ENGINEERED FOR EVERYONE

WHY TUBES?

The real reason to use vacuum tubes is the quality of sound they produce. Tubes are unique and it’s impossible to make solid state sound like them. If it was possible we’d be out of business.

The perennial debate over whether solid-state sounds better than vacuum tubes will never be resolved as it’s mostly personal opinion. Solid state proponents point to hot tubes and the need to replace them as talking points. However, no one can argue against the beauty of sound reproduction from a tube.

The hard, brittle, edgy presentation of many solid-state components is a sharp contrast to the rich, lush liquidity, and 3D sound presentation of a tube component. Tube midrange and treble are smooth, silky, and have crystal clear sound definition. We admit that solid state can usually produce a harder tighter bass than other tube designs; but because of our Odyssey Circuit, Black Ice Fusion amplifiers have the ability to match and surpass solid state bass.

Legendary producer Alan Parsons (Beatles, Pink Floyd) put it best  "There’s a place for modelling. It’s usually because of budget or convenience. But I’ve always maintained that guitars invariably sound better with a couple of those glass tubes behind them." 

OK, TUBES SOUND BETTER BUT WHAT ARE THEY?

A vacuum tube essentially controls the flow of current and amplifies a signal in audio applications. It has the added benefit of providing a touch of that tube distortion which makes a tube tone more pleasing to the ears. It's for this reason people still use tube amplifiers and components.

THE PARTS OF A VACUUM TUBE.

Vacuum Tube

The Vacuum Tube

What’s the Sequence?

The filament is the heat generator. Without heat a vacuum tube will not work. The heat causes the cathode to release electrons towards the anode due to the negative to positive flow of electrons. In the middle is the component signal and grid where the amplification takes place when there’s a positive charge. This “boosts” the signal(electrons) on the way to the anode and exits the tube on the way to the amplifier and then the speaker.

The Glass Envelope

The Glass Envelope is what contains the vacuum(no air) and all of the parts of the tube so electrons can flow.

The Filament

The first component that truly is common to all tube types is the filament.  The filament is the part of a vacuum tube that you see glowing when the amplifier is powered on. 

When an electrical current flows through the filament, it creates both heat and light. It’s actually the purpose of the filament to create heat, and therefore light. Not just something to make it look cool. The heat is essential for working with the cathode.

The Cathode

The cathode is an element located next to the filament so they can best work together. It is negatively charged.  It has a coating on it that when heated (by the filament), releases electrons.  That is the whole point of the cathode, to release free electrons into the vacuum tube after being heated. If there wasn’t a vacuum(no air) this wouldn’t work.

Electrons work like a magnet -  a positively charged electron is attracted to a negatively charged electron and vice versa.  After being released from the cathode, the electrons flow to the next component – the anode, due to this charged attraction.

The Grid

The grid is a charged piece of metal located between the anode and the cathode. It’s where the component signal enters the equation – your component signal is connected to the grid. If the grid is negatively charged, then the flow from the anode to the cathode is reduced. This is because a negative (from the cathode) and negative force (from the grid) repels. However, if the grid is positively charged then the flow of electrons is accelerated since positive and negative attract.

This is the amplification in action. The amplification process also adds that tube distortion to the mix.

The Anode

The next element is called the anode, or plate. Its positively charged. Its job is to attract the free electrons released by the cathode after being heated by the filament. It’s the end point and in a way, it “collects” your signal when it has been inserted through the next element.

THE TYPES OF TUBES IN AUDIO GEAR

Rectifier - Diodes

The purpose of a diode/rectifier is to turn alternating current from your house supply into direct current like from a battery.  A diode is a two-element tube that does not have the grid mentioned above. Nearly all electronics need to turn AC into DC.  A diode tube also needs the help of some capacitors to make this possible.

The rectifier will usually work in conjunction with the transformer. They aren’t always essential in amps, sometimes the rectification takes place using non-tube-based technology or the transformer alone.

We don’t use these because tube rectification slows the electron response down and causes smearing in the sound.

Examples Diodes:

  • 6X4

  • 5AR4 / GZ34

  • 5U4

  • EZ81

Preamp - Triode Tubes (Small)

A preamp will amplify the signal and prepare it for further amplification by the power tubes. Or it’ll act as 100% of amplification in small tube audio devices. A triode is a tube that usually does this and a triode is the most common sort of tube. It’s a three-element tube and can amplify the signal.

Triodes can combine signals and split them into two separate signals.  They can also invert the polarity or phase of a signal.

Examples of Triode Tubes:

  • ECC81 / 12AT7

  • ECC82 / 12AU7

  • ECC83 / 12AX7

  • 6922 / 6DJ8

Power Tubes - Tetrodes and Pentodes (Large)

Power tubes further amplify and drive your signal. They are required on larger amps in order to drive the large speakers. Tetrodes and Pentodes are usually used in the power amp section, as they are capable of amplifying your input signal much higher than a standard triode. Tetrodes are four-element tubes and Pentodes are five-element tubes. 

Typically, these tubes work in a similar way to triodes but have additional elements called screens.  Screens are usually in between the cathode and anode. It “screens” the anode and grid improving performance. 

Examples of Tetrodes and Pentodes:

  • EL84 / 6BQ5

  • KT66

  • KT88

  • KT120/150/170

  • 6V6

  • EL34 / 6CA7

SWITCHES: ULTRALINIAR and TRIODE MODE WHY DON’T WE HAVE ONE?

At low volume / low wattage, the Black Ice Audio Fusion is Class A and only uses the Triode side of the power tube. When the volume is increased, and the wattage/current is increased to a point where the power requested is more than the Triode can provide alone, the amplifier becomes a Class AB push-pull that uses both the Pentode side and Triode side of the tube.

