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Here's a bit of the guts of the Ampeg. Please excuse the messiness of some of the work. I mounted the post distortion low pass on top of the board. All of the larger film capacitors are new; the original caps were those tiny beige tic-tac looking things.

At this point I'm not quite done. I've tried some different speakers with the amp to try and thicken the tone, with some success, but I have another speaker being shipped right now. Once I've tried that one I'm going to make a final adjustment to the shelved low pass. The goal is to get the combo sounding big enough on its own without the amp becoming boomy when plugged into my extension cabs. Right now I have an Eminence Swamp Thang in the amp, and it sounds pretty good.

I'm also considering modding the amp to include the Variable Harmonic circuitry (also known as Flexwave in Crate amps). It's just two resistors, one electrolytic cap, and one diode added to the clipping stage. I'm not sure if it will really improve the sound or feel of the amp, but it seems easy enough to try.

some more groundbreaking earth shattering cutting edge work today 

wanted to connect signal generator to amp

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that was fun
but too easy and predictable

better yet would be to have the amp opened up and try to find the signal by probing around on some components

i made a video with outer limits sound effects

 

See this page, particularly 'differential voltmeter' and the explanation of the 5 knobs:
https://control.com/textbook/dc-electricity/null-balance-voltage-measurement/

Quote from: saturated on October 01, 2023, 02:52:19 PMon my to do list...need to build a curve tracer and connect to my oscilloscope

I don't know if you have a transistor tester yet, but a modern one can be a great item to have, for very little money you can pick up something that can do some amazing measurements on components.
I bought one several years ago but I think I need a new better one as they get better so fast.
I bought one without a case but then ended up buying a case many years later so the final cost was the same as one with a case in the first place.
The old one I have now is in this video on you-tube, the one on the right.
It would be worth spending some time and finding a very cheap one that can do everything the more expensive ones can do, just have to keep looking till you find one.

https://www.youtube.com/watch?v=-pEmM0Kt2UY

Cheers
Mick
 PS...If you find a great cheap one ....let us know

i tried it out for a while but didnt get too far

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amazingly all 4 lights at the bottom work

its def responding...if i turn the second digit to zero the meter deflects

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and back to one which i presume is ten....it goes back

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oh well that was fun

time to catch the rest of some football

so i wired up the replacement power cord..which wasnt looking so great either 
no matter how far back i peeled back the outside sheathing the insulation on the interior wires was crumbling
but it appeared the white insulation was more robust...so i went with it

also the wierd lookin fuse was blown
i do not have anything that remotely resembles this

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so based on the markings i scared up a plain ol 1/4 amp fuse and stuck it in

next up connected my UDBT (ugly dbt)

powered up...turned it on and all was eerily quiet

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I thought well something is open somewhere...this is too good to be true...was fixing to disconnect everything and to my astonishment saw a light on

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so i guess my next move is to input a known voltage and then try to rotate the bottom knobs until it matches up....

 

alright i wanted to test my new voltmeter

so first task was unsoldering the disintegrating power cord

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which wasnt easy

hot from transformer

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ground from fuse holder

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and green....common?

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and the disconnected carcass

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this is a lot of work but oh well i guess its good practice

gonna be all for naught if i get a new cord on there and it fails dbt
because at that point im stopping

also i am discouraged to see silver metal transistors...to me that means germanium...but idk i have no idea

 

on my to do list...need to build a curve tracer and connect to my oscilloscope

either that or find a tek 575 

 

btw my old coffee table got repurposed

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ok electronics work bench mk 3 is done

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im actually pretty tired even though it was only modified still took me at least 3 hrs