Ratverb

Analog reverb that gets dirty

 

   

 

The Ratverb analog reverb rack reverb effect module compares to the Radio Shack 32-1110 Electronic Reverb.  It uses Panasonic MN3207 and MN3102 analog BBD delay and clock chips to produce vintage analog reverb effect.

 

Description

Many of you no doubt remember Radio Shack stores.  And some of you may remember when Radio Shack sold some great electronics and components for electronics hobbyists.  Some of us could hardly wait to receive our Radio Shack catalogs in the mail so we could find out about the new models of TRS-80 computers, Realistic audio equipment, and all the Archer parts we needed to build anything we could think up.  Those days are long gone, but it is a testament to the quality and selection Radio Shack once offered that those old components and equipment are still sought out by those in the know.

One of the cool audio components they offered was the Realistic Electronic Reverb, Model 32-1110.  It allowed you to add a reverb effect to just about anything you wanted to connect to it, from microphones to instruments to TVs, record players, and other audio equipment.  Technically, it is a delay, not a reverb unit.  But the short delay time it produced gave a good and simple reverb effect, just like you can get with any delay pedal by shortening the delay time and limiting the repeats, perhaps adjusting the mix to be a little on the dry side.  The delay was produced by the Panasonic MN3207 BBD and MN3102 clock chips.  This was the second generation of the MN3x07 chip from Panasonic.  It ran at 9V, instead of the 15V of the first generation MN3007 chip.  The lower max voltage limits the clean headroom available, generally making them less desirable for clean delays than the older MN3007.  Since the unit was designed for a wide variety of devices, it could receive a wide variety of input signal strengths.  It has Mic/Instrument as well as Line level inputs and outputs.  Presumably to help compensate for the various input levels, Realistic added a Microphone Level control to the Delay, Repeat, and Depth (which is like a Mix) controls.  The Microphone Level control is really just an input gain control for the mic input, which is a quarter inch jack, meaning it is also used for guitars.  At lower levels, it acts like a mostly clean boost, but as you increase the Mic Level control, it begins to distort.  At the max level, it begins to enter Fuzz territory.  So, yes, you can use it as intended and get a cool analog reverb effect.  Or you can use it as distortion/fuzz with a short analog delay.  Of course it wasn't set up as a pedal, so it would be difficult to use it like a normal pedal unless you just used it as an always on reverb.

The Ratverb is the GT version of this cool effect, modified to work like the rest of our modules.  The circuit and components, particularly the BBD components are the same as the original.  Instead of having two sets of input/output for Mic/Instrument and Line level, we have a single in/out which can be switched to act as either the Mic or Line in/out of the original unit.  We also changed the "Microphone" control to "Gain", although it still works only with the Mic input setting, just like the original.  If you choose the Line input level, the Gain (Mic Level) control does nothing.

The Gain control gives you a number of interesting tones from the Ratverb.  It interacts with the other controls, but you can get a reasonably clean, somewhat dark reverb.  Or you can increase the Delay and Repeats and get a very short analog delay.  But cranking up the Gain, you'll quickly enter into a clipped distortion that will go from mild to fuzz, depending somewhat on your pickup output.  With the Gain maxed out and a bit of reverb dialed in, it sounds similar to the raunchy old Maestro FZ-1 fuzz Keith used for "Satisfaction" - rude, nasty, bright, spluttery - great if you're into that sort of thing.  

To be clear, there is no purely clean reverb setting.  Even with the Gain at 0, you'll get a little warmth and just the slightest hint of grit.  Turning the Gain past 0, you quickly get into overdrive.  Crank it further and you get distortion and spluttery fuzz.  The MN3207 provides only a very short delay time of at most around 50ms, so you can't really dial in distinct, separated repeats.  They are there, but very close together.  The short delay time also makes it difficult to dial in a particular number of repeats, or even just a single slapback.  So don't plan to use it as a delay.  It's best as a small room reverb or for fattening up your tone a bit.

"Ratverb"?  Well, with the gain turned up it is a pretty ratty, nasty, fuzzy reverb sound, perfect for sticking it to The Man.  And some of you will no doubt remember that Radio Shack was often referred to as "Rat Shack".

The default configuration gives you Gain, Delay, Repeats, and Depth controls using the Mic input circuit.  The only option is a switch that switches your input jack between Mic and Line In circuits.  The Gain control does not work on the Line In setting, just like the original.

 

Configurations

  • Ratverb - Compares to Realistic Electronic Reverb 32-1110

 

Options

  • Mic/Line In - Switches the input circuit between the original unit's Mic and Line In.  The Gain control works only with the Mic input, just like the original units.
  • Custom Op Amp - We use the AN6552 by default (same as the original circuit), but you can choose another pin-compatible op amp.
  • Custom Components - We use metal film resistors and a selection of capacitors that provide good tone and low noise.

 

Front Panel

  • On/Off indicator LED
  • Gain
  • Delay
  • Repeats
  • Depth
  • (optional) Mic/Line In switch

 

Rear Panel

  • Audio In
  • Audio Out
  • On/Off Footswitch
  • On/Off Override
  • DC Power
  • DC Power LED

 

Module Width

  • 1.5" standard
  • 2" with options
  • 2" left wing and 1.5" right wing available for 4-control configurations

 

Power Consumption (aprox)

15 - 20mA

 

Base Configurations

Part # Description List Price
MOD-RATVERB Ratverb module $250

 

Options

Part # Description List Price
MOPT-RATVERB-MICSW Clean/Dirty Switch $19
MOPT-RATVERB-OPAMP Custom Op Amp $0 - TBD
MOPT-RATVERB-CC Custom Components TBD