Some designs offer a switch that turns off the pentode side of the circuit/tube. This allows the circuit to only stay in the triode side of the tube when the volume is turned up. There are debates on which type of circuit sounds better and of course no one is wrong. We didn’t hear a benefit during design and testing the Fusion amplifiers, it was an artificial limit that could introduce unwanted artifacts in some instances. On the technical side, having a switch controlling high voltage is just another part that can cause noise and eventually fail.

Although it would make for great marketing, we chose not to include a Triode/UL switch for those reasons. It’s preference at the end of the day and no opinion is wrong.

  • This applies to the Fusion F11, F22, F35. The FX10h uses only the Triode side of the EL84 and is single ended class A only.

WHAT IS TUBE ROLLING?

There are different types of tubes from different brands in both the PreAmp - Triode and Power Tube -Tetrode/Pentode family explained above which can all sound vastly different. Some can sound better or worse at different points along the sound spectrum( treble/mids/bass) which results in a different sound signature. Every brand’s version of a tube can sound different than a competitor’s equivalent part. Combining tubes to control the final mix of sound qualities of your amplifier using tubes from different brands is referred to as TUBE ROLLING.

An example of tube rolling is where you try out different tubes in the same slot. For example, you'd try and compare a JJ ECC83 and a Sovtek ECC83 and decide which you like best. This means you could end up with a range of brands in your amp. With experience, you'll get to know the brands. So you may think "I wish my tube had more gain", so you could remove 1 of the 4 ECC83s you may have in there and replace it with a Shuguang ECC83.

NOTE - when rolling power tubes, it's best to replace a whole set at a time, and not just replace an individual one.

DO DIFFERENT BRNDS OF TUBES HAVE A DISTINCT SOUND?

  • AMERICAN TUBES

    6CA7- American- like the EL34 but with better-detailed highs, open sound, and better bass, and dynamics.

    6550- American- power control tube, Neutral highs, mids, bass, and dynamics.

  • BRITTISH TUBES

    EL34 - British- silky smooth highs, focused mids, 3 dimensional, lacks bass and dynamics.

    KT77- British-more musical than the EL34 with better detail. Made to complete with the 6CA7 tube.

    KT88- British- more musical than the 6550 with better detail and higher wattage dissipation.

  • RUSSIAN TUBES

    KT120- Russian - designed to sound like an EL34 but with more power.

    KT150- Russian- highs and mids of EL34 with better bass than 6550, KT88, and KT120. Last longer.

    KT170- Russian- like the KT150 but with better midrange and transient speeds.

  • YUGOSLAVIAN

    KT90 - Electro-Harmonix, claims that, despite its different construction, it possesses similar sound characteristics to the EL34 tube.

  • CHINESE

    KT100 - Supposed to be a drop-in replacement for the KT88. Short-lived and generally not well regarded.

INFORMATION ABOUT BUYING TUBES

NEW PRODUCTON TUBE BRANDS

All New tubes are made in one of four factories.

  • JJ Electronic is based in the Slovak Republic.

  • NewSensor is based in Russia

  • Shuguang is based in China.

  • Psvane is the Guiguang Tube Factory in Southern China


NewSensor has a few different brands which are very similar but with minor design tweaks. NewSensor’s main brand names are Electro Harmonix, Sovtek, Genalex, and Tung Sol. All other modern tube brands you see are rebrands made in these three main factories with the exception of Western Electric.

GENERAL SONIC NOTES

There are subtle differences between the four factories, the below are some generalizations about the different tube brands.

  • JJ Tubes - Tight bottom end and crisp clear tone.

  • NewSensor range – Decent amount of gain and quite a thick sound. However, there are major differences between each of the NewSensor tube brands.

  • Shuguang – Are rolled off with a lush midrange and a soft base.

  • Psvane – Are clear with tight bass.

NOS / VINTAGE TUBES

Vintage tubes are in high demand because they are thought to be incredibly well made and some folks think sonically superior. The problem is that these tubes are no longer in production and are quite rare. Consequently, they’re expensive. It’s certainly not a case of new tubes being bad and old tubes being good, like with many things in the world of tubes, it’s subjective.

These tubes are sold as NOS or New Old Stock. They are unused old tubes from brands such as Mullard, General Electric, and Phillips.

Truthfully, there will probably be minimal difference between the tone of an amp with NOS tubes, but some of us can tell and it is worth the expense to seek out these rare tubes. If you want the very very best, or are trying to find a specific sonic signature then NOS is the way to go. However, for all other purposes, the modern brands sound great and save you quite a bit of money.

Many modern brands also have premium ranges that claim to meet and exceed some of the vintage tubes. However, these will cost more than their standard range.

Some possible tangible reasons that old NOS tubes could be better are:

  • Materials used are now heavily reduced, or not used at all, due to safety concerns (such as nickel). But were actually a better material to use musically.

  • Standards needed to be much higher back then. Now if a tube fails, your amp breaks. Back then, a Supercomputer or a MIG jet failed. Vintage suppliers needed the BEST possible quality and reliability to compete for fo military contracts.

  • The new manufacturers had to start from scratch because the old tube designs had been lost. The technicians that designed and built tubes became experts at their jobs over a lifetime and in reality can not be replaced by machines or hourly workers.

Any Questions about tubes call us, we love to help our customers find their sound!

Please Burn In Your New Tubes

Burning in is the process of running a tube before it’s actually used properly. Any potential contaminants on the surface of the internal tube are removed during the burn-in phase. JJ tubes do come pre-burnt in, as do many other brands, but they should improve within the first several hundred hours of using the tube. Although we burn in your new amplifier it will not sound its best until the stock tubes burn in for a few hundred hours.