A Tale of Two Epochs
One day I was playing through some of the old amp-top effect units we have at the shop – various oil can echoes, the Space Echo, the Binson, the EP-3, the Klemt, the Fender outboard reverb, even an old Deluxe Memory Man – and I had the thought, “Why do all these things that plug directly into the wall sound so big, warm, and expansive?!” Standard 9 volt pedals sound good, many sound great, but there is a certain something-something that the big units had that was elusive. I scanned through a bunch of schematics and opened up some of the old units to examine their circuitry. I came away with a few observations:
- The plugged-into-wall units all ran their audio circuitry with a higher DC voltage – 15, 18, 22 volts, or more for the solid-state units. Just this fact alone would account for a lot of that bigger sound.
- The plugged-into-wall units typically had highly filtered DC power supplies which require a lot of big electrolytic capacitors. The way they work is they have a transformer that steps down the wall voltage. Then there is a bridge rectifier to convert the AC to DC. And then there is usually a smoothing filter network, ostensibly to smooth out the ripple from the AC to DC conversion, but filter caps also act as power reservoirs. So these units had more headroom as a result of all these reservoir capacitors.
- The plugged-into-wall units typically had much bigger components. The resistors were larger, the capacitors were larger, much larger than what you find in most small 9 volt pedals.
- The plugged-into-wall units, talking about the vintage ones from the 60s and 70s, had fairly complex discrete analog circuitry that takes up a lot of real estate. Modern equipment tends to utilize op-amps and SMD technology which makes for much smaller parts but also much smaller sound.
“Well”, I thought, “I guess pedals will always sound like pedals and big wall units will always sound bigger, warmer, and more dimensional.” But this thought-train plagued me for a while. “Is there a way to get that big sound in a pedal format?” I broke down and started researching and breadboarding. After a while, I thought, “I think I can do this. It’s gonna require a bigger enclosure though to fit all those big parts!”
The first thing I wanted to apply this new thinking to was the Maestro Echoplex, the mighty EP-3. Now, we already have the Belle Epoch “Tape Echo”, and a fine pedal it is, but we had designed that from the standpoint of making a great little compact echo unit that operated under standard pedal conventions – small size and capable of running from 9-18v – but still getting the gist of the Echoplex experience. In order to do that, some of the audio functions such as Record Level were performed digitally and of course, the circuitry and parts had to fit into a standard enclosure. For the ‘Deluxe, I wanted NO COMPROMISE in sound. I wanted that big SOUND and HEADROOM the actual unit had. And I wanted to be able to have my cake and eat it too. I wanted that big sound and feel but without the inconvenience of the wall units. I didn’t want to have to require the use of a special power adapter or anything like that.
What I ended up with was two new pedals that honor the tradition of the Maestro Echoplex EP-3 – the Belle Epoch Deluxe Echo Unit CB-3 and the Epoch Pre Preamp/Buffer.
And how did I do it?
I checked off all the boxes in my above description of the old plugged-into-wall units. The Belle Epoch Deluxe uses the EXACT audio circuitry of the EP-3, from the highly filtered zener shunt-regulated 22 volt DC power rail, to the JFET preamp, to the high gain silicon transistor based record and playback amplifiers, to the feedback loop, to the mixer stage. And the large components as well, using the big orange drop 225P capacitors and full sized resistors. There’s no SMD or op-amps anywhere in the audio circuitry. The new Epoch series is basically dead nuts 1970s technology in all its glory, folks! Basically, the Belle Epoch Deluxe is EXACTLY like an EP-3 Echoplex except for the tape. And this is where we marry 1970s tech with current tech. Instead of tape, a digital delay line is used and only the most minimal digital processing was employed. I wanted as much of the sound to be generated from the analog side as possible so I used analog circuitry to do the tape compression/saturation task. If you were to pull up the schematic for the EP-3 and compared it to the ‘Deluxe, you’d find everything identical except for the record and playback heads! There’s fine-tuning involved of course so I spent several months tuning the analog circuitry to match up with the modern digital delay line. I think I came up with the best of both eras. The glory and the sound of the old analog circuitry and the power and convenience of modern DSP. My mission was to get the SOUND. But once I got that big sound happening, once I got the big EP-3 sound, I could now think about how I wanted to push the possibilities further. My philosophy has always been to strive for utmost authenticity and then once that has been achieved, and only then, to find ways to extend the palette without losing that core authenticity. And one day I was looking at my bench and there was an old Deluxe Memory Man piled next to my EP-3. I thought, “Well now there’s two iconic delays sitting next to each other. The most used tape delay ever sitting next to the most iconic analog bucket-brigade delay ever. Wait a minute…..” The chorus and vibrato settings on the DMM are the stuff of legend. You see where I’m going with this – let’s take the modulation section of a DMM and mate that with the exact EP-3 circuitry! Boom. We did just that and it was amazing. This train of thought lead to more experiments. “What if instead of a tape cartridge it had a leslie speaker?” “How about if the repeats were going through a sweeping filter?”
