Sparkos Gemini Headphone amplifier

Sparkos Gemini: different levels of customization

The first level of customization lies in the fact that the Sparkos gemini tube can be replaced by a multitude of compatible tubes: 12AX7, 12AT7, 12AU7, 12AY7, 6AQ8, 5751, 6CG7, 6N1, 12BH7. This is made possible by an internal jumper.

The second level of sound customization is made possible by gain switches on the front panel. Each tube used will have a particular sound signature. This gain allows you to intensify the final sound signal. In fact, this gain offers simple and immediate control over the level of force with which the tube should work. This gain setting also has the effect of modifying the perceived volume level by 10dB.

The third level of customization lets you control the amount of current at which the tube is polarized. This is also made possible by an internal jumper.

Jumper caps make it quick and easy to select the configuration of the various internal jumpers.

Sparkos Gemini: jumper-selectable input attenuator

A third internal jumper attenuates the input level by -15dB. This can be used if you're feeding the Sparkos Gemini with a source device that's too powerful, or if you're using it with high-sensitivity headphones that make the volume level too high. This jumper effectively attenuates the input signal, giving you a higher range of volume control.

Sparkos Gemini jumper configuration

Here you'll find the different jumper configurations for Sparkos Gemini. For further details, please refer to the user manual you can download from our download section.

#1 Tube changing jumpers

You can use any type of double triode tube in the Gemini. However, the tube type jumper must be set appropriately, to either Type 1 or Type 2. Simply refer to the SPARKOS Gemini tube compatibility chart.

#2 Tube bias adjustment jumpers 

This jumper lets you adjust the intensity of the tube's sound signature. Without activation of the jumper, the intensity setting will be high, whereas if you add the cap, the intensity setting will be lower. The jumper is set to high polarization on receipt of the product.

#3 Input attenuation jumper

The functionality of this jumper lies in lowering the input volume by 15dB for use with high-sensitivity headphones and in-ear monitors where the volume would otherwise become too loud. The Sparkos Gemini is delivered with the jumper activated and therefore without the attenuation.