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Analog Signal Processors

Zapco analog processors are legendary for both sound quality and reliability. Zapco processing started in 1978 with the famous PEQ, 9 band, dual channel control, preamp EQ. With balanced inputs, high voltage outputs, and military grade internal components, the PEQ was the first true Sound Quality EQ for the car. The PEQ was followed a few years later by the Zapco PX. The PX was the first parametric EQ for the car. With high voltage inputs and outputs, an 18dB electronic crossover, 4 parametric EQ bands, and a noise free remote power supply, the PX became the competition EQ for the 1980s. The 90′s brought the Zapco SX series of EQs with Zapco parametric equalization, high voltage outputs, fader, and bass to highs balance control. The SX became the new top dog of the competition circuit. Then Zapco led the pack into digital processing in 2004 with the famous DSP-6 and the DC line of amplifiers.

But we know that vinyl records continue to be preferred by audiophiles over CDs and other digital media for one reason. The purity of the sound. Many aficionados of great sound prefer analog processing over digital for the same reason. Analog reproduction of music continues to have a warmth and sonic purity that is lost in the digital realm.


Now Zapco brings you the new family of Zapco analog processors. Zapco processors are designed and built for the audiophile ear. These processors use top end Elna Silmic ll capacitors throughout the signal path. The op amps are the Analog Devices  op275s, and we went straight to factory who builds the best precision potentiometers around, and had our own custom pots built for these new processors. Each of these processors is designed to do one job and to do it right. There is an audiophile EQ for the dash. There are 2 electronic crossovers, 2 signal line drivers, and OEM line adapters for upgrading factory stereos. These processors are all designed for maximum versatility to give you exactly what you need to get the most from your sound system. And they have quality touches to go a step beyond. The ASP-Q1 in-dash EQ has a copper chassis for maximum noise rejection. The larger units use a remote power supply to keep the high voltages out of the main chassis, and for maximum reliability, the under seat and trunk mount units have a plexi cover plate to keep dust and dirt out of the units after you’ve made your settings.

So; If what matters to you is music…if sound is not just the main concern but the only concern... If you want your system to put you front row center… 

Zapco makes a signal processor just for you.



ASP-Q1  Dash Mount EQ with 3-Way Crossover

  • Five bands of Parametric Equalization

  • Variable 18dB/octave electronic crossover

  • Separate Bass Control

  • Auxiliary input

  • Input gain controls

  • Balanced/Unbalanced Inputs

  • Tiffany style panel mount RCA connectors

  • Dimensions (mm): 121(W, w/RCA) x 25.5(H) x 176(L)

599.99 $

The ASP-Q1 was designed to be an effective tool in tuning and controlling the sound of a car audio system. With 5 bands of parametric equalization you can put up ±18dB of correction at any points in the frequency spectrum without being limited by fixed center points. With audiophile grade internal components in the signal path and precision pots for all adjustments the sound will be clean and transparent, with rock solid bass and crystal clean highs. The ASP-Q1 excels as a crossover as well. You can configure a 2-way with bass and dual highs or as a 3-way crossover with a band pass. The over-sized power supply gives you  a 9.5 volt line driver with 14 volts available for peaks. This gives the ASP-Q1 plenty of headroom so even on the biggest signal peaks you amp will get a clean distortion free signal.


ASP-X4  2/3/4-Way Electronic Crossover

  • 2-way, 3-way, 4-way, or 3-way plus full range Crossover

  • Two band pass outputs

  • Dual inputs allow fading between the main 3-way system and the rear fill

  • Switchable 12/24dB sub crossover

  • Selectable ground reference for noise elimination

  • 9.5 Volt RMS line driver

  • Dimensions (mm): 190(W) x 39(H) x 214(L) 

599.99 $

The Zapco ASP-X4 is definitely the “Mac Daddy” of Analog Electronic Crossovers. To begin, the very same high end audio grade Elna Silmic ll capacitors and OP275 op-amps used in the LX amps are also used in the ASP-X4. Another important factor in the sound quality is the quality of the control pots. They need to be clean, precise, and must not add distortion. Zapco went out the the maker of the finest pots around and had out own custom high precision pots built for our competition grade processors. With a high pass, a low pass and 2 band pass filter systems you can run a 3-way system or a 4-way system. You can even have an active 3-way system and a full range rear fill. And with the dual input system you can fade between the main 3-way system and the rear fill. For that extra little touch… the X4 is designed to match the Z-series chassis. Since we assume this crossover will likely be displayed with the amps, we have illuminated the clear plastic protective cover for that extra touch in the installation


