PEQ-503 Equalizer

The VPR Alliance is a program of standardization and consistency guidelines set by API Audio for manufacturers, to make our products physically fit and electronically conform to API's 500 series rack specifications. Customers benefit from the VPR Alliance through the elimination of any confusion as to which products are endorsed for placement in API racks. Customers also benefit from a wider range of module choices for their racks, safety in the knowledge that the specification of the third party unit is correct, and that there is no risk of damage occurring.

FiveFish Audio is a member of the API VPR Alliance.

PEQ-503 Equalizer

PEQ-503 Equalizer

PEQ-503 Equalizer

PEQ-503 Equalizer

The FiveFish Audio PEQ-503 is a beautiful, high-quality, single-channel three (3) band Inductor-based equalizer, designed for the popular API VPR500 Rack format.

Each frequency band has two (2) selectable frequencies, and a bypass switch. It also has an overall EQ In/Bypass switch to let you easily make before & after sound comparisons.

The equalizer's smooth broad curves makes tonal adjustments easy and fast. You can go from small, subtle changes to extreme carving or boosting, up to +/- 18dB per band. The SUB and AIR frequency bands can give your tracks the chest-thumping punch you want, and that extra sparkle at the top end without sounding harsh. The mid frequencies band takes care of adding that extra presence to your tracks to make it pop.

  • 3-Band EQ - Inductor Based EQ
  • Two Frequency Selection switch per band + independent flat/bypass position
  • 12K/AIR HF control +/- 18dB gain
  • 1.1K/3.2K MF control +/- 18dB gain
  • SUB/120Hz LF control +/- 18dB gain
  • EQ On/Bypass switch
  • Relay-controlled Bypass
  • Electronically Balanced Inputs using inGenius Technology
  • Electronically Balanced Outputs using OutSmarts Technology
  • Output Tranformer option
  • Discrete OpAmp option, or PDIP chip
  • Using Carnhill/UK VTB inductors for LF and MF control
  • WIMA caps for EQ filters
  • 1% metal resistors
  • Bourns Potentiometers
  • Solid Machined Aluminum Knobs
  • CNC-milled/engraved/paint-filled front panel
  • Double-sided, plated through PCBs
  • Low Noise Equalizer
  • Jumper settings for experimentation, changing the EQ filter frequencies

I recently purchased your peq503 pre. First I wanted to thank you for getting it to me quickly so I could use it for a big session I had, and also wanted to say that thing rocks! Used it mainly for electric guitar and vocals. Totally kills. Thanks! - Mike B, USA

I got the PEQ-503's yesterday and played around with them last night. I am really thrilled with the sound quality of these things! I ended up switching the jumpers to the 60/180hz, 350/1k positions. It is going to work really well as a mix-sweetener on the project I am working on. Thanks for the great work! - Rob O., USA

My first impression of the PEQ-503s (with DOA and Xformer) is that they are very well built. Pro. The EQs do impart a slight coloration, in a good way. The low end is beefy and the air band is very nice. I'm using them for subtle boosting on the main stereo bus. The air band is best I've heard so far in my travels! - posted on Gearslutz

Got my pair up and running (PEQ-503 EQ), they are smooth. I have a bunch of Langevin EQ's but really like the ability to dial in certain EQ ranges with the (PEQ-503). Nicer airy top too! Great Job! - post on, USA

The EQ's are wonderful. Really digging them and I have a few passive EQ's here. Now to fill those two empty slots...hmmm - Richard B, USA

The PEQ-503 arrived safely and I gave them a test. They're excellent! Using them is like "changing the sound of the mic itself" and less "like using an EQ", that's how natural/unobtrusive they sound and work. Also when I compare the sound of the signal chain with and without the EQ (hard bypass with the XLR cables), I notice it sounds subtly different in a nice way with the EQ in the path (even with the "bypass" switch engaged). The default frequency selections are a good choice although for electric guitar I may shift the lows up a notch with the jumpers; it's nice to have that option. - James Peters,, Canada

The EQ is really good! I really do not have that many external eq's but some and this one is really getting warm in the studio. I used it on about 15 tracks for my last mix and I am really happy with the result! - Dennis B, Sweden

The hi end boost is gorgeous, the air does exactly what it says, giving a smooth top end boost without getting harsh. The 12k setting gives much more detail while still sounding smooth.

I changed the mid band to 1k up, 320hz down and it really fits my needs. The 1k is quiet narrow q; perfect for cutting out a bit of boxiness when tracking a kit. The 320hz is much broader, great for cutting some mud from a mix or adding some depth to an instrument.

The lo end is huge! This is what I was hoping for, some clean, fat lo end, which is rare of eqs of this price IMO. The 2 frequencies sound quite close together, even tho it should be 120, 35. I may experiment with these, but the boost/ cut is very broad and can be as subtle or extreme as you dare!

I've also been playing with mine (PEQ-503) for some hours on a mix session. I'm very impressed. I like both PEQ-503 a lot. The low frequencies are just beautiful. Smooth even when adding quite a few db = massive. I am pretty sure this will be a to go EQ for bass from now on. - Dennis B., Sweden

Read more FiveFish reviews!

Just a quick demo of our PEQ-503 3-band EQ using a short audio clip a customer sent. He wants to hear how it will process his clip. Some intentional clipping when we boosted the low frequencies to max. +18dB. The video audio and facebook's video compression doesn't do justice to this.

Jumper Settings

PEQ-503 Equalizer

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Audio Demo

PEQ-503 Equalizer
Just a quick demo of our PEQ-503 3-band EQ using a short audio clip a customer sent. He wants to hear how it will process his clip. Some intentional clipping when we boosted the low frequencies to max. +18dB. The video audio and facebook's video compression doesn't do justice to this.