The Collatio OTL Series is a special project, and is Aries Cerat’s statement on how they think a true SOTA OTL amplifier should sound.qc1

The Collatio II istheir showcase, a statement, a cost no object approach on OTL tube amplification, “pushing the envelope on what is possible on OTL technology”.

The Collatio II amplifieruses aproprietary design, and it is in fact a current amplifier which “have their own technical and sonic advantages, and if especially matched with highly efficient horn speakers, are simply unmatched”.qc2

The output stage is a “unique Single ended stage”, a parallel-feed power stage, using 20 power tubes in parallel per channel, loaded by 4 massive chokes, and AC coupled to the output terminals, using an exotic film capacitor.

The capacitor is designed to be able to surge 20.000A peaks, and it’s ESR and ESL specifications, are an “order of magnitude lower than any audio capacitor, film or electrolytic”.

This power tubes used is the 6c19p, a small envelope tube,  a very low internal resistance tube, capable of large current swings and was “much preferred over the usual OTL tube candidates in terms of bass slam and timbre”. Also it is very cheap tube to replace.
The tube bank is biased at 2.6A per channel(20W) and at 5.2A for the 80W version! The output stage is a true single ended power gain stage and thus can only operate in Class A. No global or local feedback is used.Collatio

The power supply provides 2.6A per channel steady state and the double output stage power supplies, come with double choke filtration and 6 high current high speed capacitors.

The driving stage, is a Directly Heated triode, the 814 tube, a big bottle tube that can deliver 10W of driving power to the output stage.

Driving 20 output tubes per channel at high frequency needs a lot of current, and the 814 tube has a lot to spare. The driver tube is chple loaded, and  is DC coupled to the output stage,for supreme slew rate numbers and transparency. The driver stage power supply I s fed by separate transformers and is double filtered using chokes.

All heater and filament supplies have their own power transformer and are douple filtered using chokes and high speed capacitors.

Most OTL have a bad reputation of blowing expensive speakers,after they present DC potential after a malfunction. “The Collatio amplifiers are bullet proof in terms of stability and speaker protection.” Their output stage is AC coupled, so that no DC can be present at any times at the speaker terminal.

The Collatio 20W stereo amplifiers can be used as monoblocks, delivering 80W of OTL SE power with no modification from the user.


Full power bandwidth: 6Hz-110KHz

Small signal bandwidth: 4Hz-110KHz

SNR: 110db

Gain: X6 ( 15db)

Full power:  20W @8ohm

80W @8ohm mono configuration

Current idle per channel: 2.6A

Idle power consumption: 1190W(depending on bias level)

Dimenisons:    455mmW  X 590mmD X 480mmH (excluding tubes+cage)

455mmW  X 590mmD X 630mmH including tube cage

Weight: 120kg

Tube compliment: 2 X 814 , 40 X 6c19p-v


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