ASP-X2  2-Way Electronic Crossover

  • 2-way high/low, 2-way high/band pass, high pass front plus rear fill Crossover

  • Selectable band pass output 2 (rear)

  • Dual inputs allow fading

  • Selectable ground reference for noise elimination

  • 9.5 Volt RMS line driver

  • Dimensions (mm): 119(W) x 39(H) x 102(L)

249.99 $

The Zapco ASP-2X is a highly versatile 2-way crossover with separate front and rear inputs. To begin, the very same high end audio grade Elna Silmic ll capacitors and OP275 op-amps used in the ASP-4X are used in the ASP-2X.With two high pass filters and a low pass filter, the 2X is a very unusual 2-way crossover. Like most 2-way crossovers the ASP-2X can be used to separate the bass signal from the mid/highs signal. But the addition of a X10 switch on each filter allows the high pass to range up to 4,500 Hz, so the ASP-2X can be used with an active tweeter. In the other end, the X10 switches on the second output allow the low pass bass filter and the sub-sonic filter to become a higher frequency band pass. So the ASP-2X can give you an active tweeter and a band passed mid-range.  And with the dual input system you can fade between the two outputs. If you set the band pass at its widest you can have high pass front with rear fill and fade.


ASP-L6  6-Ch. Signal Line Driver/Distribution

  • 6-Channels in/6-Channels out line driver

  • Distribution preamp configurable for 2, 4 or 6 channels input

  • Balanced/unbalanced inputs

  • Remote power supply for channel 5/6

  • 9.5 Volt RMS line driver, 14 Volts peak

  • Dimensions (mm): 190(W) x 39(H) x 135(L)

349.99 $

If you want the best sound and all the dynamic range your system is capable of, you need a signal line driver. The Zapco ASP-L6 is a six channel line driver delivering a true 9.5 volts RMS of preamp output and 14 volts peak output. Because the line drivers job is boosting the preamp signal, it’s absolutely critical that the line driver does not induce any of its own noise or distortion into the system. That’s why we use only the premium Elna Silmic ll caps and the OP275 audiophile op-amps in the signal path of the L6 and L2 BT line drivers. You also have the option of balanced or unbalanced inputs, and selectable signal ground refrerence. All for a dead quiet, distortion free signal. As a distribution preamp,  the ASP-L6 lets you send 6 inputs to 6 outputs, but you can also send one set of RCAs to all outputs. So you can feed three amps from one set of RCA inputs, or you can send one pair of inputs to 2 amps for mids and highs send a separate bass signal to the sub amp.


ASP-L2BT  2-Ch. Signal Line Driver/Bluetooth

  • 2-Channels in/4-Channels out line driver

  • Bluetooth music streaming

  • Balanced/unbalanced inputs

  • Selectable ground reference

  • 9.5 Volt RMS line driver, 14 Volts peak

  • Remote level control for system volume

  • Dimensions (mm): 119(W) x 39(H) x 102(L)

219.99 $

The ASP-L2 BT is a true 9.5Volt output line driver with 14Volts peak. The ASP-L2 has a single pair of inputs, but it has 2 pair of outputs so you can run both a bass and a highs amplifier off the same preamp output. And, of course, each output signal gets 9.5Volts RMS. Bluetooth Streaming : The ASP-L2 BT is not just an awesome 9.5V RMS line driver. It is also a Bluetooth input for your sound system. The L2 BT also comes with a dash remote level control so you can match the level of your Bluetooth device and the level of your head unit and use the L2 BT remote as your system volume control. Lets take it a step further: If you do most of your listening to on a iPod, MP3 player, or other Bluetooth devise, why do you need a head unit? Really, when you have an ASP-L2 BT line driver you have your Bluetooth input, your signal line driver, and your volume control.


