Jadis 845SE Triode Monoblock Amplifier Pair, Barely Used

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General:
Super Rare Jadis 845 tube based monoblock amplifiers. Beautifully made in France.

Came form an avid Jadis collector, who was in the process of putting together a huge Jadis system that was unfortunately never finished.

We had a total of three sets available - one set is lightly used and the others are new in box.  This is the last set. 

We hooked them up to our Wilson X-1 Grand SLAAM speakers and were treated to the best dynamics and ease we've ever heard from them by FAR. 

This monoblock amp pair comes with the original tubes with very low hour tubes (just for testing), the original manual, and original brochure. They are near mint with no significant signs of use.

Consecutive serial numbers 079 and 080 - Low production. This model is also no longer in production.Retail price in 1992 was $20,000 ($38,000 in today's dollars).

SkyFi Technical Notes:
These amps were recently recapped with brand new parts sourced directly from Jadis in France at a significant expense.

All 8 power supply caps (the large blue ones visible) were replaced. Working like new.

Ownership:
Brand New

Connections:
RCA Inputs and 5 Way Binding Posts for Speakers, IEC Removable Power Cord

General Sound:
Smooth, uncolored, undistorted natural and clean

Cosmetic Condition:
8/10 = Very Good. Excellent front faceplate, one minor flaw on chassis side or top. See our detailed rating description here.

Working Condition:
Working perfectly and tested in our lab and listening room.

Packing:
Will be packed using our highly developed in-house process and custom packing materials.Specs:
Type- Monoblock power amplifier pure class A 
Bias- Autobias
Power- 40W class-A
Bandwidth- 20Hz to 38KHz @-3dB
Sensibility- 560 mV
Number of blocks- 2
Tubes list- 845 x 4 EL84 x 4 ECC82 x 2 ECC83 x 2
Weight- 40 Kg per bloc
Consumption- 230 VA each

Dimensions:
68x30x29cm

Weight:
200 lbs.

Recommended Cables:
Kimber Kable - RCA Interconnects - Better

Kimber Kable - RCA Interconnects - Best

Kimber Kable - Speaker Cables - Better

Kimber Summit Series Monocle XL Speaker Cables (PAIR) - Best

Kimber Kable - Power Cords - Better

Kimber Kable - Power Cords - Best

Testing Process:
We start with a visual inspection of all internal components to make sure that there are no signs of heat stress or damage. Capacitors are checked for telltale signs of predictive failure including bulging, shrunken wrappers, or physical leakage. We also inspect resistors and other passive components for signs of overheating. If tube arcing has occurred in the past we can usually spot discoloration on the output tube sockets. On vintage units we often spot check select capacitors for value and ESR.

If the amplifier passes visual inspection, we move on to a full test of all of the tubes. We use a modern Amplitrex AT-1000 Professional Tube Tester which is capable of testing both emission and Gm with a high degree of accuracy.

We document the results of each tube and replace any weak or suspect tubes before proceeding.

When we power on tube amplifiers for the first time we usually use a variac and current limited AC supply and slowly raise the voltage up to nominal mains level while monitoring plate, screen, filament, and negative bias supply voltages where applicable.

If everything is in order we feed a low level test signal into the amplifier’s input and monitor its output on an oscilloscope across an 8 ohm dummy load. At this point we are just looking to verify basic function and confirm that the output transformers are not damaged.

Once we have verified that the amplifier is safe to operate, we connected it to full mains power. For fixed bias amps we set the bias to manufacturer spec. For cathode biased amps we monitor the plate to cathode voltage to determine if the output tubes are operating in a safe range. Once the output section is verified we move onto bench evaluation.

We start by feeding the input of the amplifier with a low level 1 KHz test signal, slowly increasing its amplitude while monitoring the amplifier’s output on an oscilloscope for signs of noise, clipping, distortion, or improper channel balance. We continue increasing the signal level until the amplifier reaches clipping. At this point we take an output power measurement and compare it to the spec sheet of the amplifier to verify proper performance.

We finish off the bench evaluation with a 1 KHz square wave check and a 20 Hz to 20 KHz sine sweep to assess the amplifier’s frequency response characteristics. This battery of tests will usually reveal if the amplifier has any issues that need further attention.

Before the device leaves the bench we perform a listening test with actual music using a variety of preferred test tracks. Our benches are outfitted with familiar monitor speakers which help us identify inconsistencies that will not always show up on our test gear. The main things that we are listening for are hum or noise with no signal present, proper center image, clicks, pops, or any other obvious undesirable audio characteristics.

If the unit passes all of these tests it is moved to our long term testing rig where we simulate real word operating conditions for 6-8 hours minimum.

For tube amps we like to run this test at least twice.

This allows us to monitor the unit for signs of thermal runaway or intermittent issues that only crop up when it has fully come up to temperature. We find this step to be essential, especially for vintage units.