Chasing the Perfect Reverb: What I Learned from Vintage Ampeg Amp

I've always been fascinated by the subtle differences in sound between guitars, pedals and amplifiers. I've spent years collecting gear, modifying circuits and experimenting with components to understand what makes things sound the way they do.

Sometimes I'll hear something that catches my attention and end up going down a rabbit hole trying to figure out why it sounds so good.

That's pretty much how I ended up buying three vintage Ampeg amplifiers.

It started with the reverb

I happened to hear the reverb on an old Ampeg amp one day, and it immediately caught my attention.

There was something different about it. It had a warm, natural quality that I hadn't heard in many other amplifiers.

I've never been completely satisfied with traditional Fender reverb. It's a classic sound, but to my ears it can be a little metallic and splashy. I've always preferred something warmer that adds depth and space without drawing too much attention to itself.

That's what I heard in the Ampeg, and naturally, I wanted to know what was going on inside it.

One Ampeg turned into three

I discovered the Ampeg amplifiers I was interested in came in three different sizes, so I bought all three.

Not because I needed three more amps, but because I wanted to pull them apart, compare their circuits and experiment with the different designs.

One of the things I enjoy most about building amplifiers is understanding why something works, what gives it its particular sound, and how I can use those ideas in my own designs.

Sometimes you spend ages experimenting with a circuit, only to discover that someone came up with an interesting solution sixty years ago.

What's different about Ampeg reverb?

Most vintage Fender amplifiers use a transformer-driven spring reverb circuit. A valve drives a small transformer, which sends the signal into a spring tank to create the reverberated sound.

Some vintage Ampeg designs took a different approach, using a capacitor-coupled reverb circuit instead.

Rather than using a transformer to drive the spring tank, the circuit couples the signal through a capacitor. It's a different approach to achieving the same basic result.

Of course, the sound depends on more than just the drive circuit. The valves, spring tank, component values and the way the reverb is mixed back into the original signal all contribute.

But there's something about the Ampeg approach that really appeals to me. The reverb sounds warm and natural, with less of that sharp, metallic quality I associate with many other spring reverbs.

Bringing those ideas into Sleepwalk Amps

The Ampegs have been a valuable part of my research and development for Sleepwalk Amps.

I've taken inspiration from their capacitor-driven reverb circuits and incorporated some of those concepts into my own amplifier designs.

One feature I've added to the Sleepwalk reverb circuit is independent Send and Mix controls. Most amplifiers have a fixed reverb send level, so you can adjust how much reverb you hear, but not how hard the spring tank is being driven.

With the Sleepwalk design, the Send control changes the character of the reverb, from a subtle, natural room-like ambience through to a much more saturated spring reverb sound.

The Mix control then lets you blend as much or as little of that reverb into your dry guitar signal as you like.

Having control over both means you can really dial in the reverb to suit your playing, rather than simply turning it up or down.

For me, amplifier design isn't necessarily about copying an old circuit. It's about understanding what makes it work, experimenting with different approaches and finding ways to get the sound I'm looking for.

You can work out what a circuit should do on paper, but ultimately you need to plug a guitar into it and listen.

That's what keeps me interested in amplifier design. There's always another circuit to investigate, another component to try or another old amplifier that does something a little differently.

In this case, it led to three Ampeg amps, plenty of tinkering and some new ideas that have found their way into Sleepwalk amplifiers.

Not a bad result from hearing a reverb sound I liked.