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

Everything from original vintage Marshalls to reissues.

Moderator: VelvetGeorge

Post Reply
User avatar
CoffeeTones
Senior Member
Posts: 1112
Joined: Mon Oct 11, 2010 9:52 pm
Just the numbers in order: 7
Location: USA

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

Post by CoffeeTones » Wed Jun 19, 2019 8:23 pm

Yes, between the jack and volume pot. Just increase the capacitor to 1n, up to 2n2 and leave the same resistor. 2n2 can be a little loose in some amps. Sometimes no cap there at all sounds better that 2n2. Either will tame the harshness some and shape the mids. You might try some different value bright cap values as well (the one on the volume pot), since those two caps are so easy to clip parts across. The ceramic caps and MO resistors introduce a grating harsh upper mid and highs for me, so I use MO only in the early power supply and very few ceramic caps. Cheap MF resistors sound sterile to me.

Peter London
New Member
Posts: 11
Joined: Sun Jun 16, 2019 12:15 pm
Just the numbers in order: 13492

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

Post by Peter London » Sat Jul 13, 2019 8:03 am

"CoffeeTones" your advice was really helpful, I went through a bunch of values, and settled on 1500pf/470k on the input with 1000pf bright cap, and 250pf on Treble (instead of 470pf). Loving the sound now.
As for the "shield trick" my tech didn't seem to keen about it, so I just leave it as it is.

Now, what kind/brand of cap would you suggest for swapping out? I was thinking NOS mustard caps, or sozo caps...
Marshall 2203x #36
VOX AC15 c1
Marshall 4x12 cl80/V30 /2 x GB
SPL reducer attenuator
2 x sm57
Sennheiser e906
Warm audio WA73
GAP73

User avatar
CoffeeTones
Senior Member
Posts: 1112
Joined: Mon Oct 11, 2010 9:52 pm
Just the numbers in order: 7
Location: USA

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

Post by CoffeeTones » Sat Jul 13, 2019 1:18 pm

I recommend either Sozo, Mustards, or Roederstein for this tone. If you want more of direct, modern tone, either Mojotone, TAD or similar compostion cap will do that. I don't like the Mallory 150 caps in any application. You might like the response of a 500pF treble cap if you adjust the controls instead of leaving them stationary, when comparing the caps / tone. I find the range of adjustability to be better in some instances. You may have thought of that, but just throwing it out there. Do you have new sound clips to post?
:toast:

Peter London
New Member
Posts: 11
Joined: Sun Jun 16, 2019 12:15 pm
Just the numbers in order: 13492

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

Post by Peter London » Sat Jul 20, 2019 3:08 pm

Hey!
So, I've finished with the amp. I put a couple of SOZO and Mullard Mustards in it. The main problem with the amp was that, the tech who modded the amp put a 1000pF cap on the 2nd preamp socket. https://s58.photobucket.com/user/Peters ... sort=3&o=1

Took me a while to figure it out, when I lifted that cap it was like removing a thick blanket from the speakers .

This is how it sounds now: https://www.youtube.com/watch?v=J1rYDeB ... e=youtu.be

Some pics: https://s58.photobucket.com/user/Peters ... ary?page=1
Marshall 2203x #36
VOX AC15 c1
Marshall 4x12 cl80/V30 /2 x GB
SPL reducer attenuator
2 x sm57
Sennheiser e906
Warm audio WA73
GAP73

User avatar
CoffeeTones
Senior Member
Posts: 1112
Joined: Mon Oct 11, 2010 9:52 pm
Just the numbers in order: 7
Location: USA

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

Post by CoffeeTones » Sat Jul 20, 2019 9:24 pm

Yeah, we could have told you about that 1n cap if we had the pics earlier :lol: It sounds fine. One thing I see that may be out of place is, if you have the newly installed tube / stage as the third stage, the peaker cap is usually placed on that divider (feeding stage 4). It appears the original 470k divider is being used as the fixed, second gain pot, which normally has no peaker / bright cap. :scratch: To be closer to #36, it seems to need more gain and bite. It's pretty good as is though. Maybe jumper the resistor that is in series with the .1uf // 10k cathode as a test. I can't tell the value of that series resistor. Another thing to try would be 2k7 to 4k7 cathode on the second or third stage, with the appropriate bypass cap like .68uF to .47uF. (this often calls for the bypass cap on stage 4 to be removed). Maybe put in a temporary, second gain pot to find the best setting and then go back to the fixed resistor values that each side of the temporary pot reads. #36 has a certain compression and pinch at the top of the notes, that I don't hear in your clip. (gain, bite / peaking will bring it)

Peter London
New Member
Posts: 11
Joined: Sun Jun 16, 2019 12:15 pm
Just the numbers in order: 13492

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

Post by Peter London » Sun Jul 21, 2019 9:05 am

I'm sure using a real speaker instead of the Impulsive Response, would help a lot, but then there is no way that I could run the master at 6. :?
At the moment I'm using the Celestion Classic Lead 80 IR with Sm57. Next week will arrive a new (real) CL 80.
Let's see
Marshall 2203x #36
VOX AC15 c1
Marshall 4x12 cl80/V30 /2 x GB
SPL reducer attenuator
2 x sm57
Sennheiser e906
Warm audio WA73
GAP73

Unique
Senior Member
Posts: 229
Joined: Wed Oct 02, 2013 12:48 pm
Just the numbers in order: 13492

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

Post by Unique » Sun Jul 21, 2019 12:52 pm

That sounds pretty good Peter, I enjoyed the video. Thanks for sharing.

