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

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

Post by CoffeeTones » Sat Aug 28, 2021 1:44 pm

It seems a little too smooth and lacking in the upper ranges to me. I'd use ceramic at C5, C8, or both. Possibly ceramic at the plates, or decrease one of those for more bite.

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

Post by BRMSlash » Sat Aug 28, 2021 6:49 pm

Agreed. I'd like a bit more raunchiness in the upper ranges as well. Not sure if the ceramics will do it, but worth some experimentation. I think I'd also like to try some more Jupiter Red Astrons in some extra locations.

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

Post by CoffeeTones » Sat Aug 28, 2021 9:53 pm

Another thing I thought of is your divider prior to stage 2. The series resistor is acting / cutting as a higher value grid stopper. Instead of a divider, I usually prefer the resistor to ground from the pot output lug only, with a 33k to 47k, normal grid stopper, or no stopper - depending on whether the amp needs it.

If I use a divider at all, it would be two 68k, or that same 68k divider with a 1n cap to ground, like some of the Cameron amps. All of that said, most of the time a 470k with parallel peaking cap prior to the pot, and resistor to ground from the pot wiper works well, plus there is a lot of adjustability with that.

This might not be perfect for your mod, but check out the divider / boost here http://www.prowessamplifiers.com/schema ... cstacy.pdf. Works good in some cases, but it's been years since I have experimented with this one. One difference being that there is a bypass cap which keeps the series, 470k resistor from behaving like a high value grid stopper as much, especially for the upper range. That is obviously adjustable as well.

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

Post by dukeamps » Sat Sep 18, 2021 3:19 am

I will liven things up a bit with a couple of new clips.

Clip 1 without orig,

https://soundclick.com/share.cfm?id=14313719

Clip 2 with orig,

https://soundclick.com/share.cfm?id=14313718

:toast:

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

Post by myersbw » Tue Sep 21, 2021 1:11 pm

Well, I've been modding, repairing, building amps closing in on 10 years now. And, about to retire the day job and do more of what's developed into a local part-time business. But, this past weekend, I finally broke into this thread and it took me to an area I usually don't explore...higher gain territory.

As of yesterday, I finished the mod to my amp after gleaning for what seemed like lifetime (lol, I only made it into the first 200 pages of this thread!). I'd love to see a text compilation of the thread so we can download and search it locally. Now, to the amp in question and what I ended up doing.

My amp is a Dr. Z Antidote prototype. I like many things about this amp, (tone stack lift via footswitch, small package, KT66/EL34 at the flip of a switch) but the one handy thing it had going is pre-punched tube socket holes for a variety of models. That made the extra 12ax7 insert happen at the right location.

The amp as-is was designed to be quasi-JTM45. However, a year back I'd already converted it to 1978 2203 Master Vol. Mark II specs only with a 120pF bright cap. (I've done that mod on a lot of vintage Marsh@lls in the area...makes a huge difference and kills off ice-pick easily enough.) All that said...here's where I took this near-2203:

Stage 1 - V1a - stock 2.7K||0.68uF - all interstage coupling caps 0.022uF
- 470K metal film||470p disk to Gain pot with 120pF silver mica at the pot. Added 36K metal film to V1b grid.

Stage 2 - V1b - 10K cath (no bypass cap), 100K||470pF ceramic disk at the plate.
- 470K metal film||470pF disk to 470K (ground). The junction of the 470K resistors feed the left center of DPDT toggle.

The toggle switch is simply configured to insert or bypass V0. Viewing the switch vertically, top two poles are shorted together, middle-left 'from' V1b...middle-right 'to' V2a, bottom-left to V0 grid, bottom-right to V0 output 680K/330K voltage divider junction.

Stage 3 - V0 - 36K metal film to the grid. 10K metal film cathode (no bypass cap), 100K metal film plate, 0.022uF coupler to 680K/330K metal film voltage divider to ground. Again, output tapped from junction of 680K/330K

All switch leads are shielded, btw...no hot shield was required. From the switch 'middle-right', lead goes direct to 36K grid stopper that's soldered to V2a direct.

