The AC30 has a reputation for being a clean, jangly amp with "chime". I lot of guys use them for that I suppose (Not me!) but originally it was anything but. I prefer the thick, overdriven sound achieved by Brian May of Queen. His homemade guitar and unique tone are famous throughout the guitar world, and a big part of his tone is the AC30. That thick, creamy overdrive you get when an AC30 is cranked is amazing, and I wanted it, so I bought an AC30CC, otherwise known as the AC30 Custom Classic.
This AC30CC came with Wharfdale speakers. To be honest I could not get a usable tone out of this amp and wasn't sure what to do. Everyone says to get "that" tone you had to have the Celestion Blues. I didn't really want to spend the huge amount of money for the Celestions and a BM guitar to find out it still wasn't what I was looking for. I was on the verge of just selling the amp when I came across some mods published on an Internet forum by a tech named Lyle Caldwell. The tone of the modded AC20CC he described was just what I was looking for.
Lyle will do the mods for you, but I bought the parts and did the mods myself, which consisted of swapping some caps and resistors and other changes to make the AC30CC sound more like a vintage AC30 from the sixties. The amp now has a smooth sweet overdrive and also cleans up nicely when I back off on the volume control of the guitar. It also takes pedals well. I have a variety of overdrive pedals that sound great with it, including a vintage style Rangemaster with a germanium transistor I built myself.
It does have a master volume, but you can't get power tube distortion using it. I built an attenuator to use specifically with this amp I call the Bohemian Rhapsodyne to allow me to crank the amp and overdrive the power tubes. It is pictured above on top of the amp. Click here for more details of the Bohemian Rhapsodyne attenuator.
This AC30CC came with Wharfdale speakers. To be honest I could not get a usable tone out of this amp and wasn't sure what to do. Everyone says to get "that" tone you had to have the Celestion Blues. I didn't really want to spend the huge amount of money for the Celestions and a BM guitar to find out it still wasn't what I was looking for. I was on the verge of just selling the amp when I came across some mods published on an Internet forum by a tech named Lyle Caldwell. The tone of the modded AC20CC he described was just what I was looking for.
Lyle will do the mods for you, but I bought the parts and did the mods myself, which consisted of swapping some caps and resistors and other changes to make the AC30CC sound more like a vintage AC30 from the sixties. The amp now has a smooth sweet overdrive and also cleans up nicely when I back off on the volume control of the guitar. It also takes pedals well. I have a variety of overdrive pedals that sound great with it, including a vintage style Rangemaster with a germanium transistor I built myself.
It does have a master volume, but you can't get power tube distortion using it. I built an attenuator to use specifically with this amp I call the Bohemian Rhapsodyne to allow me to crank the amp and overdrive the power tubes. It is pictured above on top of the amp. Click here for more details of the Bohemian Rhapsodyne attenuator.
Here is a list of changes I did to the amp:
Plate Resistor Mod:
Replaced R6 & R7 (100k Plate Resistors) With Vintage Specs. 220K ½ Watt Carbon Comp Resistors
Top boost channel Mod to tame excessive treble:
Replaced C13 with a 68pf cap.
Pre-amp gain mod:
Jumpered R49 to get more Pre-amp gain on the "Normal" channel.
Brilliant switch mod:
Added a permanent 68pf cap to the circuit and replace C12 (220pf) with a 68pf cap to obtain switching from 68pf to 136pf values.
Capacitor replacements:
C10 470pf 500v silver mica
C11 .047uf Mallory
C14 .022uf Mallory
C15 .022uf Mallory
C16 56pf 500v silver mica
C17 .1uf Mallory
C18 .1uf Mallory
C19 .1uf Mallory
C20 .1uf Mallory
C23 .0047uf Mallory
Power tube mods:
Changed the 100 ohm screen resistors on the output tubes to 470 ohm, and the 1.2k grid resistors to 2.2k. This helps the amp run cooler and more stable.
Reverb mods:
Replaced R18 with a 28K ½ Watt Metal Film Resistor.
Added a 470K resistor across lugs 1 and 3 of the reverb drive switch.
Replace OEM Pan with Accutronics pan # 9EB2C1B.
There is also a Tremolo mod that speeds up the Tremolo which I did not do because I like a slow Tremolo.
I also did not change the power and output transformers for upgraded ones because I don't think the tonal gain is worth the cost. My AC30CC came with all JJ brand tubes, they sound just fine.
If you want more details of the mods, Google "Lyle Caldwell AC30cc mods". You'll get lots of hits, it's all over the Internet.
Plate Resistor Mod:
Replaced R6 & R7 (100k Plate Resistors) With Vintage Specs. 220K ½ Watt Carbon Comp Resistors
Top boost channel Mod to tame excessive treble:
Replaced C13 with a 68pf cap.
Pre-amp gain mod:
Jumpered R49 to get more Pre-amp gain on the "Normal" channel.
Brilliant switch mod:
Added a permanent 68pf cap to the circuit and replace C12 (220pf) with a 68pf cap to obtain switching from 68pf to 136pf values.
Capacitor replacements:
C10 470pf 500v silver mica
C11 .047uf Mallory
C14 .022uf Mallory
C15 .022uf Mallory
C16 56pf 500v silver mica
C17 .1uf Mallory
C18 .1uf Mallory
C19 .1uf Mallory
C20 .1uf Mallory
C23 .0047uf Mallory
Power tube mods:
Changed the 100 ohm screen resistors on the output tubes to 470 ohm, and the 1.2k grid resistors to 2.2k. This helps the amp run cooler and more stable.
Reverb mods:
Replaced R18 with a 28K ½ Watt Metal Film Resistor.
Added a 470K resistor across lugs 1 and 3 of the reverb drive switch.
Replace OEM Pan with Accutronics pan # 9EB2C1B.
There is also a Tremolo mod that speeds up the Tremolo which I did not do because I like a slow Tremolo.
I also did not change the power and output transformers for upgraded ones because I don't think the tonal gain is worth the cost. My AC30CC came with all JJ brand tubes, they sound just fine.
If you want more details of the mods, Google "Lyle Caldwell AC30cc mods". You'll get lots of hits, it's all over the Internet.