it's a...girl?

a fine line between stupid and clever

it's a...girl?

Postby nyazzip » Fri Jan 15, 2010 2:57 am

newly completed 18 watt "scratch build" based off a Marshall guitar amp, actually my first. home made turrets, board, chassis; transformers from a late 50s "lafayette" i got off ebay 2 years ago.
this really is all a result from smoking a screen grid resistor on a guitar amp i had about 5 years ago...rather than running to a "tech" and saying "here, fix it"(because i am cheap and generally poor), i took it apart, spotted a smoked part, sourced a new one, soldered it in....and the wheels started turning...bought a DIYtube ST-35 kit(which led me to this forum; at that time i literally didn't know a resistor from a capacitor), started collecting junk....and i am now just beginning to fathom the most basic things...pictures do wonders: monkey see, monkey try....monkey try not to get electrocuted
thanks for all the advice and patience with my inane questions....

Image

Image
<i>the poor craftsman blames his tools</i>
User avatar
nyazzip
KT88
 
Posts: 1073
Joined: Wed Jan 09, 2008 1:24 am

Postby Geek » Fri Jan 15, 2010 4:13 am

DIG THAT FREAKIN' COOL GREEN LIGHT! Image

...

(recomposes myself)

*ahem*

...

Looking good! Image

Cheers!
-= Gregg =-
Fine wine comes in glass bottles, not plastic sacks. Therefore the finer electrons are also found in glass bottles.
User avatar
Geek
KT88
 
Posts: 3585
Joined: Sun Oct 21, 2007 3:01 am
Location: Chilliwack, British Columbia

Postby dhuebert » Fri Jan 15, 2010 8:16 am

Upskirt please.

Don
User avatar
dhuebert
KT88
 
Posts: 820
Joined: Thu May 01, 2003 9:26 am
Location: Winnipeg Manitoba Canada

Postby EWBrown » Fri Jan 15, 2010 9:39 am

Lookin' Good, what's it got "under the hood" ? :$

/ed B
Real Radios Glow in the Dark
User avatar
EWBrown
Insulator & Iron Magnate
 
Posts: 6389
Joined: Wed Mar 19, 2003 6:03 am
Location: Now located in Clay County, NC !

Postby nyazzip » Fri Jan 15, 2010 3:26 pm

try not to laugh too hard at the craftsmanship....its a cathode biased, ez81/(2)12ax7, (2)el84 PP tone-volume thing. i still havent figured out the double input, and the filament wiring could be improved...i have that "elevated" to the cathode of an el84. i'm sure grounding could be improved a lot; i have one wire ungrounded that is supposed to be, and it seems not to make a difference. its a bit noisy for now
chassis is 26 gauge steel, a bit thin but surprisingly adequate for this project. i had to put a rubber pad under the power switch terminals to keep it away from the chassis. the lamp is a radio shack 110v neon(do they really have neon gas in the bulb? i thought neon glowed red when excited, and had to be at many 100s of volts?)
i understand an 8k OPT would be a better match; this one is around 5.2k....i hated to separate the tranny pair as they have been wed since 1959 or so
Image
<i>the poor craftsman blames his tools</i>
User avatar
nyazzip
KT88
 
Posts: 1073
Joined: Wed Jan 09, 2008 1:24 am

Postby mesherm » Fri Jan 15, 2010 6:15 pm

neon bulbs actually do have neon in them. They will glow from a light orange to a more reddish orange depending on how much current is running through them. They typically take about 90 volts DC to "fire" but any kind of EM shinning on them can lower that threshold. Once fired the voltage can be dropped 20 or 30 volts and they will stay lit. That makes them usefull in cheap sawtooth relaxation oscillators. I have even seen them used as a cheap type of radiation detector. I have seen guys with linears put them on the end of their CB antennas and they will light up when transmitting. And then there are their big brothers, the Nixie tubes.....
Mike's N-1 Rule: When looking for N number of components to finish a job, you have a 95% chance of only finding N-1 of them.
User avatar
mesherm
KT88
 
Posts: 1232
Joined: Fri Aug 27, 2004 10:33 pm
Location: Alvin Texas


Return to guitar amps

Who is online

Users browsing this forum: No registered users and 8 guests