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

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

Post by CoffeeTones » Thu Aug 29, 2019 11:18 pm

bmwfreq wrote:
Thu Aug 29, 2019 9:32 pm
Got it! Thank you.

Hey, you said something about raising the preamp voltages in my amp in an attempt to brighten it up, by lowering the PI dropping resistor value. Can you tell me exactly which resistor is the one I want to lower the value of? The reason I ask is, my amp being the PCB mounted pots/Horizontal input circuit, it's a little bit different than the amps with the PCB stand-offs. I would have attached some schematics to illustrate the differences, but it says the attachment quota for this forum has been reached...bummer.

I believe the pre-mid 1984 version amps have a few more dropping resistors than my amp does. About two to four more
[10K 5W] if I'm not mistaken.

Thanks in advance!!

PS: I shortened the length of my existing hot-shield coax, and it did add quite a bit more highs.
Pics of supposed 1984, 2203 amps show two different boards. Dunno which board you have. Yours likely has two, series provisions between the PI and bias circuit. http://www.mediafire.com/convkey/5870/x ... 21t3zg.jpg

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

Post by bmwfreq » Fri Sep 06, 2019 11:02 pm

Hey everyone.

Kind of off current topic here. How can you tell, or how do you know if your PT is on the fritz?? Is there a way of testing it to determine this?

When I bought it, and up until about 4 or 5 years ago the PT output voltage in my 1984 JCM 800 was around 468V. Now it's down around 442V output. At its highest, it may get to around 455V, but only if the supply voltage gets to 121VAC.

Anyone have any thoughts on this?? Is my PT on its way out???

Thanks in advance.
1984 2203 JCM 800
(#34 mod)
1960AV 4x12
2x12 25 watt Greenbacks
2x12 Vintage 30's
[ ..... ]
| O O |
| O O |

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

Post by CoffeeTones » Fri Sep 06, 2019 11:36 pm

Might be a power tube or something else in the power section drawing excess current. May be a filter cap.

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

Post by EddieLenz » Sun Sep 08, 2019 1:05 pm

Hi guys,

Here's my take on #34 and #36. What do you think?


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

Post by CoffeeTones » Sun Sep 08, 2019 1:19 pm

Pretty good. It does have something a little different in the upper mids which could be lack of bottom. The open, low strings sound a little thin. May be the speaker or something in the recording. Needs more bottom to balance the mids from what I hear in this clip, but if you have enough bottom outside of a recording, you might trim the upper mids a bit by changing a ceramic cap to mica for example. Could increase the 150k to ground a little to increase bass or decrease the PI tail resistor if you have 22k now, to increase bottom and pull out mids. That is if the bass and mid controls do not help. No Idea what your spec is, just throwing suggestions.

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

Post by EddieLenz » Sun Sep 08, 2019 4:27 pm

CoffeeTones wrote:
Sun Sep 08, 2019 1:19 pm
Pretty good. It does have something a little different in the upper mids which could be lack of bottom. The open, low strings sound a little thin. May be the speaker or something in the recording. Needs more bottom to balance the mids from what I hear in this clip, but if you have enough bottom outside of a recording, you might trim the upper mids a bit by changing a ceramic cap to mica for example. Could increase the 150k to ground a little to increase bass or decrease the PI tail resistor if you have 22k now, to increase bottom and pull out mids. That is if the bass and mid controls do not help. No Idea what your spec is, just throwing suggestions.
Thanks! Yeah, probably the biggest "problem" is that I can only use IRs, and can't spend money on 6550s right now. Thanks for the suggestions, I'm probably gonna leave the amp alone for a while though, as I've never been happier with it and I spent too much time on it already in the last weeks haha.

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

Post by Unique » Tue Sep 10, 2019 10:03 am

That sounded pretty good, and like what Coffee said, it seemed to lack lows. The hardest thing to determine is the sound from a video recorded with a phone or video camera because the frequency response curve from the little mic on these rolls off a lot of lows and doesn't really have the proper frequency response or dynamic range to give a good representation of the sound coming from the amp. The mics on these are made to focus on the frequency range of the human voice, which is the mids. This is so they can capture clear speech and are not really for guitar amps. So they can make the sound of an amp much thinner and more hollow than how it is in real life. The best thing to do is also set up a mic on the cab running to your DAW when making a video from a phone or camera. Then replace the video's audio track with the mic's track in whatever DAW you use and use mic's audio for the video. But I know, not everyone is equipped to do that, and how it was recorded is probably why it sounds like your amp is lacking lows.

