yes
just take care with wires, you don't want spot welding actions to happen
first arrange connection to preamp, then connect wires to battery
just take care with wires, you don't want spot welding actions to happen
first arrange connection to preamp, then connect wires to battery
Well, apparently it's the power supply. I hooked up the battery and it is dead silent through the Quad. Many thanks to Zen Mod and everyone else. I guess my second project will be a linear power supply! Either that or I suppose I could put the power supply in the same chassis, since there is plenty of room.. any thoughts on that? Or would it be best to keep them separate?
Go to the DIYSTORE and buy the $9.00 SMPS filter, build it, install it, that way you can listen to your preamp while building the linear supply.
We have used Meanwell SMPS for B1 Korg and that worked very well so why not for B1?
B1 Korg PCB has a bit of RCRCRC filter "on-board" for the PSU....don't know about B1?
Maybe that specific Meanwell SMPS has a problem?
Also Staving Student II uses a cheap SMPS but also here there is a small filter onboard (a Common mode choke) to remove most of the switching noise and it seems to work.
I built two SS II and one them suddenly created some "funny" noise and it disappeared when I used the SMPS for the other SS II. Then I decided to buy a SMPS that was a bit better (in this case also a Meanwell).
B1 Korg PCB has a bit of RCRCRC filter "on-board" for the PSU....don't know about B1?
Maybe that specific Meanwell SMPS has a problem?
Also Staving Student II uses a cheap SMPS but also here there is a small filter onboard (a Common mode choke) to remove most of the switching noise and it seems to work.
I built two SS II and one them suddenly created some "funny" noise and it disappeared when I used the SMPS for the other SS II. Then I decided to buy a SMPS that was a bit better (in this case also a Meanwell).
Just going back to the beginning... some more thoughts.
What is the recommended supply for this buffer? I ask because the Meanwell, although an excellent product, has a quoted output noise of around 200 millivolts peak to peak. That is pretty normal for an SMPS.
The buffer seems more suited to a linear supply to me as the PSRR (power supply rejection ratio) will not be very high.
The buffer circuit draws a very low current in the scheme of things and yet is shown as having a 1 ohm and 15000uF cap at the supply input.
Question... how well does the Meanwell cope with that? Excessive capacitance on the output of an SMPS can cause issues
Could the PSU be running almost in a burst mode?
For an SMPS increasing the value of that resistor significantly and adding a 1uF film cap across the 15000uF cap could be very beneficial but may still not bring the noise down enough.
I think unless you are prepared to add a lot of extra filtering (someone mentioned the filter from the store) then you will never get the noise floor really low with an SMPS with this buffer.
You also mention a Quad 303. That has a very high input sensitivity and so demands a preamp with a low noise figure... in other words the Quad is amplifying this background noise more than the Aragon you mention.
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That one is a tiddler compared to the ACA one but I suspect all the better for that 🙂
I really do wonder whether the big Meanwell is just pulsing in a burst mode because the current draw is so low compared to the PSU nominal rating. It might be interesting to add a resistive load across the PSU to pull a bit more current. Some thing like a 390 or 330 ohm. They would need to be 2 watt rated.
I really do wonder whether the big Meanwell is just pulsing in a burst mode because the current draw is so low compared to the PSU nominal rating. It might be interesting to add a resistive load across the PSU to pull a bit more current. Some thing like a 390 or 330 ohm. They would need to be 2 watt rated.