PS
You can find the exact same SMPS for ten times less.
Oh odd, I didn't even notice that and I've had a Bogner Shiva on my bench once, I think I did a recap job? But don't recall now, the mind isn't what it used to be. Thanks!
I just tested the foot switch for the NFB with straight connections to the NFB leads, 16ohm tap and 32k off of the 3rd gain stage cathode. Works fine, same as with the chassis switch. Now the question is how can I have a chassis switch and foot switch doing the same duty without relays.
So chassis switch can do on/off or foot switch can do on/off. Possible?
You can easily do 'chassis works until f/s is enabled then it's no longer useful' by following the switching used in the dumbles for any of the footswitchable stuff. Basically the 12V has two lines to two switches, one on the panel, the other on the footswitch jack. If you turn it 'on/off' from the panel alone, it works great, but once you connect the footswitch that has full control and only the footswitch works.
ODSFootswitch-panel.png
the panel one is above, the footswitch below.
~Phil
You do not have the required permissions to view the files attached to this post.
angelodp wrote: ↑Fri Nov 20, 2020 3:01 am
I must be missing something but I still don't see how I make this work with a SPDT, 11A panel jack and a Fender single button foot switch.
You can't. You need a SPDT footswitch and there will be 3 wires running between the chassis and the footswitch, none will be connected to ground. Switchcraft 11A wont work either. So, hard wire the FS cable or get a multi-pin connector/jack.
I recommend a hard wired cable. Quick and simple. Who knows, you may not even like this idea next week.
I can make a box with a stomp switch (three wires) and use a male stereo jack into a female stereo jack on the chassis to make connection (better for me to have the foot switch as a plug in). I then have jumpers over to the panel SPDT.
Just to say, instead of removing the NFB at all via footswitch, I'd go for a second set of presence&nfb values (two more pots), in order to give you more control.
pompeiisneaks wrote: ↑Thu Nov 19, 2020 7:25 pmI also don't think I've seen commercially available SMPS for 450VDC
Yes they are fully available and you can regulate the voltage you want. I've used them for preamps because they are dirty cheap DC-DC converters from 12V to up to 450V. Higher current is available, but it is no more cheap. There are some amps that have this SMPS configuration.
pompeiisneaks wrote: ↑Thu Nov 19, 2020 7:25 pmAlso, though, I don't know enough about SMPS to know if using dropper resistors on a B+ line, if you're using them, were to cause it's feedback to try to raise the voltage?
Feedback is taken at the SMPS outlet, then you can drop whatever you want. Always better to filter their outoput and avoid EMI because different HF can "beat" and create audio range noise.
angelodp wrote: ↑Fri Nov 20, 2020 6:09 am
I can make a box with a stomp switch (three wires) and use a male stereo jack into a female stereo jack on the chassis to make connection (better for me to have the foot switch as a plug in). I then have jumpers over to the panel SPDT.
You must isolate the jack from chassis, or just use a plastic Cliff style jack.
