Tube Amp Doctor - 7025 Highgrade - Preamplifier Tube
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Warm, clean tone with creamy overdrive
PREMIUM selected quality for the most demanding amp stages. This tube works greatly for warm clean tones and creamy overdrive. We recommend this tube for the 1st gain stage and as input tube. It upgrades 12AX7A and ECC83 tubes and replaces E83CC tubes.
The HIGHGRADE Selection is the tip-of-the-top quality at the lowest noise (microphony, hum, hiss) level. Tipically only 0,5-2% out of the whole production of this tube meet the HIGHGRADE requirements.
NOTE: due to extreme demanding TAD-Selection criteria, the availability of this tube is limited.In case this tube is currently not available, we recommend as replacement tube: RT080
The TAD 7025 Highgrade can replace any ECC83, E83CC, 12AX7, 12AX7A, 12AX7M, 12AX7WA/WB/WC/LPS/EH, 5751 or 7025.
Q: When does a preamp tube become a Premium Selected tube?
A: All preamp tubes labeled Premium Selected have passed the following tests:
- Low Noise Test
- Microphonic Test
- Gain Test
- Sonic Tests
- Shock Tests
- Listening Tests
- Balanced Output Test
HIGHGRADE SELECTION - But only those tubes which pass these tests best are labeled Highgrades.
Matching and Selecting Options for Preamp Tubes
Matching in Pairs for preamp tubes means that two tubes show identical gain, hence, four characteristically identical systems. This matching method includes our Balance-Selection. We highly recommend this matching method for hi-fi systems.
TAD Premium Selected/Highgrade tubes are guaranteed for a period of 6 months (according to terms of warranties) for the quality criteria mentioned above.
- Voltage (AC or DC) - 12.6V +/- 1.0 (Series), 6.3 +/- 0.5 (Parallel)
- Current - 0.15(Series), 0.3 (Parallel)
Heating - Indirect
Cathode-to-heater potential, max - 150V
Direct interelectrode capacitances, max***
- Grid to plate - 1.5pF
- Grid to cathode - 1.7pF
- Grid to heater - 0.2pF
- Plate to cathode - 0.3pF
- Operating position - Any
- Base - E9-1, small button 9-pin
- Dimensions - 56mm(height), 49mm(seated height), 22.5mm(diameter)
- Cooling - Conventional
- Approximate net weight - 13g
AF Power Amplifier
- DC plate voltage - 330V
- Positive DC grid voltage - 0V
- Negative DC grid voltage - -55V
- DC cathode current - 8mA
- Plate dissipation - 1.2W
- Bulb temperature (surface hottest point) - 160 degrees celcius