A Super-Simple 6DJ8 Headphone Amp
Feb 15, 2009 at 5:53 PM Post #91 of 490
Someone said earlier in this thread that an IRF510 should work just fine in place of the 2SK310. That's what I'd use - cheap and commonly available. That said, I do have a spare set of 2SK117/2SK310, so if you've really, really got your heart set on using them, PM me.
 
Feb 15, 2009 at 7:51 PM Post #93 of 490
I'm STILL waiting for my fets to arrive
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A domestic company taking more than two weeks after payment cleared to get my parts to me. They are quickly getting on my bad side.
 
Feb 15, 2009 at 9:46 PM Post #97 of 490
I ordered them from Chicon too, and after 3 1/2 weeks and no response to my emails, I filed a Paypal complaint. In less than 12 hours I had my money back, meaning that Paypal knows about them. The only question is why they still keep their account active.

Edit: I might have found a set, thanks to a fellow hfier (and ortho owner)
 
Feb 15, 2009 at 9:48 PM Post #98 of 490
The prices at B&D Ent. aren't really all that bad. $15 minimum order for US customers and the sell other parts too. I like B&D and have used them before.

Mouser has the NEC 2SK3105 which is listed as a drop in replacement for 47 cents each.
Ampslab has the 2sk117BL going for 20 for $20. I have ordered from these guys before. Shipping isn't much IIRC.
 
Feb 16, 2009 at 11:23 PM Post #100 of 490
I will be interested since I unfortunately ordered from a BS company... Maybe we should remove the link to them on post #11. lol

I wasn't able to pay using paypal so I've got to see what my bank can do.
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Feb 22, 2009 at 2:50 AM Post #102 of 490
I finished soldering most of the components to the board a few minutes ago. Had to go to Radio Shack for a few caps because I messed up my Mouser order. After some messing around with the power source I got the tube to light up. What threw me off for a while is that I forgot to jumper the power switch pads near the pot.

What remains is the casework and wiring up the inputs, outputs and the pot.

Another observation is that the mosfets get really hot. I also need to get right-size the fuse since I blew two of the fuses that I bought (unless there is a problem with the amp itself).

Also, my BOM is incorrect in a few places. The pot doesn't fit on the board, most of the caps are incorrect in physical size, the resistors all look physically different. I will post an updated BOM when I get a chance although I don't know if I will have a solution to all of the things.

I will work on it more either tonight or tomorrow.
 
Feb 22, 2009 at 9:10 PM Post #105 of 490
I finally finished my build. It still needs to be cased but it's otherwise working.

Building
It went together very quickly. I was surprised that it was so easy. The toughest part was soldering the FETs becaue the pads are very close. I need more practice in the soldering department, a better soldering iron and an OptoVisor to see better.

Tubes
I have two tubes: Philips Jan 6922 and Tung Sol Golden Dragon e88cc. The Tung Sol sounds incredibly good. I probably need to clean the contacts on the Philips. Will report on this later on.

Sound
Nothing short of amazing. Female vocals sound incredible. Drums and guitars sound great. I like this amp a lot better than the Starving Student. Well worth the price and the effort.

Parts
I missed a few parts ordering from Mouser so I had to get them from Radio Shack. I plan to replace two of the RS caps with Nichicon audio caps once I get the right ones. Note that the C103 I used is almost as tall as the tube. I'm using a HP inkjet printer power supply, it puts out 33 volts and 940mA (part # 0950-4466). The heatsinks specified need to be modified to fit (2 of the legs cut, and the middle leg made thinner).

BOM
I'm attaching my updated BOM. Please note that the resistors in the BOM all look different from each other. If this bothers your sense of aesthetics, please do your own research.

Pictures
See here for more pictures: 6dj8 Headphone Amplifier pictures by kansei13 - Photobucket

IMG_3779.jpg

 

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