DIY Pultec vs Warm Audio I've been debating building a DIY point-to-point Pultec from the RecPro kit at $1,645. Now, Warm Audio just released their Pultec eq for $699. Mar 24, 2016 - I got my start building gear almost two decades back by scouring the internet (a much smaller internet back then) for schematics of classic gear.
The Legendary Pultec 'Passive' Equalizer The DRIP Electronics EQP-1A kit Equalizer We have a microphone client who lives in the high Arctic, way up on Baffin Island in Canada, who bought a Pultec Equalizer Kit from DRIP Electronics. Zoom out on the map below. You will not believe how far north this is!
Our client needed a Pultec type EQ so he bought the kit and the parts and had everything delivered way up there. After surveying everything he realized it would take more time than he actually had because he is 'the' recording studio up there and is very busy. So he contacted us to ask if we could assemble it for him. Sounded like a fun thing to do and we knew it would be an excellent opportunity to find out what this work-horse of the studio really did, so we took on the project. But before we get to the Pultec performance let's talk a bit about 'passive' versus 'active' equalizers. Passive vs Active Electronics For those of you who work in audio but steer clear of the messy details of electronics it is important to start with where these terms come from.
It then will become clearer what a 'passive' EQ is. In electronics the world divides into passive and active parts. Now passive parts don't just sit around like your sister in law, looking pretty. They are not that passive. It's just that they don't consume any electricity on their own. They don't need batteries or power outlets.
![Pultec Equalizer Schematic Diagram Pultec Equalizer Schematic Diagram](/uploads/1/2/5/4/125440849/772511360.jpg)
They are just kind of. Well you know. What they do depends totally on what kind of signal or electricity is fed into them. There are essentially three kinds of basic passive components. Here is what they do:. Resistor:. resists the flow of any electrical current and turns it into heat.
makes sense, no?. Capacitor:. stores up electrical charge. But for our purposes this gives it the ability to block Direct Current (DC) electricity but let an audio signal pass through it.
![Pultec Equalizer Schematic Diagram Pultec Equalizer Schematic Diagram](/uploads/1/2/5/4/125440849/608258680.jpg)
This means it affects low frequency signals differently than high frequency signals. (DC is the lowest freq. 0 Herz). Generally high frequenecies travel through it easier than low frequenecies. AhHa!
Sounds like EQ already!. Inductor (coil):. resists any 'change' in electrical current by turning it into magnetic fields. Steady current flowing through an inductor is boring. Nothing happens. If the current changes, like with an Alternating current (AC), ie.
An audio signal, slow changing currents (low frequencies) travel through it easier than fast changing currents (high frequences). For audio purposes a bit like the opposite of a capacitor So if you were to consider these three things the 'Lego' blocks of passive electronics, you can probably already imagine how you could create something that enhances one part of the audio spectrum while reducing another. Active Electronics Active electronics are components that use a source of electricity and in general they can amplify a signal. Examples of active components are:. Vacuum Tube (Valve in the U.K.