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

Post by EddieLenz » Wed Sep 11, 2019 6:03 am

Unique wrote:
Tue Sep 10, 2019 10:03 am
That sounded pretty good, and like what Coffee said, it seemed to lack lows. The hardest thing to determine is the sound from a video recorded with a phone or video camera because the frequency response curve from the little mic on these rolls off a lot of lows and doesn't really have the proper frequency response or dynamic range to give a good representation of the sound coming from the amp. The mics on these are made to focus on the frequency range of the human voice, which is the mids. This is so they can capture clear speech and are not really for guitar amps. So they can make the sound of an amp much thinner and more hollow than how it is in real life. The best thing to do is also set up a mic on the cab running to your DAW when making a video from a phone or camera. Then replace the video's audio track with the mic's track in whatever DAW you use and use mic's audio for the video. But I know, not everyone is equipped to do that, and how it was recorded is probably why it sounds like your amp is lacking lows.
I'm sorry, but I don't agree at all.
The sound is in no way lacking any bass, compared to Slash's sound on the albums and how do you get the idea, that I recorded that with a phone??? lol
If you'd taken a second to look in the description, or at my reply to the previous post, you'd know that I used IRs.
That's because I can't crank a cab in my small, one-room flat.
If you listen closely to Slash's tone on "It's a Lie" and pretty much every other song he's ever done, there's not more bass in his sound, than in mine.

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

Post by Unique » Wed Sep 11, 2019 11:52 am

Sorry, I must have missed that in your post. But you posted this here for an honest opinion, correct? I'm not one to sugar coat things, I call it like I hear it. That doesn't mean I'm always correct, it's just my opinion. And my opinion is your sound had the sound as if it was recorded on an iPhone or video camera to some degree. I'm not saying that's a bad thing, it just sounded like there was some LF roll-off happening with your sample.

Here's the thing that I think a lot of people don't think about with their amps when comparing them to the albums. The actual #36 amp you hear on a recorded, mixed, and professionally mastered album, more than likely will sound slightly different than the amp will in real life. Simply because of the LF and HF roll-off that occurs from the mics and analog gear used in the recording and mixing process, not to mention the tape machine and console. All have their own frequency response that rolls off at certain frequencies shifting that energy to other frequencies throughout the spectrum, boosting some frequency ranges, while attenuating others. This colors the sound to some degree depending on the gear and how it's used. If you able to solo Slash's track out of the mix you would probably be shocked as to what you heard.

This is because, more than likely there was a HP filter used on Slash's tracks at some point during the mixing stage to make space for the bass and drums. Quite possibly there was also a little bit of EQ'ing to the tracks of #36 to make room for the vocals, and Izzy's guitar. On top of that, there may have been a little bit of compression added to the track, if not the whole mix. Not only do these adjustments affect the overall sound of the guitar track, but the analog gear that was used to do the adjustments often impart some of its own sound and color to the sound of the recorded #36 even further (there was no plugins at the time used on AFD, it was the last all analog album Geffen made before going to digital from my understanding). Because of this, #36 in real life, along with #34, more than likely has a bit more bass to the sound than what you hear on the albums. There's a difference in sound to the mids on a track when using an HP filter verses turning the bass down on the amp. Just like there is a difference in sound of the drive/gain when you raise the pickups verses turning up the Pre Amp or Gain.

So yes, when I listened to your sample, while I thought it sounds pretty good, I also noticed the lack of low end, which since it was a video, I assumed that you used an iPhone or a video camera to do the recording like most people do with video samples. In the end, it doesn't matter what I, or anyone else thinks. It's your amp, and if it sounds good to you, then it's good.

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

Post by EddieLenz » Wed Sep 11, 2019 12:55 pm

Unique wrote:
Wed Sep 11, 2019 11:52 am
Sorry, I must have missed that in your post. But you posted this here for an honest opinion, correct? I'm not one to sugar coat things, I call it like I hear it. That doesn't mean I'm always correct, it's just my opinion. And my opinion is your sound had the sound as if it was recorded on an iPhone or video camera to some degree. I'm not saying that's a bad thing, it just sounded like there was some LF roll-off happening with your sample.

