Q&A

TUBE AMPLIFIERS Q&A

What is your Electrosonic Aerosonic Speaker?

The Aerosonic is a speaker that was designed for use in our Thermosonic amplifier. It uses a special magnet that is a combination of Ceramic(ferrite) and Neodymium. It also uses a special spider that is optimized for low wattage applications. It has an extraordinarily high sensitivity, large voice coil, and a 50s style cone. This gives it a vintage sweet clean sound, early crunchy breakup, but with a huge modern thump. Before installation, the speaker goes through a special break-in and aging process which furthers the touch responsiveness, feel, and texture. All this and packaged in a high gloss, candy apple red basket and mag cover.

 What is the Electrolight System?

The Electrolight System is a feature of our amplifiers which illuminates the tubes with a color-coordinated wash of light. The small 9-pin tubes are illuminated from within, and the 8-pin tubes are backlit. Additionally, the Thermosonic and Solaris models feature illuminated internal chassis, which is visible through the chassis window. The system also features a slow stop 'powering down' circuit which turns the illumination system off slowly with the amplifier.

What is the difference between the Electrosonic Standard models and the Custom models?

Nothing. The Standard line was created so that customers could have the option of a non-custom, off the shelf, no wait time version of our amplifier platforms. Each amplifier is crafted to the same specs as a custom model.

What's the difference between Single-Ended and Push-Pull amplifiers?

Single ended amplifiers typically use a single output tube, and operate in Class A mode. The single tube amplifies the entire waveform. Ultimately, the Single-Ended, Class A amplifier is high in even order harmonics - which accounts for their high desirability in overdriven guitar amplifier tones.

The Push-Pull amplifier, uses two or more tubes, typically in Class AB. In this operating point, each tube amplifies half of the waveform. The signal gets split in half by a tube known as the phase splitter - and some of the even order harmonics are canceled out. The big advantage to Class AB amplifiers is the high output power available with this design. Also, Class AB amplifiers will ‘sag’ (or have a softer attack) in varying degrees typically when operated with a tube rectifier. Class A amplifiers do not tube rectifier sag, and there is no real advantage to using a tube rectifier.

Which one is better? It depends on your application. All else being equal, Class A sounds warmer, fatter, and more vintage like to most. Class AB sounds more modern, and more powerful. Because of the extra power on tap, Class AB can seem clearer when overdriven because of the extra treble and bass being pushed

The Solaris, Thermosonic, and Neptune are our Single-Ended, Class A amplifiers

The Fireball is our Push-Pull Class AB Amplifier.

How is the Neptune different from the other single ended class A amplifiers?

The Neptune is a parallel single ended class A amplifier, meaning that it uses two output tubes instead of one. This has the effect of increasing the power output of the amplifier, and is great for those who like the tonality of a true class A amplifier, but that need the higher output.

What is the 'Mixed Mode Output' option available on the Neptune?

This is an option only available on the Neptune -  Due to the unique output structure of the Neptune, this amplifier has the ability to operate two dissimilar output tubes at the same time. This offers a whole new spectrum of sounds available to the player. By selecting this option, the customer then goes on to select the two tubes that they would like the amplifier to be set up with. Thus, the opportunity arises to select two tubes that will most closely match the player's disired effect. For example, two of the most common output tubes, the 6L6 and the EL34 can be implemented to give the sparkling cleans and full bass of the 6L6 and the British crunch and warmth of the EL34. This 'best of both worlds' scenario is a great option for those wanting to broaden the range of the typical guitar amplifier. With this option, each tube has its own biasing, and input sections(for a perfect optimization of each tube), coupled into a special design output transformer for a perfect blend of tones.

With all of the preamp configurations, could you compare and contrast them? 

The standard 12AX7 preamp is a common configuration found in many amplifiers. The way our 12AX7 preamp is designed is for maximum versatility. The volume control yields approximately 50% clean tones and 50% overdrive tones. It is well balanced, with good clarity.

The 6SL7 preamp is warmer and fatter than the 12AX7. It also has less gain. It has a bit of an extention in the bass frequencies, which makes the overdrive 'looser' feeling and less tight. It has less treble than the 12AX7. The volume control yields approximately 60% clean tones and 40% overdrive tones.

