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!

It has been a while since my last update.  Our status has not changed much.  We are still unable to take new orders.  I’ve personally been off doing something completely unrelated, lots of fun, a long ways from home.  That has gone well, but is taking longer than expected.  Instead of finishing up about now, it appears I won’t finish before late Spring or early Summer.  Our status won’t change before then.

Parts availability and cost were primary causes of our current shutdown.  We use around 6500 different vintage and current production parts to build our rack effects.  It has been difficult to find good vintage parts for a while now, and it gets a little more difficult each year - nothing new about that.  Counterfeit and reject parts flood the market, and prices have soared as caches of legit parts dwindle.  The good news is that vintage parts are often not needed to get great-sounding effects.  Usually there are newer parts that will work as well or better if you can get past the volumes of misinformation and hype out there.  Listen with your ears, not your eyes!

Lack of current production parts forced us to stop taking orders.  Some critical parts do seem to be available again, at an increased price.  We want our rack effects to be affordable, and increased part prices are not helping with that.  For example, one part we use in nearly all of our modules, sometimes several per module, went from about 80 cents to around $5+ each.  Really?!?!  Fakes are also flooding the new parts market to fill the demand of the unwary.  However, a few parts are trending down in price.  In these cases there were too many manufacturers, and none of them were getting enough market share to make larger quantities to help reduce their costs.  Some have gone out of business, leading to consolidation and lower production costs.  We’ll take a cost reduction (and pass it along) anytime we can get one!  I’ll have to sort through our hundreds of effects and countless options to determine any impacts to our pricing.  My goal is to remain comparable to pedal prices.  Or better!

Where does that leave us?  The situation has improved, but we still cannot take new orders.  I’m going to work to finish up my side adventure.  I’ll pop up again, probably around June or July, and see how things are looking and provide another update.  

Best wishes for 2023 !!!

Bill Gerlt

President, Gerlt Technologies

Dallas, Texas

28 January, 2023




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.