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Why does Marshall even install the bright cap on Plexi reissues??


Ron Burgandy

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It never allows the amp to fully clean up, it makes the volume knob act like an on/off switch, forget about running pedals without running the amp full bore, and in general makes the amp stupidly harsh at anything less than paint peeling volume.

These little motherfuckers right here at c17 and c18:

2D9D43A4-1824-41E9-90F8-1D2DA2F51C50-116

My previous 1987x had the single bright cap on the high treble volume pot. 30 seconds with the soldering iron and it was in business while leaving the cap intact! This older 1959slp had 2 bright caps on the freaking PCB.

I started by clipping the 47k out of c17 since that's all the 1987x had:

BF9CFAA7-DEAC-4AEE-B375-ECAFACD2171D-116
4E4F39B2-82DD-432F-964A-00A84A1847AF-116


Plugged in and noticed the volume jump was lessened but the amp still had a lot of nasty high end below noon on the volume. Lame:

B08EB22F-B166-4668-AC81-2538D513AEBA-116

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So I took the cap out at c18 as well:

9D9834B3-3591-4C1B-8A11-DD29711101BD-116

The amp went from unusable at anything less than full blast to being an amazing clean pedal platform able to perform at any volume. At noon and above on the volume it's exactly the same as the bright caps are effectively out of the circuit at that volume but it has the punchy smooth cleans I loved on the 1987x. My drummer was actually giving me shit for getting rid of the 50 watter because he can't hear himself over the SLP. This should fix that right up love.gif



All because of these little motherfuckers:

A0AE184B-3FBD-4310-B8A8-811E9F977C15-116



If you have a plexi ri I highly recommend doing this mod.

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Quote Originally Posted by Edge11 View Post
How dare you!
You should play around with some bright cap values and then throw them on a switch.
That's what I always read but with no bright cap it's pretty damn nice. Of course I come from vintage fender amps, so without the bright cap the plexi ri reminds me of a fender with more mids. I like a very clean amp.


Quote Originally Posted by Y0UNGBL00D View Post
white coily cable ftw
For sure love.gif

Quote Originally Posted by carvinlegacy99 View Post
Was there not a cap on the actual vol pot?
Nope! Apparently the 1987x had the volume pot mounted cap until about 2003. The 1959ri were consistent in that the two bright caps are on the PCB. They use the same damn PCB so wtf mad.gif
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I think Marshall put the bright caps on there, so you take it to your tech and say "man this sounds awful. How come I don't get great vintage plexi sounds out of this ? what's wrong with it ?" Then he tells you about the bright cap.........You mod it, and.............................. void your warranty

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Quote Originally Posted by Y0UNGBL00D View Post
not to derail, but that coily cable a vox by chance? mine just shit the bed and about to try the bullet one, since its similarly priced but has an accessible sleeve
Mine is the bullet cable version thumb.gif

I love core products.


DB - this one is from the 90's so warranty is long gone icon_lol.gif
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Quote Originally Posted by telephant View Post
I thought the same thing when I clipped c17 and c18: "Why do they even put this shit in here?" biggrin.gif

Its not just killing the brightness either, the bright volume taper becomes much more even.
Yeah it is night and day!



Of course now it's like a big warm Fender with EL34's but fuck it. That's my style anyway icon_lol.gif
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I'm debating clipping mine in my new reissue.
Last time I just wobbled the {censored}er until its leg broke.

I was on the fence about the mod.

I'll see how it goes before and if I want to change it, I will.

I probably will to be fair.

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on the split to shared cathode conversion ,I cant remember which pin it is, but on a RI, you simply remove 1 wire from one of the pins, and run a jumper from it, to another one on V1. The unused wire can be heatshrinked & tucked away, in case you wanna put it back stock.

It's basically making it a superbass, but without upping the caps. Ive done it on a few reissues & its a definate improvement. Espescially on a harsh sounding amp. Again, it's reversible.

I still suggest the fixed resonance mod. Simple & effective.

Also, play around with switching what tap the NFB wire is on.

Simple stuff that a 2 year old chimpanzee could do, that yeild good results.

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