Soekris Dam Dac

[rickmcinnis]

Thanks, Randy,

I feel sure we are talking about the same measurement. I have one multimeter lead connected to the wire, at this point unconnected to a battery, from the solder pad at the place that used to hold a capacitor and the other lead connected to the power input ground point.

I unwound the wires from the high rail just to see if something was amiss with just one of the SRs but they all measured the same as they did when together which I guess means that this method would never pinpoint a certain one of the four since they are all paralleled, anyway.

Interesting that all of mine measure much higher than yours. And even more interesting that you get a different measurement for the plus and minus ones. The three that measure lower are essentially the same. I did not take note of the numbers to the right of the decimal point but remember them being close, no more than a 100r difference.

I did not think the measurement was useful for anything other than making sure I had not shorted to ground but was surprised and disappointed when three groups measured the "same" and the one, which was the first one I wired, measured higher than the other three.

I have looked at the board numerous times before I wrote to make sure there wasn't something visibly wrong.

At this point there is nothing i can do but simply turn it on and see if anything happens and more importantly if it makes music.

I have removed everything that is no longer used. I think you have retained the caps at the shift register, I have removed them all. Everything that was used for the output op amps and the Vrefs is gone - the board to the right of the resistor stacks is completely clean and the 5 volts regulator stuff is gone along with all of the original raw supply. I doubt this would account for the difference.

All I can hope for at this point!

THANKS, again.

[rickmcinnis]

Randy,

One thing to consider when using relays is that power to the relays can make a difference.

When you get a chance you should try using regulated power for the relay. It sounds crazy but it was first brought to my attention by Dave Davenport who found with his line stage that clean power to the relay makes a sonic difference. Dave is not silly tweaky so for him to use this in his designs means to me there is a sonic gain to be had, He swears it removes the sonic consequences of using relays. His line stage uses a dedicated regulator for the relay. I am lazy so would rather just use a good old switch. I would also consider using multiple contacts, also. I am using a three pole switch paralleled since I am obsessive.

When you think about it: that connection is made with electrical power holding that contact and any perturbations of this power will affect the pressure of the contact which easily could affect the goodness/consistency of the connection. Probably has the additional benefit of increasing the life of the relay, also.

Take care,

[rickmcinnis]

Went back and measured again.

21.65 neg near top of the board
22.19
21.74
24.92 pos at the bottom

So I do see the difference between + and - - ignored it before.

[jkeny]

Randy,

One thing to consider when using relays is that power to the relays can make a difference.

When you get a chance you should try using regulated power for the relay. It sounds crazy but it was first brought to my attention by Dave Davenport who found with his line stage that clean power to the relay makes a sonic difference. Dave is not silly tweaky so for him to use this in his designs means to me there is a sonic gain to be had, He swears it removes the sonic consequences of using relays. His line stage uses a dedicated regulator for the relay. I am lazy so would rather just use a good old switch. I would also consider using multiple contacts, also. I am using a three pole switch paralleled since I am obsessive.

When you think about it: that connection is made with electrical power holding that contact and any perturbations of this power will affect the pressure of the contact which easily could affect the goodness/consistency of the connection. Probably has the additional benefit of increasing the life of the relay, also.

Take care,

That sounds like good advice from Dave & makes sense - thanks for drawing attention to it, Randy

[randytsuch]

That sounds like good advice from Dave & makes sense - thanks for drawing attention to it, Randy

That was Rick's post, not mine, so give Rick the credit.

Another thing on my list of stuff to try

Randy

[randytsuch]

Went back and measured again.

21.65 neg near top of the board
22.19
21.74
24.92 pos at the bottom

So I do see the difference between + and - - ignored it before.

Thought about it some more, you're measuring four shift registers at a time, one row.
Since mine are already wired, I'm measuring 8 at a time. My measurements are like yours, but mine look like the two resistances are in parallel.

So, I just calculated 22.19 and 24.92 equate to 11.7 if you were to wire them together. That's about what I saw. To get the 11.4k I saw on the negative, the other sets would need to be around 22.8 each. A little different from what you measured, but pretty close. With your measurements, I would have seen about 10.8k when I measured the negative shift registers.

In any case, I would think it will be fine. Usually, I just make sure there is no short between power and ground, and then look around where I was working and make sure there are no solder bridges or anything else that would mess things up.

EDIT: Also, it does appear to indicate that for some reason, one row is different from the others. Maybe he connected something else to that row that is affecting this measurement. Might be worthwhile to either remove more parts, or to try to isolate the shift register power from the rest of the board.

Randy

[jkeny]

That sounds like good advice from Dave & makes sense - thanks for drawing attention to it, Randy

That was Rick's post, not mine, so give Rick the credit.

Another thing on my list of stuff to try

Randy

Sorry, yes, I meant to say, Rick but mistyped

[rickmcinnis]

Randy,

THANKS for your time and trouble.

I had not considered the parallel aspect. AND that makes perfect sense.

I feel assured and will go ahead and see what happens tonight.

Much gratitude is being sent your way.

Take care,

[rickmcinnis]

Does TIR NA accept donations to offset its expenses?

I used to send some money to AA but after the shabby treatment jkeny received there I am done with AA and would rather make a modest contribution to TIR NA if these are accepted.

[nige2000]

Randy

Was thinking that you should at least remove the 10uf caps on the shift registers
There the darker brown ones