One of my all-time favorite amplifiers is the Marshall JCM 900 MkIII Hi Gain Master Volume. It was made for just 2 years and I wish Marshall would reissue it. I'm glad I still have mine. It doesn't get a lot of play time these days but when it does, it's glorious. Here are some PDF files with info about the amp. One of them is the page from my old site minus the sound clips. Also included is the handbook, preamp and power amp schematics.
These clips are of my personal MkIII 2100. There is no post EQ at all. What you hear is the raw recording.
EQ settings on the amp: Presence = 2-3, Bass = 8-10, Middle = 3-4, Treble = 6-7, Preamp Volume = 10.
- Gain Sensitivity = 11
- Gain Sensitivity = 15
- Gain Sensitivity = 20
- Gain Sensitivity = 11 w/ MXR ZW-44 Overdrive
- Sound Clip March 2009
For the track named, "Sound Clip March 2009", this one is post-repair of the power transformer, new filter caps, new bias supply components, as well as new tubes; EH power and preamp.
- Guitar (Frankenstrat) straight in to the amp.
- Ibanez delay/echo in the loop on the echo setting.
- Effects loop volume box after the delay/echo in the loop.
- Cabinet is an Avatar Vintage 2×12 with Celestion Classic Lead 80 speakers at 16 ohms.
- Presence at zero
- Bass at 4
- Middle at 5
- Treble at 5
- Master Volume at 4
- Gain Sensitivity at 18
- Preamp Volume at 10
The Master Volume is a little touchy between 2 and 3 so the effects loop volume box lets me get past that and then choke it back down to reasonable levels.
CAUTION: Do NOT put any volume box between the amp and speaker cabinet. They are NOT attenuators!
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