Stage 4 - V2a - again, 36K metal film grid stopper, 820R metal film||0.68uF (this cap was actually already present in the Z stock...interesting enough!), typical 100K plate.

Stage 5 - typical 2203 cathode follower to the tone stack at this point. The 33K slope resistor (present already) and the 470p treble cap was replaced with a 220pF that made for a huge difference in treble response and control.

My goal here wasn't to strive for replication of AFD or any GnR tone most are seeking out. I did what I did to preserve the core 2203 tone as there was already plenty of crunch+ to make this a great amp as it was. I did find that the V1b plate bypass cap really softened the upper harmonics just enough that rolling back the volume when the master is up REALLY shines now. (i.e. removed some very subtle harshness). Thus, it only takes one switch with guitar volume roll to go from nicely clean to extremely mean. :D I'm not sure if I dare to step on the footswitch that opens the tone stack :O .

Currently, this amp is outfitted with Gold Lion KT66's and uses a GZ34 rectifier (unlike the typical M@rshall diode scheme). It's a rocking 50watt powerhouse that sounds really good with my PRS and the 57/08 pickups in it. I plan to make some video clips and will post the up when I do.

Mostly, a huge huge thanks to all of you that have ventured this realm for years now and I've really enjoyed reading the back & forth and refinements along the way. Keep rockin!

Brad
Last edited by myersbw on Wed Feb 09, 2022 5:18 pm, edited 1 time in total.

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

Post by blacklabel » Sat Nov 13, 2021 5:31 am

hi guys, you have already talked about it years ago, but it would be impossible to search in the topic :D

Do you remember the video on youtube where Slash in studio plays jcm800 # 34 on the sofa? what did you know about the sound in that video? I remember that the eq on jcm800 could have been all at 6.
in the description it is written that the cab used is the 1960B: the speakers used were the V30 marshalls, right?
do you know which microphones were used: only sm57 or royer 121 too?
And has anyone managed to replicate this sound?
I'm trying with a sm57, maybe I'm wrong position of the mic on the speaker (I have v30 marshall)

I thought the sound was completely raw, without eq corrections, then I inserted the audio of the video in cubase to understand the EQ curve of the sound with the Fabfilter proQ3 plugin and as you can see in the image a 96db cut was definitely made at 10.5k and this eliminates the presence of very high frequencies. A low cut was also made, perhaps 18db at 80hz. I don't know what else. Did you notice this?

https://i.ibb.co/jftvLN0/EQ-FABFILTER-s ... htrain.jpg



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

Post by Unique » Sun Nov 14, 2021 8:29 pm

What your seeing with your EQ graph is the frequency response curve for the sum of everything used in the signal chain together. Not much help for the amp's sound alone. If you want that sound, if I remember correctly, he had all the knobs at 7, and not 6. If you scroll through the AFD videos slowly, you will catch them. There were some pics posted from the video here at one time of them. Slash was also using the older 'coke bottle' shaped Chinese 6550's in #34 at the time of this video. I'm not sure what the preamp tubes being used here were. However, I do know that the first camo tolex covered AFD100 prototype amp, from a pic of the amp before the Bataclan show, I saw he had a JJ in the PI. The AFD100's also came with a Marshall rebranded J.J. in the PI as well. Take that for what it's worth. Combine all of that with Santiago's #34 schem posted here, a Les Paul of some type, some APH-1's and you will have that sound, or a similar flavor of it. The rest will depend on your signal chain and how you have your pups set. I would imagine they used an SM57 for the mic since that was what Slash had always used up until his first solo album for his tracks. I hope this helps.