Here's the thing that I think a lot of people don't think about with their amps when comparing them to the albums. The actual #36 amp you hear on a recorded, mixed, and professionally mastered album, more than likely will sound slightly different than the amp will in real life. Simply because of the LF and HF roll-off that occurs from the mics and analog gear used in the recording and mixing process, not to mention the tape machine and console. All have their own frequency response that rolls off at certain frequencies shifting that energy to other frequencies throughout the spectrum, boosting some frequency ranges, while attenuating others. This colors the sound to some degree depending on the gear and how it's used. If you able to solo Slash's track out of the mix you would probably be shocked as to what you heard.

This is because, more than likely there was a HP filter used on Slash's tracks at some point during the mixing stage to make space for the bass and drums. Quite possibly there was also a little bit of EQ'ing to the tracks of #36 to make room for the vocals, and Izzy's guitar. On top of that, there may have been a little bit of compression added to the track, if not the whole mix. Not only do these adjustments affect the overall sound of the guitar track, but the analog gear that was used to do the adjustments often impart some of its own sound and color to the sound of the recorded #36 even further (there was no plugins at the time used on AFD, it was the last all analog album Geffen made before going to digital from my understanding). Because of this, #36 in real life, along with #34, more than likely has a bit more bass to the sound than what you hear on the albums. There's a difference in sound to the mids on a track when using an HP filter verses turning the bass down on the amp. Just like there is a difference in sound of the drive/gain when you raise the pickups verses turning up the Pre Amp or Gain.

So yes, when I listened to your sample, while I thought it sounds pretty good, I also noticed the lack of low end, which since it was a video, I assumed that you used an iPhone or a video camera to do the recording like most people do with video samples. In the end, it doesn't matter what I, or anyone else thinks. It's your amp, and if it sounds good to you, then it's good.
Of course, I posted it to get an honest opinion. I just never had someone think, that I recorded something with a phone :wink: .I know, that it's pretty much impossible to recreate the sound without using all the exact equipment and even then, it would still be difficult. I did some low volume test recording with my 2x12 with 1988 Vintage 30s and an SM57. It's already better sounding, especially the low end, but I'd really need a 2nd, different mic to blend the two.

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

Post by Unique » Wed Sep 11, 2019 1:46 pm

Keep in mind, that it's not really about recreating a certain sound as much as it is about capturing the character and overall tone of the amp. So when you hear your amp you can hear the same elements of the tone and character you like with #36 in your amp. Just listen to Slash's tone with #34 through the years, the "Apocalyptic Love" #34 tone sounds much different than the "UYI" and first Snakepit album's #34 tone, "It's 5 O'Clock Somewhere." But yet, it still sounds like #34 and has the same character, and overall sound. You can instantly recognize it even though it sounds different. That should be the goal of every modder trying to copy a sound from an amp. And who knows, with the right tubes, guitar set up, and recording set up, your amp just might sound like #36 would if it was used on another album and recorded differently. Heck, #36 would probably sound different if Slash would have used it on another album and there was a different studio work flow, and engineer. It's quite possible that on some of the tracks on UYI may have #36 mixed in since some of those songs were recorded during the AFD sessions and almost made it on to AFD. Like "You could Be Mine" for example.

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

Post by EddieLenz » Wed Sep 11, 2019 4:47 pm

Unique wrote:
Wed Sep 11, 2019 1:46 pm
Keep in mind, that it's not really about recreating a certain sound as much as it is about capturing the character and overall tone of the amp. So when you hear your amp you can hear the same elements of the tone and character you like with #36 in your amp. Just listen to Slash's tone with #34 through the years, the "Apocalyptic Love" #34 tone sounds much different than the "UYI" and first Snakepit album's #34 tone, "It's 5 O'Clock Somewhere." But yet, it still sounds like #34 and has the same character, and overall sound. You can instantly recognize it even though it sounds different. That should be the goal of every modder trying to copy a sound from an amp. And who knows, with the right tubes, guitar set up, and recording set up, your amp just might sound like #36 would if it was used on another album and recorded differently. Heck, #36 would probably sound different if Slash would have used it on another album and there was a different studio work flow, and engineer. It's quite possible that on some of the tracks on UYI may have #36 mixed in since some of those songs were recorded during the AFD sessions and almost made it on to AFD. Like "You could Be Mine" for example.
Yeah, I agree! Cool, I didn't know, that some UYI songs were recorded that early.

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