Help identify this base amp or resistors please!

If I remember correctly this was a Crusader 300 Base Amp. Not the best of designs, some say even an electrocution waiting to happen due to its lack of a transformer. I had one many years ago, It died, I fixed it, then got rid of it....

I think I still have a Schematic for this fellow though finding it could be a project, I'll wait and see if someone else chimes in with the info, if not I'll do some digging.

Was just thinking about this a little more, may have also been badged under other names.... LDO come to mind as well as another I cannot remember.

i had one of those transformerless amps ,it was mint .lost it when i got hit by lightning.i think just the keyup resistors went or something .i forget who made those ,for tube amp questions get ahold of "alan" at tubesplus.com......he is very helpfull and can probably even tell you who made that amp.i doubt he work on it though.nobody really wanted to touch mine because you gotta take the whole chassis apart to get to the solder side of the board ,theres no other way.and theres a electrocusion hazard as well because the chassis is hot on those i was told.
funny thing was when i first bought mine i went to pick it up at the ladies house and when i picked it up i nearly threw it in the air it was sooo light.i was expecting to pick up a heavy amp ya know ..lol..

oh...and those tall caps in there you see,they are holding a big charge ..enough to lay ya flat out you get bit by that amp.so be carefull inside that thing .it can hold power for days i think unless you discharge them.

ps-i think mine was called the footwarmer 300

your welcome ..tell him its a footwarmer 300 and he will know what amp your talking about.

Like I said this amp was Branded under multiple names, I'll dig through my junk and see if I can find the Schematic. The one I had which WAS the same amplifier was called Crusader 300. The tubes in yours could be original, only difference is the heater (filament) voltage.

dude....i found inside pictures i took of my mint barefoot300.your welcome to the inside pics .drop me your email at "joe3857@aol.com"and i,ll send them to you .i got closeups and mine was mint.

sent you what i had here .hope it helps.its all i got.

I think I got ya covered!

The resistors are 10 ohm, 1/2 watt. Band colors are as follows, brown, black, black. The ones in my box are silver on the last band but that only indicates the tolerance of the resistor.


I bought one EXACTLY like this a couple months ago from a friend who had no idea what it was... paid 80 bucks for mine and it works flawless. I'm unsure of the brand name, but there's a few things that are noteworthy about this amp.

It has its own built-in 20W dummy load. You'll notice that there's 2-25 ohm, 10 watt power resistors in the back. They are tied parallel.

This box uses a diode-capacitor follower circuit as a voltage multiplier right off the 117V AC line, eliminating any need for a transformer.

I also have reason to believe that it is grid-driven on the tubes. This don't appear to be the standard grounded-grid, cathode driven setup. Driving the tubes through the grids achieves a bit more linearity than grounded grid configurations.

The amp I have works fantastic, looks good on the scope and very little splatter on AM or SSB. Below is a couple pics.






If you need help with parts identification, feel free to drop me a PM. I'd be glad to help you. Cheers!

-Exit