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

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

Post by BRMSlash » Wed Mar 13, 2019 9:55 pm

Thanks.

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

Post by herbvis » Thu Mar 14, 2019 10:55 pm

Sounds good :toast: Lower the gain for scom and add a dash of highs and see what that does

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

Post by Roe » Fri Mar 15, 2019 8:30 am

sounds great BMRS! Does anyone have a schematic (or layout) to share? I'd like to update my build. I had good luck installing LCR 50+50uf caps at the screens. Also, I am using a 100+100uf cap on the mains which read low in series with a 50+50uf cap that reads high (for a total of ca 70uf)
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Re: S.I.R. 100W SuperLead Schematic pt. II

Post by snakepit86 » Wed Mar 20, 2019 9:48 am

BRMSlash wrote:
Tue Mar 12, 2019 9:03 pm
Hopefully I've done Frank proud. I've now performed a couple more tweaks on my amp. Clip: http://sclk.co/r/s88r0f

I've increased the power tube grid stoppers to a more typical 5k6. All the B+ dropping resistors are now 1W carbon composition. The other change I did was rewire my speaker cabinet with Canare 4S6 speaker cable.

I think the amp now captures all the nuances of the tone that I've been chasing. I'm very satisfied. Cheers.
I like it!

What speakers did you use?

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

Post by BRMSlash » Wed Mar 20, 2019 4:46 pm

Thanks everyone.

I played around with settings last night to fine tune SCOM tone. I lowered the first gain, master vol and presence. Sounds pretty close to me. I'll try record a decent clip on the weekend.

I'm using Scumback H75-PVC 65W's.

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

Post by BRMSlash » Fri Mar 22, 2019 5:34 am

Here's a quick clip of SCOM: http://sclk.co/r/s88yyi

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

Post by CoffeeTones » Fri Mar 22, 2019 10:58 am

SCOM is smoother with more bottom and thickness to my ears. If you want, clip some .022uF PI output caps across the existing ones and see what comes out.

Are you using a PPIMV, turned down in this clip?
:toast:

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

Post by BRMSlash » Fri Mar 22, 2019 8:34 pm

Agreed, it could be sweeter/smoother in the treble. PPIMV was set around 6. I should have had it slightly higher or max for a purer tone. I'll have to try out a few things. A bit more body from increased coupling caps may help the tone as well.

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

Post by Unique » Sat Mar 23, 2019 8:31 am

As close as you are to nailing this thing, before you go changing components in the circuit, I would try dialing in the sound by adjusting your pups, or tweaking your settings a little. Maybe even adjust your bias. Things like this can have a huge impact on the overall sound. All of these things have their sweet spots. Keep in mind, no one is ever going to copy a sound exactly simply because sine waves are like waves in the ocean. No two are ever going to be identical, but you will always look at the waves crashing on the beach and recognize them as being the same.

About the bias, I know my amp always has a sweet spot depending on the power tubes that are in it. The sweet spot will change when I change tubes because of their inherent mA readings, but I can always find it. I know earlier in this thread that it was stated that Slash likes his bias @ 40mA. You have to remember that is probably Slash preference now, back in the day he probably didn't give the bias a second thought. So who knows what the bias was set at when he went to record. I know with my #34 modded 2203 to get the UYI sound right the bias is definitely on the cool side, well below 40mA. 40mA doesn't sound right at all for the UYI sound with my amp and it does sound more like Slash's modern #34 tone. Just my $.02, YMMV.

BMRSlash, I think you are there and the differences you are hearing with your amp compared to the #36 recordings you may be comparing your amp to is more than likely due to the recording process (even with the demos) and your set up. I can easily change my treble response by adjusting any of the above things mentioned. I also believe without a doubt that tubes make a huge difference with nailing the tone. When comparing Slash's modern #34 tone to his UYI sound, besides the bias, I think the main difference you hear are the cp tubes he uses today along with how he has been using V30's in the studio instead of the greenbacks he was using back then. So in pursuit of getting the #36 tone as close as possible, I believe you need to have the thinking of what was available back then for him to use running in the back of your mind. All in all, I think you are close enough with the circuit that you just may need to do some tweaking elsewhere.

