yes, I know that is signal ground from aleph 30 wiki, but don't understand the different between the signal ground and power ground. what is it good for. when I traced the circuit from the circuit board, look like it go no where (maybe I am wrong). and also, resistor R6 has 3 holes. I just want to understand the circuit better. look like the board can allow people to use slightly different circuit design other than the original aleph 30 design. If yes, what are those design?
hc167 said:
The GND and SG connection points have been explained here: http://www.diyaudio.com/forums/showthread.php?postid=617070#post617070
In most cases they are connected together, and that's how I did it in the amp I built for myself. You can also run separate wires from those points to your star ground, as some people apparantely reported improvement from such arrangement.
Yes, the two jumpers need to be always installed, I just couldn't run traces there.
The negative speaker terminal should be connected directly to ground of the filter capacitors, the SG and GND from the board connect to that point as well (with a single or two separate wires)
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hi Peter,
after reading your post, I think I got your idea. so ground need to connected to the ground of the filter capacitors. however, you physically separate the input signal ground and the constant current ground, you created GND and SG so that they both won't connected directly. In this case, althrough they are still connected, the ground of the signal will go directly into filter caps ground without using the route of the constant current ground. right? I believe this will have improvment (but maybe not very obvious). for the same reason, speaker ground should go from filter cap to SG and then to the speaker terminal negative output to get better performance (again, the improvement may not be obvious), do you think so?
after reading your post, I think I got your idea. so ground need to connected to the ground of the filter capacitors. however, you physically separate the input signal ground and the constant current ground, you created GND and SG so that they both won't connected directly. In this case, althrough they are still connected, the ground of the signal will go directly into filter caps ground without using the route of the constant current ground. right? I believe this will have improvment (but maybe not very obvious). for the same reason, speaker ground should go from filter cap to SG and then to the speaker terminal negative output to get better performance (again, the improvement may not be obvious), do you think so?
hc167 said:
You are correct about GND and SG.
However, the output ground is high current connection and should go directly from main filter caps to ouput terminal, you don't want to run it through the board and affect low current signals there. Connecting SG and GND with wires to main caps is basically the same though, just done away from the board.
I've built some Alephs before (usually p2p) and always had some hum problems. With those boards the amp is dead quiet.
To be diplomatic, I will say the comparison would be similar to Aleph 30 and Zv9, as the Zv9 that I've built sounds very similar to my favourite GC 
What I remember from A30 was very nice midrange: liquid and melodic. I didn't like highs that much, but it's probably a matter of components selection. Also, Aleph can be better with difficult loads.
Properly built GC has involvement factor that is really hard to match by most amps.
What I remember from A30 was very nice midrange: liquid and melodic. I didn't like highs that much, but it's probably a matter of components selection. Also, Aleph can be better with difficult loads.
Properly built GC has involvement factor that is really hard to match by most amps.
Ufff...
Peter, I just found your Audiosector web page. Very impressive.
The more I look, a chip amp might be more appropriate for my skill level (which you can guess from the kind of questions I'm asking). Putting together a power supply with 150,000uF of capacitance, I don't know....
I'll make my way through the project pages for the different boards you sell. It is possible that I might come back to the Pass Labs idea. In any case, thanks again for the information and advice.
Peter, I just found your Audiosector web page. Very impressive.
The more I look, a chip amp might be more appropriate for my skill level (which you can guess from the kind of questions I'm asking). Putting together a power supply with 150,000uF of capacitance, I don't know....
I'll make my way through the project pages for the different boards you sell. It is possible that I might come back to the Pass Labs idea. In any case, thanks again for the information and advice.
The data sheet (you can find them by searching by device name) calls out a 6-32 or m-3 screw. This implies preparing a tapped hole or drilling through and fastening a nut on the backside. Don't overlook lock washers, insulators & heat transfer grease. The washers should be those that match the screw.
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