Hello to everyone.
This is a review and test of the Linn Exotik multichannel preamplifier. It was released in 2004 and cost about $3,250 at the time. A new version having a marginally modified main printed circuit board (PCB) was released in 2007. A version with an optional digital input circuit board also existed. The digital-featured version is known as 'Exotik+DA'.
Part I: Presentation
The Linn Exotik is primarily designed as a 6 channels input to 8 channels output pure analogue preamplifier. The back of the unit shows it all:
From right to left, we have:
- 3 stereo analogue inputs;
- the multichannel input (can be transformed in 3 stereo inputs by software control);
- a fixed level stereo tape output;
- the 8-channels output;
- a pair of RCA sockets used for wired RC5 remote control;
- a block of 6 RJ45 sockets used to insert the preamplifier in a multi-room installation (requires custom wired cables);
- 2x 3.5 mm jacks for IR remote control;
- 2 independent RS232 port on RJ45.
The inside of the small form-factor, very lightweight case is full of emptiness:
But this monastic appearance is misleading. With the help of the schematics of the Linn Unidisk SC, an all-in-one disc player and preamplifier of somewhat similar design that can be found on the Internet, and a bit of reverse engineering, it is possible to figure out the overall electronic architecture. Let's do it by commenting the above picture:
This main board (a modern four-layers job with an internal ground plane) is actually shared with many other Linn products: the Kinos homecinema processor, and the Majik Kontrol and Akurate Kontrol (version '0') preamplifiers. There are few unpopulated pads and unused connectors for options that are not implemented in the Exotik.
In (A) we find a row of over-voltage protection diodes on all inputs and outputs, along with RFI low-pass filters. (B) is a small connector for an optional phono MM or MM/MC input preamplifier on a little add-on card (not mounted in this case) ; when the phono board is to be installed, the back of the unit must also be exchanged for another one having a ground connector. The two big integrated circuits in (C) are Zarlink MT8816 8x16 switching matrices (any input port may be connected to any output port) used for input selection, completely independent tape record loop and down-mixing of the mutichannel input if required. In (D), we find four Burr Brown OPA4134 quad-operational amplifiers that are used as buffers for each channel of the multichannel inputs as well as the stereo signal path, a mixer for 5.1 to 2 channels down-mixing, an output buffer for the tape output and finally to implement two differential receivers to unbalance the balanced multi-room input (more on that later).
(E) Three other MT8816 switching matrices and five quad-op amps (three OPA4134 and two TL074) are used to perform analogue bass management (with a fixed low-pass and high pass corner frequency) and channels down-mixing. Quite a lot of analogue signal processing can happen here! In (F), there are four other OPA4134 quad op-amps, half of the op-amps being used as mixers to sum all the analogue processing on each of the 8 available output channels and the other half to form DC-servos for each of said mixers. The eight blue capacitors in a row are the only through-hole parts on the board; they are molded polystyrene precision type used as integration capacitors in the DC-servos.
In (G), we have the multichannel volume control made of two four-channels Burr Brown PGA4311. These chips are 'A' graded, ie. they are manufacturer selected to best the typical SINAD of regular grade chips by 6 dB. Although the PGA4311 are specified to be capable of driving 600 ohms loads directly, Linn has chosen not to use them to drive the outputs, but to implement additional output buffers. This is the role of the two remaining OPA4134 quad op-amps on the board (H). Last, there are J-FETs, two in parallel per channel, used as switches to mute the outputs (I).
In (J), we see one of the two output sealed relays to protect the multi-room balanced outputs. Immediately under the relay, there are the balanced drivers made of two Burr Brown OPA2604 dual op-amps. For the audio power supplies, the output rails coming from the switch-mode power supply (SMPS) first pass through ferrite beads (not visible), then (K) a second stage of passive pi-filters (capacitor, inductor, capacitor) before reaching the regulated symmetrical power supplies (L). The rest of the circuitry that resides mostly beneath the metal box (M) in which seats the SMPS is made of auxiliary power supplies, current loops to remotely control other devices in a multi-room environment and, above all, programmable processors and memory, because the Linn Exotik is entirely software controlled.
The build assembly, fit and finish are very good. The gold-plated RCA sockets are of very high quality and are robust despite the fact that they are not chassis mounted. Moreover, Linn has obviously spent a great deal of time to write software to improve the user experience. Almost all functions are user programmable to customize the behavior of the preamp: display intensity, displayed input name, default input (including for recording, which by the way also works in standby), default volume at start-up, level offset between inputs, maximum volume level, rate of change of the volume control and the fade in/fade out process when switching sources, muting the output and at start up and power down. Once programmed, it is still possible to adjust the levels of the surrounds, center and subwoofer channels individually or change the balance between the left and right group of channels. The two input surround channels can be routed alternately to one of the two sets of surround outputs. All functions are accessible through the well thought out, pleasant to use, six front buttons interface or the high quality remote control unit and the menus are clearly displayed on a large blue color dot matrix screen. Navigation through the menu is easy to figure out. It should be noted that all level settings, including the master volume, are adjustable in 0.5 dB increments.
