Merlin High Gain Preamp + Firefly Output

Merlin High Gain Preamp + Firefly Output

Update 8/10/16: As the VVR was pretty pointless with this set-up I decided to remove the ability to control it with a pot. This freed up a hole on the front – I decided to put it use by altering the tone stack from a simple tilt to a Bone Ray with tilt and middle controls. I also put the 1st bright cap on a switch – makes things a little better at lower gains.

An updated schematic is here, with the original retained below. I’ve also added few extra pictures of the layout below in the gallery.

firefly_merlinhg


I wasn’t happy with my Firefly so decided to implement Merlin’s High Gain preamp design coupled to the existing Firefly output stage.

I removed the Mid control from Merlin’s design (replacing it with a 820k/220k divider following his Medium Gain design) and kept with my tilt control instead of the Bandmaster stack (both due to space constraints). Made a couple of component changes here and there due to not having them to hand.

Also implemented a MV control before the power section.

Schematic

firefly_merlinhg

Build Pics