Ok.. so the 1M to 220K swap was fantastic. I think the extra gain definitely helped tighten up the bottom end a bit more. It's absolutely playable now.
Extra gain AT what frequencies?
AND this is AFTER you lifted the 2nd gain stage K bypass cap.
So, if the bottom end was tightened up it's because of the shift of balance in the high/low end response, you caused by changing the K bypass cap and the PI coupling caps (CC).
Slow down.
Yes that helped. I played it after making that change for about 20 min. It was definitely getting there. It was still fairly flubby in comparison to then swapping the 1M to 220k (the blue one). Like the gain knob as it is now at 1:00 is about what the gain knob was when at full, and it's much more pleasant as well.
I'm guessing from 2deaf's comment we should avoid swapping the red one for now and focus on that first gain stage cap. Which I won't have a component for a few days unless my local electronics store has one.
Sorry if I missed some of your posts. There was like a bunch of them thrown at me at once and I got a little confused.
I don't know if that 220 swap has a frequency I can put my finger on with my ears at least. It gave the amp much more distortion in general. I can hear that the clean punch of the boomy stuff is now being clipped a little more, and there's a pleasant overall distortion. When I palm mute, I can hear a little more distortion where as before it was mostly flub or very little distortion. This is with the TS808 on it. Without the TS808 it's a classic rock distortion at best, or like a Mesa Recto withe the gain set at like 11:00 (not tonally, just the feel, recto has much more fizz). If I crank it to max, the flubbiness increases and the overall dynamics gets mushy (kind of expected).
Right now the bottom end sounds a bit like... i dunno ever slam something with a lot low end into a tape machine. It kind of sounds like that. I'd say we need to lose some 160ish hz and below. Then the high end still sounds a bit like it's singing with its nose plugged. It's not extreme, but it's there. I tried it with a couple different guitars to confirm. I don't know if that will balance out when we try a couple caps on that first coupling cap. Turning up the treble or fiddling with the mid does not help this.
The gain knob has a push pull that bypasses the 2nd gain stage. I don't know exactly what parts of the schematic it bypasses. I'll have to look tomorrow (it's 3am lol). I know it bypasses the 2nd gain stage because I asked the original maker of the the amp when I acquired it, but he didn't go into any more detail than that. I am bringing it up because I noticed that going to this clean channel the "boom" problem gets a bit worse. I assume that is some clues that that 1uf cap/1.8k may needs some tweaking.
As for the Earth. It adds a lot of volume. I honestly can't describe what it does. it doesn't like linearly add bottom end or anything, it adds volume and bottom end growl? Turning it down to the extremes sounds bad. Hard to explain. I'll attach some photos as you asked. Right now it sounds best at about 1:30.
It's the second pot from the right. The farthest right is the sky knob. Follow the brown plastic wire to the other photo.
Topic: 18W amp is super boomy Please help me mod it, schematics and sound clip included (Read 20899 times)