In around 2006 we started offering the cease.transmission noise maker / oscillation device on our website. You put your finger on the touchpad and it outputs a tone. These were time consuming to make but we kept them on the website for almost 10 years because they filled a hole in our lineup of oddball noise devices. Now revisiting this circuit nearly 20 years later we have a much different pedal building landscape in terms of PCB and parts availability. The original device had no PCB and everything was wired point to point. The 2025 revision has a tiny PCB mounted to the back of the output jack and also a volume trimpot as well as a tiny power LED that you can peep through a small hole drilled in the side of the enclosure. Otherwise this is the same circuit two decades later and even uses the same batch of touchpads that we ordered back in the day.

These will be available in small batches and may not always be listed on our products page.

We’ve been posting about these old Digitech PDS series pedals for years both as restoration projects and overhaul mods to make the pedal function better than new. I think we have a good sampling of the delay pedals shown above – all fully restored with various modifications performed depending on what we were experimenting with at the time.

Since these pedals are now approaching 30+ years old we like to do the basic maintenance of cleaning, replacing hardware, install a standard “Boss style” 2.1mm DC jack, new mechanical foot switches, upgrade aging components or just low quality op-amps. The goal is the improve the analog section of the pedal while keeping the original digital circuitry all original when possible. We want the pedal to be reliable but we’re not trying to reinvent the sound. The biggest sonic change that we recommend would be installing a high-cut knob to roll off the treble and give a much more ambient sounding delay.

Other nice-to-have options include replacing the LEDs with something a bit brighter or to just match the color of the pedal. For the PDS 20/20 above we installed a foot switch to bypass the modulation effect making it even more versatile. We’ve also experimented with adding modulation to the PDS 1002 but at the end of the day decided to keep it simple.

Experimental mods listed above are not necessarily available to be ordered. Please check out our modifications page for what’s currently available on the PDS series pedals.

Soldering Irons:
Hakko FX-888D – A popular mid-level soldering iron. Lots of tips available, heats up quick, good overall iron. Weller is also a popular choice but my favorite model was discontinued.
Hakko FX-971 – More than twice the price of above but is a great choice for extensive SMD soldering.

Soldering / Desoldering Accessories:
Kester Lead-Free Solder – Buy a pound so you don’t run out mid project.
Solder Reel Dispenser – Put your reel of solder on a dispenser for easier positioning.
Hakko 599B Tip Cleaner – Brass shavings to clean the soldering tip instead of a wet sponge.
Tip Tinner – Cleans and conditions soldering iron tip. Works wonders.
Solder Sucker – A great option to have on hand in addition to desoldering wick.

Hand & Power Tools:
Xcelite 170M Shearcutters – Seriously, buy a pair of shearcutters. I see so many people using wire cutters which just can’t get in tight against the PCB to clean up the leads after soldering.
Xcelite 378M Thin Pliers – Small pliers are so much easier to work with when trying to navigate inside of a pedal casing. Great for precisely bending leads, grabbing parts to be desoldered, or fishing wires through tight spaces.
ESP Spanner Wrench – This is the tool you need to remove and install knurled nuts like found on vintage MXR footswitches or Gibson guitar toggle switches. Better than using pliers and less risk of damaging the pedal’s finish.
Precision T-Rule – Accurately measure from the edge of the casing for marking where you need to drill. Down to 1/64″ so you can get very accurate center lines. You’ll need a very fine mechanical pencil to use the indexing holes.
Center Punch – Mark the hole so the drill bit doesn’t walk out of alignment. There are automatic versions but I prefer this style and find them to be less likely to slip. Wear your hearing protection because this is LOUD.
Bosch power drill – A good general purpose drill that’s not too heavy or oversized. Grab it when it’s on sale.
Seiko Step Drill Bits – Step drill bits are great to have on hand for opening up holes to a slightly larger size. Be sure to check fitment as you drill to make sure you don’t accidentally go one size too far. These are cheap ones; Irwin makes a cobalt version for harder metals (stainless steel) or heavy use.
Craftsman 1/4″ Spinner Handle – Much more comfortable and convenient for low torque applications where you don’t need a ratchet. Buy a socket set that comes with one or get one to add with your current socket collection.
Tekton 6-point SAE & Metric 1/4″ Socket Set – Covers every size you’ll find on a pedal. You’ll want both metric and SAE and up to a 1/2″ deep socket for footswitches. 6-Point sockets are more durable and less prone to rounding than a 12-point. If you’re going to use this for other projects or for daily use, buy a nice set and don’t think about it again. If on a budget, this generic set is probably fine for light use and still much better than using an adjustable wrench.
Klein Hex (Allen) Key Set – Metric and SAE, long handle with ball end for getting into tight spots.