Wait. What about the 22 volt thing?
So I DO need a special power supply? Nope! You just use any standard 9 volt power supply and an internal voltage tripler bumps it up to 27 volts and then the shunt-regulator keeps it at a strong and steady 22 volts, just like an old EP-3. Have your cake and eat it too! Plug any of your other pedals into the ‘Deluxe and you’ll hear it making your other pedals sound bigger as they are magnified by that 22 volt headroom.
Thinking more about the legacy of the old Echoplex, I made the observation that the Echoplex was more than just an echo unit. Players for decades have sworn by the Echoplex, not just for the delays, but for the sonic enhancement it did. That is a well known consensus by now as there are several EP-3 inspired boosters on the market. But the third aspect of the Echoplex was that it was a live performance instrument unto itself. Think about Jimmy Page’s theremin performances where he’d sweep the delay time slider with theatrical flair while conjuring sounds out of thin air with his theremin. Audiences had no idea how he was making those sounds, it was wizardry! Of course, we know he was just messing with the delay time. But he made it a big part of his actual performance, of the stage show. And then there’s Tommy Bolin who was a master at using the Echoplex as an instrument. He’d have his Echoplex sitting on a stool right in front of him as he performed so he could manipulate it as he went, playing it like an instrument. At first, I wanted to reproduce the delay slider but then thought it would be even cooler to be able to manipulate the sound with your feet so both hands could be free to continue playing the guitar. What I ended up with is expression pedal control over delay time, delay playback head volume, and even rotary speed and filter sweep. And then I went further and added a momentary footswitch for echo oscillation, tunable via an internal trimpot. I’m really into spontaneous sonic exploration and this palette of live control gives all kinds of cool things you can do. The Belle Epoch Deluxe is like a new instrument unto itself. And even I as the designer of it find new sounds and new techniques every time I play it. And it’s an instrument unto itself even if you don’t touch the expression pedal or echo oscillation switch. You can go from discrete delays to smeared echoes just from your playing technique.
The Epoch Pre takes the idea of the Echoplex-based booster to the hilt. I started with the exact reproduction of the EP-3 preamp circuitry, from the 22 volt power, to the mixer stage, to the circuit loading that occurred with the tape recording circuitry affecting the preamp response. But there were two main versions of the EP-3 preamp.
The first 400 units had a different spec and have become somewhat of a holy grail. This “early” spec had a tighter bass and an amazing subtle upper-midrange boost that was just the thing to push the old Marshall stacks. I’m not sure exactly what he used but when I play the early spec preamp into my Marshall it sounds like old Van Halen. Then the later models were changed to have a broader frequency response with less of an upper-midrange kick. The sound of the “later” preamp is big, warm, and creamy. The Epoch Pre gives you both modes!
