Amazing - Allows you to hear many sounds inaudible without it

Great for nature listening as higher frequencies often are not audible to older folks are now heard. Use to watch TV when the normal sound level may be annoying to others. Many applications are possible with this amazing little device,

Shotgun Microphone Project Kit Build Your Own
Also shows a Stethescopic Sound and Vibration Detector for listening through walls, etc. Experimental device, when properly constructed allows sounds to be heard from greater distances, pick out whispers in a crowd, even faintly through windows at close range, etc.

• Uses 36 Tuned Tubes
• Battery Operated
• Built In Voice Filter
• Includes Our HGA90 High Gain Amp With Headsets

SM3 - Paper Plans ... $10.00

SM3-D - Downloadable Plans ... $4.00

HGA90 - High Performance Voice Amplifier

A low cost system designed for many of our voice and sound detection products. The unit with modification becomes an excellent light detector for laser listeners and optical communications. It is built mainly for voice frequencies and includes several filters enhancing this important feature.

Super Performance
Ultra low noise design intended for acoustical or optical science project applications. Build in voice enhancement filter reduces unwanted background noises. Excellent circuit for directional mikes, nature listening, laser window bounce experiments, vibration detectors, etc. Comes with included headset and FET microphone, both of which can be unplugged and replaced with any other headset or microphone that fit a standard audio RCA jack or 3.5mm jack with adapter.

Stereo Headset 8 Ohm Output/3.5 mm Jack Sensitive Cap FET Mike On/Off Switch With Gain Control 9 Volt Battery Operation 1.5" x 5" Board - Easily Enclosed in a small box

HGA9K - Kit/Plans ... $49.95

HGA9 - Paper Plans ... $8.00

HGA9-D - Downloadable Plans ... $4.00

NC40 - Noise Curtain Generator

A simple little circuit for generating white noise

little circuit plugs into existing stereo, radio recorder and produces a band of noise containing a wide spectrum of frequencies [white noise]. Jams microphones - Provides a soothing relaxing sound. NC40 - Assembled ... $24.95 NC4K - Kit/Plans ... $14.95 NC4 - Paper Plans ... $5.00 NC4-D - Downloadable Plans ... $3.00

TELEPAL - Telephone Amplifier

Allows you to hear what is being said in the background of the premise being called and other covert applications using the phone.Can be re-purposed for many interesting uses.

This mini and compact Telephone Amplifier significantly increases the volume of any telephone handset or even cellular phone. Ideal for phone conversions in noisy locations and for people with hearing trouble.  Uses 1 "AAA" Battery. Small size (2 X 2.25 X 1.25). Allows overhearing othet background sounds in adjacent area to the person you called.

TELEPAL - Ready To Use ... $7.95

CYBEREAR - Cybernetic Ear