Santi,
You are welcome.
Pleased that you found the solution.
The reason of 221R (or other optional value) is mainly to limit the maximum volume level. Everywhere, we have naughty kids around. While we enjoying the music on our headphones, relaxing with absent eyes, the naughty kids sometimes sneak in and turn up the volime knob to the end, enjoying the surprise to our ear pain. We need to feel our own responsibilities for our healthy ears.
Enjoy the music!
Regards
You are welcome.
Pleased that you found the solution.
The reason of 221R (or other optional value) is mainly to limit the maximum volume level. Everywhere, we have naughty kids around. While we enjoying the music on our headphones, relaxing with absent eyes, the naughty kids sometimes sneak in and turn up the volime knob to the end, enjoying the surprise to our ear pain. We need to feel our own responsibilities for our healthy ears.
Enjoy the music!
Regards
Submitted for your approval JH...
As an exercise for myself, I decided to try designing a PCB of your Zeny variation. If I can, I'd like to ask for your help reviewing the design, as well as the help of the community. I'll attach the pcb art work, schematics, and my digikey shopping list.
Oh, and for that 221ohm resistor on the output, I think I remember reading that for a head phone amp (and general impedence matching) the output impedence should be lower than the impedence of the headphones. I'll be using mine with a pair of Grado's (32 ohm), so I'll likely jumper that spot, but for the purpose of a general pcb, I left it in.
Cheers,
-Scott
As an exercise for myself, I decided to try designing a PCB of your Zeny variation. If I can, I'd like to ask for your help reviewing the design, as well as the help of the community. I'll attach the pcb art work, schematics, and my digikey shopping list.
Oh, and for that 221ohm resistor on the output, I think I remember reading that for a head phone amp (and general impedence matching) the output impedence should be lower than the impedence of the headphones. I'll be using mine with a pair of Grado's (32 ohm), so I'll likely jumper that spot, but for the purpose of a general pcb, I left it in.
Cheers,
-Scott
Attachments
Who will stop . . . ?
This project is a returning-the-favor to diyAudio community as a result of
valuable lessons especially from the energetic Pa Pa, Nelson Pass, and also
other great contributors.
I hope that PCB experts will join you with any kind of advices.
Particularly with headphone amps, I do focus on the quietness upon no signal
so that I do my best to have a good grounding arrangement.
O, I use two thermistors (CL60 is okay I think): one at the primary
side of the transformer and another between the star ground
and the chassis. The chassis is directly connected to the
protective earth (of the wall power socket).
The ground plate in your supply PCB would work well, no doubt.
By the way, I am approching in a different way without having
the ground plate. Refer to the attached example (from another
project). You will see the star ground and branches from it.
This also works well.
side of the transformer and another between the star ground
and the chassis. The chassis is directly connected to the
protective earth (of the wall power socket).
The ground plate in your supply PCB would work well, no doubt.
By the way, I am approching in a different way without having
the ground plate. Refer to the attached example (from another
project). You will see the star ground and branches from it.
This also works well.
Attachments
steenoe said:Those boards are great looking, adolphe. Any chance to have a PDF in B/W of those tracks when you are done, finetuning? Sure would be nice to compare the Zeny to an original downscaled Zen HP amp
Steen
yo,mate-you are really something!
!
?? I dont think so
So far (when winter comes around) I am gonna finish my A-X's and build the Babbelfish. Thats my only plans for now, so you can tell this is gonna be one boring winter Ofcourse I will attempt the new preamp that NP promised us, also Thats 3 projects, so not that much A little headphoneamp would be a nice addition indeed Steen
Steen,
Here's the pdf's. Let me know if they're good enough quality for you. I'm new to this stuff
http://www.mcaficionado.com/diyaudio/mono.pdf
http://www.mcaficionado.com/diyaudio/psu.pdf
-Scott
Here's the pdf's. Let me know if they're good enough quality for you. I'm new to this stuff
http://www.mcaficionado.com/diyaudio/mono.pdf
http://www.mcaficionado.com/diyaudio/psu.pdf
-Scott
adolphe said:
Hi Scott,
The concern is that Zeny has 0dB gain.
My current pre is balanced variation of Zeny with gains.
(Not released to the public as the design is still a trial version.)
BTW, please note that the concept of the grounding above is assuming
that both the amp and the supply PCBs are floating above the
chassis by the thermistor bridge between the PCBs and the chassis.
- Status
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