We love the old Roland AP7 Jet Phaser and have seen a few in over the years for modifications and repairs. Warm Audio’s clone is fairly accurate to the original which means it benefits from our modifications to separate out the Phaser and Fuzz circuit into two separate foot switches that can be activated independently. We also break out the goofy 6-position Mode switch which combines the bypass switch for the fuzz, tone control for the fuzz, and depth control for the phaser.

It’s interesting to note that the pedal is being marketed as true bypass, however the two units we’ve reviewed absolutely are not true bypass and use the same FET bypass system found on the pedal this was copied from. The first one we received also had a defective power supply that sounded considerably worse than battery power. A bit concerning for quality control on an otherwise beautiful pedal.

Mods include:
1. Install additional center footswitch so Phaser and Fuzz can be activated separately.
2. Convert pedal to true bypass.
3. Install status LEDs for phaser, fuzz, and fast footswitch.
4. Install fuzz Tone knob in place of the Mode 6-position rotary switch.
5. Install phaser Depth 3-way toggle switch: Low, Medium, and High settings.
6. Install volume boost circuit to increase the output of the phase circuit. This can be adjusted internally

This pedal has a unique design with a thick, aluminum plate on top of a steel enclosure. That makes it time consuming to drill and requires special hardware with a longer shaft. For those reasons the mods on this page will not be offered in this form as an Overhaul mod. We expect to have a more practical overhaul mod available in the near future which utilizes the two existing footswitches to act as bypass for fuzz and phase circuits.

Don’t own one already? Purchase a stock Jet Phaser and have it modified.

In a previous post we combined a Pro Co Rate and EHX Big Muff into one enclosure with a few modifications. We decided to take this one step further and add both a Rat and a Tubescreamer into this USA Big Muff for an even more versatile sound. We didn’t want to dramatically change the tone of each effect but we did decide to go with some minor tweaks on each circuit.

Big Muff: We added our “Body Knob” to adjust the lower midrange and help the pedal sit well in the mix. We also moved the stock LED right next to the footswitch so it would match the layout of the added footswitches. This pedal already had true bypass so we didn’t need to change the switch but we did install a “Boss style” barrel jack to make it easier to power.

Ibanez Tubescreamer TS-9: For the TS-9 we converted the pedal to true bypass and simply replaced the stock IC with a socket and a JRC4558D as it should have had from the factory.

Pro Co Rat: While I think this pedal needs a bass boost we decided against putting that modification in as that may muddy up the Big Muff which is located down the signal path. We simply removed the stock chip and installed the LM308N and left the rest of the audio path unchanged.

This has been a great way to utilize the empty space in the cavernous Big Muff enclosure and make a convenient, all-in-one distortion pedal to cover a wide variety of tones.

First up is the Script Logo Phase 90 which gets its name from the elaborate script font used on the casing. This is the holy grail of Phase 90s and has been in such high demand that MXR reissued the pedal made using the same circuit board as the original one seen below:

The most noticeable difference between this model and the future iterations is this one has six ICs all of which are single op-amps. This likely has little to do with tone and more to do with the availability and cost of ICs at the time. This model was released in 1974 and lasted until 1977.

