The Retro
The Retro is a Heathkit A7E mono amp converted into a guitar amp. It has a unique set of tubes (6SN7 and two 12A7's) in ultralinear mode. The sound is absolutely amazing! It has the original paper-in-oil capacitors, which give a creamy clean. Turning it up to 5 gets a smooth distortion.
The Retro is an extremely dynamic amp that really lets the guitar's tone shine through. You can really hear a difference when you switch pickups and change your picking to get different sounds.
Hear for yourself (sorry about the quality, I'm figuring out how to use my Boss BR8 recorder).
- Retro2.mp3 Volume on 6 for creamy blues clean and crunch
- Retro3.mp3 Volume on 9 for distortion
- Retro1.mp3 Volume on 10 & extra gain for hard rock
- Retro4.mp3 Volume on 8.5 for crunchy blues
The recordings were made with the Retro through an EV SRO 12" speaker (no effects). The guitar is a Samick Les Paul with a pair of Dimarrzio humbuckers. I switched pickups but did not touch the amp during the recordings.
The Retro has a James tone stack tuned for guitar. It has a flat response with the treble and bass on 5. Turning up the treble and bass results in scooped mids. In the recordings, the bass is on about 2 and treble is on 10, which gives it a mid dip and a bright tone.
More preamp gain is available by pulling out the treble pot. This adds preamp distortion.
The amp does have negative feedback, which helps create those beautiful clean sounds. A simple modification would be to lower the feedback (by changing the resistor), which would add more "grit". Personally, I like the clean and smooth overdrive.