Now that I had the exact sound and response of the early and later spec preamp, I thought about how I could now extend its range. First, let’s talk about the intention of the original Echoplex. It wasn’t designed as a booster. The design goal was to make a driver that would sound basically the same as the instrument signal and at about the same volume. What players found out though was that it altered the signal in a subtle way that made the guitar just sound better – bigger, more 3D, wider. Many players through the years have noted that. “It just makes my guitar sound better and easier to play!” The original EP-3 preamp circuitry had a lot of potential boosting power in it that was purposely turned down to achieve their goal of a unity driver circuit. Just by adjusting the bias of the JFET gain stage I could get it to boost a lot without losing any of the character or any of the headroom. So I provided that as a panel control so you can go from EP-3 spec unity gain all the way to big healthy boost with all the headroom of a 22 volt power rail. I realized I could get even more boost out of that circuit by applying a big bypass capacitor like you’d see in an amp tube stage. I made that foot switchable so you can get any amount of preset boost with a stomp of the foot. When you engage the Boost function, the soundstage gets even wider while still retaining a huge amount of headroom. You can set the amount of preset boost with the Boost control. I came up with what I think is the ultimate clean boost!
If we continue examining the Echoplex circuit we find that the mixer output stage has a fairly high output impedance which accounted for some of the warm character of the EP-3. Most people had their Echoplex on top of their amp with a short cable running to the amp so the loading from the high output impedance wasn’t too much of a problem. But put it on your pedalboard with a long cable running to the amp and a bunch of other pedals in line and the sound can become too “warm” and undefined due to the impedance loading. So I set about coming up with a switchable buffer circuit that would eliminate those problems. Now I’m not usually a fan of buffers. I find they often make the sound tinny and hollow and the playing feel disconnected. So I experimented with all kinds of buffer circuits until I found something that retained the big feel while providing the right drive to the amp. I ended up with a silicon transistor based buffer circuit that also runs on 22 volts for huge feel and big headroom and enhanced clarity and detail. For the tech types, it’s a “bootstrapped bipolar emitter follower”. You can make a transistor buffer with just four or five parts but the Epoch Pre’s buffer has quite a bit more involved supporting circuitry, including the higher filtered power supply and the bootstrapping. I made the buffer switchable from a panel control and you can use the buffer independent of the preamp. So, you have the option of the original Echoplex response, big and warm, or you can switch in the buffer to get more clarity and detail and even bigger soundstage.
The Epoch Pre can be used anywhere in your pedalboard chain but one of the best uses of it is having it as the very last pedal before your amp. When used this way, the Epoch Pre is like a mastering plug-in. You know how when listening to a rough mix, if you slap a mastering limiter onto the master buss, your entire mix sounds bigger and more cohesive? Well, the Epoch Pre does just that for your pedalboard! It will make your entire pedalboard sound better and at any volume you choose, including turning it down! A lot of pedals, especially overdrives and fuzzes, sound their best when cranked up but sometimes they hit your amp too hard or you have to play too loud to get the sound. By turning the Balance control down on the Epoch Pre, you’ll get that huge sound even at bedroom volumes. Or, you can boost your amp to the high heavens. So whether you’re playing the big stage or you’re jamming through your pedalboard at home and trying not to wake the kids or the neighbors, the ‘Pre will be your best friend.
And that’s the tale of two epochs, the Belle Epoch Deluxe and the Epoch Pre. Thanks for reading the story of their creation and I hope you get a chance to try these out for yourself and see how they can enhance your rig, making your sound bigger, wider, and more dimensional.
Catalinbread Mechanisms of Music
Epoch Pre Specifications
- Exact preamp circuit from the EP-3 including JFET gain stage, the mixer stage, and the circuit loading from the tape circuitry.
- Operates on standard 9 volt pedal power supply, internally converted to shunt-regulated 22 volts, just like an EP-3.
- All-discrete, through-hole construction with orange drop 225P capacitors, carbon composition resistors, and other premium parts.
- Early or Later preamp voicings switchable from front panel button. Early voicing has tightened bass and upper-midrange boost. Later voicing has extended bass and a broad, creamy response.
- Balance control replicates EP-3 mixer stage. From minimum to noon it controls the volume. From noon on up, subtle frequency and phase shifts occur.
- Bias control ranges from EP-3 unity gain response all the way to a huge amount of clean boost.
- Boost control sets the amount of preset boost activated via the Boost footswitch. The Boost function adds even more boost to wherever the boost level from the Bias control is set.