Prowler
Senior Member
Posts: 168
Joined: Fri Feb 07, 2014 9:57 pm
Just the numbers in order: 13492
Location: Finland

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

Post by Prowler » Sun Jul 21, 2019 12:56 pm

Peter London wrote:
Sun Jul 21, 2019 9:05 am
I'm sure using a real speaker instead of the Impulsive Response, would help a lot, but then there is no way that I could run the master at 6. :?
At the moment I'm using the Celestion Classic Lead 80 IR with Sm57. Next week will arrive a new (real) CL 80.
Let's see

Sounds very good Peter! You are very very close. Thanks for the pictures also!

Peter London
New Member
Posts: 11
Joined: Sun Jun 16, 2019 12:15 pm
Just the numbers in order: 13492

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

Post by Peter London » Mon Jul 22, 2019 11:29 am

CoffeeTones wrote:
Sat Jul 20, 2019 9:24 pm
if you have the newly installed tube / stage as the third stage,
I had no idea... :shrug: that means if I want to swap V1 preamp tube, that's still my original V1?
I just received a NOS Beijing 6N4. Also a used Classic Lead 80 speaker :drool:
Marshall 2203x #36
VOX AC15 c1
Marshall 4x12 cl80/V30 /2 x GB
SPL reducer attenuator
2 x sm57
Sennheiser e906
Warm audio WA73
GAP73

User avatar
CoffeeTones
Senior Member
Posts: 1112
Joined: Mon Oct 11, 2010 9:52 pm
Just the numbers in order: 7
Location: USA

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

Post by CoffeeTones » Mon Jul 22, 2019 2:35 pm

Traditionally, the first preamp tube in the circuit is V1. In your case, the second preamp tube appears to be stage one and two, and is the original V1A and V1B. The added tube is often labeled V0 in the #36 amps.

Peter London
New Member
Posts: 11
Joined: Sun Jun 16, 2019 12:15 pm
Just the numbers in order: 13492

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

Post by Peter London » Mon Jul 22, 2019 4:06 pm

Thank you Coffee!

The speaker and the preamp tube has arrived, and I'm blown away! Very very happy with the sound now, and I think this is the point where I don't touch it anymore.
Here is the link to the 2nd video, with miked up cab.
https://youtu.be/Zc0EsMCOXig
Marshall 2203x #36
VOX AC15 c1
Marshall 4x12 cl80/V30 /2 x GB
SPL reducer attenuator
2 x sm57
Sennheiser e906
Warm audio WA73
GAP73

User avatar
CoffeeTones
Senior Member
Posts: 1112
Joined: Mon Oct 11, 2010 9:52 pm
Just the numbers in order: 7
Location: USA

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

Post by CoffeeTones » Mon Jul 22, 2019 4:26 pm

That will work!

Unique
Senior Member
Posts: 229
Joined: Wed Oct 02, 2013 12:48 pm
Just the numbers in order: 13492

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

Post by Unique » Tue Jul 23, 2019 10:40 am

That even sounds a little better than before! I have to say you've nailed it about as good as one can do. Congrats Peter.

keelan1031
New Member
Posts: 2
Joined: Mon Jul 22, 2019 6:52 pm
Just the numbers in order: 13492

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

Post by keelan1031 » Tue Jul 23, 2019 3:20 pm

Hey all! Im not totally sure where to begin. Im a big nooby. But I have always loved the #36 tone A TON! Im soon buying a JCM 800 of my own, but i would like to get a #36 Mod on it. Where should i begin? Should i read all 700+ pages ? lol. Or is there some instructions i can follow or a schematic i can take? or anything at all to get me started?

keelan1031
New Member
Posts: 2
Joined: Mon Jul 22, 2019 6:52 pm
Just the numbers in order: 13492

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

Post by keelan1031 » Tue Jul 23, 2019 3:26 pm

Hey all! I have always loved the #36 Mod A LOT ! Im soon planning to purchase my own JCM 800 and hopefully apply this mod to my amp! But im a noob, and im not totally sure where to start. Can anyone point me in the right direction? Are there some basics i should know? Is there a schematic i should follow? Are there instructions? Anything to get me started with this mod and how it works? Thanks !! :)

Post Reply