ASP-OE8  8-Ch. Signal Level Adaptor/Preamp

  • 8-Channels in/8-Channels out line driver

  • Bass Recovery Equalization

  • 8-Channel 9.5V RMS Preamp Outputs

  • Variable Bass Recovery Treshold

  • Switchable Smart Auto Turn-on

  • Dash Remote for Bass Recovery Level

  • Dimensions (mm): 190(W) x 39(H) x 230(L)

369.99 $

Zapco’s ASP-OE8 OEM integration processor permits you to achieve superb sound quality when adapting an aftermarket audio system to a factory-installed radio or amplifier. Using premium components and Zapco’s passion for excellent audio, the ASP-OE8 is going to make your new audio system sound like it should: clean, precise, and more importantly, enjoyable. High end op-amps, Elna Silmic caps, low noise design, channel summing, bass recovery system built in w/remote power supply.


ASP-OE2  OEM Spk Level to Pre with Bass Recovery

  • 2-Channels in/4-Channels out line driver

  • Distribution preamp configurable for 2 or 4 channels

  • 9.5 Volt RMS line driver, 14 Volts peak

  • Dash bass remote

  • Bass Recovery for factory head unit

  • Dimensions (mm): 119(W) x 39(H) x 102(L)

149.99 $

The ASP-OE2 is an OEM adaptor designed for superior sound quality, with top end internal parts and Zapco’s custom built high precision pots. It is an active device including the line converter and a signal line driver that puts out 9.5V RMS and 14V peak signal voltage. Bass Recovery: If you are driving a fairly new car, you’re probably noticed that when you turn up the volume of the system the bass seem to drop out. That’s because the auto makers are actively equalizing your system. They do think to protect the the factory speaker from the damage when you crank up the volume. One way to avoid the bass loss to leave the volume range of the head unit low and turn the gains of the amps way up. That way the head unit does not know how loud the system is. Unfortunately this does terrible things to the sound. The OE2 can seamlessly put the bass back ino the system regardless of the head unit volume control. With the ASP-OE2, you can leave the amp gains down and get crystal clear mids and highs and rock solid bass from the factory head unit at every volume.


ASP-OEB  2-Ch. OEM Spk Level to Preamp

  • 2-Channels in/2-Channels out line driver

  • Distribution preamp configurable for 2 or 4 channels

  • 9.5 Volt RMS line driver, 14 Volts peak

  • Auto on w/defeat

  • Preamp gain control

  • Dimensions (mm): 59(W) x 26(H) x 79(L)

69.99 $

For many years people have been using passive LOCs to adapt speaker level signals to RCA signals so they can add amplifiers to their systems. The results have been less than satisfactory. In fact many (if not most) folks out there have come to accept the fact that the factory stereo signals are just not good enough to be adapted into a top quality sound system. But they are wrong! The ASP-OEB is a basic 2-channel line converter with a difference. The ASP-OEB is a true active peramp with exactly the same circuitry that is in our other active adapters. The OEB has the same 9.5- Volt preamp that all our signal processors have. It also has adjustable preamp gain and Automatic Turn-On that can be defeated with the flip of a switch if desired. With the ASP-OEB you will get the same crystal clear mids and highs and rock solid bass you expect from any Zapco signal processor. And at just 2½” by 2¼” it will fit anywhere. If you are using the OEB to add a woofer, wow! You get a flat response down to below 20Hz and you get a 9.5 volt strong signal for your bass amplifier. Now that’s the way to put bass in a car.


ASP-L2T  2-Ch. Line Noise Filter

  • 2-Channels in/2-Channels out noise filter

  • Custom designed and custom wound high efficiency transformers

  • Signal to Noise is over 130dB

  • THD+Noise is less than 0.1%

  • Dimensions (mm): 59(W) x 26(H) x 79(L)

199.99 $

The RCA signal from a head unit is a very low level signal, and it is fairly easy for a noise source like an ECM or other component of the cars electrical system to enter the signal path through the RCA cables. The Ground Loop Isolator has been the "easy" answer since the mid 70's. The good news - the Ground Loop Isolator does indeed work to eliminate the ground loop noise. The bad news - the Ground Loop Isolator destroys the signal by acting as a high-pass filter and eliminating bass frequencies. It also adds multiple layers of distortion to the signal.  Why does the old Ground Loop Isolator damage the signal? Because it was designed ONLY to stop the noise with no thought to signal quality. Zapco introduces the ASP-L2T signal noise eliminator. The ASP-L2T utilizes custom designed and custom wound high efficiency transformers and other high SQ components to remove the direct connection between the different reference ground systems and eliminate noise, without affecting the bass content of the signal and without adding distortion into the signal.

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