Stereo Madness!!!

Saturday, 29 September 2007 18:54

Last Updated on Friday, 20 August 2010 06:13

Not content to change just the sound of your guitar or other instrument, EH also ventured into the realm of stereo for a brief time.

Nearly all of their stereo products can be found on a single flier dating from the early 70’s. This sheet showcased their line of boosters and sound enhancers specifically designed for the stereo systems of the time. While most of their stereo products were designed to actually enhance your listening pleasure, there were times when they just couldn’t help themselves.

EH stereo products


First off, there were the Linear Stereo Boosters (LSB) models 1 and 2. Both units were simple boosters utilizing 2 transistors per channel. The difference was that the LSB-1 had a non-adjustable output while the slightly larger LSB-2 included an output level control for each channel. Simply hook them up inline with RCA cables and get a nice boost to your input signal, be it from a tuner, 8-track, or other device. Switching them to the OFF position bypassed the boost effect.

EH Linear Stereo Boosters 1 and 2

The Stereo Tone Expander was similar in build, but allowed you to adjust the tone of each channel via a TONE control. According to EH literature, the controls had the effect of extending the existing preamp tone controls one extra rotation.

EH Stereo Tone Expander

We looked at the Stereo Pulse Modulator in another article, but a recap is called for here. Imagine two tremolos for each channel, each with it’s own VOLUME and SPEED controls, along with a MASTER VOLUME and you’ve got stereo insanity! EH claimed that by tuning in to your resonant frequency with the SPM you could get stoned electronically. Presumably, there are no laws to prevent this.

EH Stereo Pulse Modulator

Finally, we come to the Stereo Ambitron (also mentioned here). Basically, it was a rackmount delay unit designed to convert mono recordings to stereo and was designed by Howard Davis for use with his mono jazz recordings.

EH Ambitron rackmount

EH’s stereo products came and went pretty quickly. It seems that they lasted for only a year or 2 at the most and all are rare items today. Not really usable to most musicians today, but nonetheless they’re an interesting chapter in Electro-Harmonix history.