LaChapell Audio 583E 500-series Tube Mic Preamp with EQ

Boutique-quality, transformerless vacuum-tube preamp with independent EQ for the 500 format

More than just a LaChapell 583s preamp with EQ, the 583e is more than the sum of its parts. The 583e’s preamp and EQ sections can be operated independently or together, which means that one of two rack spaces the LaChapell 583e module takes up in your 500-series lunchbox does more than bring you one of the best-sounding tube preamps in the business. Big, spacious, full of air, the LaChapell 583e preamp also features an ultra-clean, transformerless three-band EQ section with fully sweeping frequency controls and cut/boost. The equalizer section of the 583e can run as an integrated EQ (serving the preamplifier) or separate as its own autonomous module independent of the preamplifier. The LaChapell 583e is like having a LaChapell 583s and Model 503 EQ (with a little something extra) in only two rack spaces.

LaChapell 583e unique features:

• EQ section can operate independently of preamp
• Center-chassis mounted tube prevents heat transfer to other 500 modules in power rack
• Swappable tubes for sonic variation

LaChapell 583e key features:

• True vacuum tube amplifier
• Fully variable input/output control
• Robust construction
• Transformerless Hi-Z input
• Premium components
• 80% nickel output transformer
• Clean, attractive layout

INSIDE THE BOX — LaChapell 583e

The Model 583e features the same amplifier stage found on the LaChapell 583s, including the Jensen JT-115k input transformer coupled with an ultra-clean transformerless three-band EQ section with fully sweeping frequency controls and cut/boost settings of +/- 8dB. The EQ can run as an integrated equalizer serving the preamplifier or separate as its own autonomous module where both units run independently.

Based on LaChapell’s popular 992EG, the 583e is quickly becoming the next must-have preamp for those looking to add that extra warmth and character to their lunchbox collection found only within the thermionic realm. Scott LaChapell’s initial design approach was simple: identify and extract the key design elements of the 992EG that directly contributes to its’ sound signature, and then inject that into the 583e.

The LaChapell 583e module features single-ended vacuum tube preamplifiers designed for use in the “500 series” format. The microphone input configuration is based on the 992EG and consists of an input transformer with a turns-ratio of 1:10 and one ECC83/12AX7 vacuum tube. The instrument input stage is transformerless with the signal essentially going straight to the grid of the tube. The output stage utilizes premium Burr-Brown and THAT Corporation line drivers along with an 80% nickel alloy core transformer to generate a balanced line-level output signal. The Model 583e features an ultra-clean transformerless three-band EQ section with fully sweeping frequency controls and cut/boost settings of +/- 8dB. The EQ can run as an integrated EQ (serving the preamplifier) or separate as its own autonomous module apart from the preamplifier.

Another exciting feature on the 583s is easy tube access; allowing you the ability to experiment with vintage premium tubes! The stock tube for the 583e is the JJ ECC803; a great tube with loads of character. But, you might find yourself preferring a vintage Telefunken ECC83 for female vocals or, a 1960’s RCA 12AX7 black plate for acoustic guitar. The point here is to allow you every possible avenue to refine and tailor your signal to be the best for whatever you may be tracking. No other 500 series preamp allows this level of sonic flexibility.*

The 583e is also built to be a “good neighbor” to your other 500 series modules. The 583e dissipates roughly 3 watts, not enough to generate heat that would cause any worry, now or in the future. The tube itself is intentionally located in the center of the chassis with generous vent holes in the PCB, There is also a large cut-out on top of the chassis allowing additional ventilation (and access to swap out or play with different tubes). Also, the API Lunchbox™ itself has sufficient top ventilation.

The tube in the 583e generates roughly the same amount of heat as any tube microphone would. The 583 benefits in cooling over tube mics due to its larger housing, versus a slender tubular body. The point here is that if you're not concerned about your mic over-heating, don't worry about the 583 over-heating either.

With the exception of the tube access opening, the 583e preamp/EQ has an enclosed chassis, which helps direct cooling and prevents any unwanted interference. In operation, the user has individual control over the input and output gain stages via fully variable potentiometers. This, like its 992 older brother, provides total flexibility to explore the 583e’s broad sonic pallet. Additional functions include four illuminated NKK toggle switches for 48V, 20db input pad, polarity reverse, and input select.

* Note: The 583’s standard tube is the JJ ECC803. However, there are many different ECC83/12AX7 variants that are virtually identical and can be used in either 583 modules. These include: ECC803, E83CC, CV4004, 6057, M8137, C492, 7025 and the 5751 (you will notice a slight drop in gain when using the 5751).

OUTSIDE THE BOX — LaChapell 583e

• Input: Drives more or less current into the tube stage
• Output: Drives more or less current into the cleaner output stage
• 48V: Supplies 48 volts of DC current for condenser microphones
• Pad: Reduces microphone input signal by 20dB
• Polarity: Reverses the polarity of the output signal
• Input: Activates Hi-Z or microphone input jacks
• High: Frequency sweep range: 2.5kHz to 20kHz
• Mid: Frequency sweep range: 325Hz to 5kHz
• Low: Frequency sweep range: 30Hz to 400Hz. Each frequency band has a cut/boost potential of ±8dB
• PRE + EQ: In this mode, the EQ section is internally routed to serve the preamp’s output signal; effected signal is sent out the left bay output jack
• Independent EQ: In this mode, the EQ section is available as a completely independent module. The corresponding rear right side connections are now active allowing you to use the EQ on any external souse while the preamp remains available on the left bay

About LaChapell

Scott LaChapell manufactures a purposely limited range of handcrafted products, such that each model will fit your recording studio like a fine leather glove. LaChapell has designed a line of mic preamps that will give your recording the rich sonic characteristics that can only be coaxed out of a tube circuit. These all-tube designs feature a gain structure that allow you to obtain a sound ranging from pristine and transparent to warm vintage, with just a twist of an input and output knob. What makes the LaChapell tone so unique and musical (from a technical and philosophical point of view)?

Aside from the obligatory obsession that you will find from most "boutique" builders when it comes to component selection, you will undoubtedly appreciate the fact that you can also request a Telefunken or Amprex tube as a way to get even more flexibility from his products.

Add to that what is probably the coolest lighted LED toggle switches that you can find on any piece of outboard equipment and of interesting note, LaChapell rack mount gear uses hand-wound transformers to create a power supply that has a true 250V DC rail, which provides the best possible performance from tube circuits.

If you’re ready for the kind of mojo that can only come from thermionic devices, put a LaChapell 583e in your 500-series lunchbox. For more information, call or chat with an RSPE representative today.

Don’t forget to check out RSPE’s Rack Revolution, a virtual 500-series rack builder that lets you custom-configure the perfect 500-series lunchbox for your studio, DAW, or mobile recording rig. RSPE carries every 500-series module imaginable, including mic preamps, compressor-limiters, equalizers, and 500 power racks.