aaa

papaya86,

currently the damage for parts and expendable(not counting the parts that I bought for it but never use) is about $600, I expect it to grow a little more as I'm still building the power solution.

av98m,

ehh... let me know if you can find a black anodised version.

tropicalrips,

the length is 285mm

Mackie,

thanks for your compliment.

Q00,

The 9V battery thing is unpractical. The current draw of the amp is about 150mA, with 9V type rechargeble, even the largest capacity won't last more than 80min.

Firefox,

You got it right!

with both my Pimeta and PPA clone project completed (for the PPA, it is almost), I'm really eager for a meeting to try out different source/amp/headphone combinations.

It is very likely that I will not be building any more amps since practically these two serves all I need (portable and transportable)

case closed with battery pack shown outside.

I did not expect the Q3 rail isolation J-FETs to eat so much voltage (5-6V per rail), so I will increase the battery from 16 cells to 24 cells in the future (MAHA AA 1800mAH NiMH)

top view

It is very loooooong.

battery is below the PPA PCB

Silmic rail caps.

front panel- made of PCB (copper side at the back)

notice that one screw for the Locking jack is missing? story behind it.

size comparison

I need a adaptor that can output at least 40V DC from 230V AC supply.

I will be used for building a charger to charge a 24 cell NiMH (for my PPA) is series.

Since it for charger I don't need any quality with the output.

Preferably with at least 1A output capability.

The highest I can find on market is 32V output. Anyone have seen one with 40V or higher?

I guess I might have to look for non-consumer oriented products since such high voltages is capable of killing (though unlikely)

http://www6.head-fi.org/forums/showthread.php?t=101434

as the link above I'm facing some problems, can anyone here help?

yes, the black resistors are 0.1% Welvyn RC55.

I did stripped some pads intentionally bcos I don't like the idea of having the bare circuit wire (mostly from the legs of reisitors) having contact with unnecessary metal parts.

The electolytic caps are Elna Silmic, they have the lowest lost of tangent that I can find amount E-caps.

it will be runing of 16 AA cells NiMH batteries in series.

May increase to 24 cells if I settle for a TI op-amp that's tolerable of 36V max.

is it following the original PPA? or are there changes made? there seems to be a few extra caps on your board

I used 3 layers of C5, which I know is a little excessive.

The yellow polyester cap is for the TLE-2426.

I used so-8 ver of TLE2426 and converted it into SIP-4.

otherwise it follows the PPA1.1, except that there's changes in the value of a few resistors

soldering

has yet to assemble the connector and casing.

Anyway its tested and it works.

hopefully to get is fully assembled in 2 weeks time.

The size of the PCB is 100X250mm

pictures are taken before active components are mounted (except for J-FETs)

from the picture it looks like it cuts with a width of about 1cm, so not very useful for the kind of size of holes ppl on this forum will need to cut.

(8th Jan 2005) will be my choice.

Have to hurry up the work since my PPA clone has yet to start the 1st soldering point.

Bram is on vacational leave till 4th Jan, so he won't see the message.

I hope that with the new copyright law next year, consumers will not be criminalized for using pirated hardware...

a multimeter and soldering iron is a must. Even the cheapest will cost about S$35 for both

not really, an Sunwa (not Sanwa) multimeter plus a no brand solder iron should cost less than $20.

If you are really interested in DIY or learning more electonics, I will suggest you to learn more theoretical knowledge first, since doing practical work at this stage will not be very helpful for you to gain knowledge about electronics.

If you are practical and just want to get a value amp (since 50 bucks will not buy you any commercial amp), then I will suggest you to pay someone to do it for you. I believe there's definitely someone here willing to make you a Cmoy with OPA2134 or OPA2228 for $50 or less.

mirage,

I have calculated that if I will to buy another complete set of parts for such an amp, the total cost is about S$#125.

Since this is make by point to point soldering and not from a printed circuit board, it take quite some time and efford to make one.

So if you are willing to pay at least $200, PM me.

electronics in school?

Not really, A level Physics teached next to nothing about electronic.

I just read a lot of datasheet.

I have thought of it.

I believe the base of the tin will be blocking the big radius wheel of that type of puncher.

Forget to mention,

I must thank Bram and Heady for helping me to get parts from farnell, or else my amp will never be finished.

aluminium Hammond is out of question bcos:

1. it's too ex here.

2. I don't have anything to drill hole through it, and tools are expensive.

The quiescent current is about 35mA, anyway this number can easily calculated by adding the Iq of opamp + Buf + biasing current, and was calculated as I was designing the amp.

the active current is negligible, at least on the HD650.

Zinc carbon last like 5-7 hours.

for NiMH the capacity is well stated so you can calculate your self.

with Alkaline it should last more than 10hrs, though I have't try it 1st hand.

The puncher totally don't work

In fact it screw up the 1st hole that I was trying.

I guess there's great variation in the quality of these cheap puncher.

in the end I go back to hammer + pen-knift (a slim solid aluminum one).

the outline is far from beautify, but it works.

The uneven edge in pointed to the inside anyway.