Happy New Year!
Sure - I'm just buying another myself http://www.ebay.com/itm/Newly-Pure-Class-A-Headphone-Amplifier-AMP-1969-Circuit-DIY-Kits-for-HD600-K701-/262199545918?hash=item3d0c4f903e:g:G1IAAOSw3ydV2YxKor search for 'class a headphone amp' for some alternatives.I went for this one becuse of the compact pcb 10cmx6cm - if more space is available, I think there are a few similar but better packaged pcb kits out there.Also, I just went for these for 11usd
I found the parts to be quite decent quality on the tiny jlh 1969 headphone amp kit. The audio performance is pretty good, and can be very good - I'll be doing some more measurements soon.......One problem I had was mounting the pcb - the pot doesn't mount flush with the edge of the pcb at the front - meaning it sits back from a front panel .. just enough so that the small amount of pot thread isn't able to secure it strongly. I use a froont panel thickness of 1.5mm.I had to grind off some of the pcb front edge to make it work. Also, I had to use a couple of brackets to securely mount the pcb to the fron panel. A couple of nut-heads protruding on the front panel face.Best to do before soldering up the jack and pot Apart from that - took me a while to figure the output devices mounting on the underside of the pcb - no documentation of course Get it the wrong way and you'll know it quick enough!And of course, those itsy bitsy tiny smt resistors are a royal pia for me - I can barely see them let alone solder them. I used some tweezers and so on. What normally takes 15seconds takes a few minutes Progress, right?The upside (apart from allowing the small form factor) is they are supposedly tight tolerance which makes for excellent matching -- I verified very close performance, left and right.
I can take a photo of the underside to show the bjt orientation ... will do tomorrow.The little documentation, such as it is, is a little inaccurate - I built to the pcb overlay and for the components which are of different values, I left those to last then did a 'best guesstimate' approach. There were quite a few differences, but nothing serious.I'm pretty sure the parts are mostly the cheap and generic end of town, but seem to be fine, excepting the pot mounting arrangement - best to check before final solder of jack and pot.I wouldn't be basing my neve desk build on them, tho' Apart from that, still going strong - it's integrated into my latest summing bus box - a Lawo dv975 module mashup Looking forward to resuming the class a journey - next week I start soldering and measuring the new modules from the ebuy sino sweat shops
With the output devices mounted on the underside, the device writing faces should face the rear.ie. looking back from the rca jacks towards the front of pcb, you can read the devices writing.
Hey,am looking for headphone amp, can be cheap but decent or at least easy to mod Anyone found something decent direct from China (without european/us sticker on it )? Anything which can work up to 800ohm headphones.For listening during recording.