never replied to any of my inquiries, not by mail, not by forum and not via his webshop.
LJM if You read this, please contact me
As I described in the above linked thread it may be useful to tweak the bias resistor, since the bias currents on my modules differed more than I liked.
Apart from that the L12-2 are simply great little amps and are exceptional priceworthy.
jauu
Calvin
I use these amps since years and remain impressed about their drive capability into difficult, complex loads and their sonic qualities.
Mostly ordered from Along's ebay shop.
Unfortunately LJM never replied to any of my inquiries, not by mail, not by forum and not via his webshop.
LJM if You read this, please contact me
As I described in the above linked thread it may be useful to tweak the bias resistor, since the bias currents on my modules differed more than I liked.
Apart from that the L12-2 are simply great little amps and are exceptional priceworthy.
jauu
Calvin
Bumping this old thread.
Still haven't got around to building the amp but the heatsinks are here and the power supplies are on the way.
Here's a list of ebay amps I've been compiling.
L12
L20
AP30
Quad 405
MT150
MX50
MX50X2
MX40
DX amp / DX Destroyer (same thing?)
If I find time I'll gather the specs and photos.
For myself, I'm trying to pick between the L12, MX40, MX50X2, and the DX amp. I'm leaning towards the DX amp like this one. Toshiba A1943 C5200 DX Amp Power Amplifier Kit 2 CH | eBay
Still haven't got around to building the amp but the heatsinks are here and the power supplies are on the way.
Here's a list of ebay amps I've been compiling.
L12
L20
AP30
Quad 405
MT150
MX50
MX50X2
MX40
DX amp / DX Destroyer (same thing?)
If I find time I'll gather the specs and photos.
For myself, I'm trying to pick between the L12, MX40, MX50X2, and the DX amp. I'm leaning towards the DX amp like this one. Toshiba A1943 C5200 DX Amp Power Amplifier Kit 2 CH | eBay
The DX amp is the first and simplest of several by, of course, Destroyer X here. The thread started in 2007 and is 700 odd posts long. You might understand he isn't happy about this blatant rip-off for profit by a kit manufacturer, without consent or compensation. http://www.diyaudio.com/forums/solid-state/96237-destroyer-x-amplifier-dx-amp-my-amplifier.html It was though, probably the most popular DIY project on the forum for a couple of years.
There are threads discussing pretty much every other commercial kit on sale over the past 10 years but you surely don't need people to show you how to search them with Google. Your problem for comparisons is that no one will have tried them all so opinions will be of limited value to compare them. I agree though with Calvin, just as the thread shows, that L12-2 is about the best quality sound I've heard in such low cost products. Quality audio though, is only what we come to accept as good - just a little more so
There are threads discussing pretty much every other commercial kit on sale over the past 10 years but you surely don't need people to show you how to search them with Google. Your problem for comparisons is that no one will have tried them all so opinions will be of limited value to compare them. I agree though with Calvin, just as the thread shows, that L12-2 is about the best quality sound I've heard in such low cost products. Quality audio though, is only what we come to accept as good - just a little more so
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The DX amp is the first and simplest of several by, of course, Destroyer X here. The thread started in 2007 and is 700 odd posts long. You might understand he isn't happy about this blatant rip-off for profit by a kit manufacturer, without consent or compensation. http://www.diyaudio.com/forums/solid-state/96237-destroyer-x-amplifier-dx-amp-my-amplifier.html It was though, probably the most popular DIY project on the forum for a couple of years.
There are threads discussing pretty much every other commercial kit on sale over the past 10 years but you surely don't need people to show you how to search them with Google. Your problem for comparisons is that no one will have tried them all so opinions will be of limited value to compare them. I agree though with Calvin, just as the thread shows, that L12-2 is about the best quality sound I've heard in such low cost products. Quality audio though, is only what we come to accept as good - just a little more so
I emailed the designer of the DX to verify that the ebay one I was looking at was a clone. He verified, but didn't offer me an option to buy from him or answer any other questions.
That kinda leaves me no choice but to buy the clone? I guess he's better at amp building then marketing.They're so cheap, buy them all & compare
lol I wish I had the money to throw around but being a small business owner in America, it's rough.
Other then power handling, are their any advantages or disadvantages in signal quality using two smaller transistors in parallel (4 for PP) vs. one larger one (2 for PP)?
Is this amp correct without emitter resistors? Is that common with mosfet outputs?
Class AB MOSFET L7 Audio Power Amplifier Board Kit Mono 300 350W New | eBay
Class AB MOSFET L7 Audio Power Amplifier Board Kit Mono 300 350W New | eBay
Probably depends on the devices - one of the 'advantages' suggested years back was that they had a negative temperature coefficient, so didn't require emitter resistors.
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