API pioneered the 500 series modular signal processing, and through the VPR Alliance, has established chassis and power standards to encourage other pro audio manufacturers to build their own 500 series modules. Sonic Circus carries a selection of the best 500 series modules from API, A- Designs, Purple, Chandler, Empirical Labs, and many more. We also carry alternative modular systems from SSL, Rupert Neve, and Audient. Each of these systems combine compact size with awesome signal processing power. Maybe its time for you to go modular.

		Featured 500 Series   Get a great deal on our featured 500-series Modules. We recommend these as the best of the 500s. API Lunchbox 500 6B Rack A classic tool for the itinerant engineer who wants to easily tote his/her favorite API modules (or any other of the scores of compatible third party modules) to different studios. The Lunchbox provides regular and phantom power as well as XLR in and out jacks. Load it up with mic pres, EQ's, compressors, or any combination and you're good to go. Price: $424.15 Skibbe Electronics 736-5 500 Series Mic Preamp Adapted From Sly Stone's 70's Flickinger Console THE SKIBBE ELECTRONICS 736-5 500 series microphone preamplifier has been adapted from the preamp in Sly Stone’s custom Flickinger MOD-N-32 matrix console (circa 1970). Great care has been taken in creating this module to keep the original tone intact. Only the highest quality components are used, for a superior build quality in the 500 series format. Price: $749.00 Moog Analog Delay Module 500 Series Analog Delay Module The Moog Analog Delay is the world’s first delay designed exclusively for the 500 series format. It is a MIDI syncable module that features a 100% analog signal path, front panel MIDI, and an assignable Tap Tempo/CV jack. Included with each unit is a free VST/AU/RTAS editor for easy implementation into any recording, live, and performance situation. Price: $899.00 API 550A Production Model Classic Discrete 3 Band EQ for the 500-Series Rack API made a lot of friends when they reissued the stalwart 550A EQ module a few years ago. Original specimens were going for crazy money and of course didn't always work. Fifteen points of astoundingly musical equalization housed in a compact yet wonderfully ergonomic module, the 550A works with all 500-series powered racks. Price: $1,015.75 API 550B Discrete 4 Band EQ for the 500-Series Rack The 550B takes API's legendary 550A equalizer module and kicks it up a notch, adding an extra filter plus several additional frequencies to the proceedings. The singular 550 sound has been a part of countless hit recordings since the 60's. Works with all 500-series powered racks. Price: $1,100.75 API 560 Discrete 10 Band Graphic EQ for the 500-Series Rack One of our favorite graphic equalizers out there, the 560 is a compact vertically mounted (surprise!) module that is amazingly intuitive and ergonomic. Works with all 500-series powered racks. Price: $803.25 API 512C Discrete Mono Mic Preamp & DI for the 500-Series Rack One of the most famous mic preamps around, the 512C uses the sought-after 2520 op-amp, which yields 65 dB of distinctive, clean/creamy gain. Based on the original API 512 mic pre, the modernized 512C has an astounding amount of headroom, making it one of our favorite preamps for use with ribbon microphones. Works with all 500-series powered racks. Price: $803.25 API 527 Discrete Mono Compressor with Thrust Circuit and 10 Segment LED Meter - for the 500 Series Rack The API 527 Compressor is a single channel 500 Series module based on API's 225L discrete channel compressor - incorporated with ''Thrust'' circuit! Price: $930.75 SSL 611DYN 500 Dynamics Module E-Series 500 Format Dynamics Module The new E Series Dynamics Module for 500 Series racks reproduces the legendary sonic signature of an early 80's classic, the SL 4000 E console channel strip, which was featured on countless 1980's recordings. The E Series Dynamics Module features a compressor/limiter and an expander/gate, both of which return faithfully to the circuitry and key components which define the sound of the original SL 611E Series channel strip. A true RMS converter is used in the side chain while the gain element is an all discrete design identical to the Class A VCA chip used in the original unit. The compressor contains additional switching options to defeat the over-easy curve and to use a linear release instead of the more usual logarithmic curve. The result is a compressor with three distinct voices, each with its own musical character. Price: $889.00 SSL 611EQ 500 EQ E-Series 500 Format EQ Module The E-Series EQ Module for 500 Series racks reproduces the legendary sonic signature of an early 80's classic, the Solid State Logic SL 4000 E console channel strip, which has featured on countless classic recordings from the 