Marshall Super Lead with Mods - Too Bright

  • Thread starter Thread starter Cap217
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Cap217 said:
If 100/4 is too bright which a lot agree with. Then we go to 47/4 but is 100/8 the same thing? Or is there an advantage either way of 47/4 vs 100/8.
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Again, remember the rule of 1.4 with NFB. The resistor size would need to be multiplied by 1.4 on each successive tap from 4 to 8 to 16 to be relatively the same. 100 x 1.4 = 140. So 140/8 and 100/4 would be similar. Some say if you change taps and compensate with the proper size resistor to achieve the same overall NFB, there is no difference whatsoever. I feel like I do still hear /feel a difference. Whether or not I'm a victim of psychoacoustics I don't really know. I can't confirm this is scientifically the case.

For your 47/4 to be the same on the 8 ohm tap it would need to be a 65.8k resistor (68k is the closest available). 100/8 would have less feedback than 47/4.
 
RedPlated said:
I feel like I do still hear /feel a difference. Whether or not I'm a victim of psychoacoustics I don't really know. I can't confirm this is scientifically the case.
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I figure that since the purple NFB wire can interact with other things around it, having twice the voltage on it using the 16 ohm vs the 4 ohm could make a difference in that interaction. In a vacuum I've always chosen the 4 just because it has less voltage swing on it and I figured...less interaction. But I'm just guessing here.
 
My 68 and both 69’s have the purple nfb wire attached to the speaker jack. At some point later they switched to the 4 and 8 ohm taps. They used one for amps with el34’s and the other for 6550’s. Been too long and I don’t remember which is which.
 
Greazygeo said:
My 68 and both 69’s have the purple nfb wire attached to the speaker jack. At some point later they switched to the 4 and 8 ohm taps. They used one for amps with el34’s and the other for 6550’s. Been too long and I don’t remember which is which.
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Haven't seen you around in forever!
 
I just wanted to update this. I got a fryette ps100 and finally used it with this amp and tested it out. It allowed me to max the master and then dial it back on the PS100. That in turn really made the harshness go away. Everything was neutral on the PS100 so I even had room to cut the highs or lower the presence if I wanted to. Its also not as bright as I complained. You have to work on blending the 2 volumes for the channels that are internally jumped and the bass knob is very sensitive depending on volume 2. It goes from perfect to mud instantly. The mid pot is more of a low mid as well it seems.

Amp sounds great. It has that marshall snarl but tight and open.

I might start messing with preamp tubes. It has chinese 12ax7b in there now but I think they might be adding to the brightness.
 
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braintheory said:
I can ask my tech about that, I’m not a tech savvy guy at all, but it seems all the ‘67 or earlier Marshall’s I’ve tried so far sound like mine or at least in the same ballpark in being darker. It sounds great and not necessarily looking to change it, it’s one of my best amps, but more thought I may as well find a later Marshall to give me that brighter, more aggressive sound. My ‘67 I’d describe more as being rich, warm, pretty, very pleasant, but still lotta balls and cut and has certainly those distinctive Marshall mids
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Use a 6" patch cable as a cord. that will brighten it up
 
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