Another Project Update – Headphone Tub Amp

So I received my PCB’s in the mail a week or two ago now.  They were wrong. Within the CAD drawing the actual dimensions of the board were incorrect. If you reference the picture below you will see that there are gray holes in the 4 corners. Those symbolize no copper through holes for mounting. Well the way the Eagle CAD file is setup, the PCB fabricator see that as the outside edge of the board. So the traces stop in alignment with those dimensions, as well as the actual board itself get clipped. This is no good. Results in missing Ground and 12v traces, as well as a few components don’t make it onto the board.

Here’s were things get really good though. I was going to live with this problem and just eat the 20 bucks. I emailed OSH Park just looking for help with my CAD file. Not only did Laen at OSH fix my CAD file, rather quickly, but he refunded my money, apologized and said my next boards would be on them. You don’t find many places anymore that give service like that. I can’t recommend OSH Park for PCB work more. What a great company!!

So presently I’ve resubmitted the corrected CAD files and there already at the fabricators.

Eagle CAD

OSH Park



Last Project of the Year-Tube Headphone Amp

41xLzbeWL-L._SL500_AA300_This is just a little write up for you all of what I think will be my last project of the year. This one was an easy one. I did very little work on it. Mostly just a few modifications of a previous design and when everything arrives, assembly. Now as I said, not my original design this time, but that’s ok. It’s a epic design none-the-less.

What is it you ask? A Tube Driven Headphone Amplifier. Link below.
Specifically it is a 12AU7(ECC82) Tube / IRF510 MOSFET Headphone Amplifier.

It uses one 12AU7 vacuum tube for signal amplification and a pile of other great passive components and a few semi-conductors.

So far I’m not very far into it. I have ordered all my parts. As of Sunday November 25th I have received:

  1. Groove Tubes ST-12AU7 Preamp Tube Silver – Link
  2. 9-Pin Tube Socket Ceramic PC Mount – Link

Printed Circuit Board – PCB

In addition to all that I’ve also out-sourced my PCB construction to a pretty awesome service. Which is called OSH Park. These guys, best I can tell, round up multiple orders for PCB’s and submit them as one board to there builders. This makes it worth while money wise and your not stuck with 50 copies of one board. This is what has forced me in the past to make my own PCB’s. Which I hate to do!

With this service you create your circuit board in Eagle CAD and then upload your design to there website. It will ensure a proper design and tell you how much your going to be charged. It also renders you out pretty pictures of basically how your board will look. I included mine below. Now when you order, you have to order in multiples of 3, but that beats 50 or more. I paid $21 USD for my project. Which to me, that’s not bad. I’ve got 3 boards coming, that’s 7 bucks a piece. I can sell 2 of them if need be to pay for the entire project easily.

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