TAD Super Lead 100w - My first build

[Carbia]

If you want tight bass, the Ppimv doesn't help at all...

Try the amp with mv at 5 and tell me the difference...

The ppimv reduces nfb, which make the bass soft.

[danman]

If you want to tighten up the bass you could add a fixed resonance cap. Just place a .0047uf cap between the purple nfb wire and the impedance selector tap. You can also use .0033 for even more bass but I prefer the .0047 myself. Give it a try and see if you like it.

[GilmourD]

It's always nice when a package that you weren't expecting until Monday shows up on Saturday.



Unfortunately, I probably still won't get to pop them in until Monday. LOL

[Prowler]

It's always nice when a package that you weren't expecting until Monday shows up on Saturday.



Unfortunately, I probably still won't get to pop them in until Monday. LOL

How do those tubes sound?

[GilmourD]

It's always nice when a package that you weren't expecting until Monday shows up on Saturday.



Unfortunately, I probably still won't get to pop them in until Monday. LOL

How do those tubes sound?

Sadly, between other obligations I had yesterday, I never got to trying them out. I don't have my usual days off from work these couple weeks, so I'm all over the place. Tomorrow definitely.

[Carbia]

That amp deservers better tubes... I've tried the chinese ones and aren't good at all. The Tung Sol is fine, but now I only use old tubes on the preamp, at least, the V1.

[GilmourD]

So, finally got to try the tubes. Tung-Sol went in first, but I found the low end to be boomy. Then I tried the Chinese 7025. Holy shnikies! It's more solid in the bass region without being boomy and harmonics were popping out all over. I might have to order some more of these! I didn't even try the 12AX7B. They may both be Chinese tubes but the construction is completely different.

[Prowler]

Glad you found the tube that you like!

I am looking for a layout for doing the cascade mod without any added switches or pots.

Is this the correct layout?

http://1drv.ms/1ttSVXH

[stef]

http://home.comcast.net/~jbjdav26/2204/2203%20stock.JPG

http://home.comcast.net/~mamp17/2203%20layouts.html

[Prowler]

Ok, I tried the one-wire mod with a shielded wire and the amp got pretty loud and squealed and the volume pots crackled.

http://1drv.ms/1ttSVXH

Maybe I should try doing the mod like Stef posted above.

[danman]

Hey Prowler, what Stef posted wasn't exactly a one wire mod but instead is a layout for the 2203/2204 preamp which cascades one channel into the other by rewiring the input jacks. Is this what you wanted to do or are you looking to do the simple one wire mod to cascade the channels? With the one wire mod you will still have one channel that remains normal and another channel that cascades the inputs. It's a very easy mod that only involves swapping a few wires and components instead of completely rewiring your amp to the 2203/2204 spec.

[danman]

Sorry, I should have clicked on your link first to see what is was that you did. It appears that you did the "one wire mod" after all. Do you get the squealing at all volume settings? There are several different ways to do the mod and I recently tried one posted by a member (Michael RT) here that worked very well in my 1987 build.

[Prowler]

The Volumes set on 3 the amp squealed, made crackling noises and was so loud that I didn't turn them past that. I uninstalled the mod and modded the amp like Julkke did:

v1b: 820ohm/.68uf
bright ch coupler .0022uf
mixer 470k/470k/560p
v2a: 820ohm/.68uf+25uf
tone stack 33k/560p

Now I can get a pretty nice hard rock tone. I quickly recorded some Dio and GNR riffs. Sorry about my sloppy playing

http://1drv.ms/1wSp3H6

I think the gain was on 10.

Danman could you post Michael RT's one-wire mod? I can't find it

[danman]

If you go to Youtube and do a search for "the one wire mod (series) to add tons of gain" you will find Michael Rt's video of the procedure and a bunch of clips of his plexi with the mod. So far it has been the best version I have tried yet. You can also do a search on "marshallforum.com" and find the info also. I really do need to learn how to post links someday...lol!

[Prowler]

I guess this is the one-wire mod:

1. Move the wire from the center term on Vol. II over to the ground lug.
2. Add a wire from the center term on Vol II and join it to both 68K input resistors (where they join) on channel I.
3. Swap the couplers around, .0022uF and .022uF.
4. Mixer cap change from 500pF to 470pF.
5. Remove bypass cap on V2a and run just a 820r cathode.
6. Change bypass cap on V1b to a 1uF over 2.7K cathode resistor.
7. .68uF on the presence control.
8. 100k NFB on a 4ohms tap.
9. No bright cap on Vol I.
10. Lar/Mar PPIMV mod.
11. I like to use a 50pF fizz cap in most cases. The rest of the circuit is stock Marshall Super Lead model # 1959.

I think I will try it today.

Here's the video of how to do the mod:

https://www.youtube.com/watch?v=9Dc2ARDaV64