- Switchable output buffer via front panel control. When buffer is on, it remains on even when preamp is bypassed. The buffer runs at 22 volts and is an all-discrete silicon transistor based circuit (bootstrapped bipolar emitter follower).
- Dual outputs to drive two amps or two different signal chains.
Belle Epoch Deluxe Specifications
- EXACT EP-3 circuitry, from the 22 volt power rail, to the JFET preamp (later spec), to the mixer stage, to the high gain silicon transistor based record and playback amplifiers, to the feedback loop. All circuitry is faithfully reproduced and fine-tuned from the original EP-3 specifications. The only thing missing are the record and playback heads, with a 24-bit high-fidelity digital delay line taking the place of the tape.
- All-discrete, through-hole construction with orange drop 225P capacitors, carbon composition resistors, germanium diodes, and other premium parts.
- True-bypass or “trails” mode selectable from internal switch.
- Expression pedal control over delay time, delay playback volume, rotary speed, and filter sweep. When delay time expression control is selected the panel knob (Echo Delay) controls the maximum delay time when expression pedal is at full-toe. Minimum delay time can be set from most expression pedals giving control over both minimum and maximum delay times, from full-heel to full-toe.
- Echo Oscillation momentary footswitch allows instant runaway repeats. Internal trimpot allows this function to be user tunable.
- Echo Delay (digital) – controls delay time from 80ms to ~680ms, exactly like an EP-3.
- Echo Sustain (analog) – controls the amount of delay feedback and is tuned to function like the EP-3.
- Echo Volume (analog) – controls wet/dry mix using exact EP-3 mixer circuit for the same subtle phase and tone shifts of the dry signal.
- Record Level (analog) – controls the gain of the input signal hitting the record amplifier. Ranges from no signal all the way to heavily overdriving the transistor record amplifier. Record Level only affects the level of the initial repeat. Once repeats are regenerating this control has no effect on them, just like the EP-3.
- Depth (digital) – controls the modulation depth. The type of modulation depends on the setting of Echo Program.
Echo Program (1-6). Selects from six different options for the “tape”.
- Bright and tight EP-3. Voiced with classic EP-3 tape echo sounds in mind. Classic shimmering tape echoes. Depth controls the amount of undulation from tape wow and flutter, from none to severe. Start with Depth at noon. Exp (V) controls volume.
- Full range EP-3. Thicker sound than Echo Program 1. Great for really prominent echoes. Quicker onset of oscillation. Depth controls the amount of tape undulation, from none to severe. Start with Depth at noon. Exp (V) controls volume.
- Roto-Swirl. As if the tape was replaced by a rotary speaker set to fast. Depth controls the intensity of the rotary sound. Using an expression pedal allows the rotary speed to be changed from fast rotor (full-toe) all the way down to slow rotor (full-heel). Exp (V) controls rotary speed.
- Sweep-filter. Like replacing the tape with a sweepable wah-like filter. Without an expression pedal, you get a bright delay tone that cuts through nicely and doesn’t cloud things up as much. Using an expression pedal unlocks the resonant filter that sweeps from low (full-heel) to high (almost full-toe). Full-toe cancels the resonant filter giving you the default bright delay sound for this Echo Program. This program has a quick onset of oscillation when using Echo Sustain. By continually moving the expression pedal some amazing resonant filter sweep echo sounds can be achieved. Exp (V) controls filter sweep. Depth controls the amount of tape undulation, from none to severe.
- DMM Chorus. Reproduces the chorus mode from the classic Deluxe Memory Man. The Depth control can get into very extreme pitch-bending, just like an old DMM. Exp (V) controls volume.
- DMM Vibrato. Reproduces the vibrato mode from the classic Deluxe Memory Man. The Depth control can get into very extreme pitch-bending, just like an old DMM. Exp (V) controls volume.
- EXP toggle switch – selects expression pedal function. To the right (D) the expression pedal controls delay time. To the left (V) the expression pedal controls either delay playback volume, rotary speed, or filter sweep, depending on which Echo Program is selected. When using the expression pedal to control delay playback volume, you can go full heel to turn off the delay and use just the preamp. Pushing expression pedal forward is like turning up the volume at the playback head.