New LockTone™ Stopbar/Tune-o-matic System

Background: Since their invention in 1954, the original stopbar and tune-o-matic have changed very little, if at all, which is a testament to their design quality and timeless functionality. Looking closely at this classic bridge/tailpiece combination that graces such legendary instruments as the Les Paul and the SG, it’s easy to see why.

Tune-o-matic: With the ability to easily adjust each individual string length using the six corresponding screws, precise intonation can be achieved. Two thumbwheels allow for bass and treble string height adjustment while two large bolts securely mount the bridge directly into the wood of the guitar effectively transferring string vibration and tone.

Stopbar: Positioned behind the tune-o-matic bridge, the stopbar uses two very large bolts and anchors that mount directly into the guitar. Because of its weight and stability, it is very effective at keeping the instrument in tune because it does not move. It is also very effective at transferring every string vibration to the guitar contributing to increased sustain and the overall tone of the instrument. Additionally, the height of the stopbar can be adjusted to create more or less string “break angle” over the tune-o-matic bridge by rotating the two large bolts. In general, the greater the string angle over the bridge the better for tone and sustain but if you find that you are breaking a lot of strings at the bridge, you might try raising up the stopbar a little.

The Challenge: Despite the success and integrity of the tune-o-matic/stopbar system, over the past year Dr. Epiphone and his staff have been conducting tests and experiments to see if and how this classic combination might be improved upon. During this time, it was determined that two improvements could be made:

During string changes when and if all the strings are removed, both the tune-o-matic and the stopbar can and often fall off of their anchor bolts. This can result in a wide range of minor problems ranging from them disappearing under a road case to being put back on incorrectly to just general annoyance. Therefore, there needed to be some way to “lock” both the tune-o-matic and the stopbar on their posts – ideally, without the need for tools.

After conducting sustain tests, it was determined that the tighter the fit of the tune-o-matic and stopbar on their posts and hence, the greater surface area contact – part to part – the longer the sustain and the better the tone.

With these two goals in mind, Dr. Epiphone set out to further perfect the design. Now, almost one and a half years later, the laboratory is proud to announce the development and introduction of the new “patent applied for” Epiphone LockTone™ tune-o-matic/stopbar system.

Without adversely affecting their classic appearance and without the need for additional tools, this new system not only “locks” onto the posts automatically and eliminates accidental drops, it also adds “tone” and sustain.

Proof of Performance: In order to validate the above claim regarding sustain and tone, Dr. Epiphone conducted the following lab tests. Below are excerpts from the Doctor’s notebook:

For the first test I plucked the string under test and recorded the signal using Sonor™.  After the signal was captured I analyzed the wave form using Sound Forge™.  I made note of the RMS power (in dB) of the signal at impulse for 0.1 sec.  I then made note of the RMS power for 0.1sec at 5 seconds from impulse.  At this point I calculated the drop in decibels from impulse to 5 seconds for each string.  I listed the average drop (over the 3 trials) for each string and then the overall average of the 3 strings combined.

Here is the average decline in dB’s from impulse to 5 seconds for each string and the overall averages for the strings combined:

Epiphone tune-o-matic/Stopbar System
6th : - 6.53dB
4th : - 23.79 dB
1st : - 37.31 dB
Average of all three string averages combined = - 22.54 dB loss

Epi LockTone™ tune-o-matic/Stopbar System
6th : - 6.9 dB
4th : -15.36 dB
1st : - 29.70 dB
Average of all three string averages combined = -17.32 dB loss

Based upon the above, the new Epi LockTone system showed a nice increase over the Epi non-locking system. In general, the Epi Locking system was over 5dB better after 5 seconds.

The other interesting conclusion is the fact that high strings do not sustain as well as low stings.  After looking at the physics involved this result supports this theory.  High frequency signals are dampened much quicker than low frequency signals. This fact also plays a large part in how well harmonic content is perceived in a signal.   If you look at only the 1st string the increase from the Epi w/o lock to the Epi Locking system was over 7.5dB better.  This increase should help with both the sustain on the high notes and the harmonic content of lower fundamentals.

For the second test, I simply removed all the strings on a guitar equipped with the new LockTone system. After removal, I turned the guitar upside down and shook it vigorously. Unlike the regular system, the LockTone did not move or come off the guitar.

Based upon the above, I am satisfied that we have accomplished our two design improvement objectives.

Thanks to the work of Dr. Epiphone, his staff and their passionate pursuit of performance, Epiphone is proud to announce the new LockTone tune-o-matic/stopbar system. Unlike other systems that require tools to adjust and remove, the new LockTone automatically locks the tune-o-matic and the stopbar onto their posts for added security and improved sustain.

The new LockTone system will be standard equipment on all tune-o-matic/stop bar equipped Epiphone electric guitars. Look for them at your authorized Epiphone retailer soon.