Fantastic!! So glad they are finally available in the store !
https://diyaudiostore.com/collections/new/products/pearl-3-phono-preamplifier
https://diyaudiostore.com/collections/new/products/pearl-3-phono-preamplifier
Order in! Thanks to everyone who has worked hard to make this happen. Excited to join the build train in January!
So the hum that was in my system mysteriously went away after leaving the Pearl 3 on continuously. The hum was the 'angry bee' type and I no longer hear it, but there's a dry staticky whoosh that I tend to call 'shot noise' which can be heard with the knob cranked to max, down around 5 O'clock. There's so much gain from this phono stage I'm not sure I'll be cranking it much past 11, so no bother. This is with a 3-pin XLR umbilical where ground return is the umbilical's shield wire, and the Pearl 3 chassis is floating relative to circuit ground.
If you want to know for sure, Fourier transform it and look at the spectral distribution.
Okay, just started looking at the articles which will likely require reading, re-reading, re.....but from a very quick look it seems that the subject of gnd & gnd loops is waaaaayyyyyyyy deeper than I had a clue.
So if I am getting it a floating gnd does not go to earth or chassis, but here's the part I'm struggling a bit with, the shield can be connected at 1 or both ends or none at at(????) that's the 1 I'm not wrapping my head around.
I’m running 3 twisted wires with no shield, and my setup is quiet.
I may try the Jim 6L6 trick of buying a 4 pin xlr mic cord, clipping one end, and then playing with shield setup.
I may try the Jim 6L6 trick of buying a 4 pin xlr mic cord, clipping one end, and then playing with shield setup.
Yeah, ultimately if one wants to know it requires some experimentation. From what I understand you can have no discernible noise, ie. hum/buzz but still be increasing the noise floor of the signal
Thanks everyone who worked on this and for doing this for the DIY community. One on order. Good project to work on in the cold months!
Either:
1. Connect the shield to ground at the PS enclosure, or
2. Float the shield at both ends.
I've done both in my various builds. My Iron Pre has the shield connected at the PS enclosure only, but my Pearl 3 has only a floating shield.
My preference is to never use the shield as the ground, or in a single supply, the negative feed.
Except I’m not much a believer of clipping one end of the shield… where will the current go? I suppose it could guard against some interference like a chassis, but if it’s an open connection somewhere, where would those currents go if not connected to something…? As for the shield on an unbalanced connection being connected only at one end, that’s never worked well for me. YMMV, of course.
There’s absolutely some experimentation upcoming. The first most obvious thing to try is making the actual shield connected to chassis at both ends and having a conductor in the cable for ground.
There’s absolutely some experimentation upcoming. The first most obvious thing to try is making the actual shield connected to chassis at both ends and having a conductor in the cable for ground.