My new ZEN-like headphones amp

[Algar_emi]

After reading so much about Tortello's Zen-like headphone amp (I own a Grado headphone too), I decided to try it someday. Then, I got my hand on a very nice enclosure for this project. It was a HP scsi Tape drive. It is build like a tank and the size is just perfect.

I removed the tape unit and put the Neutrik jack and volume pot on a little maple wood plate. I'll put a piece of aluminium over the HP lettering later. There is an already built-in led. I'll replace it for a blue led.

Thanks Tortello for your nice desing and sharing your PCB's and thanks Mr. Pass for letting us using your ideas.

Here the front panel.

[Algar_emi]

This is a view of the case's inside. It is divided in two main sections. On the back they are already built-in EMI filter, main power switch and a nice little 12Vdc fan running on ball bearings, the HP way

I'll keep the fan running at low speed if I need it. On the bottom I'll mount the 2 channels PCB's. The two IRF610 FET per channel will be mounted directly on the case bottom plate to use as an heatsink. The case has plenty of ventilation in this section that use to have a power supply. The fan is designed to cool this section in particular.

On the top section, I'll mount the EQ-Timer PCB, the Supply PCB and a well shielded toroidal transformer.

I'll mount remotely to the back the DIP switch of the EQ. I already built a small PCB to receive the remote DIP switch.

On the back, I'll install an aluminium plate to cover the two scsi connector mounting holes. I'll install 2 Neutrik RCA output jacks on this plate and the DIP switch.

[Algar_emi]

The case side view showing the nice finish and the little square ventilation holes. Pretty nice

[Algar_emi]

The project wouldn't be complete without some nice PCB's. Tortello did the original desing, Thanks to you. Since I had only the PCB images, I used PaintShop Pro and cut and paste, to do some slight modifications to the PCB's.

I increased all main supplies traces on the Supply and Amplifier PCBs. To the Supply PCB, I replaced the rectifier diodes by bridges, I increased the filering caps to 10,000uF, added the option of adding an other R-C filter to the already built-in C-R-C supply filtering. I plan to remove all supply noises as possible, since headphones are very sensitive. I also added a drop-out voltage resistor and a connector for the fan supply, if needed.

On the Amplifier PCB, I increased power traces width, added an other input cap in parallel (if I want to try different input caps, with or without bypass) and I increased some pads dimensions.

On the EQ-Timer PCB, I increased some pads dimensions, reduced the PCB width (to fit the PCB in the case top section) and added the option fo connect a multipair cable to mount the DIP switch remotely. I did also a small PCB for the switch.

Here the etched PCB before drilling and assembly. I got all the parts in stock and should start to assemble the PCB this week.

[karma]

yes thay do work good for projects nice work

[Blues]

Very nice....

[Algar_emi]

Thanks...

[Algar_emi]

All the PCB are completed and working perfectly.
I installed matched IRF610 FET. They are mounted under the amp PCB and will be mounted on the case's bottom plate.
I checked them using a square wave and they seems OK.
I'll do measurements in a few days. Here the PCB view.

[Algar_emi]

Here my bill of material. If it can help you...

[Leolabs]

Looks so neat.How does it sound???