In a stereo-only multi-room environment, a single Exotik is able to remotely drive up to 4 different zones through balanced output connections or being remotely taken under control by another Linn device to reproduce receiving sound through balanced input.
So, this device may look empty, but it actually provides quite an impressive package in such a small form factor.
I have to say this preamplifier is a delight to use. How will it behave on the bench?
Part II: Measurements
All measurements were taken with an Audio Precision System One+DSP SYS222A (nominal input impedance: 100 kohms per phase in parallel with 170 pF). Unless otherwise noted, all measurements were performed using standard Audio Precision tests.
As all 6 inputs and 8 outputs are identical (a good point to listen to multichannel music program materials), I did not bother to measure them all, only the two front and left channels. Let's first see a dashboard at unity gain, 2 V in/2 V out, to follow the practice set by Amirm. Please keep in mind that it is not possible to get at the output exactly the same voltage than at the input because the volume control is stepped:
There is a fair bit of low-level hum (probably magnetic coupling from the mains) and low harmonic distortion. Nevertheless, the SINAD is better than CD-level quality. Not shown is an excellent matching of 0.01 dB between the two channels.
Reducing the level at 500 mV RMS (a widely followed standard input level for measurement in the old days) shows less distortion:
The THD+N versus input level amplitude sweep in absolute value (0 dBV=1 V RMS) shows a clipping level at about 6.3 V RMS output:
Best performance is retained up to about 2 V RMS input/output, which is convenient and conforms to the specifications of the device.
The SMPTE intermodulation (low frequency+high frequency tones) vs level sweep shows good results:
The CCIF intermodulation (twin high frequency tones) vs level sweep is even better, revealing good high frequency linearity:
Finally, the last intermodulation test shows transient intermodulation distortion (DIM standard: high frequency sine + filtered square wave) vs level:
I have not yet many experiences with this measurement and its relevance.
The THD+N vs frequency sweep at a standard 500 mV input level reveals no frequency dependency, as the curve is mostly noise dominated (same in an 80 kHz bandwidth, where there is only elevated noise, not shown):
At 2 V RMS (the level at which Amirm performs this test with unbalanced devices, I believe) and inside an 80 kHz measurement bandwidth, the picture is different and we see frequency-dependent effects:
So, the Exotik would be best paired with relatively high-sensitivity amplifiers. The Linn amplifiers of that time were specified for full power output a about 1 V RMS input, by the way.
I have measured signal to noise ratio at unity gain, 2 V in, and I also followed a old habit of German reviewers to measure signal to noise ratio (always in a 22 Hz to 20 kHz bandwidth) referred to usual output levels set by the volume control during casual listening with a standard 500 mV RMS input level signal. Overall, the results are pretty good:
The separation between the two front channels is good, rather than great. We are far from the state of the art:
The frequency response is very flat in the audio band, the -3 dB point being at about 160 kHz:
Because the frequency response extends less in very high frequencies, the input/output phase test shows more changes than with the already reviewed Vincent SAV-C1:
Audio Precision provides a test of the input/output linearity, in order to check if the output level does change linearly with the change of the input level. The Linn Exotik is nicely linear, save for levels above the clipping point:
This curves can be compared to this of the above mentioned Vincent SAV-C1, in which a noise-gate function impacts very low level linearity.
Finally, one of the most important features of a preamplifier is, to my mind, the accuracy of the volume control, which has to preserve an identical balance between the left and right channels (or all channels of a multichannel preamplifier) whatever the volume setting. I have created a test to show both the accuracy of the volume control step size and the matching of two channels:
This curves show the entire range of the volume control (100 dB down to just above complete mute). The volume control is remarkably accurate, both in step sizes and channels matching. The worst case deviation between left and right channels is about 0.1 dB from about -50 dB and below. Above that attenuation level, there is almost no errors whatsoever.
CONCLUSIONS:
The Linn Exotik is an elegant, compact and well designed piece of electronics. Overall performance in common use cases is very good. I have noticed no sonic impairment. To the contrary, noise is very low. The unit does not noticeably warms up above ambient temperature. I think this is a very interesting preamplifier for multichannel music enthusiasts, especially since multichannel devices are sadly very rare outside the homecinema market. Its only real downside is the low number of available inputs.
This ends the review. I hope you find it interesting.
This is a review and test of the Linn Exotik multichannel preamplifier. It was released in 2004 and cost about $3,250 at the time. A new version having a marginally modified main printed circuit board (PCB) was released in 2007. A version with an optional digital input circuit board also existed. The digital-featured version is known as 'Exotik+DA'.
