Elekit TU-8600R 300B Power Amplifier / Headphone Amplifier Kit
>>> Please note that tubes are not included in this kit <<<
"A world-class, four-star 300B tube amp that should cost $20,000 but will cost you only about $2,000 because you've assembled it yourself"
Herb Reichert Stereophile Magazine March 2019
The TU-8600R is a 300B single ended audio power amplifier kit. This is a special edition for the diyAudio store that includes upgraded 2% REX50G Takman resistors.
The 8600R has been reviewed by Stereophile and is now a Stereophile recommended component.
- TU-8600R Product Leaflet
- Review of TU-8600R in March 2019 Stereophile magazine
- Stereophile recommended components list
It's available as a SE version for $1,229 (TU-8600R with Takman resistors) or a deluxe version including the Lundahl transformer, for $1,785.
The Lundahl transformer is also available separately (including wiring harness and everything you need to perform the upgrade on a stock 8600R), for $650.
Power circuit enhancement
- High efficiency, low magnetic flux leakage R-core transformer
- Schottky barrier diodes for shorter recovery time
- Individual windings for the filament heater (A power), high voltage (B power), and bias to stabilize the negative feedback circuitry (C power)
- All power stabilized to reduce residual noise as much as possible, resulting in a noise level as low as 1/10th of the TU-8300R
Stable NFB circuit for high quality audio
- Improvement to various parts and circuits including OPT to make the most of 300B tubes
- NFB applied to cathode of 300B by the third winding of the OPT as well as to the voltage amplifying stage
- NFB is minimized as well as transient response
New active automatic bias adjustment
- Bias power is supplied separately
- New "Active automatic bias" used where the amp detects plate current and automatically adjusts the grid voltage, rendering the TU-8600 both self-biasing as well as having fixed bias.
- Current detecting circuit moved from cathode side to the B power side for better sound quality
Full power use of 300B tubes
- Orthodox voltage amplification stage to make the most of the 300B's outstanding sonic characteristics
- 12AU7 (ECC82) used in parallel for 2nd stage to drive the 300B tubes to full power resulting in 200Vp-p without clipping
Tube friendly design
- Warm up times for directly heated and indirectly heated tubes differ. Most designs warm up both at the same rate.
- The TU-8600 heats up the directly heated 300B tubes after the indirectly heated 12AU7 / 12AX7 indirectly heated tubes have warmed up.
- This is a very tube friendly design that will not overload tubes that have not warmed up fully
Output level section for headphones
- There are jumpers on the board to allow for headphone impedance matching
DIY friendly design
- The TU-8600 comes with high quality polymer hybrid electrolytic caps and polypropylene film caps, however extra space has been designed into the PCB for audiophiles to add (larger) after market caps
- The TU-8600 operates at very high voltages, and includes a safety cover
- Tubes: 300B x 2, 12AX7x1, 12AU7x2 (TUBES ARE NOT INCLUDED)
- Rated output: 9.2W + 9.2W (10% THD)
- Rated input: 320mV
- Residual noise: 36uV (IHF-A)
- Frequency response: 7Hz-40kHz (-3dB)
- Input impedance: 50kΩ
- Output impedance: 4-6.3Ω, 8-16Ω selectable
- Input: Line1 (2 x RCA)
- Output: Gold plated speaker output terminals (banana plug compatible)
- Power input: 100/115/200/230V 50/60Hz (IEC inlet)
- Power Consumption: 90W
- Dimensions: 385x217x325mm (including projections)
- Weight: ~12.6kg assembled
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