Gerlt Technologies makes hundreds of customizable rack effects, at prices comparable to guitar pedals.  It's time to dump that pedal board and get Your Tone off the floor!


 What We Do

You know them as guitar pedals

We build them as rack effect modules you can customize to get Your Tone

Put several rack effect modules into a 3U rack enclosure

Connect power and audio on the back like guitar pedals, adding connections for remote switching

Add a remote footswitch unit to turn rack effects on and off

Add as many rack effect modules, enclosures, and third-party products as you like. Plug in your guitar and amp. Rock it! It's that simple.


Quick Hits:

  • Check out our GT Effects Overview to see why we do this

  • Check out our Compares To charts to see the full list of effects we offer

  • Follow the menus from Products, to Modules, to Modules By Type to get a list of our effect types.  Select any effect type to get a list of all our effects of that type.  Select any effect to get full information including pricing.



Hello Effects Fans!

In my last update I was excited after finding some small quantities of critical components that are needed to build our effects. I hoped that to be a sign that perhaps some of our supply chain problems were easing. But it seems those were just one-off lucky finds. I haven’t found any more since then. On top of all the other problems, we now have the ripple effect of the conflict in the Ukraine, which has caused even more parts to become unavailable and/or very expensive.

It’s one thing to be optimistic, but another to be unrealistic. This is no longer a time for simple optimism. It is a time for handling unpleasant realities. Our reality is that it seems very unlikely that enough positive changes will occur quickly enough for us to re-open in 2022. While the corporation is in a good position to weather a continued lengthy shutdown, the people are not able to. We need to take some time to go do “other stuff” for a while.

We still have several new modules to announce. The work is complete on almost all of them, so I’ll try to get those announcements out in April and May. Other than that, I’m afraid it is going to be pretty quiet here until we are able to reliably source parts at reasonable prices again. I probably won’t have another update until late summer or into autumn.

The good news is that Gerlt Technologies is still here and alive. We haven’t “lost” anything. We still have the largest selection of rack effects available, getting close to 400. Our effects still sound great. And we still want to make them available to you. We’re just going to have to continue our break for a while until the business and economic conditions improve to the point that we can provide outstanding products and support at affordable prices.

I apologize for the continued delay and will do everything I can to get us going again as soon as it becomes feasible.



Bill Gerlt

President, Gerlt Technologies

Dallas, Texas

11 April, 2022




Hello, Effects Fans!

Today we announce our new Earthquake module.  It compares to the Demeter Tremulator, Fulltone Supa-Trem, and Joyo JF-09 Tremolo pedals, which all share a base optical tremolo circuit.

Tremolo is one of the simplest effects.  In its basic form, it just turns the volume up and down at some rate.  The depth is simply how loud and how close to silent it gets as the volume adjusts.  Deeper and faster tremolo can produce choppy, helicopter sounds, like the intro in Green Day's Boulevard of Broken Dreams.  Medium to low levels of depth at slower speeds can yield classic Creedence Clearwater Revival tones or give you some cool, subtle movement in your sound.  The Demeter Tremulator is considered by many to be the best tremolo pedal ever produced.  It has simple controls for a simple effect, just Depth and Speed.  The Joyo JF-09 is similar.  The Fulltone Supa-Trem adds a few extra controls to let you tweak your tremolo effect, but is essentially the same circuit as the other two.  Our Earthquake module compares to all three of those tremolo pedals.  It comes in three base configurations that differ primarily in the controls that are included.  Note that the Danelectro Tuna Melt also sounds and works similarly, but the circuit is just enough different that it isn't covered by our Earthquake module.

Overall, this is a very nice tremolo, pleasant and warm.  Ours is quieter than the stock Supa-Trem pedal we compared with.  There is no distortion if you have the Volume set properly, although our test Supa-Trem pedal does have bits of distortion or clipping now and then.

All the controls and optional controls interact to some extent, so you may have to fiddle around a bit to dial in the exact sound you want.

Without the external Volume control or internal volume trimmer, the volume in the circuit is set to a fixed level.  That level is generally OK, unless you use settings near the max or min for Depth and Speed.  Then it might be a bit above or below unity volume.  The Volume control lets you set your unity volume level.  Volume on a tremolo is a little funky.  Depending on your wave shape, Rate, and Depth, you are changing the amount of time the volume is cut, as well as the amount it is cut, affecting the perceived volume.  This usually isn't an issue with "normal" settings, but may cause lower/higher volume at some extreme settings.  Set it where you need it, of course.

Depth has a a good range, skewed more toward the shallow end, allowing good control over more subtle settings.  With the Hard/Soft switch set to Hard, higher Depth settings get very choppy.  Depth can be smoothed out with the Bias control when the Hard/Soft switch is set to Soft.

Speed also has a good range, although it probably goes faster at the max than is necessary.  The Half Speed switch option gives you a range of slower speeds and better control over them.  We do the Fast/Slow switch a little differently from the Supa Trem pedal,  Ours will tend to have a slightly lower max speed, although it seems unlikely anyone would use it near those max speeds anyway.  We've included a blinking Rate LED, too.

Bias changes from the Hard default wave shape to a range of smoother wave shapes when you have the Hard/Soft switch set to Soft.  This control isn't used when the Hard/Soft switch is set to Hard.  Setting the switch to Hard is the same as turning the Bias pot all the way one direction.

You can see the details about our Earthquake module at: Earthquake.  Or look for it in the Tremolo Modules section under Products -> Modules -> Modules By Type.