Equipment Setup Used for Review and Measurement
The “Home System” shown in Photo 5 and Photo 6 includes:
 
Analog Sources:

• EMT938 direct drive broadcast turntable with EMT-929 pickup arm, Denon DL-103R and modified EMT RIAA preamp (Pikatron step-up transformers and Lundahl LC-equalization),
• Denon DP-62L direct drive turntable with Denon DL-103 or DL-301, Lundahl step-up transformers and Creek OBH-15 RIAA preamp (modified circuit),
• Telefunken EBU3156 Broadcast relay receiver with R&S MPX Stereo Decoder module, quartz-tuned to NPO Radio 4 (NL)

Digital Media Sources:

• DAC: Benchmark DAC1 fed from TC Electronic Digital Connect X32 via AES-3
• CD: Mark Levinson No. 39S (analog output into preamp, AES-3 output into DAC1)
• High-resolution digital file playback: Apple Mac Mini Core i7 (2x1TB SSD), connected via Firewire hub into Apogee Duet feeding preamplifier, inputs on preamp tape out.
• Wireless streams: Wi-Fi and Bluetooth receiver feeding DAC1 through TDIF.
• SACD: HHB UDP-89, analog output feed into preamp, SPDIF output into DAC1

Preamplifier:

• Mark Levinson No. 380S with Danner HpHCF-4k/85 ear passive curve correction equalizer for low volume listening, looped through preamp tape loop
• Eckmiller MR90-St-D-600/200-K symmetrical passive faders (200Ω output impedance) as passive volume control for level trimming

Power Amplifiers:

• MB300+G2: Home-made 300B SE Amplifier with C3o low distortion driver with local NFG, Lundahl small signal and Tamura Permalloy output transformers, no overall NFB—used for the new production WE300B listening tests (see Figure 7).
• For comparison, Graaf GM-20 OTL (6S33S-V PPP/circlotron output stages, augmented with speaker protection crowbar circuits) and Hovland Sapphire (EL34 hybrid PP, modified gain stages, power stage, power supplies) were used.

Loudspeakers:

• Tannoy DMT-12 ii (impedance-corrected), sensitivity 95db (1W/1m)
• “Sanity Check” speakers: Sonus Faber Guarneri Hommage (impedance-corrected), driven by BAT VK-55 PPP or Graaf GM-20 OTL, augmented with Neumann KH-810A subwoofer combined with DSP Anti-Mode bass management system

Cabling, Connectors, Meters, Power Supply:

• Power cords, small signal, measurement—balanced and unbalanced—Amphenol, Belden, Cordial, Eupen, Sommer, Suhner
• Passive loudspeaker cables: vdHul The Clearwater on DMT-12ii, 10 AWG Silver/PTFE home-configured speaker cables on Guarneri Hommage
• Connectors: Amphenol, Hirschmann, Neutrik, WBT, Furutech
• Level Meters: RTW 1113 analog (balanced), NTP277-401 digital/AES3, Bruel&Kjaer 2235 SPL meter with capsule 4165, filter 1625, calibrator 4230
• Ground loop isolators/distribution units: Lundahl, Pikatron, Samson
• Mains Supply: Samson mains conditioner/surge protection unit, Suhner mains filters, Brennenstuhl, Knuerr power distribution strips, Eupen and Sommer cables

Test Equipment:

• For 300B distortion characterization, I used a homemade power amplifier with a stepped attenuator at input (2dB steps to -40dBr), low distortion hybrid driver stage, stabilized operating point output stage for 300B, low distortion James Audio output transformers reflecting a 3.5 kΩ resistive load into the 300B under test and 8Ω dummy load made from Vishay induction-free power resistors. This amplifier is the “MB300+” mentioned in the introduction.
• Distortion measurements were done with a “homebrewn” setup using Rational Acoustic SMAART V7 software on OSX, and USB/Firewire-connected measurement ADC/DAC setup (24-bit, >19 bits usable dynamic range, generator output +24dBU at 0dBFS, better than 80dB harmonic suppression), assorted Anritsu and Eckmiller attenuators, for calibration Rohde&Schwarz SUN2 and UPA, Wandel&Goltermann TFSK-40, TFEK-41, Fluke 8920A, Siemens and HP stepped attenuators were used. Accuracy is better than 1dB down to -90dBr.
• For 300B static characteristic measurements, a homemade test setup was used. I built it using Heinzinger, Delta Elektronika, Statron, HP, and Meanwell (filament) power supplies, Fluke, Keithley and APPA (TRMS) multimeters, Dale precision measurement resistors, Johnson UX4 socket, homemade sine and pulse generators and Owon digital oscilloscopes (8 bit and 14 bit). Calibration was done with Tettex (CH) calibration resistors/capacitors and a Fluke calibrator was used. Accuracy is better than 0.5% for DC static parameters and better than 2% for AC parameters.

 
The System used at the French Audio Event (November 2021) shown in Photo 7 includes:

• CD and Broadcast Wave file player: Fostex CR-500—balanced output 5.5 Veff @ 0dBFS
• SACD: TEAC CD-1000 modified with balanced Nuvistor output stage
• Preamplifier: Krell KSL-2 with phono board and modified output stage
• Power amplifiers as described in measurement and auditioning systems
• Loudspeaker: Tannoy DMT-12 ii (impedance-linearized)
• Cabling: Speaker cable vdH The Clearwater with Hirschmann plugs, Interconnects balanced Belden/Cordial with Neutrik (XLR), Interconnects unbalanced Suhner PTFE dielectric dual shield coax/Furutech (RCA connectors) connectors
• Power distribution/mains filter/OVP: Knuerr power strips, Eupen and Sommer cables