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

Post by Unique » Sun Nov 14, 2021 8:39 pm

Unique wrote:
Sun Nov 14, 2021 8:29 pm
What your seeing with your EQ graph is the frequency response curve for the sum of everything used in the signal chain together. Not much help for the amp's sound alone. If you want that sound, if I remember correctly, he had all the knobs at 7, and not 6. If you scroll through the AFD videos slowly, you will catch them. There were some pics posted from the video here at one time of them. Slash was also using the older 'coke bottle' shaped Chinese 6550's in #34 at the time of this video. I'm not sure what the preamp tubes being used here were. However, I do know that the first camo tolex covered AFD100 prototype amp, from a pic of the amp before the Bataclan show, I saw he had a JJ in the PI. The AFD100's also came with a Marshall rebranded J.J. in the PI as well. Take that for what it's worth. Combine all of that with Santiago's #34 schem posted here, a Les Paul of some type, some APH-1's and you will have that sound, or a similar flavor of it. The rest will depend on your signal chain and how you have your pups set. I would imagine they used an SM57 for the mic since that was what Slash had always used up until his first solo album for his tracks. I hope this helps.
I should add, after watching to video again, it sounds like they mic'd the cab up close (touching the grill, or an inch away) and straight on center, or maybe just slightly off center. Just play around with it until it sounds correct to you.

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

Post by CoffeeTones » Mon Nov 15, 2021 9:05 am

Some of you might want to pick this apart https://www.youtube.com/watch?v=6l4xzGA11po

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

Post by Unique » Mon Nov 15, 2021 11:24 am

CoffeeTones wrote:
Mon Nov 15, 2021 9:05 am
Some of you might want to pick this apart https://www.youtube.com/watch?v=6l4xzGA11po
Been there and done that! This video came out right around the same time the AFD100 vlog came out. There's a lot of good info hiding in that video on how Slash has his pickups set. I would focus more on the beginning of the video, and how the pickups are set then and prior to them being taken out, as opposed to how they are after the new bridge is on and the pickups have been reinstalled. Also, keep in mind that Derrig would set his necks a little deeper with a slightly more shallow neck angle than how Gibson does it today. This can be a little deceiving when your trying to gauge the pickup height.

One thing I noticed, when comparing how Slash has his neck pickup set at the beginning of this video to older pics I could find of this guitar, as best as I could tell, it appears that the neck pickup has pretty much always been set the same, i.e., screw height and orientation, possibly the pickup height itself, since around the Snakepit days and on. I did find one pic from the UYI era that has the screw orientation different on the neck, but the low E was the same. I've yet to see a pic where the low E screw is different. In this pic, the low was the same as it is in the SD video, and rest of the screws went like this on the neck: E \ \ / / / While the bridge screws in that pic went like this, in the opposite direction: / / / \ \ \

The bridge on the other hand, from what I've seen when comparing pics, has went through some changes through the years, as far as these things go.

Surprisingly, I've found that screw orientation has a slight effect on the sound. Such as having the screw's slot run parallel to the string vs perpendicular, as well as crossing under it at a 45* angle. This could be mainly because even the slightest turn will affect the height to some degree, which can possibly affect the sound to some extent. To me, it seems to affect the sound of the pick attack the most, which can change the way a note sounds when played more so than chords. It's just something you need to try for yourself. Pickups and their screws are a simple thing to play around with to see what you hear. In the end, I found that what you see in the SD video, as far as screw height and orientation goes, sound the best when you get the pickup height right.

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

Post by dukeamps » Wed Feb 09, 2022 4:22 am


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

Post by SoFa Granny » Wed Feb 09, 2022 2:36 pm

myersbw wrote:
Tue Sep 21, 2021 1:11 pm
Stage 4 - V2a - again, 36K metal film grid stopper, 820K metal film||0.68uF (this cap was actually already present in the Z stock...interesting enough!), typical 100K plate.
Hi, there is a mistake:
Obviously it's not 820K, should be 820R.

:peace:

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

Post by myersbw » Wed Feb 09, 2022 5:20 pm

SoFa Granny wrote:
Wed Feb 09, 2022 2:36 pm
myersbw wrote:
Tue Sep 21, 2021 1:11 pm
Stage 4 - V2a - again, 36K metal film grid stopper, 820K metal film||0.68uF (this cap was actually already present in the Z stock...interesting enough!), typical 100K plate.
Hi, there is a mistake:
Obviously it's not 820K, should be 820R.

:peace:
Yep...thanks! Just edited! (That was a LATE night of finishing up!!!) Still love the result of that endeavor.

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

Post by dukeamps » Fri Feb 11, 2022 2:32 pm


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

Post by dukeamps » Sat Feb 12, 2022 7:03 am


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