The EF86 preamp is clear and full. It is a single stage tube(the 12AX7 and the 6SL7 are dual stage) so the output is very pure and uncolored. Unsurpassed clarity lets notes ring out with every nuance. The EF86 also has a slight compression effect due to the pentode design - increasing the sustain of notes even in clean operation. The volume control yields approximately 70% clean tones and 30% overdrive tones.

The High-Gain 2x12AX7 preamp is an add on option for those wanting maximum overdrive form the amplifier's preamp. It uses 2 12AX7 tubes to achieve near-metal levels of overdrive. Overdrive tones are tight and articulate with just the right amount of aggressiveness. The design is a blend of vintage warmth and modern bite. The volume control yields approximately 30% clean tones and 70% overdrive tones.

The Medium-Gain 2x12AX7 preamp is a mixture of the standard 12AX7 preamp and the high-Gain 2x12AX7 preamp. In effect, it is similar to having a plexi or bassman amp with the two channels jumpered. The first preamp stage is paralleled, and the tone controls are cathode follower driven. It has slightly more gain than the standard 12AX7 preamp, about 40% clean, and 60% overdrive tones. 

The Hybrid EF86/12AX7 is an add-on option for those wanting a unique blend. This preamp combines attributes of both preamp tubes. It uses one of each to achieve increased gain, and the ability to add  3-band tone controls(the standard EF86 preamp is limited to a special single tone control). Lots of clarity and sparkle, yet never thin. The fullness of the EF86 hits the 12AX7 to achieve a very detailed overdrive. The volume control yields approximately 50% clean tones and 50% overdrive tones.

You offer so many different output tubes, why don’t you offer an amp that can run all of them?

We design around a single output section for a reason; to exploit the given tube’s full potential. All the various tubes have operating points at which they sound best at. Things like output transformer primary impedance, and B+ voltage levels are biggest issues at play. The small EL84 tube for example, commonly operates at around 260v, while the large KT88 is quite happy at 450v+. These are two extreme examples of course, but there is usually some sort of compromise going on with amplifiers that run “any” tube. Go ahead and ask their manufacturers, they will tell you the same thing. These Swiss army knife amplifiers may be an ok experimenters tool for getting the general idea of the way the various output tubes sound like, but when you find what tube you like, wouldn’t you want an amp designed specifically for that tube? You’d be shortchanging the tube’s performance in any other capacity.

Can my Electrosonic Ampifier be re-optimized for a different output tube type?

Often times yes. Our amplifiers feature individual cathode bias pots which makes re-optimization possible. With our single ended and parallel single ended amplifiers rewiring of the output transformer's secondary is also involved. Its best to contact us to see if re-optimization is possible with your model.

What brands of tubes are standard issue with the amplifiers?: Either JJ, or EH "reissue" brands like the russian made "mullard" "tung-sol" or "gelenex" we equip with what we feel is the best sounding and most reliable tube for that particular circuit, but if you have a preference, please let us know when ordering.

I heard that the output transformer is an integral part of an amplifier’s tone. What kind of Transformers do you use?

We use special custom-designed Transformers in our single-ended, Class A designs, and our push-pull, Class AB amplifiers. The custom units are huge, oversized transformers designed for clarity, bass response, and presenting a very big and open sound stage. They add a modern edge to vintage circuits. They do not compress and saturate the way vintage output transformers often do. For those wanting a strict vintage sound throughout their Class AB amp, we offer vintage reproduction output transformers built around classic amplifier output transformer specs. These are available as an Ala Carte option.

How are your output sections structured?

The setup we use on most of our amplifiers is Cathode bias, with a zero-negative feedback output section. This setup was common with smaller classic amplifiers. We use it on our higher powered amplifiers as well as the smaller ones. Most commercially produced amplifiers in the 20 watt and up power range are fixed bias, mostly for higher power output ratings. Cathode bias/ZNF amplifiers tend to have a more ‘singing’ quality than their fixed bias/NF counterparts, which can be overly tight and sterile sounding in comparison. This setup is also unique for the way it reacts to one’s playing dynamics. Vox and Matchless amplifiers use this type of output section. While often clouted as 'Class A' amplifiers, Cathode bias or zero negative feedback alone does not make an amplifier Class A - such as is the case with the Vox AC-30. In reality, this amplifier is a hot-biased class AB amplifier. This is also the case with our Fireball amplifier.

Do the finishes you use make the amplifier more fragile?

