More headroom on Marshall 1959SLP RI

[Dave1992]

Hey guys! So this as probably been answer a billion time but hear me out.

I want to have more headroom from my 1959slp but still going on the edge of breakup. I want something close to John Frusciante's tone since I'm in a RHCP tribute band. I do am aware that he's using a Major/Jubilee setup*

I'm playing on a Fender Stratocaster ( '09 American Deluxe, stock pickup rated at 6.5k) with a couple of dirt boxes ( DS-2 and Big Muff) and the amp's setting are at P:2 B:6-7 M:8 T:4 V1:4 V2:5-6 (with a patch cable) and there still just too much grit on the amp. I do need it to drive the power tubes for the compression but the preamp is too much distorted. ( There's a thd hotplate and a power amp in my setup to manege the overall volume)

I've heard about the usual suspect for the more headroom ay7, au7, at7 and the 5751 but I want your advice on wich too put where.

Thanks alot

[Nicolas]

Colder bias....or more power !

[Pressed_Rat]

Okay, I'll bite.

I've tried all these, except for the 5751, in a JMP50 clone to try and get a different balance between headroom and breakup. I like to play at full volume - no hotplate - no pedals - straight in, only about 20 minutes or so at a time . 6CA7s in the poweramp. My clone has a pre-PI MV to dial down the volume and keep the grit up there for extended playing; Frankly nothing sounds like the full plexi roar. This is with a Studio LP. At least you know where I'm coming from here.

Tried a Sylvania 12AT7 in V1 - sounded absolutely terrible. I mean really bad. Supposedly these are a good fit in the phase inverter of a plexi. I tried this also - lost a lot of character IMO. You may find it okay - just wasn't for me. Sonic-wise, I don't think much of that tube - strictly useful as a reverb driver IMO.

I tried a EH 12AY7 and a RCA 12AU7 in V1. For some reason, not sure why, but the AU7 sounded very good - even though it has much less gain than a AY7. It sounded very similar to a 12AX7 in V1, but with higher preamp voltages - I had tried paralleling a 10K resistor with the last dropping resistor in the power supply. The AU7 produced this sort of Santana-like sustain without a crushingly harsh distortion at full volume. Hard to describe, I am not good at flowery audio descriptions, but the sound reminded me of some of Carlos' tones on Abraxas. One of my friends plays with two Soldano Astroverbs, using the 12AU7 I gave him in V1 in one of his amps for a cleaner, stinging sound. The two amps sound very good together. This is with LP Standards w/Burstbuckers I think.

Currently I am using the standard plexi preamp tube complement (all EH tubes), but replaced the HotRod Duncans in my LP with a set of Gibson 490s from my son's SG. I find the sound is much more manageable now with the guitar volume knobs than with the Duncans - better balance across the strings at full power. I still get a good hard crunch without the previous harshness. Given that you are using a Strat this isn't really an option for you, but it works well for me.

If you already have these tubes, give the 12AU7 a try in the V1 slot. If you lose too much gain go to the 12AY7. If this is still is too much of a loss try the 5751. Frankly, I think you'll wind up with a 5751 in V1.

I didn't try swapping these tubes in V2 - that might have been interesting too. Probably would have driven me mad.

Hope this helps.

[wdelaney72]

5751 are your best option to reduce the gain and retain the tone of 12AX7.
6CA7 in power section was a good move...that'll help with headroom.

My closest RHCP amp is my JTM 45/100....KT66 tubes, shared cathode. You'd have to swap out OT to use KT66, but that's a much closer sounding amp.

[JimiJames]

yo,
for needed head room, perhaps 6550's could be used, changing out the bias resistor.