Park G25R mod time ... please bear with me

[Steben]

We lost the thread of this one, didn't we?
How did it turn out?

thx for the interest... alas this one got shuffled and set aside many many times. My main focus was on the bluesbreaker pedal lately (which sounds already better than this amp).
You know how it goes... it is not a 1000 bucks amp you want to get working. It was a 20 bucks wreck which I surprisingly got working and wanted to mod.
First mod was good already (for a cheap SS amp).
But... now I think of it, this is a great next project. Although I need to fix an Electric Mistress as well...

I think of swapping the jFET idea altogether for a slight "even order harmonic mod" on the input stage and throwing out the complex switch system. This means making the first opamp a fixed gain stage and levelling all gain settings between clean and drive.

[Steben]

Marshall knobs! The rest is details 

[Steben]

This will be implemented soon.
- input "triode" stage: very gentle, only really in play with booster in front or a heavy humbucker
- gain stage with low region zener diodes. They are quite soft. I liked this before.



Transfer equivalent of input with choosen values (ideal diodes, in reality the knees will be a bit softer):

[Steben]

I finally put back all in ori state to get back a simple practice amp except for the clipping diode section which set with one schottky diode extra. This asymmetry adds a touch. And the hard clipping keeps the marshall-esque character.
The sag section was subtle and clumsy to put in and get in balance. I decided to make the idea something aside from this amp for now.

I did swap the cloth, giving it a JTM look. 

[Steben]

OK.... I did mod again...
Very nice clipping. I like it. Although I like it the most with a treble booster in front of the amp. Like in front of any amp....