I am trying to stick with what I have on-hand for tubes & other pricey parts here. I'm not ruling out 7189s or the original 6973s at some point, but with EL84s & acouple 6V6s I can use tubes I have on hand.
Justin
Announcement
Collapse
No announcement yet.
Dual Power Supplies?
Collapse
X
-
Originally posted by Leo_Gnardo View PostThere's a sort of good idea. You would have a bit of a rise in B+ for the output tube pair left running. I'll leave it to you whether you make a more complicated compensation for that when the amp's running one channel only. I'd say don't sweat it, chances are pretty good the bias current won't go way out of whack, but it is bound to rise a chunk, when you go single channel.
I can see shutting off filament current to the "sleeping" output tubes too, if you're worried about cathode poisoning which may take place in tubes left filament on with no B+ if left that way for extended time.
A swtich like Justin is looking at would be better, particularly with as Leo Suggested killing the filament connections as well. I like the idea Justin has overall, and may incorporate it myself instead of doing it the primitive way.
EL84M or 7189 are supposed to handle 400v on the plates, and 13.5 watts or so plate dissipation. They are the same pin outs. I saw something about an IC connection, but this didn't effect anything in my amp at least.
Leave a comment:
-
Originally posted by g1 View PostThat's how the Hughes & Kettner I referred to in post #21 does it. There's a schematic link there.
Leave a comment:
-
Originally posted by Justin Thomas View PostSo lemme get this straight. If the cathodes are ungrounded, I can leave all the other stuff (voltages - plate, screen, heater, bias) running, AND not blow up my OT if I don't have a speaker plugged in?
(No details right now, just "doofus-level concept) but, am I hearing this concept right?
Justin
Leave a comment:
-
Originally posted by Justin Thomas View PostHooray! Okay, that sounds a LOT easier & cheaper! I'll give it a shot.
Good thing I make my own front playes, covering up all those rendered-unnecessary holes I drilled last night!
Justin
Now you can have a single standby switch. Or no standby switch. Many posters here have determined there's no real advantage to them for guitar amps. Well, other than actually using them to put the amp on standby so the filaments remain hot rather than turning the amp off. But as for the standby switch making for a gentle startup or shut down there are several threads here where it's been pegged as a misnomer.
Leave a comment:
-
Hooray! Okay, that sounds a LOT easier & cheaper! I'll give it a shot.
Good thing I make my own front playes, covering up all those rendered-unnecessary holes I drilled last night!
Justin
Leave a comment:
-
Originally posted by Justin Thomas View PostNope, didn't sleep well.
Clear on the jacks. So if I use those, my OTs & tubers won't blow up? Even with all the other voltages appied?
Justin
Leave a comment:
-
Nope, didn't sleep well.
Clear on the jacks. So if I use those, my OTs & tubers won't blow up? Even with all the other voltages appied?
Justin
Leave a comment:
-
Yes. Non shorting plain ol' Switchcraft "stereo" jacks. And lifting the cathodes from ground is pretty common. Used as a method of standby and also as a half power circuit where the cathodes of two out of four power tubes is lifted.
I hope you're still sleeping I didn't sleep well.
Leave a comment:
-
And, I think TRS (STEREO) jacks come in shorting & non-shorting versions. I think. I'll look again. Do I want the NON-shorting Stereo Open-Frame Switchcrafties, right?
Justin
Leave a comment:
-
It's now 3:15a.m.!
So lemme get this straight. If the cathodes are ungrounded, I can leave all the other stuff (voltages - plate, screen, heater, bias) running, AND not blow up my OT if I don't have a speaker plugged in?
(No details right now, just "doofus-level concept) but, am I hearing this concept right?
Justin
Leave a comment:
-
Originally posted by Justin Thomas View PostFor the record, I always use Switchcraft jacks & plugs unless I'm repairing an amp with a PCB. So I'll look into all of that. I just didn't think it was a great idea to leave a speaker jack shorted to safely kill output. I'll read over it when it's not 3:00a.m. That solution sounds cheaper, too...
Justin
Leave a comment:
-
For the record, I always use Switchcraft jacks & plugs unless I'm repairing an amp with a PCB. So I'll look into all of that. I just didn't think it was a great idea to leave a speaker jack shorted to safely kill output. I'll read over it when it's not 3:00a.m. That solution sounds cheaper, too...
Justin
Leave a comment:
Leave a comment: