SPL IRON Mastering Compressor

SGD 6,995.00

*Special Order


SPL’s Iron allows sculpting compression at the circuit design level. I could customize this compressor very specifically to produce the perfect style and amount of processing for any job. Iron is a powerful instrument for mastering, mixing or recording, and it’s difficult to get a bad sound on any source, from full stereo mixes to vocals to drums to acoustic guitars. Incredible kit! – Mix


I print the stems one by one back into the same Pro Tools session, going through my SPL Passeq EQ and my SPL Iron Compressor. Every stem goes through that chain.” – Four-times Grammy Award winner David Reitzas


Mastering Tube Compressor/Limiter with 3 Tube Bias Modes, 6 Rectifier Circuits, Sidechain EQ, and 2 Passive EQ Modes


The SPL IRON is a tube compressor aimed at mastering use. Unlike reissues or revised classics, IRON is a refreshingly new product — a unique design born from the mind and experiences of Wolfgang Neumann, mastering engineer and cofounder of SPL. IRON is inspired by the legendary vintage tube compressors à la Fairchild, Collins or Gates and has been developed in a way to give modern productions more energy and power with the advantages of the 120V technology.

Input & Output

Input and output levels are switchable in a control range of +/- 12dB. An increase of the input level leads to more intensive compression. When mastering full scale material, the reduction can be useful. The output is used to adjust the level ratios of input and output.


Side Chain EQs

With the side chain EQs, compression can be focused on frequency ranges. In addition to an inserted EQ, there are four internal EQ presets with a partly complex frequency response.


Attack & Release

The time parameters Attack and Release are switchable in six steps from Slow to Fast. The times vary depending on the rectifier circuit selected.



The tube stage is controlled by a rectifier circuit. There are six diode control characteristics generated by germanium, silicon and LED diodes or combinations thereof.


Variable-Bias Limiter/Compressor

The IRON Mastering Compressor is a variable-bias (variable µ) limiter/compressor from the basic concept. IRON works on the principle of the bias controlled remote cutoff tube. Parallel to this, a medium-variable-bias triode (sharp-cutoff tube) with a steeper characteristic is connected. The tube bias voltage (BIAS) can be adjusted in three steps. The tubes are integrated into special Lundahl manufactured balanced high-level double core mu-metal-iron transformers.


AirBass & Tape Roll-Off

The compressor is followed by a passive filter network with two equalizer presets: AirBass and Tape Roll-off.

The AirBass filter boosts low and high frequencies by about 1.5 dB and the Tape Roll-Off filter emulates the typical frequency response of a tape machine.


All functions can be set via switches and the threshold via a rasterized potentiometer which makes recall easy.

The settings of Threshold, Bias, Attack, Release, Rectifier and Side-Chain-EQs are transferred from the right side (channel 2) to the left side in Link Mode, in which the compressor operates with summed control signals.


Channels 1 and 2 are activated with the large illuminated IDEC switches.

In Auto Bypass mode, the channels are automatically switched on and off, which leads to a more objective assessment.

The Interval control is used to adjust the time window continuously between two and 20 seconds.



* A “Special Order” is a product that we normally do not keep in stock. We order it from the manufacturer as soon as you order from us. We are the exclusive distributor for SPL, so we can get your special order to you fast, in about 1-2 weeks. Remember that special orders are non-cancelable, so make sure the item you are ordering is correct. Call us at +65 63388657 if you need assistance.

*Delays may be expected in the event of high order volumes or unforeseen circumstances.

Contact Us


Tel: +65 6338 8657

Email: sales@sinamex.com


Tel: +60 3 7954 0316

Email: smx@sinamex.com

Myanmar (Burma)

Tel: 09 7997 36933, 09 2562 61519, 09 4430 47478

Email: sinamex.myanmar@gmail.com

Phone Hours

Weekdays: 10.30am – 7pm

Saturday: 10.30am – 3pm


Touch and Experience the Gear

Get hands on with our selection of the best gear available in a controlled, studio-like environment in our showroom. Visit us at our store


Meet With A Passionate Product Specialist

Our sales staff are on hand to answer all of your questions. Whether you’re picking up your next microphone, an audio interface or planning a new studio from the ground up, we can help. Contact us or visit our showroom

Get 0% Interest Financing

Now is the optimal time to get the gear of your dreams with simple interest-free financing. With your POSB, DBS, Standard Chartered or UOB credit card, you can enjoy up to 24 months interest-free payments. Click for more details

Flexible Delivery Options

Get the products you want when you want it. Enjoy flexible delivery options and pick options from our store. Learn More