Part I: Presentation
The Linn Exotik is primarily designed as a 6 channels input to 8 channels output pure analogue preamplifier. The back of the unit shows it all:
From right to left, we have:
- 3 stereo analogue inputs;
- the multichannel input (can be transformed in 3 stereo inputs by software control);
- a fixed level stereo tape output;
- the 8-channels output;
- a pair of RCA sockets used for wired RC5 remote control;
- a block of 6 RJ45 sockets used to insert the preamplifier in a multi-room installation (requires custom wired cables);
- 2x 3.5 mm jacks for IR remote control;
- 2 independent RS232 port on RJ45.
The inside of the small form-factor, very lightweight case is full of emptiness:
But this monastic appearance is misleading. With the help of the schematics of the Linn Unidisk SC, an all-in-one disc player and preamplifier of somewhat similar design that can be found on the Internet, and a bit of reverse engineering, it is possible to figure out the overall electronic architecture. Let's do it by commenting the above picture:
This main board (a modern four-layers job with an internal ground plane) is actually shared with many other Linn products: the Kinos homecinema processor, and the Majik Kontrol and Akurate Kontrol (version '0') preamplifiers. There are few unpopulated pads and unused connectors for options that are not implemented in the Exotik.
In (A) we find a row of over-voltage protection diodes on all inputs and outputs, along with RFI low-pass filters. (B) is a small connector for an optional phono MM or MM/MC input preamplifier on a little add-on card (not mounted in this case) ; when the phono board is to be installed, the back of the unit must also be exchanged for another one having a ground connector. The two big integrated circuits in (C) are Zarlink MT8816 8x16 switching matrices (any input port may be connected to any output port) used for input selection, completely independent tape record loop and down-mixing of the mutichannel input if required. In (D), we find four Burr Brown OPA4134 quad-operational amplifiers that are used as buffers for each channel of the multichannel inputs as well as the stereo signal path, a mixer for 5.1 to 2 channels down-mixing, an output buffer for the tape output and finally to implement two differential receivers to unbalance the balanced multi-room input (more on that later).
(E) Three other MT8816 switching matrices and five quad-op amps (three OPA4134 and two TL074) are used to perform analogue bass management (with a fixed low-pass and high pass corner frequency) and channels down-mixing. Quite a lot of analogue signal processing can happen here! In (F), there are four other OPA4134 quad op-amps, half of the op-amps being used as mixers to sum all the analogue processing on each of the 8 available output channels and the other half to form DC-servos for each of said mixers. The eight blue capacitors in a row are the only through-hole parts on the board; they are molded polystyrene precision type used as integration capacitors in the DC-servos.
In (G), we have the multichannel volume control made of two four-channels Burr Brown PGA4311. These chips are 'A' graded, ie. they are manufacturer selected to best the typical SINAD of regular grade chips by 6 dB. Although the PGA4311 are specified to be capable of driving 600 ohms loads directly, Linn has chosen not to use them to drive the outputs, but to implement additional output buffers. This is the role of the two remaining OPA4134 quad op-amps on the board (H). Last, there are J-FETs, two in parallel per channel, used as switches to mute the outputs (I).
In (J), we see one of the two output sealed relays to protect the multi-room balanced outputs. Immediately under the relay, there are the balanced drivers made of two Burr Brown OPA2604 dual op-amps. For the audio power supplies, the output rails coming from the switch-mode power supply (SMPS) first pass through ferrite beads (not visible), then (K) a second stage of passive pi-filters (capacitor, inductor, capacitor) before reaching the regulated symmetrical power supplies (L). The rest of the circuitry that resides mostly beneath the metal box (M) in which seats the SMPS is made of auxiliary power supplies, current loops to remotely control other devices in a multi-room environment and, above all, programmable processors and memory, because the Linn Exotik is entirely software controlled.
The build assembly, fit and finish are very good. The gold-plated RCA sockets are of very high quality and are robust despite the fact that they are not chassis mounted. Moreover, Linn has obviously spent a great deal of time to write software to improve the user experience. Almost all functions are user programmable to customize the behavior of the preamp: display intensity, displayed input name, default input (including for recording, which by the way also works in standby), default volume at start-up, level offset between inputs, maximum volume level, rate of change of the volume control and the fade in/fade out process when switching sources, muting the output and at start up and power down. Once programmed, it is still possible to adjust the levels of the surrounds, center and subwoofer channels individually or change the balance between the left and right group of channels. The two input surround channels can be routed alternately to one of the two sets of surround outputs. All functions are accessible through the well thought out, pleasant to use, six front buttons interface or the high quality remote control unit and the menus are clearly displayed on a large blue color dot matrix screen. Navigation through the menu is easy to figure out. It should be noted that all level settings, including the master volume, are adjustable in 0.5 dB increments.
