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www.tedweber.com

www.tedweber.com

5f6A

(With mods for harmonica) by Walter

Hello all, this is the 1959 Bassman 5F6 Weber amp kit

Built with much help from Scott Chainey and some modifications for harmonica.

If you try this at home, be certain you have some electronics background, work very carefully, and most importantly learn how to solder well. My first run through had a number of cold solder joints. If you have little experience, start with a very simple kit or pay an amp builder to do it for you.

Photos are followed by some building notes and a list of modifications for harmonica 

Kit building notes:

1) Capacitor board hole drilled opposite power switches to alleviate space crunch near main board.
2) Adjustable bias pot mounted on metal bracket using old hole for cap board.
3) Bolts with insulation used to tie in main circuit board because of possible shorting of r22 to chassis, also teflon sleeves added to open wires of r22 and nearby cap.
4) Input jacks mounted alternating 180 degrees so ground runs down middle of board
5) Bolt to chassis used instead of a number of brass plate solders for ground.
6) Added hook to keep cord away from hot rectifier.

Modifications for Harp (Mark Burness supplied most of these as well many helpful suggestions along the way)

1) c17 to 0.1 uF, r33 to 100K (change tone stack to reduce feedback)
2) r1 changed to 8Mohm to allow lower impedence mic
3) did not install c11 (no bright channel)
4) added adjustable bias circiut (will put in upstream of 56K resistor, to allow colder power tubes, not done yet)
5) tube swaps to V1, V2 and V3 (now 12AU, 12 AX, 12 AU) to lower gain, still messing with tube combos here
6) switch speaker polarity
7) substitute speakers from Weber, 1 Sig10A, 1Sig10As (smooth cone), 2 Sig 10F. (this follows Sonny Jr. scheme of multiple speaker types and some heaver magnet speakers) 

Have gigged with it and sounds good to me.