Decware Zen Triode Sarah SEWE300B - W/ Manual + Power Cord

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General:
The Decware Zen Triode SEWE300B is a low power tube amp perfect to match with a pair of high efficiency speakers. As Decware is a small family business, the SEWE300B has been named after Decware's founder's daughter, Sarah. The original owner of this amplifier waited 3 years to receive this amplifier! Since Decware is a low volume company waiting years is common practice if you would like one new. MSRP on this amp is $4900.  This is your chance to cut the line, albeit it at a premium.  

Key features include a beautiful wood base which looks very classy and elegant. It also features all point-to-point wiring just like classic designs from the 1960s for the shortest and purist signal path and ultimate sound quality.

Electrically it is a pure Class-A amplifier equipped with analog current meters for each 300B output tube to allow for easy monitoring. It is capable of delivering 4 to 7 Watts into an 8 ohm load depending on your specific output tube selection.

This amplifier is perfect to pair with a set of Klipsch speakers or any high efficiency speaker rated at 90dB sensitivity or above.

Additional key features include a convenient voicing switch plus a versatile output design that allows it to drive speakers ranging anywhere from 2 to 16 ohms.

Due to the nature of the design, on very high efficiency speakers you might hear from low level hum.  This is due to the fact that the tubes are heated with an AC power supply, which is done intentionally to maintain the vintage signature sound.  There are two knobs available to help "tune" or minimize the him but there will likely be some residual noise.  In my system utilizing high efficiency JBLs it was not distracting.  

Included will be its original power cord and manual. It will be packed with extreme care.

From Decware: 
The main directive behind each Decware amplifier has always been to see '_how good can we get it to sound'_! Since we make our amplifiers here in the USA we have dreamed of being able to put modern day USA made tubes in them. When we heard Western Electric was considering producing several common guitar amp tubes, many of which Decware amplifiers actually use, we knew the best way to fast track that effort was money. To show our support we decided to design an amplifier for the audio tube that Western Electric does produce, which is the legendary 300B. Decware customers have been asking for a 300B amplifier for nearly 20 years...

The end result was over a year in the making. In the spirit of this classic vintage tube and Decware in general we choose an old school design approach that supports the lifetime warranty and has the best sonics. Things like cathode bias, AC heaters, point-to-point wiring and exotic transformers were all sound quality motivated. A year for such a simple amp design is the result of bending the design through all the possible windows of operation across many different circuits and tubes until we heard everything that was possible and knew there wasn't anything in this category / price point that was likely to sound better.
 
This amplifier has some real voicing features using simple switches and your choice of three different Voltage Regulator tubes. Each VR tube sets the plate voltage for an input or driver tube so that you can make the amp sound your choice of nine different ways ranging from lush to super clean.

The voicing switch for each channel took months to develop and test across a wide range of speakers. It was primarily about imaging. In one position the amp images deeper and in the other position it has more midrange presence. You can operate it while listening.

Different rectifier tubes also affect the overall character of the amp and all of these things come together to bring the amp through a range of being slightly lush to super neutral and from laid back to snappy. All of this voicing can be done without rolling the 300B output tubes. 

The amp works with all 300B output tubes, but the real Western Electric 300B was the most transparent and neutral that we tested and closest to the Decware sound we all love. Many other popular 300B tubes have been tested in this amplifier and they all sounded good -- each with its own positive contribution to the pleasing sonics of the Sarah 300B. One of particular notice is the Cryotone 300B-WC.

SkyFi Cosmetic Notes:
Looks basically new, practically no signs of wear.

Ownership:
Single Owner

Connections:
RCA, Binding Posts, IEC Power Input

General Sound:
Smooth, uncolored, undistorted natural and clean

Cosmetic Condition:
9/10 = Excellent. Perfect physical condition, gently used. See our detailed rating description here.

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

Included:
Unit, manual, and power cord.

Packing:
Will be packed using our highly developed in-house process and custom packing materials.Original MSRP:
$4,900.00

Specs:
- Power & Compatibility: World voltage compatibility (50/60Hz); can be bridged into either single-ended or differential balanced monoblocks
- Tube Complement:
- Driver Tubes: 6N6P, 6922, 6N1P
- Input Tube: 12AU7
- Output Tubes: WE300B
- Voltage Regulator Tubes: OC2, OA2, OB2
- Rectification: 274B, 5U4, or 5AR4
- Performance & Specifications:
- Power Output: 4 to 7 Watts per channel into 8 ohms @ 3% THD (depending on VR tube used)
- Impedance & Sensitivity: Input impedance of 100K ohms; input sensitivity for full power @ 2.0 volts
- Speaker Outputs: LO & HI terminals for 2–6 ohm and 8–16 ohm speakers
- Electrical Specs: Idle current of 65–75 mA per output tube; high voltage of 390 VDC at transformers; -80dB noise floor
- Inputs & Outputs: Two pairs of isolated 24K gold RCA inputs with switching; machined gold RCA input jacks; red copper binding posts
- Internal Components & Build Quality:
- Capacitors: Foil signal and bypass capacitors; F&T electrolytic capacitors; Nichicon Muse and Atom cathode caps
- Hardware & Construction: Machined steel chassis with powder coat finish; hospital-grade dual fused IEC connector with noise filter; dual contact silver switching; EIZZ gold ceramic tube sockets; analog current meters (0 to 100 mA)

Dimensions:
7-1/4" wide x 13-3/4" deep x 9-3/4" high;

Weight:
31 lbs.

Approximate Age:
2024

Link to Manual:
Click Here

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.