A GC Layout check.

[Nuuk]

S.G. The resistor between MG and the case connection should be 100R not 100K and the capacitor is in parallel with it and 0.22uF should be fine (use a small film type).

One end of the resistor/cap goes to MG; the other end is connected to the metal case.

 

[jackinnj]

like so

don't try to bend the pins to fit a 100 mil grid, they'll break. the pins for the 1876 -- (more pins than the 3875 I believe, but same layout) go something like this:

 

[S.C]

Dip is a good idea, but I already bended the leg b4 I start this thread. It fit the board, but question is do you think it is a good idea to cut off leg 5?

 

[S.C]

V9 is on, I hope I understand what you say Nuuk. My English kindla poor too.

 

[Nuuk]

An externally hosted image should be here but it was not working when we last tested it.

S.C. This shows the resistor/cap in parallel connected to PG with a hole at the other end to connect a wire to the metal case.

 

[S.C]

V10, I'm kinda tire today. Thx for the advice, I'm going to sleep now. Continue tomorrow, our hard working DIYer. GN, sleep well.
http://hk.geocities.com/solomon_choi/GC2.html
A Xfeed Plug that I finished in two days. http://hk.geocities.com/solomon_choi/Xfeed.html

A Question about power supply, should I follow the LM3875 Data sheet's equcation to calculate the Max PS, or just use whatever. However, I don't know how to measure the Max V out of my laptop, MD recorder, and the CD player. Also the Impedance of those sources. The eq from the data sheet http://hk.geocities.com/solomon_choi/GC.html

 

[carlosfm]

The final touch

Some serious copper.

 

[Nuuk]

QQq

A Question about power supply, should I follow the LM3875 Data sheet's equcation to calculate the Max PS, or just use whatever. However, I don't know how to measure the Max V out of my laptop, MD recorder, and the CD player.

S.C. if you are not completely worn out by drawing all those circuit diagrams, I would suggest building the 'standard' GC PSU as shown on my FAQ page .

Go with a 18-0-18 transformer and MUR860 diodes and you won't go far wrong.

And in all the posts that I have read about the GC, I haven't yet seen anybody complain that a device wouldn't work with the GC because of an impedance mismatch.

 

[carlosfm]

Psu

S.C.,

The voltage for the transformer is 2x22V.
It's about the ideal, at least for me.
But from 18 to 22V you can use any.
If you're in for two transformers, 2x22V at around 160~200VA.
If you're going to use one transformer, 2x22V at 320~400VA.

 

[S.C]

Ok, then I whatever I got that under 40V.

 

[S.C]

Re: The final touch

Some serious copper.

Is it good to have that much copper?

On the previous post, I mean I need two around 35V, but whatever Amp I got.

 

[ronc]

IMO on any NC lead , it gets clipped off as close to the chip as possible, but all i use is P2P wiring.I have found out (the hard way) to bend any real functioning chip leg as little as possible or not at all.
ron

 

[carlosfm]

Re: Re: The final touch

Is it good to have that much copper?

Yes, it is.
Good ground and thick tracks for the PSU pins.
This isn't a preamp...

 

[S.C]

OK Let me try to send that to ADvcircuit, and had convertion of the ExpressPCB, then let them analyze too. Hehe, can't wait for the board.

 

[S.C]

I think I gonna send this

An externally hosted image should be here but it was not working when we last tested it.

http://hk.geocities.com/solomon_choi/GC2.html

P.S: Man I can never make the picture link right.

 

[Nuuk]

I think I gonna send this

Looks OK to me!

 

[S.C]

Also plz help me out on the other pic which locat under the circuit pics. I don't know how to test those stuff, and Nuuk, your site that wiring tips won't help me. It is because the coloring code of the transfromer isn't the same.

 

[Nuuk]

Also plz help me out on the other pic which locat under the circuit pics. I don't know how to test those stuff, and Nuuk, your site that wiring tips won't help me. It is because the coloring code of the transfromer isn't the same.

Sorry S.C. I don't think that I can help you on this one. IF you know what you are doing, the only way to find out what those transformers are, is to connect them up and measure them. Even then you may not know what they are rated at.

And it should go without saying that you must know which are the primary leads and which are the secondary leads BEFORE connecting them to a mains supply.

 

[carlosfm]

And it should go without saying that you must know which are the primary leads and which are the secondary leads BEFORE connecting them to a mains supply.

You can look at the wires.
The primary wires are much thinner.
But if you have 3 wires on the primary (115, 230...) and no indication at all, you'll have difficulty in knowing which ones to connect.

 

[S.C]