If the entire enclosure is wooden, you may have to create what I've called an intentional ground plane. Essentially you create a isolated, conductive path for ground instead of relying on the chassis. In essence, create a backplane/star ground point that you then run grounding wires to.
For example, you can simply screw a nylon standoff near the back cover near the IEC entry point and run grounding wires from the board, pot, and negatives of the incoming RCAs and inlet phono connector to that single, isolated screw, and then from there connect the .1 uf cap/diodes or diode bridge/resistor to the IEC's ground lug so that ground is isolated until needed.
This should create the lowest impedance path to ground. Just be sure that it is indeed isolated from the chassis except at the star point. You can verify this by probing around the chassis with your DVM set to continuity/diode mode.
--Tom
Agreed. The best builds I've seen (or heard) like this use the vintage wooden enclosure as a "skin" that house a metal enclosure inside. OTOH I've seen a bunch that look awesome but have grounding/noise issues just like the one we're trying to debug now. That is why I personally went with good looking, well constructed metal enclosures a long time ago.
For bipolars you want to use a darlington. So BD139/140 is not appropriate.
Sanken make some nice Darlington bipolars. You might need to increase the resistance at the base eg 1k
My understanding is that capacitance in series with the gate does not affect bandwidth like the parasitic capactance from gate to drain and gate to source of the mosfet.
Sanken make some nice Darlington bipolars. You might need to increase the resistance at the base eg 1k
My understanding is that capacitance in series with the gate does not affect bandwidth like the parasitic capactance from gate to drain and gate to source of the mosfet.
Last edited:
Which depth dimensions did you go with for the Galaxy 2U? I'm looking for a chassis that fits comfortably, but not with too much room to spare.
Yes it does it with certain op amps. It's normal. If you use an OPA2107. The problem will disappear.
I didnt need any gain on my whammy so i took out the 1k5 resistor to ground from the - pin of the opamp, which r ne5334 in mine, and it works. Works really well and the offset is stable at .001, hehe. I even changed the feedback resistor to 150ohm and it still sounds wonderful. 😁
Should i maybe put 100kohm resistor from the negative pin to the gnd to define the impedance? What would that do?
Should i maybe put 100kohm resistor from the negative pin to the gnd to define the impedance? What would that do?
I've built one of these and am now building another for a friend. My previous headphone amp was a Schiit Magni, and, well, no contest. (Headphones are Focal Elear.)
I also muck about with woodworking, so the cases are made from wood. The images below are from the first version, built from some gorgeous jotoba (aka Brazillian cherry, although it is not a kind of cherry) that I bought years ago and have been waiting to find a good use for. The finish is just polyurethane. It really is a great wood, with this deep color and great grain. The top is made from luan (stained cherry) and will probably be replaced at some point with something veneered. But I'm just learning to do veneer....
(It appears I need to stain the insides of the vents. The camera shows everything!)
As you'll see, I've left some extra room in this box in case I want to get creative with the volume control. Unfortunately, the volume control is not vertically centered on the first one. It will be on the next one. This is the tricky dimension.
The other box, which I'm building from redwood left over from another project, will be done in a few days. I'll post pictures then. I have just enough of the jatoba left for one more case, I think, so some other friend is likely to find one of these in their stocking....
How much interest is there in building cases from wood? Having built two of these now, I have a pretty good sense for what a set of plans would look like and could produce something along those lines pretty easily. But if it would just be a waste of time....
I also muck about with woodworking, so the cases are made from wood. The images below are from the first version, built from some gorgeous jotoba (aka Brazillian cherry, although it is not a kind of cherry) that I bought years ago and have been waiting to find a good use for. The finish is just polyurethane. It really is a great wood, with this deep color and great grain. The top is made from luan (stained cherry) and will probably be replaced at some point with something veneered. But I'm just learning to do veneer....
(It appears I need to stain the insides of the vents. The camera shows everything!)
As you'll see, I've left some extra room in this box in case I want to get creative with the volume control. Unfortunately, the volume control is not vertically centered on the first one. It will be on the next one. This is the tricky dimension.
The other box, which I'm building from redwood left over from another project, will be done in a few days. I'll post pictures then. I have just enough of the jatoba left for one more case, I think, so some other friend is likely to find one of these in their stocking....
How much interest is there in building cases from wood? Having built two of these now, I have a pretty good sense for what a set of plans would look like and could produce something along those lines pretty easily. But if it would just be a waste of time....