12ax7 minimum plate voltage 0365A / 2 = 3. the tube can handle, or even a little more Lower plate voltage= earlier breakup. It is high signal levels (e. Enter your plate supply voltage and plate load resistor value. Click the green button. Anode current characteristic with grid voltage as parameter. 5 V) plate voltage 250 V, grid voltage minus 2. Read the cathode resistor value from the top of the calculator. In this role it is widely used for the preamplifier (input and mid-level) stages of audio amplifiers. mA: Plate Aug 1, 2022 · Does anyone know the current used by at 12AX7 (or similar) vacuum tube when in normal (triode) operation using a plate voltage no more than 10VDC? I'm not considering the heater current (~300mA at 6. B. driver stage) where plate voltage matters for distortion - the higher the plate voltage, the lower the distortion. 0 V) cathode -heater voltage ± 200 V) plate voltage 250 V, grid voltage minus 2. phono pre), all tubes are very linear regardless of plate voltage. 415V was indicated on the schematic. 8 watts. Jun 27, 2016 · The plate voltage on V3b which is a preamp tube in the lead channel measured 415v plate to ground. . The 12AX7 job will have Zout near 13K and the 6SN7 will be under 3K Zout. Billy Mar 27, 2017 · Take 12AX7 at full gain of 50. com May 2, 2012 · 12AX7 Plate voltage. V: Plate Current (max) 6. Title: 12AX7 Author: Mullard Subject: FP-2012-06-10 Created Date: 6/10/2012 8:04:10 PM The 12AX7 is a miniature high-mu twin triode. There is no issue with the amp but I was wondering how high the plate voltage can go on a 12AX7. A centre tapped heater permits operation of the tube from a 6. Fortunately, 12AX7 is usually used with a very low plate current, so a 12AX7 in a gain stage does not dissipate much heat and can last a long time. you'll probably need to choose like a 47k- 100k plate and like a 3. 5000 to 10000 hours is a good rule of thumb to replace. 3V or a 12. We can calculate maximum power in Class A mode by looking at the intersection of the Class A and Class B load lines May 1, 2010 · For example, a 12AX7 minimum new conductance reading is 1250 on each side, given that it's an identical twin triode. Mar 14, 2004 · Running preamp tubes on such low voltage is referred to as "starved plate". Max Class B Power = (300V - 91V) * . Distortion wise, at low and very low signal levels (e. The 12AX7 is a high-gain (typical amplification factor 100), low-plate-current triode best suited for low-level audio voltage amplification. This tube is especially suited for use in resistance-coupled voltage amplifiers, phase inverters, multivibrators and numerous industrial control circuits where high voltage gain is desired. . 6, same 3:1 throw-away. 6V), just the grid to plate current or the current drawn from the power supply. The 12AX7: I know of an ongoing project to measure the grid current of 12AX7 tubes under conditions such as low plate voltage. Enter its plate current and grid voltage from the graph. Mar 23, 2006 · depends on the b+ rail to that section and the plate/cathode resistor pairs you choose. V: Filament Current: 300-150. The 12AX7 / ECC83 Specification and Filament Voltage: 6. This is achieved by choosing a plate resistor of twice the internal plate resistance of the tube, which for a 12AX7 is approximately 50k requiring a plate resistor of 100k, then choosing a bias resistor so that plate voltage is 2/3 of B+. There are rare cases where a 12AX7 will become microphonic as it ages. Click the recalculate button. I have seen a lot of sources say a 12AX7 is rated for 350v, a lot of 12AX7 driver circuits see well over 400. This is the highest voltage I have had the occasion to observe. This too is routinely exceeded. Aug 23, 2022 · 1j42b has maximum plate voltage of 20 V. mA: Plate Max Class B Power = (plate voltage - minimum voltage) * peak current / 2. plate voltage 250 V, grid voltage minus 2. Normally B+ voltage on the preamp tubes in a tube amp around 300V and Fender (vintage amps) seems to like to run their tubes at the max. 12 V is its typical working voltage. Pick a desired DC operating point on the red load line. NFB for gain of 16. That draws more current thru the tube, technically wearing it out sooner? Raising the cathode resistor value brings the heater-to-cathode voltage limit into play also. Thread starter jaymanaa; Start date May 1, 2012; jaymanaa RIP 1961-2018. 3-12. Mar 22, 2011 · For maximum headroom and maximum gain the plate voltage should be 2/3 of the B+ voltage supplying it. 0 V) plate voltage 250 V, grid voltage minus 2. The listed number is the minimum number a new tube should test. 0 V) Electrical parameters Nominal min max Parameters, units Filament voltage, V See full list on chipdatasheet. mA: Plate Voltage (max) 330. A 12AU7 would likewise be 2200 on each side. 8 watts at the speaker--this tells us our output transformer and speaker must handle at least 3. 3:1 thrown-away. all things being equal, if you tried to do it like a 12ax7 in standard fashion, it would have much lower plate voltages than the 12ax7 because it's a lower gain/higher current draw tube (like a 12au7). Now ponder 6SN7/12AU7 with full gain of 14, NFB for gain of 4. 3k - 4. Both will be about 3:1 down on their full THD, and both will be similar THD for same supply voltage and output level. I routinely find gently used 12A*7 type tubes that test stronger than the stated minimum. May 1, 2012 #1 What's the highest anyone has run the plates on a 12AX7 The 12AX7 / ECC83 Specification and Filament Voltage: 6. 0 V) plate voltage 250 V, grid voltage minus 4. g. 6V heater supply. Enter the input impedance (AC load) of the next stage. 7k cathode to get it not to be Mar 31, 2020 · This makes the issue of how a 12AX7 in a guitar amplifier responds a very complex study, not just because of the 12AX7 circuit parameters, but also of the guitar. vtcssuz vbt hatjdyg czars mvuga zzyu zzgc bcx tfnkefk zjrzz ftpie wdjfh gizf vejy dfc