Hello everyone,
I have a Marshall Valvestate VS102r Orange crunch (which I still don't understand the difference between the stock ones except the orange cool look)
When I started into buying amps and stuff, I bought it for a couple of bucks and repaired it, then I kept on playing it and somehow I liked it. Then I got a fender hot rod deluxe and started to notice something was wrong with this amp. Then came the JCM900 and it was clear.
It is true I compered it with tube amps but still, I have a Hughes & Kettner Attax 80 which sounds pretty good and it has no tubes in it.
So after a few months of the Valvestate sitting in the studio, I decided to mod it, and noticed there are not much of mods out there.
More proof that solidstates can sound good like the Marshall Lead 100 Mosfet
led me to actually mod the preamp as it is and not remake a whole new preamp.
So I started to take a look at the schematic and analyse the problems, find solutions..
A few problems I actually felt on mine:
The solutions
Note that I'm only 18 and I have a limited knowledge into all this.
I have also took a look into other amps schematic as the JCM900 4100, Lead 100 Mosfet, Valvestate 8100...
1/Master Volume
A useless 12AX7 that can get its effect only when you crank up the 100W amp, not so practical, so lets do it the valvestate mk1 way.
I decided to add a master volume to the OD channels right after the EQ.
I was lazy to actually do it the normal way, so I decided to replace R77 with a A100K pot (I used 100K because it was the closest thing I had at the moment, but you should use a A470K pot)
Also, R22 to 220k
This first mod allowed me to crank up the volume on the channels and to have access to tube saturation.
2/Crappy diode clipping
Many of you might have noticed how uncontinuous the diode clipping is.
At first I remove the diode clipping from OD1 and decided to use tube only saturation but there wasn't enough gain to drive a solo, so I decided to put back diodes, but in a difference manner, JCM900 style.
I used a diode bridge, with one end of the AC coming from the signal, the other end going to ground, and an approx 3V LED going from the anode to the cathode, note that you can put the LED as you want)
It gave me enough drive, and it sounded warm. 😀
3/Too much treble
All I had to do was a low bypass filter after the OD EQ and before the master volume mod, exactly between R78 and VR12.
I used a 1nF ceramc circular capacitor with one end connected to ground, the other between the resistor and the pot. It sounded good enough for me, so I decided to go ahead and put a B100K pot to control how much signal goes thru it, kinda like a presence control.
I also changed C33 to 1nF ceramic circular.
4/Too much bass
A high bypass filter..
I started by changing C34 to 22n ceramic
C25 to 22nF ceramic circular
5/No mids
Well, by fixing the too much treble, and too much bass, I felt like the amp gained back in mids, so nothing to do here.
Note, all these mods will kill your reverb on the OD channels, I have decided to remove the reverb from my amp, while you can just put an other TL072 in there to boost the signal of the reverb and put it into the preamp out signal line.
So this is it, it sounded much better to my ears but I have to say that it is still not perfect, but for me, it was enough to actually haul it with me next time to a jam instead of my poor JCM900 with its 23 years old power tubes..
I used my 1994 Fender Mexican Stratocaster and my Hofner verythinn CT.
I play mainly blues and rock, so gain all the way up all the time.
Samples:
#1: https://www.dropbox.com/s/qqfzmhsv888hybt/Sample.mp3?dl=0
Stereo rythm guitar: Contour on 7 o'clock. flat EQ, Presence on 9 o'clock, gain all the way, volume all the way, master volume on 7 o'clock,
Solo guitar: Contour on 8 o'clock. Bass on 1 o'clock, mid all the way up, flat treble, Presence on 7 o'clock, gain all the way, volume all the way, master volume on 7 o'clock,
Stratocaster -> Marshall VS102r -> Hughes & Kettner Red Box Classic -> M-Audio Firewire 1814
Next sample will be with the hofner for the the humbuckers.
These mods are for the VS102r/VS100r but I guess they can be applied to other second gen valvestates with a bit of brain work.. 😛
I hope you this will save your amp from accumulating dust!
