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Ebay audio kits - opinions

D

df_genius

Solder slinger
I thought we can start a thread to share opinions on the literally thousands of audio kits and PCB's there are on ebay (which we know can be a minefield) I've bought a few of them (and spent alot of time reading up on them) so am happy to share my opinions. Please note I'm not endorsing anything, with DIY it is your job to know what you are doing, don't blame me if you hurt yourself or your own kit.

Amp kits

There are plenty of JLH kits around for the class A circuit, this is a kit for the basic circuit from 1969:

http://rover.ebay.com/rover/1/710-5...0001&campid=5338728743&icep_item=131318577539

this is the kit I bought, it all seems fine, although the MJ15003 seems to be a drop-in upgrade and these can be source locally.

This is an LJM kit for a class AB amp, the L12 and L20 amps are very similar (more output transistors and more power), performance is very good. I have the MX50SE, L12-2 and L20 kits and they all work fine

http://rover.ebay.com/rover/1/710-5...0001&campid=5338728743&icep_item=251530857897

There are plenty of Class D amplifers on ebay, the TPA3116, TDA7498 seem to be well regarded. If you need more power the IRS2092-based boards work well, here are a few:

http://rover.ebay.com/rover/1/710-5...0001&campid=5338728743&icep_item=351407762007

http://rover.ebay.com/rover/1/710-5...0001&campid=5338728743&icep_item=161615780458

http://rover.ebay.com/rover/1/710-5...0001&campid=5338728743&icep_item=200860017702

LJM also designed the L15D and L25D amps, he regularly posts on DiyAudio about his designs and I've read many more good opinions on them than bad. Have a look for yourself. The L15D is optimised for 4 ohm, and the L25D for 8.

What experiences do other people have?
 
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I remember a few from here building the Silicon Ray JLH and seemed to be quite pleased with them.

not tried myself but I've heard that the boards are nice, quality wise.

I've built a few Jim's Audio kits which are also OK.
 
I have the MX50SE, L12-2, L20 and L25D LJM amps and they all seem fine, no no-name chinese caps or other parts that I found, they tend to be either Nichicon or Rubycon.

It does make you wonder how they do it for the money, but the MX50SE is used on 31V rails in the amp I made it for and it quite happily pumped out over 90W sine into a 5 ohm dummy load
 
Alan, that looks very interesting, I wonder what it is a clone of?

I've also just finished building a pair of these up, they haven't been tested yet

http://rover.ebay.com/rover/1/710-5...0001&campid=5338728743&icep_item=221887433126

The LME49810/11/30 look like they deliver top drawer performance, the 10 and 11 are for BJT outputs and the 30 is for MOSFET. I've also built up some Leach boards from the same seller, boards from this seller seem great but they are made to be as small as possible so it can be tight if you're components are bigger than intended
 
This site contains affiliate links for which pink fish media may be compensated.
Thanks Andy/Alan, yes the similarity is there to see now. Wonder how the clone compares to the original sound-wise?
 
Damn that's an interesting looking kit. I really must stop reading these pages, I need another power amp like I needed the new set of bits that's just arrived that will shave a few grams of my MTB!
 
I know what you mean, I have enough PCB's and kits for about 20 class A/AB amps and another 10 for class D, more than I'll ever need. Having said that one of the most enjoyable parts of DIY Audio is building an amp up from scratch, especially stuffing the PCB's.

Building something up from a pile of parts (and also fixing something that was previously broken) is very rewarding.

I've ordered the cheaper "clone" kit with two output pairs per channel :)
 
Well my Dartzeel clone kit arrived a couple of weeks ago. It all seems fine to me, although I haven't fired them up yet as I have been modding them a bit, the 47pf, 100pf and 150pf are getting replaced with polystyrene and I have changed the input cap for a PETP, the Wima it came with looked to be a reclaimed one. Output transistors are TTA1943 and TTC5200, and the boards came shrink wrapped so I think they all come from the same manufacturer.

I have moved all of the output transistors and drivers to the bottom of the board and mounted on right angled aluminium as they will be used in my Bel 1001 enclosure, with a circa 800VA custom frame transformer and huge 42,000uF caps per 40V rail. This is what the inside of the Bel1001 looks like:

http://www.soundsgoodtomehouston.com/bel/1001/bel1001_inside2.jpg

I'll put some pics up when the rest of my polystyrene caps have arrived and I can continue.

I've had a quick search on Aliexpress, this is the cheapest price I can find the kit I bought for:

http://www.aliexpress.com/item/DART..._73_74_75,searchweb201527_5,searchweb201560_9
 
This is my Dartzeel clone, I am waiting on 150pf and 220pf polystyrenes and can then put the amp together::

https://drive.google.com/file/d/1tLvcf5kCfOR8HlOhMVNpmd45b9VxPTkl1g/view?usp=sharing

I am expecting to have to reduce the bias current with my heatsink, but hopefully not by much. the Bel 1001 transformer gives me 40V rails, compared to the circa 50V rails of the original (the 1:1 clone uses 35V AC transformers), so my idle power dissipation will be lower anyway

That Dartzeel amp is interesting when you read the manual, it states an idle power consumption of 150W, yet it only has one pair of output devices per channel, so each device could easily be dissipating 30-35W at idle, add some temperature derating and those output devices are probably near their limits in use. The clones use 2SC5200/2SA1943 equivalent, these can do 3-4A at 50V (at 25C) and then you have to derate from there.

My clones use 2 pairs per channel, assuming the bias current is the same each output device will be only dissipating 10-12W at idle at 40V rails

I'd say if you're buying the 1:1 clones and using them at 50V rails you might want to consider the something like the MJL4281/4302 instead of the 2SC5200/A1943

I am waiting on 150pf and 220pf polystyrenes and can then put the amp together:
 
I've just received my 1:1 clone kit as linked to by Alan above.

The boards are good quality, and the components appear to be kosher. Pairs of transistors are in separate plastic bags, but I haven't checked if the pairs are actually matched yet. There's even 2 AVX bestcaps included for the upgrade as seen in the later models.

BTW this kit uses MJL3281/1302 as the output transistors, which hopefully will be man enough for the job.

I'd be interested to hear the difference between the kits, as it's often said that layout has a big influence on an amp's sound. However this build will wait for 2 other projects to complete while I gather a case, transformer, etc.... so it could be some time before I have a working amplifier.
 
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