I would like to have a completely clear conscious before trying to sell it. So I also tried calling the dealer today. Apparently their email server is messed up. He never got my emails. So he was still unaware of the situation. He is going to have the manufacturer send me a return shipping label.

Okay. Bought a piece of equipment from a out of town dealer. The unit was drop shipped by the manufacturer. It broke after one day. Called the manufacturer to see if they could figure it out. They had me send it back to them for repair. After I thought about it, I called the dealer and told them...

Quote: Originally Posted by threepointone imo it seems a bit expensive for the design simplicity (though of course, simplicity doesn't always mean it sounds bad) my biggest problem is with the opa1632--the entire design seems to be based around the chip, which you can't swap out like...

Quote: Originally Posted by jbloudg20 I never said it was designed to be cheap, I said it was cheap. It is, when compared to any other high end headphone amp offering, when going balanced. There is a point where it must be considered the pros/cons of going balanced over building a...

Quote: Originally Posted by ezkcdude Put up a schematic, and you may get more attention...I mean comments. I provided the schematic, tons of comments, and even the complete Eagle pcb file ready to be sent for manufacture. Quote: Originally Posted by jbloudg20 My...

Come on guys... Doesn't anyone besides NikonGod have any feedback? Thought you guys would have been a little more excited to see a new and somewhat different design.

General attributes: Single-ended input, derived balanced output. Bad part is any headphones need to have the 3 conductor jack replaced with a 4 conductor jack to be used with this design. Contains Jan Meier's crossfeed circuit, switchable on/off. Nice big ground plane on the bottom of the PCB...

The opa1632 does convert single-ended to balanced. Both outputs are swinging (in opposite phase of course) relative to ground. I will get into details about the theory of operation and design choices tomorrow.

For those who may not want to download the Eagle PCB Layout program, attached are some images of the top and bottom layers. Note: All signal traces are on the top. Only a few power traces are on bottom. The rest of the bottom is ground plane.

Greetings. Here is a little (literally) headphone amplifier design I have been working on. By little, I mean mostly surface mount with a board size of 3.75" x 2.35". Fits nicely inside the board size limitation for Eagle layout freeware license version. It takes a single ended input and provides...

Greetings. The spice model for the AD8610/20 from Analog Devices doesn't seem to be fully compatible with Beige Bag's spice simulator. Something about how polynomial controlled sources are not berkeley spice3 compliant. It supposedly converts it to a non-linear dependent source. Okay, whatever...

Thanks for the pointers. I remembered I had asked this question a while ago but didn't get any responses. The second link was very usefull. I am using roughly 10m cables. So I am guessing roughly 1.5nF lump capacitance.

Does anyone know what the equivalent circuit model for regular headphones would look like? If it makes any difference, I am considering the AKG K701s. They are 62 ohms. Also the cable. Want to check with circuit simulations to verify general loop stability. Thanks.

Mark Levinson uses these CMOS analog switches in their reference No32 preamp attenuation board. Edit: You would have to account for their 45ohm on-resistance though.

I'm thinking of using an optical encoder type rotary control connected to a quadrature decoder/counter to cmos switches. I'm at work right now, so I don't have the exact part numbers off hand. But I will post them later. This creates a very simple solution. optical encoder: Bourns EN series...