The Amp Garage

if you want something closer in age to your amp instead of brand new and don't mind that it doesn't have open end bell covers, the output transformer from a hammond ao-43 organ chassis could work here

i dig the minimalism and the mock-eyelet board!

TUBEDUDE wrote: ↑Sat May 28, 2022 7:24 am Higher current applications may benefit by using higher wattage metal films also.

oh definitely. my point was mainly based on failure mode. a metal 'coil' glowing hot orange can wreck a lot of stuff

Stevem wrote: ↑Fri May 27, 2022 8:58 pm The make up of a metal film type is such that the resistance material is like a gray spiraling wrap from end to end on a core material.

i watched one of these glow BRIGHT orange and smoke in a malfunctioning kustom amp. it's what sold me on metal oxide resistors in higher current applications

i for one am interested in what amp it is

so many replies and still no pictures from the thread starter....

power output mostly limited by the power transformer
bias to 60-70% and don't overthink it

i'd be willing to bet the deep control is a pot on a cathode bypass cap
the original graphic series had a dc-coupled cathodyne

bepone wrote: ↑Sun May 01, 2022 9:07 pm but what i can see from schematic it is using 6KG6a tubes

i'm showing 6ca7/el34 besides the very first ones with 7027: https://www.thetubestore.com/lib/thetub ... ematic.pdf

trimpot is the better option. maybe order 5 of them so next time you don't have to wait

I am thinking - would it be possible to get away with just one 12ax7 and a transistor without loosing sound, depth and speed of the oscillator Kingsley Bard style? oscillator don't care if it's made of sand or glass or it's generated digitally because it's out of the signal path. what really matter...

i had similar symptoms from the tubes getting so hot they melted socket solder/lifted traces and only one tube was conducting (also had ribbon cable issues not putting bias on the control grid)
these amps sound great when working but damn if they're not an engineered nightmare

why not pull all four and throw new production 6ca7 in there? if they're all good and matched a quad of mullards is about 4 times as valuable as a pair
or play em like they are and enjoy it

your picture shows two 240r resistors so i'm guessing that the 470r was split?

personally i wouldn't shield that wire but i would shield the wire to that next stage's grid
yeah of course make all wires as short as feasible. no need having cbs fender spaghetti in there potentially oscillating

start playing with standard component values and see where the sweeps go
it would probably be easiest to download and install instead of messing with the web app. then you can save stuff you like: http://www.duncanamps.com/tsc/download.html