In 1977 the Phase 90 transition into its Block Logo form which more or less was the same exact pedal except for one resistor. This resistor– which later became known as “R28″– gives a bit of a midrange boost and adds more resonance in the circuit. Below is a circuit board from 1979/1980 with an arrow highlighting the added feedback resistor.

A short time later MXR introduced an updated version of the Phase 90. This version has R28 mounted on the circuit board and also switch from six op-amps to three TL062 dual op-amps. Some other changes include minor value changes throughout the circuit, modified bias circuit for easier calibration, and pre-emphasis and de-emphasis capacitors. Below is a circuit board from the early 1980’s.

MXR went bankrupt in 1984 and was later purchased by Jim Dunlop. The Phase 90 reissue (M-101) was a modern adaptation of the late block logo circuit with only minor changes to the circuit including better power filtering and using a single TL064 quad op-amp in place of two TL062 ICs. The reissues also have all board mounted components including the potentiometer, jacks, and switch. This makes for easy assembly by the factory but is more expensive to repair and not very good for reliability.

Currently Dunlop has more variations and signature models of the Phase 90 than I could keep track of but they all stem from these original designs (and can all be modified!).

Adding an expression pedal jack to control the rate of an effect is a common request that we get for a variety of pedals. The Phase 90 is mentioned quite a bit but unfortunately it uses an uncommon potentiometer value which isn’t found in any expression pedals on the market. Our solution was to build a custom expression pedal from an old wah pedal. A few key features of this setup:

• The slowest phaser rate (heel down) is set by the Speed knob on the Phase 90 itself.
• The fastest phaser rate (toe down) is set by a Rate knob on the opposite side of the expression pedal.
• The maximum rate can go even faster than when the pedal is in stock form.
• Unplug the expression pedal and your Phase 90 is back to working like normal.

The only downside to a setup like this is the added cost of building a custom expression pedal. Our future builds will be using a Roland EV-5 expression pedal which is readily available, easily replaced in the event of failure, and is less expensive. Unfortunately the expression pedal jack occupies the battery compartment so this pedal requires an external power supply.

For years we’ve had people send various Big Muff pedals for rehousing into a smaller casing. The circuit board isn’t nearly as large as the casing that it ships in (specifically in the USA reissue) so it’s a great candidate for space savings. Just recently we had a customer request that a Rat be installed inside of the Big Muff to save space. We also installed a Clean Volume knob to each circuit to allow the original signal to be mixed in with the distortion. The end result is two independent distortion circuits in one casing to save space and help simplify a pedalboard.

This Small Stone has had quite a history of tinkering and modifications. When it arrived it had broken wires and was literally falling apart. We decided to take it on as a complete rebuild. Every single wire was removed from the circuit board and all modifications were removed so we had a reliable starting point for the restoration. Some of the mods include:

• Complete rehousing in a 3.5″ x 4.5″ casing with new jacks and switches
• True bypass with an LED
• Color switch converted to a stompswitch; the LED turn blue when in Color mode, green when in regular mode, and is off when bypassed
• Mix and Volume knobs installed
• Aging capacitors replaced and LFO ticking removed
• Boss style DC adapter jack installed

Overall this pedal is awesome! These vintage Small Stones just sound amazing and with the new modifications it should provide years of reliable operation.=

We’ve seen all sorts of Mu-Tron III variations throughout the past year. Some early models that don’t have a DC jack, some late models that didn’t have an option for batteries, some bare circuit boards in need of rehousing. These pedals really do sound amazing although their large footprint and heavy casing can be annoying for gigging musicians. My personal favorite mods so far:

1. Install a charge pump so the pedal can operate off of a single 9V battery.

2. Remove the Gain knob and install a Filter Sensitivity knob. The Gain knob adjusts the volume of the pedal both while on and when bypassed which can be a nightmare for keeping a consistent volume throughout your signal chain. Bypassing the Gain knob would set the volume to unity gain; Installing a sensitivity knob would adjust how wide the filter opens without changing the overall volume of the effect.

More info on our Mu-Tron mods can be found on the main site.