Recently I had two Darkglass pedals in with the same problem: HISS! One of the owners of this pedal contacted Darkglass; they told him to find a local tech to fix the issue. No comments were made on how this issue should be resolved.

The first pedal, the Darkglass Vintage Deluxe arrived in april. The B7K only recently. The issue was simple:

• The pedal’s effect works perfectly; no issues on the overdrive effect, all potmeters worked, volume is enough;
• The power supply works and the LED engages by turning the pedal on;
• When the pedal is turned off the bypass signal is heard; there is no coloring of the audio signal;
• When the pedal is turned on there is a loud HISS. Even with all controls set to zero the HISS is still there. The volume of the HISS does not change with the volume adjustment. The Treble EQ can add a secondary hiss when set max;
• The HISS is available on both the jack output as well as the XLR output;
• The HISS was not there when the pedal was bought. The pedal worked perfectly without HISS before. After the HISS entered the pedal it didn’t go away;
• Changing cables, power supplies or instruments/ amplifiers give no change in the HISS.

A quick internet search determines that more people have the same issues. No clear solution is presented.

The circuit

Opening up the pedal gives a nice view on the SMD circuit. I traced the circuit (but as this is still a model in production I won’t give out the schematic).

The fix

I thought the issue should be searched in the circuit as the issue only arrived when the pedal was turned on. But a probe of the circuit revealed that the HISS was not in the signal on the output of the pedal. I then looked at the connections afterwards and YES:

The issue were the ribbon cable from the PCB to the output jack and the ribbon cable to the XLR!!!!

I removed both ribbon cables and soldered new cables to the pads on the PCB. Three new cables for the XLR, two new cables for the output jack (the output jack uses three cables originally; just connect the two new cables to the outer pads and leave the middle cable empty).

The result is NO MORE HISS!!! Why this problem occurred is still unclear to me. The bypass signal also travels through these cables but is not affected by the HISS. I measured the cables and could find no problems in capacitance or resistance between the cables. Maybe the output impedance of the effect signal does this??

Good luck fixing this pedal!!