01 November 2012

Home Studio: SPL Track One MKI pre amp


Note: this entry was already published during August 2009, in my old Spanish version of this blog. I am just revisiting it here, with added information.

After visiting for some time the studio of a friend of mine, I've realized about the difference that makes a good pre-amp for recording stuff (and, if you already read my article "The Cost of Cup of Tone", you will easily understand why).

Possibly, I could obtain acceptable results for my mixes using some quality plugins but, I will never get good mixes if the recording hasn't quality.
Once more, I am just a guitarist, not an audio engineer in the search of mythical outboard gear. I've just needed some acceptable pre-amp, versatile enough to be used with vocals, bass guitars and, eventually, acoustic guitars.

After searching and filtering information in Internet, I've decided to go for the SPL Track One, that seemed to suit my needs whitin my limited budget. And, I've ordered one.


The Track One comes in a 1U rack format and, seems well made and, with quality components.
More than just a pre-amp, is a Channel-strip, with 5 differentiated sections.
In the front panel, we can see the following sections:

  • Pre-amp
  • De-Esser
  • Compressor/Limiter
  • Equalizer
  • Output & Metering
Of those, the only two sections that are always working are the pre-amp and the Output & Metering sections. Rest of sections are switchable on or off.

Pre amp section

The pre-amp section has:

  • Microphone Gain Knob
  • Line/Instrument push/push switch
  • 48V push/push switch
  • 90Hz cut-off push/push switch
The Rear panel has two different inputs, one balanced XLR input for Microphone levels and, one more unbalanced TS input for Line/Instrument levels and, a push/push switch to select which input do you want to use if the Mic or the Line/Instrument one.
If you choose Mic then, the frontal switch Line/Instrument makes nothing.
If you choose Line/Instrument then, you can decide if that unbalanced input comes with Line or Instrument levels, in order to adapt the gain of the preamp to the right signal level and impedances.

For Mic input (XLR), we can decide to switch on the 48V switch, that will feed a mic needing phantom-power.

Finally, the cut-off filter can be used with any input and, will give a good roll out of frequencies below 90 Hz (as typically seen in lots of mixing board pre amps).

De-Esser section

SPL pre amps are famous for having one of the most efficient hardware de-essers.
This section has just an S-Reduction knob, that allows you to select the amount of reduction for that narrow band where the "S" sound happens and, an On switch to switch the effect on or off.

Compressor / Limiter section

This dynamics processor can be used as a compressor or a limiter but, not both at same time.
The Compression knob allows you to fix the compression ratio, while the Make-up knob allows you to increase the average level of the sound before compressing it.
The switch Limit changes the behaviour to Compression or Limiter and, the switch On allows you to switch the processor on or off.

Equalizer section

Allows you to work in three separate bands, Lows, Mids and Air.
For Low Band and Mid-Hi Band, there are two knobs. The first one allows you to choose the center band where the equalization takes place (from 33 Hz to 720 Hz in Low Band and from 740 Hz to 15 KHz in Mid-Hi Band) and, the second knob allows you to cut or boost the EQ around this center band (in up to 14 dB plus or minus).
The Air Band is over 15 Hz and, has a single control, the dB for that cut  or boost.
The switch On, allows to switch the equalization on or off.

Output & Metering section

A single knob gives you control over the output in decibels and, two meters report you about what's happening inside the unit. The PPM Output turns to red when the output it is being saturated and producing overs. But, this same meter is used to show the "S" level detection if the de-esser section is on.
The Lower Meter gives you the information about the gain reduction, for Compressor, or Limiter or De-Esser.

Rear Panel

Together with the two inputs already mentioned above, it has two balanced TRS outputs (at Line level), 1 TRS jack for linking this unit to one more Compressor (in Master or Slave modes), and an additional input 2.

Using it

I've compared recording in three different ways: inputs direct to Rack-003 pre-amp, inputs thru a DI box, as the Radial J48 and, inputs thru the pre amp of SPL Track One (an article to come in a future, already published in my old Spanish blog, has some sound bits to compare results).
Clearly, the results achieved with the Track One are better than with the other two methods, even that you cannot expect same quality level as you will find using a high quality (and expensive) pre-amp, as seen in Studios. But results are good enough and, the pre amp is versatile enough to handle any kind of sound source.

I thought that the output level of this unit should be Studio level (+4dBu) but, after trying several things, I've found that the output is delivered at Line levels (-10dB). This information isn't included in the user's manual.
So, I had to change the input (without pre-amp!) in Rack 003, from one at +4dBu to other at -10dB.
This made the unit to work with a clear and loud sound.
(One article to come in a future, already published in my old Spanish blog, will talk about how I've routed my Home Studio gear).

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