Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Big_Mike on June 23, 2019, 02:50:13 pm

Title: Hoffman 6v6 Plexi Master Volume mod
Post by: Big_Mike on June 23, 2019, 02:50:13 pm

Hi guys -

Just thought I would pass on a really simple but useful mod for the Hoffman 6v6 Plexi.  In stock form with the pre-phase inverter master, at lower volumes you lose bass frequencies.  This is because the pot forms a high-pass filter.

To solve the problem, insert a 220K resistor in series just before lug 1 on the master volume pot.  This will preserve bass frequencies.  To let in some bright tones, also insert a small cap, something between 5-10p between lug 1 and 2 of the MV pot.

This works great and preserves all frequencies at lower volumes.