Hey everybody, new guy here.
I recently constructed a modkitsdiy.com 102 tube amp. It works just fine, however, it is a bit noisy with nothing connected and the input jack grounded. I imagine there's excessive ripple in the power supply and I ordered a few parts to quiet it down.
Attached is a section of the schematic. As you can see, perhaps to keep costs down, the filters caps are rather small. I intend to parallel a 100 uF capacitor across the 47 uF and the 22 uF caps. I also want to replace the 100 ohm resistor with a 1.5 H choke and form an LC Pi filter. According to some Butterworth calculators I found online, this should give me some pretty good rejection above 20 Hz (basically anything audible).
Does this modification make sound sense? My concern is mainly the choke having a 52 ohm resistance and replacing that 100 ohm resistor. Should I place a 47 ohm resistor in series to keep the resistance around 100 or enjoy the extra current available with the choke by itself? Would this change cause any appreciable concerns with the tube's biasing? The circuit itself is fairly conservative.
Thanks everybody.
P.S. - Sorry, doesn't appear I can upload an image from my phone. I'll try when I get home. In the meanwhile, just imagine a Pi filter with a 47 uF cap connected to ground, a 100 ohm resistor on top, followed by a 22 uF cap to ground.
--------- 100 Ohm -------------
....|................................|
....|................................|
47 uF........................22 uF
....|................................|
....|................................|
...V...............................V
I recently constructed a modkitsdiy.com 102 tube amp. It works just fine, however, it is a bit noisy with nothing connected and the input jack grounded. I imagine there's excessive ripple in the power supply and I ordered a few parts to quiet it down.
Attached is a section of the schematic. As you can see, perhaps to keep costs down, the filters caps are rather small. I intend to parallel a 100 uF capacitor across the 47 uF and the 22 uF caps. I also want to replace the 100 ohm resistor with a 1.5 H choke and form an LC Pi filter. According to some Butterworth calculators I found online, this should give me some pretty good rejection above 20 Hz (basically anything audible).
Does this modification make sound sense? My concern is mainly the choke having a 52 ohm resistance and replacing that 100 ohm resistor. Should I place a 47 ohm resistor in series to keep the resistance around 100 or enjoy the extra current available with the choke by itself? Would this change cause any appreciable concerns with the tube's biasing? The circuit itself is fairly conservative.
Thanks everybody.
P.S. - Sorry, doesn't appear I can upload an image from my phone. I'll try when I get home. In the meanwhile, just imagine a Pi filter with a 47 uF cap connected to ground, a 100 ohm resistor on top, followed by a 22 uF cap to ground.
--------- 100 Ohm -------------
....|................................|
....|................................|
47 uF........................22 uF
....|................................|
....|................................|
...V...............................V