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

Post by CoffeeTones » Sat Mar 23, 2019 10:10 am

I agree. BRMSlash has closely nailed the AFD tone AGAIN and has certain characters about the sound adjusted to what he personally wants it to be. His spec has not changed much in a while, but tiny things like the composition of components and voltages have. He and I bounce ideas back and forth all of the time but that doesn't mean he changes the spec nor that I expect him to. I would imagine he as well as Nigel, has experimented more than anyone in this topic and as much or more than I have, but different experiences and ideas add up. We try stuff, we keep, we eliminate. Rest assured the PPIMV is adding fizz and rolling off bass, etc and BRMSlash knew it.

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

Post by BRMSlash » Sat Mar 23, 2019 10:31 pm

Thanks Unique,

I've adjusted everything on my guitar & amp as much as possible, as you've suggested. I'm just ultra fine tuning now.

Here's a new clip with larger PI output coupling caps (22n//22n). I've also used 1n TAD mustards to drop & smooth the treble after the 22n coupling caps on the 1st & 2nd stages. The 1n's are probably a touch large in value, but I like their smoothness. I tried 500p & 1n ceramics and mica's, but didn't sound as smooth. I think I'll have to order some 470p and 680p MKT1813's to see how they go. I probably need to get the correct value mustards for the output caps as well (33n, 47n or 68n) (Note: 100n sounded too thick).

http://sclk.co/r/s88zju

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

Post by CoffeeTones » Sat Mar 23, 2019 10:48 pm

Cool. Yep, 100nF is FAT. .047uF opens up and thickens the amp. As for the 1nF caps, that is why I suggested 680pF to 1nF - really because you already have a snubber cap on a couple of plate resistors. I figured 1nF would be a little much. In the long run, I decided using more than one of those following the CC, was too much in my amps and kept one on either stage one or two. Most AFD stuff needs some fizz and attack, SCOM likes the smoothing. Fizz and attack usually sound better in live situations though. That is why I like to use switches when it makes sense and there is room. You know all of this, I'm just bored and wanted to comment.

I think with these mods (likely the .044uF output caps) the mid character has changed in a way that takes some of the AFD vibe away. If you have a few of the same brand / part number PI tubes, roll them and listen for the best one. Then compare the voltages. That can be surprising. Please keep us posted.

:thumbsup:

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

Post by Unique » Sun Mar 24, 2019 11:51 am

CoffeeTones wrote:
Sat Mar 23, 2019 10:10 am
I agree. BRMSlash has closely nailed the AFD tone AGAIN and has certain characters about the sound adjusted to what he personally wants it to be. His spec has not changed much in a while, but tiny things like the composition of components and voltages have. He and I bounce ideas back and forth all of the time but that doesn't mean he changes the spec nor that I expect him to. I would imagine he as well as Nigel, has experimented more than anyone in this topic and as much or more than I have, but different experiences and ideas add up. We try stuff, we keep, we eliminate. Rest assured the PPIMV is adding fizz and rolling off bass, etc and BRMSlash knew it.
I know you guys have experimented with everything and it's been briefly discussed. In fact, it's you guys who are keeping this thread alive. Some of things I mention are also for others who are reading because not much is talked about them and they are an important part of the overall sound.

About the PPIMV, my PPIMV doesn't really add much fizz at all. My sound doesn't change much when I crank the power up, other than what is normal between quieter volumes and louder volumes. This is the main reason why lower and higher frequencies are not as present when you have PPIMV set low. It has nothing to do with the PPIMV causing this, or rolling off lows, but rather how our ears respond to frequencies. It's called the "Fletcher Munson Curve." When you are listening to sounds a lower volumes, the mid range frequencies are more prominent while the lows and highs will seem to lack. As you turn your power up and the levels increase, low and high frequencies will rise and become more prominent. Rest assure, if you record your amp at a low volume, then turn it up loud when you play it back, these frequencies will be there, as well as a higher noise floor.

However, I'm sure in some cases, depending on the components you used for your PPIMV, it could be adding some fizz. I think the tubes your using has a lot to say about this as well. Some tubes are just more fizzy sounding than others, especially at lower volumes where it's more noticeable.

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

Post by Unique » Sun Mar 24, 2019 12:01 pm

BRMSlash wrote:
Sat Mar 23, 2019 10:31 pm
Thanks Unique,

I've adjusted everything on my guitar & amp as much as possible, as you've suggested. I'm just ultra fine tuning now.