I have a Marshall Valvestate VS102r Orange crunch (which I still don't understand the difference between the stock ones except the orange cool look)
When I started into buying amps and stuff, I bought it for a couple of bucks and repaired it, then I kept on playing it and somehow I liked it. Then I got a fender hot rod deluxe and started to notice something was wrong with this amp. Then came the JCM900 and it was clear.
It is true I compered it with tube amps but still, I have a Hughes & Kettner Attax 80 which sounds pretty good and it has no tubes in it.
So after a few months of the Valvestate sitting in the studio, I decided to mod it, and noticed there are not much of mods out there.
More proof that solidstates can sound good like the Marshall Lead 100 Mosfet
led me to actually mod the preamp as it is and not remake a whole new preamp.
So I started to take a look at the schematic and analyse the problems, find solutions..
A few problems I actually felt on mine:
- Too much treble on the ODs, sounds too fizzy and *solidstate*-ish
- Too much bass or I'd say, sub-80Hz bass
- Mids are like cut, maybe it was designed for metal?
- Crappy diode clipping, not continuous
- 12AX7 does nothing
The solutions
Note that I'm only 18 and I have a limited knowledge into all this.
I have also took a look into other amps schematic as the JCM900 4100, Lead 100 Mosfet, Valvestate 8100...
1/Master Volume
A useless 12AX7 that can get its effect only when you crank up the 100W amp, not so practical, so lets do it the valvestate mk1 way.
I decided to add a master volume to the OD channels right after the EQ.
I was lazy to actually do it the normal way, so I decided to replace R77 with a A100K pot (I used 100K because it was the closest thing I had at the moment, but you should use a A470K pot)
Also, R22 to 220k
This first mod allowed me to crank up the volume on the channels and to have access to tube saturation.
2/Crappy diode clipping
Many of you might have noticed how uncontinuous the diode clipping is.
At first I remove the diode clipping from OD1 and decided to use tube only saturation but there wasn't enough gain to drive a solo, so I decided to put back diodes, but in a difference manner, JCM900 style.
I used a diode bridge, with one end of the AC coming from the signal, the other end going to ground, and an approx 3V LED going from the anode to the cathode, note that you can put the LED as you want)
It gave me enough drive, and it sounded warm. 😀
3/Too much treble
All I had to do was a low bypass filter after the OD EQ and before the master volume mod, exactly between R78 and VR12.
I used a 1nF ceramc circular capacitor with one end connected to ground, the other between the resistor and the pot. It sounded good enough for me, so I decided to go ahead and put a B100K pot to control how much signal goes thru it, kinda like a presence control.
I also changed C33 to 1nF ceramic circular.
4/Too much bass
A high bypass filter..
I started by changing C34 to 22n ceramic
C25 to 22nF ceramic circular
5/No mids
Well, by fixing the too much treble, and too much bass, I felt like the amp gained back in mids, so nothing to do here.
Note, all these mods will kill your reverb on the OD channels, I have decided to remove the reverb from my amp, while you can just put an other TL072 in there to boost the signal of the reverb and put it into the preamp out signal line.
So this is it, it sounded much better to my ears but I have to say that it is still not perfect, but for me, it was enough to actually haul it with me next time to a jam instead of my poor JCM900 with its 23 years old power tubes..
I used my 1994 Fender Mexican Stratocaster and my Hofner verythinn CT.
I play mainly blues and rock, so gain all the way up all the time.
Samples:
#1: https://www.dropbox.com/s/qqfzmhsv888hybt/Sample.mp3?dl=0
Stereo rythm guitar: Contour on 7 o'clock. flat EQ, Presence on 9 o'clock, gain all the way, volume all the way, master volume on 7 o'clock,
Solo guitar: Contour on 8 o'clock. Bass on 1 o'clock, mid all the way up, flat treble, Presence on 7 o'clock, gain all the way, volume all the way, master volume on 7 o'clock,
Stratocaster -> Marshall VS102r -> Hughes & Kettner Red Box Classic -> M-Audio Firewire 1814
Next sample will be with the hofner for the the humbuckers.
These mods are for the VS102r/VS100r but I guess they can be applied to other second gen valvestates with a bit of brain work.. 😛
I hope you this will save your amp from accumulating dust!
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