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Olympic MkIIIS Support Page

Shift Line Olympic MkIIIS is a tube bass preamplifier with a built-in cabinet simulator based on the Impulse Response Convolution technology.

This page contains extra info on the device's operation:

Standard mode

The device can utilize both stock and third-party impulses in WAV format. All the needed folders are automatically generated on the microSD card upon initial use (those folders are SD:\SL_IR\A\ and SD:\SL_IR\B\). In order to replace an impulse, simply delete the old one from one of the folders and place the new file into the same folder. For instance, to replace impulse A, go to SD:\SL_IR\A\ and replace Sunn_200s.WAV with an impulse file of your choice (required format: 24bit 48kHZ WAVE PCM1, uncompressed). Next, insert the microSD card into the Olympic MkIIIS and set the CAB switch to A in order to hear the new impulse. When no microSD card is inserted, the Olympic MkIIIS uses built-in impulses. This way, you can extend your impulse pool to four or pair a stock impulse with a third-party one on the microSD card.

In this mode, the Olympic MkIIIS will apply the built-in neutral power amp simulation to any impulses you upload.

Advanced mode

To simulate a different power amp, use the patch generator or create your own patch in SigmaStudio. Then, create an SL_HEX folder in the root directory of your microSD card. In the SL_HEX folder, create folders A and B (corresponding with the CAB switch positions on the device). Place the HEX file into any of the two folders (for example, SD:\SL_HEX\A\drive.hex). Each of the two folders can contain one HEX file. Make sure to observe folder hierarchy. Note that each HEX file's name should only consist of numbers and Latin letters.

If the microSD card has an SL_HEX folder in its root, the device will ignore the SL_IR folder and use alternative patches instead of impulses. The original firmware and impulses are still available for use: just eject the microSD card from the device.

You can download an archive with correct folder hierarchy below and extract it to a blank microSD card. The archive contains two power amp simulations with the stock cabintet impulses: SUNN 200s (2х15) and AMPEG SVT-810E (8х10). After that, you can simply replace the patch files with your own.
You can also download the archive containing all power amp simulations created for the Olympic MkIIIS so far.
WARNING: HEX files created for the CabZone LE/CabZone X will NOT function properly with the Twin MkIIIS/Olympic MkIIIS because of level mismatch. We strongly advise against using CabZone LE/X patches in our preamps.

The same patches can be used both in the Twin MkIIIS and in the Olympic MkIIIS. Either device can utilize guitar and bass cabinet impulses.

Online patch generator for Olympic MkIIIS

The Olympic MkIIIS has only one power amp simulator (neutral) in stock. In most cases, it is enough — but you can also simulate other power amps if you wish. To do that, you need to create a user program (patch) containing the cabinet impulse and the power amp impulse of your choice (this can be done with our online HEX file generator). Once the patches have been uploaded to the device, the CAB switch will select between "power amp + cabinet" combos, which means you can create a pair of presets tailored to your needs.

This tool allows you to create a HEX file, which is an alternative control program / patch for use with the Olympic MkIIIS's digital cabinet simulator.

To create and download a HEX file containing a "power amp + cabinet" combination, follow 3 simple steps:
  1. Select an impulse from the list:
    or upload your own: (wav pcm, mono, 24 bit, 48 kHz, uncompressed):
  2. Select power amp:
    Select power amp set:

Power amp models

The patch generator currently offers 10 power amp emulations which can be split into pairs, each pair containing classic and alternative settings of a power amp type.
Power amps that introduce no harmonic distortion:
  • Neutral Bass. As clean and loud as possible, this neutral power amp has a characteristic roll-off at the edges of the frequency range (-1dB in the lows and highs) which stems from design limitations of the output transformer. The frequency range is interpreted in a way that the signal feels closer and more saturated but doesn't sound compressed. This power amp is practically impossible to overload with input volume. It's a great choice if you want a perfectly clean sound. This power amp is NOT a direct copy of the stock neutral power amp emulation.

  • Deep Bass. A loud and clear power amp with characteristic correction in the lows and highs. The slight boosts at 55Hz and 10kHz suit modern musical styles very well. The "defined" edges of the frequency range help the bass to cut through the mix. The frequency range is interpreted in a manner similar to Neutral Bass; just like the latter, the Deep Bass power amp is almost impossible to overload with input volume.
Power amps with minimal 6L6 tube saturation:
  • 6L6 Bass. A classic American power amp which has given birth to a whole variety of modern solutions. This virtual push-pull (Class AB) amp is based on 6L6 tubes and has been adapted to bass duties. It's almost as straightforward throughout the whole frequency range as the Neutral Bass model, but it does show its own character. It doesn't remain perfectly clean at all volumes, but this "flaw" is what makes it a key element in the bass signal chain. The signal gets saturated with even and odd harmonics in the low end; the lows also have a very slight boost around 100Hz. There's a mild roll-off at 20Hz and 18kHz. This power amp makes even quiet sounds very nuanced, which is something we tried to capture in the emulation. This preset is recommended if you want to round out your sound without introducing considerable distortion.

