Gerlt Technologies makes hundreds of customizable rack effects, at prices comparable to regular 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.





Who doesn’t want Twofers on a Friday?!?!  Enjoy our twofer of new modules and have a great weekend.  We hope to see you at the Amigo Nashville Guitar Show in Franklin, Tennessee next weekend!

New Module:  Funkbox

Today we announce the availability of our Funkbox envelope filter module.  The Funkbox compares to the Musitronics Mutron III envelope filter pedal.  In 1972, the Mutron III was the first effect of its type, quickly setting the standard for other envelope filter and auto-wah pedals, a standard many feel has never been equaled.  Bassists such as Bootsy Collins and guitarists such as Jerry Garcia used the effect to achieve their iconic tones.  There were multiple versions of the original pedal, as well as several related pedals from Electro-Harmonix and other companies, from the 70’s right up to current new models.  But the originals seem to be preferred for their superior tone.  They used an optical part that is simply not available any longer.  There are substitute parts, some with similar specs, some with very different specs.  Here at GT we tried several different parts before we settled on one that we greatly prefer over all the others. 

How does it sound compared to the originals?  That’s a difficult question to answer.  Originals are pushing towards 50 years old.  Many of them do not sound good at all.  At this point, originals often need to be “recalibrated” or reconditioned to produce good tone, or to even work properly at all.  The original Mutron III we use for testing at GT works, but we suspect that it is probably past its prime.  Another consideration is that even an original in great shape is “fussy”.  It takes some time to find those good settings.  There are lots of settings that maybe aren’t particularly usable.  Finding the “good” settings to compare one unit to another can be tricky.  We could probably go buy a few more $600+ originals and compare to some aggregate version of the original tone.  But we’re taking a little different path.  We already know that our optical part is slightly different, so instead of trying to reproduce the exact same range of tone, we have produced what we consider to be a good envelope filter that compares to the Mutron III in functionality and range of tones.  We think there is good overlap in the tones for much of the useful range of the controls, but there are some differences.  If you are a die-hard Mutron III player, then the differences may be enough that you wouldn’t say the Funkbox duplicates the Mutron III sound.  If you aren’t that die-hard Mutron III fan and you just need to “play that funky music” with a good envelope filter similar to the Mutron III, then we’ve got you covered.  The Funkbox has all the same controls and features as the Mutron III, but also adds a Volume control.  Different settings of the other controls can have a major impact on the volume of the original units.  The added Volume control lets you compensate for those volume differences as you dial in different sounds.

To see the details of the Funkbox, go to Funkbox


New Module:  Ocean Blue

Today we also announce our new Ocean Blue delay module.  It compares to a variety of simple digital delays designed around the PT2399 digital delay chip.  One of those pedals you may know is the Mad Professor Deep Blue Delay. 

As the analog BBD chips began to go out of production years ago, digital delay chips were becoming available.  Some of those digital chips are extremely good, but are proprietary to a small number of companies for use only in their own products.  Over the years, several less expensive digital delay chip alternatives have been released for general use, with varying levels of success.  Of them, the Princeton Technology Corp PT2399 has been one of the more popular.  Although designed as a component for karaoke and other consumer electronics applications, it was quickly adapted for use in guitar delay pedals.  It is not a pristine delay.  It has some color and noise that can make it sound about as much like an old analog BBD chip as it does a digital delay.  But the repeats can be tailored in the effect circuit, producing some very nice delays. 

The Ocean Blue is a simple delay, with the same controls as many of the older analog BBD delays:  Delay, Repeats, and Mix.  It uses a single PT2399 chip to achieve from very short slap-back up to medium delays of about one-third to one-half second.  Easy to use and sounds good for the most common short to medium delay needs.  You can use it to add just a hint of fatness, get simple slap-back, or provide some space and air with longer delay settings.  The PT2399 chips vary a little from chip to chip, primarily in terms of the noise generated along with the repeats, very much like the original analog BBD chips did.  We avoid using any that are excessively noisy – no one wants that.  Just be aware that if you are used to really pristine digital delays, then most delays using PT2399 chips may not be what you want.  Ours turned out quieter than our original Mad Professor Deep Blue Delay, but not as quiet as say, a t.c. electronics Nova-1 delay.  You might want to think of PT2399-based delays as a digital simulation of the older analog BBD delays, complete with a little bit of coloration and delay noise.  If you’re an analog BBD delay junky, then you may be happy with a PT2399-based delay if you are looking for some of the features more likely to be found on a digital delay than an analog delay – tails, tap tempo, subdivisions, etc.

Now here’s the cool part, but don’t tell this to everyone just yet.  Most of this has not been announced...  The Ocean Blue is a configuration of a module we call our Digital Delay.  Our Digital Delay module is designed in a unique way that allows us to combine different circuit boards with different functionality to build a huge variety of digital delay modules.  This gives us the ability to offer a wide range of features, create many different delay configurations, offer different price-points, and allows you to customize your delay design to get the features you want at a price you can largely control.  Instead of seeing an “Ocean Blue” page at out website, you’ll actually find the page for our “Digital Delay” module.  For the moment, the Ocean Blue is the one standard configuration you’ll see for the Digital Delay module.  But that is going to change soon, and there will be many other configurations of our Digital Delay module.  There will also be a large number of optional features you can choose from.  A number of those options will be available for the Ocean Blue configuration, like modulation, tap tempo, switchable tails, and many others.  But don’t tell anyone yet, especially if you go to the Nashville guitar show next weekend or the Dallas International Guitar Festival about a month later and try them there...

To see details for the Ocean Blue configuration of the Digital Delay module, go to Digital Delay