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

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

Post by herbvis » Wed May 09, 2018 12:20 pm

nice, didn't know they were doing a single CD release.

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

Post by Unique » Wed May 09, 2018 12:57 pm

herbvis wrote:
Wed May 09, 2018 12:20 pm
nice, didn't know they were doing a single CD release.
I was a little surprised to when I saw it. I know one thing, one of the new songs added "Shadow Of Your Love" sounded pretty darn good remastered. The old original demo of it sounded like crap.

https://www.youtube.com/watch?v=aHUmy5PvPjQ

This is probably #36 or #39 Slash is using here if it is from the original sessions. He could of recently redid his parts too. I read not too long ago where Richard Fortus said they were in the studio recording "some of Slash's old material."

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

Post by Big Mike » Wed Jun 06, 2018 4:50 pm

Sounds good,. part of me wonders if the rhythm is Izzy's boogie though. It's got more that tone to it than the marshall tone.
Solo sounds like marshall.

Could be the mix.
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Re: S.I.R. 100W SuperLead Schematic pt. II

Post by BRMSlash » Wed Jun 20, 2018 4:34 am

So I've figured out where the harsh highs were coming from and managed to fix them. A lot of it was the Sozo NexGen caps. They have a nice clear tone, but there is a more pronounced, complex sounding, treble. I've since changed them all out for TAD mustards which have a similar sound, but the complex tones are shifted to the mids. The other source of pronounced highs were the cathode bypass caps that were rated higher than needed. I've dropped them back to a 100v dc rating and the treble has evened out. I had to make a few adjustments to bring back the clarity as well. I changed the PI fizz cap to a 2kV N750 ceramic which helped stabilise the treble too.

I've also been playing around with electrolytic caps and voltage ratings for the 1st stage cathode. Currently I'm using a 1uF 70V Mundorf ECap AC PLAIN.

http://sclk.co/s86k04

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

Post by Unique » Wed Jun 20, 2018 3:14 pm

BRMSlash wrote:
Wed Jun 20, 2018 4:34 am
So I've figured out where the harsh highs were coming from and managed to fix them. A lot of it was the Sozo NexGen caps. They have a nice clear tone, but there is a more pronounced, complex sounding, treble. I've since changed them all out for TAD mustards which have a similar sound, but the complex tones are shifted to the mids. The other source of pronounced highs were the cathode bypass caps that were rated higher than needed. I've dropped them back to a 100v dc rating and the treble has evened out. I had to make a few adjustments to bring back the clarity as well. I changed the PI fizz cap to a 2kV N750 ceramic which helped stabilise the treble too.

I've also been playing around with electrolytic caps and voltage ratings for the 1st stage cathode. Currently I'm using a 1uF 70V Mundorf ECap AC PLAIN.

http://sclk.co/s86k04
That sounds pretty darn good and a lot of the character is there. Nice job!

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

Post by BRMSlash » Wed Jun 20, 2018 7:38 pm

Thanks, I like it a lot too. I think the electrolytic cathode bypass probably needs a bit more time to burn in to bring out a bit more grind. I also tried a 4u7 50v Elna Cerafine, which I loved except for the lack of high end sweetness & chime. But the Cerafine's grind and attack is outstanding.

One other thing I'm considering is replacing the 180k resistor to ground after the 1st stage gain pot with another pot. The 180k is about as high as I can go and still keep the chime and cleans, but 220k or higher does give more of a grind and gain that some of the AFD songs have. I think it would useful to have it adjustable.

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

Post by jarrodthebobo » Wed Jun 20, 2018 10:29 pm

What exactly does the resistor to ground do on the preamp gain pot? Does it just add more gain the higher the volume or does it change the tone shaping somewhat?

I'd assume it'd just elevate the signal from ground, correct?
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I know you've been drinking Gin." -Louis Jordan

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

Post by BRMSlash » Thu Jun 21, 2018 5:46 am

The resistor on the gain pot leaks more signal to ground, thus reducing gain, compared to a pot by itself (i.e. it cleans up the tone). As the value of the resistor is increased, less signal is bled off which leads to higher gain.

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

Post by reychapa » Thu Jun 28, 2018 9:47 am

Hello everybody!, It's been a while,
with everything that has caused the return of the band made me remember this section and I see that they continue to give valuable information about this mod.

my best regards.


:rock:

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

Post by snakepit86 » Sat Jul 07, 2018 5:31 pm

Hi everyone! its been time

ive been working a lot.

I know its not a SIR#36 exact tone but this is my new amp, it has all the marshall SIR DNA, i promise a video with all the Slas lynch riffs!

[youtube]https://www.youtube.com/watch?v=Mg0K9gwb3QM[/youtube]

Hope you like it

PD: I've got the AFD remastered, im working on a double mono Slash side afd and a Izzy one, if someone its interested to jam over it, im using this to record :hairband: :hairband:

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

Post by snakepit86 » Thu Jul 19, 2018 1:32 pm

Guys here is the AFD 2018 resmastered Slash side double mono to jam along and compare guitar tones :hairband: :hairband:

https://files.fm/u/n46ryqy5

enjoy!

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

Post by CoffeeTones » Thu Jul 19, 2018 1:46 pm

Cool! Thanks :toast:

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

Post by bmwfreq » Thu Jul 26, 2018 6:48 pm

JCM800 2203 issue. Help needed!

Hello, everyone!

I recently replaced all of the resistors in my JCM800 2203 #34 with 1/2 watt 1% tolerance resistors (resistors located on the PCB only.). After the change, the amp has very low output. Even with the volume turned up. And the voltages on pins one and three of the PPI tube (V3) are now incorrect.

The voltage on pin one of V3 is about 395 volts (way too high. it should be around 245 volts), and the voltage on pin three is only 5.5 volts (which is way to low. it should be around 45 to 60 volts.)

I've checked and triple checked all continuity and component values with no discrepancies.

At this point I don't have any idea what the issue is.

I did reinstall the original resistors for the PPI tube, which did not fix the issue. So, I don't believe this has anything to do with the new resistors. I've also tried multiple tubes in the V3 position, so we can rule out a bad tube.

Any suggestions or thoughts would be greatly appreciated.

Thanks in advance.

BMWFREQ
1984 2203 JCM 800
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1960AV 4x12
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Re: S.I.R. 100W SuperLead Schematic pt. II

Post by CoffeeTones » Thu Jul 26, 2018 8:25 pm

Post some pics of the wiring and we can help you more, but it sounds like the PI may not be grounded through the presence / NFB circuit correctly or some other value in the PI is wrong. Check that wiring, the 470R bias resistor value, tail value of 10k - 22k, whichever you are using. Also check 4k7 to ground in the NFB circuit.

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

Post by bmwfreq » Thu Jul 26, 2018 9:32 pm

Thanks, Coffee!

I’ll give all of that a look see. I’ll get some pics taken and posted.
1984 2203 JCM 800
(#34 mod)
1960AV 4x12
2x12 25 watt Greenbacks
2x12 Vintage 30's
[ ..... ]
| O O |
| O O |

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