Nice Mercury OT. Is the power transformer Mercury too, or is it a Weber?I'm already lost. Should I mount the choke in the middle or on the end?
Leo DID skimp and he was the A+#1 cheap bastid of a gent (aka NoCaster, hmmm?). Sometimes a happy mistake, the 16uf at 25 percent less filtration does contribute to the sag and softness of attack. I've played with that a whole bunch, and for me, my taste... the 20's are better. Folks talk about hum, but again, just me, I didn't notice any difference at all.The 20 uF capacitors will be fine. You probably won't notice any appreciable difference in sound. The impact of bigger filter caps is less hum (smaller ripple voltage), and better bass handling. Too big and the bass will flub out, even bigger and they'll kill your rectifier on startup.
But 20 uF will be fine. A lot of people think Leo Fender skimped on his filtering anyway.
You are right about the topology on real Fenders. The Weber chassis seems to be set up to put the choke in the middle. There probably needs to be another hole to route the wires from the OT closer to the power tubes to put the OT in the middle.I'm paying attention to this, I want to build a tweed super but saving up the money is slow-going. I'm no expert on tweed era stuff, but I can see that's the "big" choke, filters entire power supply, and I've seen original tweed supers with them mounted on the end (with OT in the middle) and with it mounted in the middle.
I think from a topology point of view, mounting it in the middle to me makes more sense keeps it close to filter caps. Just my opinion. Nice kit! Good luck, please keep us posted on developments....very exciting!!
I like to get all the components in place before running the underboard wiring. That way I can check to make sure that everything is in the right place before anything is soldered.And also, FWIW, I try to get the underboard wiring done first, then the components. If you're good, you can use the leads from the caps as the underboard ground buss. Make sure you have an air gap between the cathode resistors and the cathode bypass caps. No sense cooking those caps on purpose.
My own take on things: If I'm spending my money to build an amp, I try to not cut corners to terribly badly. I don't have to have the very most expensive output transformer, I can't hear to difference in 'em and the middle of the road ones. I like good tubes but don't go gaga over vintage shmintage ones. If I can get good capacitors for a few bucks more, I do. I want my amps to be decent, if not great sounding, and they gotta be reliable as the ones that Leo made.
I just ordered some of the Mojo Dijons for the hell of it. I was ordering a tube rectifier anyway and had them throw the caps in. I also emailed Weber about them sending me the wrong filter caps. I actually like the sag so I'm thinking I might want the 16uf caps instead of the 20uf. I'll just wait to see what Weber does. Also, I got your message about twisting the wires for the secondary and the heaters.Agree.
I figure that a few extra bucks for decent caps (as opposed to 'boutique' caps) is not just money well spent, it's also a relatively piddling amount of money I'll forget spending long before I finish my first gig with my awesome new amp.