I like the compression aspects of the bulb attenuator so I'm going to avoid the parallel bulb option. I was thinking that maybe two 4W bulbs in series would work. If a single bulb went then the second bulb (I think, still need to crunch a couple of numbers) would be able to handle the full load for a short period of time, long enough for me to notice and replace the dead bulb. I do like the idea of just running a power resistor though as that makes for a pretty good failsafe. When you say 20x the nominal impedance are you talking about the impedance of the speaker? For example, if it's a 4 [ohm] speaker I would want something on the order of 80 [ohm]? I'm going to sit down tomorrow with a couple of my old Electrical text books and see if I can't figure everything out. Thanks for your help though, I've been scouring all of your posts on that site!
Well, I just got back from picking up my new toy! Plugged it in, cranked it and was blown away by the volume! This sucker gets LOUD... sounds great though, the bridge pickup of my MIM HSS Strat gives a cool twang through this amp, almost like there's a little bit of wah. The neck pickup gives a rich deep sound and combinations in between are just that. I'll have to pull the Epi G-400 Vintage off the wall and see how that sounds. There's a huge amount more breadth to the sounds I get I'm finding (in compairson to my little 15W Marshall MG). It's gonna be fun playing around with this sucker seeing what I can do with it. I gotta say though, you all were right! This is a really fun little amp to play with!
:D Glad you like your new amp! :D I love mine! Welcome to the club! 8)
Dan
"The only way I know that guarantees no mistakes is not to play and that's simply not an option". David Hodge
Enjoy! It sure is a loud little imp! The real problem with it is that I can' t play it when anyone is in the house :twisted:
--vink
"Life is either an adventure or nothing" -- Helen Keller
I like the compression aspects of the bulb attenuator so I'm going to avoid the parallel bulb option. I was thinking that maybe two 4W bulbs in series would work. If a single bulb went then the second bulb (I think, still need to crunch a couple of numbers) would be able to handle the full load for a short period of time, long enough for me to notice and replace the dead bulb. I do like the idea of just running a power resistor though as that makes for a pretty good failsafe. When you say 20x the nominal impedance are you talking about the impedance of the speaker? For example, if it's a 4 [ohm] speaker I would want something on the order of 80 [ohm]? I'm going to sit down tomorrow with a couple of my old Electrical text books and see if I can't figure everything out. Thanks for your help though, I've been scouring all of your posts on that site!I guess you're talking about putting 2 bulbs in series with the speaker and parallel with each other. If they're in series with each other, if either one blows your output is unloaded.
Yes, I'm talking about 20x the rated impedance of the speaker. Lots of amp builders put such a resistor across the output jack to save the OT if the speaker's unplugged.
"A cheerful heart is good medicine."
yea, I wasn't thinking and thought that when the bulb died it would act like a short, but of course it would be an open. Right now I'm trying to decide between a larger resistor in parallel with the lightbulb or just running a resistor from the input jack to the attenuator. Having the resistor in series with the speaker and in parallel with the bulb in convenient in that I can enclose everthing in an external box and unplug everything to go back to stock very easily. On the other hand it will have unknown (to me) effects on the sound. Worst comes to worst I can try it both ways!
Yep.
A 20X resistor always in parallel with the output will have no audible effect on your sound. I've put that on my amps for no-load protection, as do many amp builders.
"A cheerful heart is good medicine."
