S.I.R. 100W SuperLead Schematic pt. II

[dukeamps]

That is with the gains on 3,5 and 2.

Needs a bit of tweaking to get the bass under control.
Change the second stage to 10k .1u and the 220k on the gain pot to 150k or even 100k.

[gluke]

Needs a bit of tweaking to get the bass under control.
Change the second stage to 10k .1u and the 220k on the gain pot to 150k or even 100k.

Will do! It will be more #34 like though?

[gluke]

Needs a bit of tweaking to get the bass under control.
Change the second stage to 10k .1u and the 220k on the gain pot to 150k or even 100k.

150k and 10k/.1 sounds like this:

WTTJ:
https://youtu.be/iWcioYVXeaM

[gluke]

If you take that MK7 topology and plop another modest gain stage in somewhere, you might find the golden egg. Many times modders follow a trend like that and I'd bet that many 80's rock records have MK7 lineage amp tones on them. I might not put a snubber on stage 1 plate since that stage is not peaked much. I'd try snubbing one of the later stages unless the stage 1 snubber is made necessary by some behavior. I doubt .68uF presence will work with the MK7 since the first stage is passing most frequencies. I may do that mod myself in a few days. There is a JCM 800 circuit just sitting here

Here you go. Mk7 with a 10k/.1 stage and .1 presence.

WTTJ:
https://youtu.be/UvRL0YDmH8M

Nightrain:

https://youtu.be/Xj8FQe791k4

[gluke]

Mk7 with the 10k/.1 stage between the two stages.

WTTJ:
https://youtu.be/U5vx22X_5q4

Nightrain:
https://youtu.be/3OUCdE-oajo

[dukeamps]

Needs a bit of tweaking to get the bass under control.
Change the second stage to 10k .1u and the 220k on the gain pot to 150k or even 100k.

150k and 10k/.1 sounds like this:

WTTJ:
https://youtu.be/iWcioYVXeaM

Me likey! Good job!

[CoffeeTones]

If you take that MK7 topology and plop another modest gain stage in somewhere, you might find the golden egg. Many times modders follow a trend like that and I'd bet that many 80's rock records have MK7 lineage amp tones on them. I might not put a snubber on stage 1 plate since that stage is not peaked much. I'd try snubbing one of the later stages unless the stage 1 snubber is made necessary by some behavior. I doubt .68uF presence will work with the MK7 since the first stage is passing most frequencies. I may do that mod myself in a few days. There is a JCM 800 circuit just sitting here

Here you go. Mk7 with a 10k/.1 stage and .1 presence.

WTTJ:
https://youtu.be/UvRL0YDmH8M

Nightrain:

https://youtu.be/Xj8FQe791k4

10k // .1 placed where? NFB value?

[CoffeeTones]

Mk7 with the 10k/.1 stage between the two stages.

WTTJ:
https://youtu.be/U5vx22X_5q4

Nightrain:
https://youtu.be/3OUCdE-oajo

10k // .1 between which two stages? NFB value?

I would try 68k to 100k NFB if you have lower. Below 68k is pretty lethargic. 10k with no .1u or 820r with no .47u. Then adjust bright caps and resistor value from gain pot wiper to ground, and retain .1u presence for now. Experiment with plate snubber location or deletion. Try the 10k stage, with or without bypass between 1 and 2 or 2 and 3, to see which you like best.

In the schemes I posted, you can read Levi's notes. He wrote that he modified JCM 800 amps, and made no mention or drawings of mods to the power section. Not saying that he never did mod the power section, just pointing out the info we have.

[gluke]

10k // .1 placed where? NFB value?

First one is first two stages if mk7 then 10k/.1 stage

1k5/22uf/.022/470k+470p/120pf/150k

2k7/.68/.022/470k+470p/470k

10k/.1/.022

820r

100k/4ohm/.1

[gluke]

10k // .1 between which two stages? NFB value?

That one is 10k/.1 on the second stage.

1k5/22uf/.022/470k+470p/120p/150k

10k/.1/.022/470k+470p/470k

2k7/.68/.022

820r

100k/4ohm/.1

[gluke]

Me likey! Good job!

Thanx! I think I need to get a LP of some sort. SCOM just doesn’t work on a P90....

[CoffeeTones]

You could try increasing the 150k till the sound fills out. MK7 shows no such resistor and could possibly have no pre gain control peaker, but that might be going too far with your current spec. It sounds good, just missing a little something - that might just be in the recording.

[Unique]

Needs a bit of tweaking to get the bass under control.
Change the second stage to 10k .1u and the 220k on the gain pot to 150k or even 100k.

150k and 10k/.1 sounds like this:

WTTJ:
https://youtu.be/iWcioYVXeaM

This sounds pretty darn good!

[gluke]

This sounds pretty darn good!

I’ll do some more clips. We are back at the office now so I don’t have the whole house to myself all day long anymore....... coffee breaks at the home office was brilliant for small tweaks and recording clips.

[Unique]

This sounds pretty darn good!

I’ll do some more clips. We are back at the office now so I don’t have the whole house to myself all day long anymore....... coffee breaks at the home office was brilliant for small tweaks and recording clips.

I'll be looking forward to them!