VARIS is our very well known (this is its fourth incarnation, “blueface”) compressor with automatic gain control. This type of compressors is also known as variable Mµ. However we expanded the traditional circuit with our own designs, which made the VARIS an original unit in its own right since no other compressor on the market offers triode and pentode modes in tube stage  that is directly responsible for compression. Aside from the original sound signature triode and pentode modes offer different compression curves. You can see these differences on the meters, which have not one but two scales – one for each mode (Tr/Pt). The triode scale (Tr) exhibits a wider step from 0dB to 1dB. However after the 1dB mark the step gets narrower, i.e. the ratio of compression increases. On the other hand the pentode mode (Pt) shows a somewhat narrow step at the beginning of the scale (compared to the Tr mode) but starting approximately with the middle of the scale the step becomes wider. Different compression curves allow for interesting and unique results during both tracking and mastering. Also it needs to be mentioned that part of the reason why VARIS’ sound is unique is because it is not using  traditional types of tubes with no precedents as for variable gain compressor. (Actually all of our designs traditionally use tubes virtually never seen elsewhere in the industry).                                                                           Another original and unusual implementation for compressors of this type is the side chain, which can be run in two modes: FeedForward or FeedBack* (FF/FB). FeedBack mode is a more traditional design for this type of compressors. The side chain (SC) is hooked up to the compressor’s output and detects the signal that has already passed through the compression stage (which is being controlled by the side chain). Thus such system self-adjusts and displays the limiter characteristics with the ratio of up to 1:5. In turn in the FeedForward mode the side chain is hooked up to the compressor’s input and detects the signal before the compression stage. Thus it displays the compressor characteristics with the higher ratio of up to 1:20.              Any of the tube modes (Tr or Pt) can be used with any of the side chain modes (FF or FB). This allows for completely different compressor behaviors/signatures in a single compressor which can be applied to  various sources with any combinations of the channel settings in the dual mono mode.                                                                                Overall VARIS displays fairly transparent sound with high headroom and overload capacitance at a low THD @ reduction 3-5dB.

The controls are: Level knob – controls the signal level post-compression. It does not affect the compression and allows to control the output stage drive level, Threshold knob – sets the side chain threshold, Attack/Release knobs – set the timing, x2 multiplier switch – increases the timing settings by 2, Tr/Pt mode switch – sets the compression stage mode to triode or pentode respectively, Full Range/150Hz/75Hz switch – enables the high pass filter, which alters the side chain mode to compress less at the given frequencies, Zero Adj.trimmer – adjusts the meter hand position (on the right of the meter when there is no signal), FeedBack/FeedForward switch – sets the side chain mode, In/Bypass – cold bypass, Stereo Link – links the side chains of both channels for a stereo mode. The Left channel takes control over the stereo mode (except for the Level knob, which must be adjusted separately on each channel). New incarnation got calibration controls (Tr/Pt) for  each  triode/pentode modes, with 10-turn pots, for exact pre-session L/R matching.

The VARIS is enclosed in a massive 1.6 mm steel chassis with a 6 mm thick faceplate.

All audio chains are built with high-quality thick non-shield wire.  The high quality and miltary grade passive components are used throughout.

Also, new incarnation got  improved powerful output stage with big octal tube, what positively affected the bass articulation and transients dynamics.

All rotary controls are multi-pattern stepped switches. Level and Threshold have 24 steps. Attack and Release have 11 steps.

The device input is outfitted with specially designed, and output with powerful (10WA) custom wound transformers (with a Hi-Mu core made of rare material), and which can be subjected to any active load with no harm to the sound or matching with other devices.

The signal path is pure tube.  The entire signal path is executed as point-to-point design between tube pins and solder lugs, with no PCB’s in the tube signal chain. To eliminate ground loop hum the device  assembly is completed with consideration for the topology of the given circuits. All tube sockets are exclusively military grade (ceramic, of course), specifically the avionics version – the highest heavy duty there is. There are no electrolytic capacitors - only high quality film capacitors. Electrolytic capacitors are only used in the power chains.

In order to minimize power net noise and hum the compressor  power circuit uses a stabilized DC voltage for plate and filament.

As a power transformer the VARIS uses either a conventional laminated toroidal transformer.

The rear panel houses balanced XLR Inputs and Outputs (or dualoutputs how extraoption), goldpinned, SC Insert TRS connectors, SC sensitivity switches, Ground/Lift switches connects/disconnects the ground pin 1 of the output connectors with the internal signal ground whenever necessary), IEC power socket, fuse. 

Discussing for VARIS on Gearslutz >>


Input level,balanced


Output level,balanced


Gain reduction

up to 17 dB

Threshold level

from -30dBu

Attack Time, msec

15-20-50-65-85-100-115-130-150 -165-180 and x2 multiplier

Release Time, msec/S

150-180-215-285-350-426-500-1S -2S-4S-6S and x2 multiplier

Noise Floor


Input  Impendance  Output Impendance

2.5k                         can drive load=0,5к

Frequency response,(+/-1,0dB)


THD less than (with reduction 3-4dB)

0,23%@+4dBu 3,00%@+24dBu


230/120V,50-60Hz, 60WA


WxHxD:   19"x5,2"x12"   (occupies 3U);  Weight:   11,0 kgs/24,25 lbs.

*(for more detail  on FF/FB modes see link - SideChain Bar 1 - Detector and Side chain, Side Bar 2 - FeedMe )

Triode FF

Triode FB

Pentode FF

Pentode FB

HPF 75Hz

*FB - FeedBack is mode of side chain


*FF - FeedForward is mode of side chain

*HPF - High Pass Filter of Side Chain

All files are 10,6mB non-compressed WAV 1411kbit/s

Some new files were added in customer Review >>>
music mixing studio



HCL © All rights reserved, 2003-2016  Use and copying of any materials of this site without our prior written consent is strictly prohibited.