jwb's ultimate aleph headphone amp

[grataku]

****

I am surprised that a fine linguist like Pinkmouse hasn't implemented a filter for this word. I know it would have immediately come up if the post was mine.

 

[Jocko Homo]

What's your problem anyway, mate....?

The title of this thread is jwb's ultimate aleph headphone amp, not
"Let's ***** about Phred making fun of Zane Grey's latest novel, The Art and Zen of Crossover Maintenance.

If you have a problem about someone or something, then take it to the appropriate thread. And butt out of this one.

As for:

"Beside 's my inbox is spilling over with messages of agreement."

If you want to get into a ****ing match over this one, you may find yourself on the losing end of yet another argument.

And, no, I don't share my hair brush with anyone. I have enough problems already without worrying about getting someone else's cooties.

"I don't want to have to 'splain this again."

-Joe Bob Briggs, Drive-in Movie Critic of Grapevine, Texas.

(Glad to see that the filter really does work.)

 

[jwb]

I'm not too happy to report that a substantial amount of the audible noise on the output of this amp is contributed by the relay attenuator. I haven't really figured out why yet. The micro was putting some nasty noise on the power rail of the relays, but placing a small cap between the power pins (there's just enough room for an 0805) on each relay cleaned up the scope trace without reducing the audible noise. Neither does removing the microcontroller altogether help.

With the attenuator disconnected and the inputs shorted, there's still some barely audible noise. My only idea for getting rid of it was to place a cap across the LED stack reference in the diff input's current source, but that point is extremely quiet already. I added the cap to test but of course it didn't help.

 

[peranders]

First of all, I'll guess that you have diodes across each relay coil? Then, you will have 0.7 volts transients on the power line. One method to avoid this is to make the relay switch off slower (less dV/dt).

 

[jwb]

They make a cute couple, don't they?

 

[grataku]

Hey what's the story with the noise? You tell me that AFTER I paid the money? Just kidding. My plans for volume control are much simpler anyways.

 

[Fred Dieckmann]

Macka attacka

"Please take your pointless attacks somewhere else."

Apparently he did.......... but with a link pointing back to this thread.

http://www.diyaudio.com/forums/showthread.php?postid=272259#post272259

 

[Elso Kwak]

Problem?

The point is no body likes insults but Fred thinks he can sneer in anyones thread about anything that suits him at the time purely because of the soft **** mentality of the on lookers who then go on to copy him.


macka

Hi macka,
I just got an email from Alma Crocker dealing with this little problem.

 

[jwb]

Since my wife bought me a new camera -- this time, not attached to a cell phone -- I've resolved to atone for my previous photographic crimes.

 

[jwb]

With the new cans.

 

[grataku]

Looking very good, makes me want to get mine done too.
Are those the new grado? I recall seeing somethink like that in some magazine recently.

 

[jwb]

They are the RS-2, which I think have been around since at least 1997. I prefer the sound to the more expensive RS-1.

 

[akira]

PCB ?

Hi,

Would it be possible to get the layout files for building the PCB ? Or to buy it to somebody ?

Thx

Akira

 

[jwb]

I sold the last PCB already. I can post the Gerber files, but you should understand the following:

1: The mounting and cooling are designed for the Sun 411 SCSI disk case
2: Some devices are mounted under the board. It is difficult to build

If you still want, I will post the Gerber files.

Cheers
jwb

 

[akira]

Oh yes, if you could post it, it would be great. I may try to adapt it to my own setup but that would be a great first step ...

If the gerber files are not to huge, my email is :
akira9b@hotmail.com

Thanks a lot ...

 

[Brian Donaldson]

So how does the sound compare between Aleph cs and ccs.

 

[sparkle]

Hi to all!

Recently I have bought a new heaphones - MBQuart QP450 Pro. I have built a little portable amplifier to use them with it. I would like also to build high end amplifier- rally good one and I think that this project would be suitable for it. My head's have internal impadance of about 300R. WOULD THIS AMP WORK WITH THEM GOOD?
Could somebody tell me please the subsitutes for the current diodes J506 and J511 used in this project so I don't have to buy them from mouser.....

JWB- it looks really nice. Nice job and thanks for posting it here.
regards
daniel

edit:
btw: how does it sound zen like and aleph like....?


OOOPSSS: MY FRIEND LET ME KNOW A MINUTE AGO THAT I COULD FIND THOSE DIODES IN RS- COMPONENTS CATALOGUE. Anyway- nice job JWB!

 

[jwb]

I prefer the sound of the Aleph CS versus the regular (Zen) CCS. It simply sounds a little more pleasant, less tiring than the Zen setup. It may be that with the Zen CCS the amp clips at my preferred output. I haven't measured it. And contrary to what somone said upthread, efficiency does matter, even in a headphone amp. Aleph is well known for having lower distortion at the same output power compared to Zen.

 

[jwb]

Here's the Gerbers for production. Sorry, but there's no part references. If you understand the circuit well you can match the part placement from the schematic. If you don't understand the circuit well, then I suggest you study the schematic!

 

[sparkle]

HI!
Would this little amp drive my 300R headphones easilly?
regards
daniel