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 Making an Ovation® Acoustic
Electric Sound Incredible
Improves any A/E

German Microphone Transformer Rewinding Service

      Any gigging musician who uses an acoustic electric guitar in live performance situations knows that getting an excellent sound with even the most expensive instrument is next to impossible. Most well recorded acoustic guitars are not piezo type acoustic electrics, they are usually quality acoustic guitars with expensive mics in front of them going through expensive preamps, EQ's and possibly compression. Several gigging friends and myself have auditioned dozens of hybrid acoustic electric guitars and available electronics packages in a quest to find an A/E preamp that actually lives up to it's hype. To date we haven't found one example that didn't have severe drawbacks. Personally, I like to use Ovation acoustic/electrics on stage for no other reason than they are fairly bullet proof and resilient to humidity and bar cheese. After owning a guitar shop for years I can tell you that I never heard a really good sounding Ovation. The plastic, space starved bodies simply don't allow many of the frequencies that an acoustic guitar produces to develop. The early ones had finish on the tops that was so thick it caused cracks in the wood as the finish shrank. The thick finish also didn't help the sound.

Most players try to EQ the missing frequencies into the sound. That approach is really doesn't help much and the reason is simple. It is difficult for the EQ to accentuate parts of the spectrum that are *not* there to begin with. Since the guitar isn't producing the frequencies that are audibly missing, the EQ is only actually boosting frequencies near the passband that it is centered at. EQ's don't *add* frequencies to the program material. This leads to over EQ'ing and over EQ'ing leads to phase problems which makes an acoustic guitar sound honky and more electric. Another problem with most acoustic on-board preamps is the output swing is small due to power supply constraints of using small batteries.

In the 70's a company called Alembic took on a similar problem with a decidedly different approach. Alembic wanted to develop a great bass and found that the industry type instrument electronics that were standard for years just weren't up to par with what was happening sound wise in recording studios at the time. Alembic decided to design electronics for the bass more like studio gear was made. One of the differences with an Alembic bass is the external power supply (there are batteries but they don't have the same v as the external supply). Alembic also used low I pickups fed into beefy FET's and the EQ section was based on a 5534 IC just like you would find in recording consoles of the day. The sound of those basses is without equal.

    It is this same approach that we implemented when designing the AEEQ-1A. This unit is basically a high quality discrete FET recording console preamp feeding a complete Pultec EQP-1A equalizer. The units run on an internal +-24V well filtered power supply. The combination of the much lower phase shift  of the LC EQ, and the 24V rails make this unit a stunning live performer. It turns the sound of even the anemic acoustic electric into a HUGE room filler.

Vintage Windings Acoustic Electric Guitar AEEQ-1A Equalizer Preamp

 Here is a photo of the prototype that was built several years back. Since then we have started building them into 2 space cases using the Vintage Windings EQ-1A Filter unit. The circuit is fairly simple. This example has optional input/output transformers. The input is switchable to the transformer (w/ an XLR or 1/4" balanced input) which goes directly to the EQ, or the front 1/4" input can be routed through a 500K pot to the FET input preamp (a separate Forsell Opamp) through another 500K pot, then on to the EQ. This setup maximizes the Pultec EQ portion as the unit can be used as just the standard Pultec EQ when the preamp section isn't needed. The input transformer can be eliminated but I wouldn't eliminate the quality output transformer, even for guitar (it provides gain in this circuit and it helps with noise).
This is a great DIY project for the guitar player who wants a killer sound !!

Please e-mail for details. Note: The Pultec EQ project can be found here.



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