Taming a Marshall ’ s Extreme Treble
ASK AMP MAN
Taming a Marshall ’ s Extreme Treble
BY JEFF BOBER
Q :
Fig . 1
Dear Amp Man , Short story : I have a 1978 Marshall 50 Master Volume head that I bought in 1978 . Yep , I bought it new . The amp sounds great with my old 1970 Les Paul Custom loaded with a Gibson 500T .
A few years ago I switched to Strats with Floyds , and now I want to get back to my �a�orite all-time pickup�a �uncan �ustom���roblem� While the Duncan Custom always sounded great with the shorter Gibson scale in a LP and responds perfectly to the Marshall ’ s gain and breakup , that same pickup is crazy bright in a Strat with a Floyd . Even with the treble , middle , and presence at zero , the amp is still too bright to use . Yes , I could switch pickups or use the guitar ’ s tone pot , but I want to be able to work my amp ’ s controls with the Duncan Custom . Is there a relatively easy mod to take the amp ’ s treble down a notch ? Jimmy Saviano about the rest of the electronics ? Your Gibson could quite possibly have 300k volume pots , and they may be a great match for the Custom pickup in that guitar . But if you take the same pickup and install it in a guitar that may have 500k pots , the results will definitely be different . Then there ’ s the value of the tone pot , how it ’ s wired to the volume control , what the value of the tone cap is , and even the possibility of the Strat having a “ no load ” pot . Any one of these variables can make a difference . And if they ’ re all added together … wow ! Then there ’ s the guitar ’ s wood . And the pickup mounting method ( pickup ring verses cavity mount ). All these things can make a huge difference when they become additive . Many things to think about , if you haven ’ t already . Be that as it may , let ’ s see if we can tame your amp a bit , as some of these can be notoriously bright anyway .
The pickup is far from the only thing that determines a guitar ’ s electric sound .
A :
Hi Jimmy , Marshalls and Les Pauls , Marshalls and Strats — these pairings make iconic sounds for sure ! But as with most things in the gear world , it takes the right combination of elements for the best results . While I can and will give you some small modification suggestions for your amp , I think you first need to make sure that you ’ re comparing apples to apples , as much as possible , of course , when it comes to comparing the two guitars .
Here ’ s what I mean : The pickup is far from the only thing that determines a guitar ’ s electric sound . Have you thought
WARNING : All tube amplifiers contain lethal voltages . The most dangerous voltages are stored in electrolytic capacitors , even after the amp has been unplugged from the wall . Before you touch anything inside the amp chassis , it ’ s imperative that these capacitors are discharged . If you are unsure of this procedure , consult your local amp tech .
Head ’ em off at the high pass . First , let ’ s start with one of the quickest tricks that many players do to these and similar amps . There is a high-pass cap ( C103 ) connected to the preamp control between the wiper and clockwise terminals ( Fig . 1 ). The value of this cap can be traditionally high in these amps , as the schematic calls for a 1 nF (. 001 µ F ) cap . This value will pass a great deal of high end and is generally the first thing players and techs remove from these amps when they ’ re simply too bright . This , in essence , is the same cap that would be switched in and out by the bright switch on most older Fender amps . The difference is that most Fenders will use a much smaller value cap to pass less highs . If you remove this cap and there is now not enough high end , you could certainly experiment with
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