Here's a new clip with larger PI output coupling caps (22n//22n). I've also used 1n TAD mustards to drop & smooth the treble after the 22n coupling caps on the 1st & 2nd stages. The 1n's are probably a touch large in value, but I like their smoothness. I tried 500p & 1n ceramics and mica's, but didn't sound as smooth. I think I'll have to order some 470p and 680p MKT1813's to see how they go. I probably need to get the correct value mustards for the output caps as well (33n, 47n or 68n) (Note: 100n sounded too thick).

http://sclk.co/r/s88zju
Your welcome. That sounds awesome dude! As in my last post, I'm confident you have ran the gamut as far as experimenting goes, and your sound proves it. It's a thread in a forum, so I threw it out there for discussion. You and Nigel, as far as my ears can tell, are the epitome of what this thread is about. I hope to see others succeed as well. Sadly, we no longer have Frank to confirm or deny any results, not that he would with #36 anyway, but you guys have proven that his confirmation is not needed. Whether you figured out the mod component to component, value to value, or you have found another way to skin a cat, we may never know. But what we do know is you guys have done it. Congrats to the both of you and thanks for sharing!

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

Post by CoffeeTones » Sun Mar 24, 2019 1:41 pm

Unique wrote:
Sun Mar 24, 2019 11:51 am
CoffeeTones wrote:
Sat Mar 23, 2019 10:10 am
I agree. BRMSlash has closely nailed the AFD tone AGAIN and has certain characters about the sound adjusted to what he personally wants it to be. His spec has not changed much in a while, but tiny things like the composition of components and voltages have. He and I bounce ideas back and forth all of the time but that doesn't mean he changes the spec nor that I expect him to. I would imagine he as well as Nigel, has experimented more than anyone in this topic and as much or more than I have, but different experiences and ideas add up. We try stuff, we keep, we eliminate. Rest assured the PPIMV is adding fizz and rolling off bass, etc and BRMSlash knew it.
I know you guys have experimented with everything and it's been briefly discussed. In fact, it's you guys who are keeping this thread alive. Some of things I mention are also for others who are reading because not much is talked about them and they are an important part of the overall sound.

About the PPIMV, my PPIMV doesn't really add much fizz at all. My sound doesn't change much when I crank the power up, other than what is normal between quieter volumes and louder volumes. This is the main reason why lower and higher frequencies are not as present when you have PPIMV set low. It has nothing to do with the PPIMV causing this, or rolling off lows, but rather how our ears respond to frequencies. It's called the "Fletcher Munson Curve." When you are listening to sounds a lower volumes, the mid range frequencies are more prominent while the lows and highs will seem to lack. As you turn your power up and the levels increase, low and high frequencies will rise and become more prominent. Rest assure, if you record your amp at a low volume, then turn it up loud when you play it back, these frequencies will be there, as well as a higher noise floor.

However, I'm sure in some cases, depending on the components you used for your PPIMV, it could be adding some fizz. I think the tubes your using has a lot to say about this as well. Some tubes are just more fizzy sounding than others, especially at lower volumes where it's more noticeable.
To expand on this, since most here likely use the LarMar PPIMV, I will refer to that one. It diminishes NFB which affects a few things like effectiveness of the presence control and general response of the PI. The PI output load and time constant / frequency changes when using this PPIMV. As you turn down the PPIMV, there is more resistance between the PI output and power tube grids. These things certainly affect the bass and presence outside of the Fletcher Munson Curve effect. It will make certain amps sound as if they have more gain than without that PPIMV.

Keep in mind that I have used these in amps with no NFB or presence control as well as with cathode bias on the output tubes and that can give more of an idea of how things besides the NFB and presence control react to a PPIMV.

Take a dual gang pot and use it to ONLY adjust the PI load resistors from 220k, gradually down to 68k and you will hear how anemic an amp will get simply by adjusting those two resistor values. That is part of what this PPIMV does. Even going from 220k to 180k is audible in that the bass and drive diminish. As many of us have experienced, the LarMar is pretty good from 4 to 8 on the dial. Below that, it gets gradually more buzzy but is still cool for friendly volume levels.

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