PT with no HT center tap

[Baxtercat]

...too late [I told the sit-in guy anyway, a few weeks ago] :-D

Yes, I use an old DOD comp. for my boost and tend to run cleaner than some. [that grit was great in the late '60s and '70s but I get tired of hearing it all the time]

Technically minded readers....I bought a purple/blue 6-LED 12V assembly to light up the inside of this combo. I thought just a little cap and recto off the 6.3V would be enough [gives me under 9 volts DC] but the 6 diodes don't light up [they do with a 12V wallwart but I have no room in back for that].

Is there a way to bump up that DC another volt or two?

[Chuck H]

How about a voltage doubler rectifier and regulate back down with a zener. Plenty of current at the wind to support it.

Chuck

[Baxtercat]

[I got it louder too]

I finally got the LEDs goin' in the Jetson TV amp. I found a cheap little chrome bezel w/ 6 UV-colored LEDs in front. That'll finish it off, at least until I find a Philco or some other TV badge.


I bought a similar fixture for inside, a 7-inch bar w/ about 8 blue LEDs. There's really nothing worth lighting up back there, but what the heck. They're a lot brighter and nearly wash out the orange pilot light.
I like 'em. I'll probably get some more blue ones if/when the purple front ones burn out.


To power these I found a small 11+ volt wallwart and installed it under the chassis to an RCA jack, to plug in the light leads.
I didn't know enough to figure out an 11v DC scheme with a Zener diode and a little voltage doubler off the 6.3V. Next time though.

Now I know why the thing sounded like 35 watts. I had too large a cathode resistor to the power tubes. They were only running around 18 ma each. I found a 250 ohm/12 watt and swapped out the 650 ohm. Now I'm getting from 32 to 39 ma.
That sounds hotter than I run a Fender; you think that'll be OK in a K-bias amp though?

[JHow]

Awesome amp! This is just the kind of creativity I would expect from a denizen of Pacific Grove! Nice job!

[Baxtercat]

Denizen! ...good word. Like skulker, lurker, cave dweller. All apt for Summer here today: it's downright cold and damp. Might as well stay in and tinker.

[txstrat]

Now I'm getting from 32 to 39 ma.
That sounds hotter than I run a Fender; you think that'll be OK in a K-bias amp though?

I think 32 to 39 ma is not to hot for k-bias. 250 ohms is the value most k-biased Fenders with two 6L6 ran at, anyway. Do the tubes redplate?

[JHow]

..Summer here today: it's downright cold and damp...

I feel your pain. Some of my mis-spent youth was mis-spent at the Presidio. P.G. always impressed me as being kind of quirky and artsy (I mean this in a good way). I was really into rock-climbing in those days and we used to go "bouldering" on the sea-wall at the local park. There were often a bunch of SCA guys in the park wearing armor and whacking each other with rattan "swords". It had a fun vibe.

[Baxtercat]

Hiya Tx...[just saw your reply here; thanks]
No, the 6P3S's seem to be running fine. The amp is nice and loud too.

It's still a tad 'bluesier' than the Twins or Bassman amps I'm used to.
So, next I'll try:
a) deleting some midrange with a cap and resistor,
b) a slightly larger K resistor, and/or
c) fixed bias, once I figure out where to get some voltage for that.

[Or leave it softer—some folks pay for that feature.
Heck, I've got plenty of amps.]

[Baxtercat]

...now featured in our 'video'

I added a plexiglas porthole to beam more sterilizing blue light rays out.


...and my daughter just made a 'video' from an old TEAC deck original instrumental I'd recorded about 23 years ago.
She shot the footage around the neighborhood [and in the house] and put it all up on YouTube.

[Reef Walker]
YouTube - Reef Walker (Original Instrumental)