  • 6L6 Deep Bass. This model has the same 6L6-based virtual push-pull amp specs as the 6L6 Bass; the difference lies in frequency correction. The mild boosts at 40Hz and 15kHz make the sound "wider" and highlight the edges of the frequency range. This power amp doesn't remain perfectly clean at all volumes: the incoming signal is saturated by even and odd harmonics both in the low end and in the high end. The dynamic curve is similar to that in the 6L6 Bass model.
Power amps with 6550/KT88 tube simulation:
  • 6550 Bass. This model is an emulation of power amps that based on large beam tetrodes and has a characteristically sharp low-frequency response. 6550 tubes have found their home both in guitar amps and in Hi-Fi equipment; in our case, they aren't about crystal-clear sound but rather about the thunderous swings of a sledgehammer! This power amp has soft clipping with harmonic distortion in the lows and low mids, resulting in a compressed dynamic range. The highs are open and clear, while the lows are slightly boosted around 40Hz. This power amp model is perhaps the most universally applicable one in the pack.

  • KT88 Bass. The British take on power amps, built on KT88 beam tetrodes (similar to 6550 tubes). The tight bass, harmonically saturated low mids and mild highs result in a very neat sound character. With no highlighted string clanging, this model works best for classic rock. The harmonic saturation is subtle yet quite noticeable. The dynamic range is less compressed than in 6550 Bass. This model also has a substantial roll-off in the ultra-lows along with a boost around 100Hz.
Power amps with EL34 tube simulation:
  • EL34 Bass M. The British influence continues — this time, with an EL34 tube push-pull amp based on the same principles as its guitar counterpart. This model has a bass boost around 80Hz and a rather steep cut below 40Hz (this eliminates excess subharmonics and makes the core frequency range cut through the mix better). Harmonic saturation is rather noticeable across the whole spectrum, with pronounced distortion in the mids. At the same time, the dynamic range isn't distorted too far, so the power amp has an excellent dynamic response. The larger the input signal amplitude is, the more distortion you hear. This virtual British amp works great for classic rock: just push it with preamp gain or put a +4-6dB boost into the loop.

  • EL34 Bass O. One more British bass amp option which is also based on EL34 tubes. This version boasts more "open" lows (without the ultra-low roll-off) with a boost around 60Hz; there's also a mild cut in the highs. This virtual power amp has a sharper dynamic curve and introduces way more compression into the signal. Unlike the previous model on this list, EL34 Bass O is better suited for aggressive genres calling for heavy distortion. Harmonic saturation happens across the whole frequency range and is particularly prominent in the low mids. This power amp has a great response to increased gain both in the preamp and in the loop.
Power amps with significant harmonic distortion:
  • KT66 Bass Overloaded. This version of a virtual KT66-based power amp pushes it to the limit. Imagine a tube bass monster with its master volume set to the max, and you'll get the idea. This model introduces compression at strong attack along with a gradual increase in even harmonic towards the low end. The emulation is set to medium damping which results in more "air" in the lows. The higher the volume is set, the more compressed and distorted the output signal becomes. This model feels at home in heavy styles and at high gain settings. It also works great with fuzz pedals. The frequency curve is slightly biased towards the low end.

  • 6550 Bass Overloaded. Unlike the 6550 Bass model, this one simulates a monster amp with four tubes of this type which are pushed to the limit and beyond. This results in rather peculiar features, such as growling low mids and aggressive highs. Throw in a classic Rat, and you can play doom metal while wearing headphones with no fear of having your ears bleed. This might be the least widespread power amp model in the selection, but we just couldn't leave it out. Unlike the one featured in the Twin MkIIIS patch generator, this one has a more pronounced low end and a slightly different gain structure that works better for bass.

Additional info

  • The digital cabinet simulator used in the Twin MkIIIS is based on DSP ADAU1701 (input: ADC0, output: DAC0).
  • The built-in DSP chip sees the microcontroller as a ROM chip in selfboot mode.
  • SigmaStudio is the official programming environment for the DSP chip. SigmaStudio allows to download ROM files in HEX format for use in selfboot mode. This can be used to create custom patches. Create a program, compile it, give the resulting HEX file a name in Latin letters and place it into either folder on your microSD card (for instance, SD:/SL_HEX/A/olympic_patch.hex).
  • The FIR block in SigmaStudio accepts mathematical impulse factors. To turn a WAV impulse into a list of factors, you can use the WAV2FIR online tool.

User guide

Impulse packs

We have released several impulse packs for guitar and bass, and we are going to keep adding more packs in the future. You can either use those impulses in our devices directly or generate complex patches with them.