They can’t. The 270s are in the power supply.If those 270Rs are the cathode resistors, how does that result in 465.5?
Roger.The 270s are in the power supply.
Thank you CorlissR22 and 30 are dropping resistors in the power supply.
Good call NTC. That looks right.They are simulating the response of a vacuum tube rectifier, probably a 5Y3.
All was good with the new tubes in when, again, it wouldn't power up. I removed all the spade terminals from the switch and tested continuity on switch and all was good. I popped the terminals back on and it fired up.On the s/h Excelsior I owned it worked for 20 minutes then fizzled out. After a half hour it'd fire up again.
Maybe not. If they used one resistor, it would probably be the same value but would have to be twice the rated power. 2x 10W at twice the quantity may very well cost less than 1x 25W resistor. It may have been a space consideration as well, but I doubt it as there seems to be plenty of room there either way - though THAT could also play into how many boards they got per panel (don't ask!).Good call NTC. That looks right.
why would they place one resistor on each ‘leg’ of the rectifier.
they could use one resistor downstream of where the two legs join together.
one component instead of two
less chassis space used.
two fewer electrical connections
they could have saved big bucks.
All was good with the new tubes in when, again, it wouldn't power up. I removed all the spade terminals from the switch and tested continuity on switch and all was good. I popped the terminals back on and it fired up.
I then went to play and immediately the volume fizzled. I shut it off and removed the 6V6S power tubes and they looked OK. I put them back and no change. I then went to observe all tubes under these conditions, so with the volume down I removed the shields on V1&2 and right away it worked!! It has kept working fine since yesterday through 3-4 power ups and downs so, being curious, I popped the old 6v6s back in and it has now been on for over an hour and working fine. I must say that the JJs sound noticeably better. This amp is dead quiet until 2 o'clock on the dial but that is way too loud for my purposes. Turning it to 12 o'clock and using V on the guit works but 8:30-9 is fine. I have the tone control in the 'middle' position and alternate between the guit. and acc. inputs.
My acoustic Yamaha APX600 tuned to open G with slide is surprisingly satisfying.
If it pooches again, My plan is to first chopstick (with amp on) and then examine all spade terminal connections (with amp off and drained) and then maybe reflow all solder connections on the power board.
Thanks again for all the input. I have a schematic. It's a cheap amp (that sounds great!) and there could be lots of gremlins lurking. I'll learn something by chasing them!!
Will do.reflow the solder joints on the heaters.