[ATAT]

I layed out the schematic and layout for sijosae's MHHA. 2 potential layouts, 2 layer and 1 layer. I'd rather keep it 1 layer (so its possible to etch) but 2 layer seems much cleaner.. I'd HIGHLY appreciate any advice on the schematic as well as the board (I'm unsure of pin-layout as well as the common LED layout..) this is the revision 3 board shown http://www.headphoneamp.co.kr/bbs/zb...sijosae&no=246 here.

I would also appreciate design change suggestions .. such as a CRD instead of the Q1 or whatnot...

Schematic

1 Layer

2 Layer

Pending todo:
1. Move 470 uF PSU caps upward.

 

[ChickenScrtchBoy]

ooh looks cool, what kind of case are you trying to cram it into?

 

[nikongod]

that design looks pretty sweet.

you (i would) may want to move the 470uf caps so that larger ones may be used if desired. there looks to be PLENTY of room in the upper corners of the board.

 

[ChickenScrtchBoy]

Quote:

Originally Posted by nikongod that design looks pretty sweet. you (i would) may want to move the 470uf caps so that larger ones may be used if desired. there looks to be PLENTY of room in the upper corners of the board.

good idea...
but if you have to, you can always creatively topple

 

[ATAT]

Okay.... I dont think it's that important though.. it IS a 9v battery based design., but i'll see how that affects the layout

 

[ATAT]

Quote:

Originally Posted by ChickenScrtchBoy ooh looks cool, what kind of case are you trying to cram it into?

Not sure if it'll fit in an altoids tin.. that's one of the goals.. If not, then one of the smaller hammonds or such.

 

[ChickenScrtchBoy]

Quote:

Originally Posted by ATAT Not sure if it'll fit in an altoids tin.. that's one of the goals.. If not, then one of the smaller hammonds or such.

well, for the hammond, you will need to make sure that the transistors, etc, if you want to topple them sideways like that, you need to have them at the rear of the board... but that is only needed if they require heat sinking.

also, for the altoids tin, do you think that it's possible to do some board halving (ala tangent's mint) and putting the tube sideways in the tin?

even then, will the battery(s) fit in there too?

 

[ATAT]

I'd highly appreciate it if someone gives me the dimentions for an altoids tin .. (useable). so I can shrink the board to the necessary size.. (2.2 x 2.5 right now)

 

[ALBQ]

ATAT,
Here is single sided multi-hybrid amp PCB design I posted a long time ago on HeadWize. Here is a picture of the finished amp, PCB and link to EagleCAD file.
Cheers -ALBQ

Link to board file:
http://mywebpages.comcast.net/gilles...neAmp-R2-2.brd

 

[ATAT]

do you have the schematics by chance? The main fear right now is that my schematic is flawed.. but thanks ALOT for the board =)

I've got a few questions.. hope you dont mind
1. whats the point of C5? I thought pin 4 and 5 were linked> (they're both heater right?)
2. Isnt pin 9 grounded for 12AU7?
3. is there a reason you picked 90 degree angles? IIRC they were supposed to be avoided if at all possible
4. Is this for the rev 1 board? (then 6922 and 12AU7 is different and that explains all but #2).

 

[ericj]

Quote:

Originally Posted by ATAT Okay.... I dont think it's that important though.. it IS a 9v battery based design., but i'll see how that affects the layout

Um, no, it's not. The MHHA is 24vdc about 500ma and runs HOT -- the batteries just provide bias voltage.

Have you seen sijosae's website? He has very clean single-sided pcb artwork downloadable for a few different revisions of the MHHA. Lots of other amps, too.

If you don't read korean you won't be able to understand a thing he's written because you can't actually translate korean to english with software (it comes out very funny, with a lot of references to linnens, and sounds nothing like techspeak) -- but the schematics more or less speak for themselves.

http://www.headphoneamp.co.kr/bbs/zb...esc=asc&no=247

 

[ATAT]

SHOOT. I misnumbered the pins... anyone familiar with 12AU7s can confirm this

1Plate
2Grid
3Cathode
4Filament
5Filament
6Plate
7Grid
8Cathode
9Filament center tap..

Revised and uploading now..

 

[ATAT]

Quote:

Originally Posted by ericj Um, no, it's not. The MHHA is 24vdc about 500ma and runs HOT -- the batteries just provide bias voltage. Have you seen sijosae's website? He has very clean single-sided pcb artwork downloadable for a few different revisions of the MHHA. Lots of other amps, too. If you don't read korean you won't be able to understand a thing he's written because you can't actually translate korean to english with software (it comes out very funny, with a lot of references to linnens, and sounds nothing like techspeak) -- but the schematics more or less speak for themselves. http://www.headphoneamp.co.kr/bbs/zb...esc=asc&no=247

I was trying to implement his v3 as a PCB.. I havent seen sijosae's v3 pcb.. if that could be found.. then you've saved me alot of time =p also about the battery issue, I was intending to run this off of an offboard battery pack of 3 9v DC + for 27 volts w/o 2 bias batteries. My point was that the capacitors werent too big of an issue.. but of course now that it's come up, I should probably add a power jack & allow for bigger caps huh? =p thanks!

(redid pcb because of prev post)



2 layer

Also, I'm wanting to modify the orignal circuit for SQ purposes..

 

[~n00beR]

Quote:

Originally Posted by ATAT I was trying to implement his v3 as a PCB.. I havent seen sijosae's v3 pcb.. if that could be found.. then you've saved me alot of time =p ......... Also, I'm wanting to modify the orignal circuit for SQ purposes..

Here is a link to at least a picture of the v3 PCB hope this is of some help.

http://www.headphoneamp.co.kr/bbs/zb...sijosae&no=246

 

[sijosae]

Thanks for the interests in my amp.

I attached layout (12AU7 version) of the MHHA v3.0.

ps) ATAT, LEDs (blue <--> red) were swapped in your schematic.