Hartke HA3500

Together with its predecessor, the HA3500, this model is described as the best-selling amplifier in the bass guitar industry - and that's already quite a testament to its quality. It delivers up to 350 watts into a 4-ohm load, and can produce up to 240 watts into 8 ohms. This gives you the option of using both sounds and possibly mixing them together.

In terms of construction, the HA is designed very clearly and simply. On the front panel, on the far left, there are two inputs, one for active, the other for passive instruments. Behind them are two potentiometers that affect the gain for preamp A and preamp B. A is a tube preamp, B is a transistor preamp. These controls are followed by the built-in compressor potentiometer, where you can change the compression level or turn it off completely.

The rest of the controls, except of course the Master Volume on the far right, are for adjusting tone parameters. Here you'll find a 10-band graphic equaliser, with which you can vary the volume by +/- 15 dB at frequencies of 30, 64, 125, 250, 500, 1000, 2000, 3000, 5000 and 8000 Hz. Together with the Contour High-Pass and Contour Low-Pass, whose controls are right next to the equalizer, it's possible to set the sound exactly to your liking. Just to add, these filters allow you to boost or attenuate by 18 dB for bands below 100 Hz and above 10,000 Hz, and the graphic EQ can be switched out of the signal path.

The rear panel is designed in a similarly spare manner, with only the effects loop input and output and, of course, two outputs for connecting to speakers. The load of the connected speakers must be at least 4 ohms. The advantage is that the effect loop is parallel, so you can mix the ratio between the original clean and the newly created refined sound. The last element on the rear panel is the XLR Direct Output, which is great when connected to, for example, mixing consoles or PA sets. With this output you can switch between Pre- and Post-EQ and of course it has a switchable Ground-Lift.

The Hartke HA3500a is an instrument where the "simplicity is power" approach is clearly a success. On the one hand, it's a simple instrument, but it contains all the necessary features a bassist might need.