2.5A Tentlabs (Netherlands) Filament Supply (pair)

Original price was: $171.00.Current price is: $159.00.

Please contact us for availability

SKU: 71304002032 Category: Tags: ,

Weight 270 g

For filament supply of 300B, 2A3, 45 etc. Output voltage 1.5V to 9V / 2.5A


TentLabs filament supply is designed to heat DHT’s the cleanest way possible, without affecting the music currents generated inside the tubes’ heater. The supplies generate a very low noise output while maintaining its’ high output impedance.

Result areas are:

  • Bigger soundstage
  • Better focus
  • Cleaner tone
  • Better resolution


A typical example is shown below:


Each tube needs its own filament supply, in turn, fed by a separate winding from the power transformer. The whole supply then is floating, and only has one connection to ground, as shown above. This example above shows the DHT in fixed bias mode. When using cathode bias, the grounded leg has to be connected to the top of the cathode resistor instead.

These are the only connections to the filament, so no caps, no hum-bucking pot, no nada!

The total output current is limited, depending on the version, but they all start-up slowly. Especially when the tube is cold, this is a nice feature. Cold tubes, when heated with traditional supplies, draw currents up to ten times their nominal current. Using the TentLabs heater supply will gently switch on your tubes.

The units are factory adjusted at your order. After installation, the supply needs minor DC adjustment, to compensate for possible voltage losses in the wiring (some 100 mV are easily lost at high currents). During use, no adjustments are needed anymore, not even after changing the tubes!

The new generation filament supplies have an over-temperature indicator and shutdown, in case the heatsink-temperature exceeds 90C. The LED and wiring is supplied separately with the modules.




All versions

  • Output Voltage adjustable between 1.5V and 9V, specify when ordering.
  • Higher output voltages available on special order
  • Output current: automatically adapts to the required level to reach the voltage specified above.
  • Input voltage should not exceed 1 V above specification (see application info).
  • Output noise < 20 uVrms (1 Hz – 20 kHz).
  • Output hum < 200 uVpeak at 100Hz / 120Hz.
  • Output impedance 10 mOhm at 0Hz.
  • Output impedance 10kOhm > 5Hz.
  • The heatsink is electrically isolated from the circuit and can be attached to a chassis
  • Over-temperature shutdown with LED indication


  • Total size 50*90*40mm (W*L*H, heatsink included, standoffs excluded).
  • Weight each 90 gram (each, excluding packaging)
  • Hole pitch 41* 81mm.
  • Needs 10mm stand-offs to mount on chassis, supplied with modules.



5 years of warranty is provided by Tentlabs (the Netherlands), provided that the products are used according to application information.



As this is a true DIY product, no additional support can be given. More information can be found on the Tentlabs website.