Do EL84 tubes need to be biased?
Do EL84 tubes need to be biased?
Some amps have cathode-biased output tubes (EL84) and unlike fixed bias amps, these amps don’t need biasing.
How long do JJ EL84 tubes last?
I estimate that I have somewhere between 100 to 120 hours on these tubes.
What amps are self biasing?
A self-biasing amplifier, also know as a cathode bias amplifier, has a cathode resistor that sets the bias current of the tube. Typically these are in the 30 watt and under power range, but not all lower wattage amplifiers are cathode biased amplifiers.
What tubes does Dr Z use?
Current tube line up November-2020
- Carmen Ghia. V1: JJ ECC83, V2: Tung Sol 12AX7, V3/4: JJ EL84 (matched pair), V5: 5Y3.
- CAZ 45. V1: 12AX7WB, V2: 12AX7WB, V3: EHX 12DW7, V4: 12AX7WB, V5/6: Tung Sol 6L6STR (matched pair)
- Cure.
- EMS.
- EZG 50.
- Jetta.
- Maz 18 (reverb)
- Maz 18 NR.
Do Blackstar amps need biasing?
I’m pretty sure all Blackstars are Cathode based so there is no actual need to bias them. They can be made to sound better by biasing them though and I’m fairly certain there are internal trim pots for this.
How does tube bias affect tone?
Under bias means the tube will not reach full conduction and will sound too “cold”. It can even result in crossover distortion (the positive half cycle will end before the negative half cycle begins). Over bias will cause the tube to run hot and distort the signal.
What amps use EL84 tubes?
The most common tube amp that uses EL84 tubes is the Vox AC30, as well as most other amps manufactured by Vox. Their circuit design is generally regarded as the “classic” use of EL84 tubes, providing a sweet gain-y midrange sound and a medium output volume.
What is a cathode biased amp?
In electronics, cathode bias (also known as self-bias, or automatic bias) is a technique used with vacuum tubes to make the direct current (dc) cathode voltage positive in relation to the negative side of the plate voltage supply by an amount equal to the magnitude of the desired grid bias voltage.
What do you need to know about EL84 plate voltage?
What you really want to know is the plate voltage, and then set current draw of the tubes by adjusting the bias voltage. Example: You know the amp has roughly 350 volts on the plates. You know the EL84 is a 12 watt tube. You divide the wattage by the PV 12w/350pv = .034 Thats 100 percent dissapation.
Which is the best EL84 tube to use?
When pushed into distortion the Mullard EL84 tube has a softer, creamier overdrive that is more musical than other EL84 tubes and is the tube to pick if you want dirt. Electro Harmonix EL84-EH – For most applications this is a good bet. The sound of these tubes is very smooth when biased correctly. Tonally, it’s hard to go wrong.
Can a Vox EL84 be used in a Vox amp?
In cathode biased amps like the VOX they get a premium workout and will suffer some effects from heating and cooling. Being prone to mechanical noise in a combo amp, the EL84 is not recommended for amps with poor air circulation.
What kind of sound does JJ vacuum tube make?
JJ’s rugged construction of this tube offers high reliability without any compromise to the sound. This tube has solid lows with warm bright mids and shimmery highs. When saturated the harmonics are rich and dynamic. The JJ EL84 nails the classic sound of this tube.
