Hartke HA-3500 Head - UsedLight marks and slight tear in tolex from general use The HA 3500 from Hartke is a lightweight 350W hybrid bass head. Featuring blendable tube and solid state preamp circuits, 10 band graphic equalizer, and low and hi pass controls, this amp can blend frequencies at any point in the signal path. A one band compression is also on board after the preamp stages. On the back panel, two speaker outs (one each for either 8 or 4 Ohms), parallel effects loop,