Double Cross Rear Panel

by James Brown

Recently I spotted a lot of questions on Harmony Central about the Double Cross, and in particular people wondering about the back panel.  So here it is:

This shows the final chassis, and you can see the added 12AT7 crammed in by the power amp tubes.  5-12AX7s, 1-12AT7s and 6-6L6’s(or EL34’s).

Here’s the Speaker Output system:

It has an impedance selector so you can switch to 16, 8 or 4 ohms and includes 2 parallel speaker jacks.

Here’s the Direct Out:

The DI was a lot of fun.  Using the same method as when we designed the Coupe DI, we positioned a Blue large diaphram studio mic about head-height, and made small adjustments until it sounded the same through headphones as live.  Our lab was designed on a separate slab from the rest of the building, and we have 12 foot ceilings to eliminate the possibility of creating weird resonances.  The resulting curve helped us figure out what to do for the direct output in order to simulate the speaker’s contribution.  Then we replaced the slant with the straight, and redid the curves.  I think it’s very effective, and we had a lot of excited artists at NAMM who were tired of roadies kicking over their carefully positioned ‘57 and ruining their whole nights guitar sound…..and it has the added bonus of being able to mix the sound.  I.E. you could use a slant so it cuts through on stage better, but still use the straight DI sound if you prefer that.

Here’s the Effects and Footswitch area.  The Effects loop is a tube driven effects loop, series connected, and it’s of course footswitch-defeatable.  There are separate Send and Return level controls, which lets you set the level of the loop between about -10dBV(0.3VRMS) and 0dBV(1VRMS)….and there’s sufficient overall gain to compensate up to 10dB for lossy effects!  This is very handy if you have some old delay you love, but you hate when you kick it in and the volume drops a tiny bit.  With this system you can easily make this up.

The Footswitch is a single 1/4″ cable(see the picture in my earlier posting), so it’s easy to replace in the field as opposed to DIN jacks or wimpy Ethernet cables or something like that.  The footswitch cable is usually a weak link of any amp system, so I wanted to make sure to toughen this up.

The MIDI system is very simple.  It works like this:  You plug a MIDI pedal into your effects rig, and the MIDI Out of the effects product into the Double Cross’ MIDI IN jack.  Now to program it, all you do is follow these 3 steps:

1) Send MIDI preset Number to amp.

2) Switch your Double Cross footswitch to the preferred setting.

3) Press and hold the Save button to store it.

Now every time that particular MIDI preset number is sent, the amp will respond accordingly.  You can then either leave your Double Cross footswitch at home, or more likely, you can still use it in conjunction with the MIDI system.  Most other manufacturer’s require you to use complicated MIDI mapping to get to all the footswitch combinations, but I hate that kind of stuff.  Of course it costs more to do it this way, but for this model the cost was of secondary importance to the functionality.

Hope this sheds some light.