ClinchFX

 NOTE:  August 2010 - EP-PRE wait time is now 2-3 weeks

What is the EP-PRE

The EP-PRE is a JFET preamplifier that is based on the preamp section of the Echoplex® EP-3® tape echo unit. It will deliver a few db of boost, but I don’t consider it as a boost.

Words such as Enhance, Fatten and Enrich all cover the effect that the EP-PRE has on your tone, but I have yet to find a word that really captures the magic of this amazing little circuit. A friend who has one of the prototypes calls it a “Tone Polisher”.

My own feeling is that it creates a “focus” in my tone and helps me to play with more confidence.

Please Note:

There appears to be some confusion about similarities between the EP-PRE and competitive products that claim to be Echoplex Preamps.  The EP-PRE and one of the competitive pedals share similar cosmetics and are both based on a Common Source JFET stage, however that’s where the similarity ends!

As I and others have stated on forums, the EP-PRE is a faithful reproduction of the preamp section of the Echoplex EP-3, complete with a power supply that is close to 20V DC, high output impedance and passive level control.  At this point in time, competing products claiming to be “Echoplex Preamp” have very little in common with the original Echoplex design.

EP-PRE Background

I built my first EP-PRE prototype while recovering from heart surgery in 2007, in response to a thread on “The Gear Page”. A couple of forum members suggested that the preamp section of the Echoplex® EP-3® should be built into a pedal. I took a look at the schematic, and couldn’t really see, at a glance, how such a simple circuit could affect tone, however I was curious and built my version of the preamp. To my surprise, it fattened my tone and sounded great. At this point, I began to seriously analyze the behavior of the circuit, and found that, apart from a small amount of top and bottom cut, the circuit had a non-linear phase response. I believe that this phase response is the secret of the magic tone.

I enjoyed using the prototype and didn’t really consider building the pedal for sale, because my other pedals are my own original designs. Before long, word got out and I began to receive enquiries from guitar players who wanted to buy this pedal. I designed a PCB, and the EP-PRE is now in production.

EP-PRE Features

Volume Control

The Volume control is the equivalent of “Echo Volume” in the tape echo unit, wired in reverse, because there is no echo in the EP-PRE. Because I insisted on keeping the circuit interaction the same as in the original tape echo unit, the Volume control works for only about half of its travel. I considered replacing it with a lower value pot and a fixed resistor, but found that, as you wind it further round, while it doesn’t change the volume, it makes a subtle difference to the tone.

Stomp Switch

We have these switches custom made to our specification, which includes gold contacts for maximum reliability when switching very low current in pedals.

PCB

For best compatibility with either Lead-Tin or Lead-Free solder, the PCB has gold plated pads. The use of SMDs for most of the components keeps the PCB small, and there is a full ground plane on one side of the PCB, to minimise induced noise.

Power Supply

The EP-PRE pedal operates from a 9V DC, Centre Negative power supply that has become the standard for most pedals.

The original EP-3® preamp operates from a zener regulated supply of about 20 Volts DC. The characteristics of the power supply are significant to the operation to the circuit. It just doesn’t work properly on 9 Volts, so the EP-PRE has a Charge-Pump power supply that converts the 9 Volts to more than 17 Volts. A Charge-Pump came closer to recreating the dynamics of the power supply in the EP-3® than I could achieve with an external 18 Volt supply.

The plastic housed DC sockets that are readily available have a very small flange that can be broken if the power cable is accidentally kicked. On all of my pedals, I mount the DC socket on a nylon washer that is cut to an exact fit on the threaded part of the socket. The washer cushions any shock loading and helps protect against breakage of the socket.

Pricing

Pricing for the EP-PRE is USD $159 plus postage.  Air Mail with insurance to the USA costs USD $20.  If you are not from the USA, please contact us to ask if we can accept your local currency and for postage rates.  We use PayPal for payment.  As we are based in Australia, we can accept deposits in Australian Dollars from Australian customers only.

Sound Clips

I’ve been too busy building pedals to do any recording. Cary Chilton has recorded some clips, and you can listen to them on his SoundClick site here. Cary is a really hot guitar player, and I’m grateful for his enthusiasm and support.

Dave Leslie from 90s Aussie legend band Baby Animals sent me some clips of the EP PRE with his Aussie Aussie made Grubisa Merlin guitar and Reynolds Valveart amp.  You can listen to them on the Sound Clips Page.

Ordering

My health issues finally seem to be under control, and Mandy is now working full time with me to build pedals and to complete design of some new pedals

If you are interested in ordering an EP-PRE, please use the “Contact Us” page to send an email.  When you email, please let us know what part of the world you are from.

® Echoplex and EP-3 are registered trademarks of Dunlop Manufacturing.