1980's to the present. The E-Series EQ Module features two different EQ's found on editions of the console produced between 1981 and 1989. Each EQ has unique response curves and tonal character. Historically the type of EQ fitted in an individual console was distinguished by the colors used on the LF knob caps so the two flavors have become known as the 'Brown' and 'Black' EQ's. On the E Series EQ Module you can switch between these two different flavors of EQ that have been loved by generations of professional producers. Price: $889.00 Avedis MA5 - Red Knob 500 Series Class A Mic Pre The MA5 was created to fill the need for a high-quality microphone preamplifier with the characteristic sound of early ‘70s British Class-A consoles. The re-engineering in the creation of the MA5 stemmed from years of experience restoring both American and British modules, deeply rooted in classic transformer-balanced, discrete electronics. Only the best and most suitable components are used throughout, regardless of cost, to attain the best sound. Price: $775.00 BAE 312A Module - Black Single Channel Discrete Mic Preamp & DI Module, Based on the Classic API 312 Design - for the 500 Series Format Modeled after API's signature preamp, the 312A features the Avedis 1122 opamp and Jensen input/output transformers; all at an affordable price.  Their punch and clarity make them a favorite for drums and percussion. Price: $790.00 Elysia Xpressor 500 500 Series Compressor The Xpressor 500 is an extremely versatile stereo compressor available in API's 500 series format. With its many unique features taken from our flagship products, you not only get great compression, but an amount of control on processing which is hardly ever experienced elsewhere. Price: $975.00 Elysia Nvelope 500 500 Sereis Compressor Module The nvelope 500 is a powerful audio processor capable of making subtle or drastic changes to a sound by providing control over its attack and sustain characteristics. This is extremely useful for reshaping all sorts of individual tones, and is a wonderful tool in any mixing situation as well. Price: $975.00 Pendulum Audio OCL-500 Class-A Electro-Optical Transformerless Compressor / Limiter, for the 500-Series Rack Brace Yourself for the Highly Anticipated Pendulum Audio OCL-500 - Based on the Classic OCL-2! Price: $1,250.00 Burl B1D Mono Class-A Discrete Microphone PreAmp / DI with Custom Transformers, for the 500-Series Format Introducing the B1 and B1D Microphone Pre Amps from Burl Audio.  Based on the API 500 series form factor, the B1 was designed to complement the B2 Bomber ADC, and give you multi-channel pleasure. With the proprietary BX3 input transformer and BX2 output transformer, the B1 Mic Pre delivers warmth with depth and clarity.  The B1D is the same as the B1 except that it has an all iron BX4 output transformer giving it a more terrifying rock tone. An all discrete transistor, class-A, direct coupled, capacitor free circuit path, gives the B1amazing punch on drums, beautiful tonality on guitars, and warmth with presence on vocals. Price: $775.00 A-Designs P-1 Discrete Mono Mic Preamp & DI Module with Custom-wound Transformers, Phantom Power, 20dB Pad, and Phase Button for the 500-Series Rack The P-1, loosely based on the classic Quad-Eight mic-pre, is the highest fidelity preamp of the A-Designs 500 range. Using the proprietary custom transformers, the P-1 provides 65db of clean gain, and a unique DI circuit. The fast transients make it great for percussion, piano, and acoustic instruments. Sonically, the P-I is big, broad, detailed and open. Or as we like to say, it sounds like a record. Price: $795.00 Purple Audio PANTS A four opamp, single channel diferential mic preamp with DI - Designed to work in standard 500 series racks. Price: $725.00 Rupert Neve Designs Portico 543 500-Series Mono Compressor-Limiter The Portico 543 Mono Compressor delivers the unobtrusive, musical-sounding dynamic control and brick-wall limiting made famous in the Portico 5043 to the 500 series format. The 543 features a fully controllable compressor-limiter with feed-forward / feedback modes, Peak / RMS detection and a built in side chain high pass filter. With an unrivaled heritage and a tremendous feature set, the 543 yields a combination of rich warmth, flexibility and precision that is sure to resonate in the ears of sound engineers the world over. Price: $995.00 Rupert Neve Designs Portico 517 500 Series DI/Pre/Comp with Variphase Specifications Based on the Portico 5017 Mobile Pre, the 517 provides world class, transformer-coupled preamp, compressor and DI circuitry, with Vari-phase, Silk and DI/mic blending capabilities in a 500 series model. As the first 500 series module designed by Mr. Rupert Neve, the 517 incorporates outstanding sonic quality with an indispensable feature set. Price: $795.00