apheared 47 amp beginner questions

1. It can be omitted.

2. You can add switch right after the power. Let's say. between + and D1.

3. You don't have to if you have 9~16V wall wart laying arround.

4. Those are 47 ohms. 47.5 ohms, 50 ohms, doesn't really matter.

5. Panasonic 10K potentionmeter. Brand doesn't matter as long as it's descent. Also you can use 10K ~ 100K ohm pot if you want.

6. I can't remember the part # now. Whatever jack you choose, make sure it's not too cheapy, and it has thread and bolt if you wish to attach it at altoid can.

You need a dual ganged 10K LOG pot, not the two you have listed,

scrap the Schottky diode and the 1uf Ceramic use a film type 1uf capacitor

the Resistors you need metal film 1% 1/4W

values

2K x2

10K x2

100K x2

47R x4

cheers

FRED

Sorry that pot will be fine I thought you'd chosen 2 single pots, that cap should be fine, You should be able to get a wallwart at any electrical store 12-18volts will be fine

cheers

FRED

The diode is only a shunt to protect the circuit if you connect the power the wrong way, so I would not use it but your call :-)

Prices I'm not sure I'm in Australia so a lot difference,

but why are you getting 10 x 1uf caps and 10 x 47R resistors??

You are ordering 2ohm, 10ohm and 100ohm resistors

You need 2Kohm, 10Kohm and 100Kohm resistors

The jacks look ok, theres hundreds of different ones, but those have a threaded mount which will help when casing up

good luck

cheers

FRED

I would keep the crowbar diode for protection. One thing you don't have in your parts list is IC sockets. Something like A400-ND or an equivalent Mill-Max ED3308-ND. For resistors, I always liked the BC SFR25 series (PPC100KYCT-ND, PPC10.0KYCT-ND, PPC2.21KYCT-ND, etc.). For AC adapters, I'd look at the Reliapro series from Jameco... good and cost effective. I would also use the Alps RK097 pot (w/switch) from Tangent or Amb over the Panasonic pot from Digikey, but if you are trying to order from one vendor, then understandable. I would also use Panasonic FM caps over the FC you have listed.

Personally, I'm not sure why you are building an A47... a Mini3 would not cost much more and will kick its ass.

Let's say this way.

A47 is sort of basic amp design just like Cmoy + buffer. Nothing new, but quite nice for grado phones. M3 is more complicated, better design, requires little bit of pair matching and stuff. I recommend you try A47 regardless of existance of other amps. Don't worry too much about getting exactly the same parts on the list. All can be subsituted with similar parts.

For the wall wart, I have bunch of them laying arround from answering machines, phones, old crappy PC speakers, cable modem that died 2 years ago etc. You may be able to find something like that. If you can't find it at home, get any wallwart that is 9~18V range. A47 does not require whole lot of voltage or hefty current. Just make sure the polarity is right when you connect it..

It's a cheap switch mode adapter.... Which means it's going to be noisy.

You might want to pick a panel mountable jack instead.

Try something like # CP-5-ND instead?

FWIW the parts for a Mini3 without the custom end panels are roughly $80 and it's a no brainer compared to the A47 with Grados.

Not sure if you already knew this, but GlassJar Audio sells an entire Mini3 kit for ~$95 that appears to include everything (case, nice knob, wallwart, etc.)

http://www.glassjaraudio.com/product.sc?productId=9&categoryId=2

While the A47 was good for its time, particularly for Grados, it isn't in the same league with the mini3. Most of the Cmoys that I built were done as A47s (not from the feist article that you posted though), as it was a) easy and b) sounded better. Mini3s weren't around then though.