What is reverb on an AMP

Reverb effect: which reverb would you like?

G&B Workshop Amp Station
by Udo Pipper,

In this episode, we're looking at alternatives to the good old Fender Tube Reverb. There are numerous product groups that also require differences in application. If you have a small effects board and want to mix in a little reverb in the background in addition to other effects, you can get by with an upstream effects pedal. Whether analog or digital, inexpensive or expensive, is decided by the taste and budget of the user.

With reverb fans you can argue for days about the supposedly best reverb effect. Some swear by vintage sounds such as the Holy Grail from Electro-Harmonix or the Replex from Hughes & Kettner, others demand modern flexibility, which is offered by the Strymon Big Sky or Eventide Space. Since I'm always asked about it, I would also like to reveal which reverb effects are my favorite devices.

A test of the popular TC Electronics Hall of Fame 2 can be found here!

When connected directly in front of the amp, I actually only like two devices. My absolute favorite is the large tube reverb from Thomas Reussenzehn. The device is roughly the size of a 100 watt top and costs over € 1500. A heavyweight in every respect. However, the sound results are so seductively dense and warm that the device could be described as unrivaled in this league. Depending on your wishes, you can play in a telephone booth, in Cologne Cathedral or in Frankfurt Central Station. The reverberation rooms are huge, but always extremely complex, warm and melodious. When I asked Thomas Reussenzehn some time ago what his reverb would sound like, he said, "... like John Lord's organ on 'Child In Time'." And that's pretty much it.

There are plenty of workshops and reverbs at the Guitar Summit!

One of the most important qualities of this reverb is its unproblematic behavior in front of a guitar amp. Here you can hear no difference to the direct signal. An advantage that hardly any other device offers. And that's what makes it so difficult with the reverb units. For a long time Henrik Freischlader played a Holy Grail by Electro-Harmonix in the looping path of his Realtone amplifier. This low-fi reverb has its charm, but only in the loop-in path. Upstream, it reacts a bit bitchy in connection with boosters and dampens the quality of the guitar signal. But there is a second device that I can take upstream quite well: an ancient Yamaha FX-500 multi-effects. I've used this 9.5-inch device at live gigs for years, even before my 1956 Tweed Tremolux, without having to forego the crunchy vintage tone of this amp.

At some point it broke and was scrapped. The reverb was okay, if not impressive. At least my sound was preserved. Shortly thereafter, I found a true reverb pearl for my sound: the old Lexicon LXP-1. I found the Hall chip uniquely good. The sound was warm and thick. Before switching on the amp did not work so well. The sound changed drastically. So I used a trick to grind in the LXP-1. At the time I was playing a Marshall JTM-45 with two channels (high and low) and four inputs. I plugged the guitar into channel 1 (high input). Then I went with a patch cable from the low input back into the Lexicon Hall and connected its output to the low input of the second channel.

Now I used the volume control as a return control for the reverb effect. That worked perfectly. No trace of digital cold or overload in the signal path. But an unbelievably high effect quality. Later I had a loop-in path built into the Marshall, but continued to use the mix option via the two channels because the sound was better here. You could also connect the output of the reverb device to a second amp. I also used that sometimes. You then play in a wet-dry mode, which can create a lot of depth. After a while, I got an old Guyatone microverb that I could integrate into my footboard. Incidentally, it had the same Lexicon chip as the LXP-1 on board and is therefore a real insider tip.

Unfortunately, the microverb is no longer being built. Looped in via the two channels of an amplifier, the Room-Mate from TRex or the T2 from tc electronic also produce quite good results, even if they sound a little cooler and more sterile than the Microverb or LXP-1. I have been playing a single channel for a long time, which is why I had to do without my auxiliary loop-in path. But I quickly found an equally useful solution. I copied this circuit from Jeff Beck. Beck uses the line-out of a load box (THD Hot Plate) on his Marshall to control various effects that are housed in a rack on the side of the stage. The advantage here is that you can control the effects with the complete signal from the power amplifier, which makes the sound for the effect even thicker and more musical.

The output of the effects then goes to the monitor mixer and finally to the P.A. And the side fills on stage. Jeff Beck has gigantic rooms on stage. Larry Carlton does the same thing, only instead of the line-out he uses a microphone in front of the speaker, which is fed into a mixer into which the effects are looped. Very comfortable. A similar setup is used by Pat Metheny.

In the rehearsal room I don't need a second amp behind my effects, I just go into the vocal system. That makes a huge sound. A line-out can easily be built into the external speaker socket. You only need a 270 ohm resistor between the tip and ground of the line-out socket. Then connect the tip of the line-out socket to the tip of the speaker socket via a resistor. I use a 22k resistor for this, because the output signal then roughly corresponds to the unamplified guitar signal.

After all, you don't want to overdrive your effects. Even if you incorporate (reverb) effects into your signal path in this way, the power supply is the linchpin of the sound quality, especially with digital effects. If you want a particularly natural and dense Hall effect, you should use the best power supply. And that is currently the GigRig system with the Timelord module. Without this supply, you will hardly be able to enjoy the benefits of the Strymon or Eventide products.

The sound differences compared to conventional power supplies literally blew me away. A good alternative to the LineOut or two-channel mix is ​​of course a well-built loop-in path. Here, too, I've experimented diligently in the past. Unfortunately, I didn't like most of the solutions. The direct signal suffers audibly (so you could also switch the effect directly in front of the amplifier) ​​or there are problems with the volume balance.

That can be quite annoying. I only found very good loop-in paths with the high-quality amplifiers from Larry Grohmann (Larry amps) or Schröter amps. I also liked the adjustable and tube-buffered solution of the Rivera Fender amps from 1982 to 1984. This loop-in path was really excellent, because it could be controlled in send and return and worked with no sound loss. Today, however, many guitarists play smaller 18-watt amps or small tweed combos that don't have a built-in loop. The so-called Parallel L-Box from Burkhard Lehle can also help here. This is an upstream loop-in path with send, return and mix controls. The reverb effect is therefore not directly in the signal path, but rather contributed in parallel, which works very, very well. In the next issue we'll cover a few vintage Hall legends.

From guitar & bass 07/2015

Test yourself through reverbs and learn from experienced professionals - at the Guitar Summit in Mannheim. More information is available here!


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