In a stereo-only multi-room environment, a single Exotik is able to remotely drive up to 4 different zones through balanced output connections or being remotely taken under control by another Linn device to reproduce receiving sound through balanced input.
So, this device may look empty, but it actually provides quite an impressive package in such a small form factor.
I have to say this preamplifier is a delight to use. How will it behave on the bench?
Part II: Measurements
All measurements were taken with an Audio Precision System One+DSP SYS222A (nominal input impedance: 100 kohms per phase in parallel with 170 pF). Unless otherwise noted, all measurements were performed using standard Audio Precision tests.
As all 6 inputs and 8 outputs are identical (a good point to listen to multichannel music program materials), I did not bother to measure them all, only the two front and left channels. Let's first see a dashboard at unity gain, 2 V in/2 V out, to follow the practice set by Amirm. Please keep in mind that it is not possible to get at the output exactly the same voltage than at the input because the volume control is stepped:
There is a fair bit of low-level hum (probably magnetic coupling from the mains) and low harmonic distortion. Nevertheless, the SINAD is better than CD-level quality. Not shown is an excellent matching of 0.01 dB between the two channels.
Reducing the level at 500 mV RMS (a widely followed standard input level for measurement in the old days) shows less distortion:
The THD+N versus input level amplitude sweep in absolute value (0 dBV=1 V RMS) shows a clipping level at about 6.3 V RMS output:
Best performance is retained up to about 2 V RMS input/output, which is convenient and conforms to the specifications of the device.
The SMPTE intermodulation (low frequency+high frequency tones) vs level sweep shows good results:
The CCIF intermodulation (twin high frequency tones) vs level sweep is even better, revealing good high frequency linearity:
Finally, the last intermodulation test shows transient intermodulation distortion (DIM standard: high frequency sine + filtered square wave) vs level:
I have not yet many experiences with this measurement and its relevance.
The THD+N vs frequency sweep at a standard 500 mV input level reveals no frequency dependency, as the curve is mostly noise dominated (same in an 80 kHz bandwidth, where there is only elevated noise, not shown):
At 2 V RMS (the level at which Amirm performs this test with unbalanced devices, I believe) and inside an 80 kHz measurement bandwidth, the picture is different and we see frequency-dependent effects:
So, the Exotik would be best paired with relatively high-sensitivity amplifiers. The Linn amplifiers of that time were specified for full power output a about 1 V RMS input, by the way.
I have measured signal to noise ratio at unity gain, 2 V in, and I also followed a old habit of German reviewers to measure signal to noise ratio (always in a 22 Hz to 20 kHz bandwidth) referred to usual output levels set by the volume control during casual listening with a standard 500 mV RMS input level signal. Overall, the results are pretty good:
| Input Level | Output Level | Left Channel SNR (ref. to output level) | Right Channel SNR (ref. to output level) |
|---|---|---|---|
| 500 mV | 30 mV | 73.7 dB (75.8 dBA) | 73.4 dB (75.7 dBA) |
| 500 mV | 300 mV | 90 dB (93.2 dBA) | 91 dB (92.9 dBA) |
| 2 V | 2 V | 104.1 dB (106.9 dBA) | 104.7 dB (106.7 dBA) |
The separation between the two front channels is good, rather than great. We are far from the state of the art:
The frequency response is very flat in the audio band, the -3 dB point being at about 160 kHz:
Because the frequency response extends less in very high frequencies, the input/output phase test shows more changes than with the already reviewed Vincent SAV-C1:
Audio Precision provides a test of the input/output linearity, in order to check if the output level does change linearly with the change of the input level. The Linn Exotik is nicely linear, save for levels above the clipping point:
This curves can be compared to this of the above mentioned Vincent SAV-C1, in which a noise-gate function impacts very low level linearity.
Finally, one of the most important features of a preamplifier is, to my mind, the accuracy of the volume control, which has to preserve an identical balance between the left and right channels (or all channels of a multichannel preamplifier) whatever the volume setting. I have created a test to show both the accuracy of the volume control step size and the matching of two channels:
This curves show the entire range of the volume control (100 dB down to just above complete mute). The volume control is remarkably accurate, both in step sizes and channels matching. The worst case deviation between left and right channels is about 0.1 dB from about -50 dB and below. Above that attenuation level, there is almost no errors whatsoever.
CONCLUSIONS:
The Linn Exotik is an elegant, compact and well designed piece of electronics. Overall performance in common use cases is very good. I have noticed no sonic impairment. To the contrary, noise is very low. The unit does not noticeably warms up above ambient temperature. I think this is a very interesting preamplifier for multichannel music enthusiasts, especially since multichannel devices are sadly very rare outside the homecinema market. Its only real downside is the low number of available inputs.
This ends the review. I hope you find it interesting.
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