Sovtek EL84 / 6BQ5
The Sovtek EL84 / 6BQ5 tube has been a staple for Fender, Boogie, Crate, Peavey and other manufacturers of tube amps using the EL84 tube. This Sovtek tube really is a good value whilst being predictable, reliable and affordable with that great Sovtek tone.
The Sovtek EL84 tube has been around a long time, and it has shown continuous improvement over the years. Using a matched set of properly biased tubes will yield a clear smooth sound that is fairly warm and transitions into a smooth breakup with that singing tone that EL84 tubes are known for. 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 tube is not recommended for amps with poor air circulation. The heating/cooling cycle inside an AC30 easy bake oven seems to loosen up the mechanical structures within the tube causing them to become very noisy (mechanically) with time.
Note: These tubes have a slightly larger diameter than other EL84 tubes so they can not be installed into some ’90’s era Marshall DSL201 or DSL401 amplifiers, some ’90’s era reissue Vox AC15 amps, and Bad Cat amps