Obviously, the types of finishes we have available are not as rugged as tolex or carpet coverings. Most people who use our amplifiers also do not throw them in the trunk of a car either. Most of them that get transported on a regular basis usually ride in a road case. The 2K urethane-based clear coat finishes we use are similar to the ones used on cars. The gloss finish being the most susceptible to scratches and scuffs, while the satin finish hides a little more wear. The hand rubbed oil finish is the most wear resistant, and has a feel of natural wood, with no clear coating on the wood surface. For the ultimate in durability, we offer Durabak as a standard finish. This is a no-charge standard coating and is available in many colors. The texture is similar to tolex, with a slightly glossy sheen.

Can you elaborate on the stained cab finish process?

The colors that we use on the stained cabs are aniline dyes. These are spray applied, much like a guitar. The rubbed oil finish is a special product called Waterlox. It is Tung oil based. It is a finish used on restoration of antique floors and fine furniture. It has great water resistance and is the toughest oil based, 'close to the wood' finish we have ever found(and we have used them all!) The process gets about a dozen coats with steel wooling down between for a really slick, polished feel with a 'glow from within' look. Indeed, the finish is IN the wood and not ON it.

The satin and high gloss finish process is a bit different. After the dye process, the wood is saturated with a 2-part sealing epoxy (usually 2 coats). This accomplishes two things, 1. It seals the wood and makes the grain 'pop'. 2. Epoxy saturation strengthens and stabilizes the wood, making it less prone to dents and cracks. After a week or so of curing, the 2-part urethane clear coats are applied, usually around 6. With the satin, a special clear is used to make the finish. With the gloss, the finish is sanded and buffed out.

How our your cabs constructed?

The amplifier cabs; heads, combos, and speakers are all constructed out of solid woods. Knot free White Pine is our standard wood, with many other species to choose from, incuding hardwoods and exotics. Joinery is all of half-blind dovetails, with front panels being face laminated. All adhesives used are top of the line, mil spec 2-part epoxy. This is the same adhesive used in boat and experimental lightweight aircraft construction. There is no stronger joint, period.

Why solid hardwood construction over plywood/MDF?:

Because real wood resonates. like a fine musical instrument, the construction matters. The cab is just as instrumental as the speakers used in it. Man made boards sound acousically dead, while real wood resonates and adds its own character.

Why use one type of wood over another?: 

Aside from the distinctive look each type of wood has, the denstity of the wood has an effect on sound. The less dense and lighter pine, for example, has a warm, subdued tone, with a softer attack and a lively resonance like a fine violin top. Oak, on the other end of the spectrum, is very dense and heavy. Cabs built from oak are very bright, vibrant, dynamic, and have a stiff attack. Poplar, one of the softer hardwoods, is a middle of the road option, providing a good balance of warmth and clarity.

Why finished wood over tolex/carpet coverings?:

Coverings such as these actually dampen resonances...finishing the cab with a lacquer based clear coat, or hand rubbed oil, interferes very little with the resonances, while still providing protection.

What about the baffle?: The Baffles are constructed out of 14-ply 3/4" Blatic birch plywood. It is the finest plywood you can buy, and the strongest. Some refer to it as 'aircraft grade' plywood.

What is this 'unipressure' Baffle mounting system?: This is a system designed by Electrosonic to virtually fuse the baffle to the inside of the cab structure, increasing the transference of vibration and resonances to the sidewalls and rear of the cab. This makes the cab much more resonant and acoustically "alive". On top of that, the large steel fusion plates makes for the toughest baffle mount in any speaker cab produced today.

How are the speakers aged and broken in?: The speakers undergo a special process involving the use of a signal being passed through the speaker for several days. this loosens up the speaker's suspension. In addition, the speaker cone is chemically treated and aged using heat and UV. The result is a consistant tone through the life of the speaker. It also increases sensitivity and bass resonance. There is no company offering speakers today that we know of that has such an elaborate process for delivering an authentic clone of a classic speaker.

In addition, custom built speakers are available using modified cones, dustcaps, spiders, doping procedures, boosted magnets, as well as custom painted finishes.

What's the difference between an open back and a closed back cab?: 

The open back cab has an overall difused sound, easily filling up a room with both the output from the front of the cab and the rear. Very open and loose are terms used to decribe this type of enclosure. This is the sound that nearly all combo amplifiers have. The closed back cab, on the other hand, is very tight and focused in comparison. The sound is very directional, having no rear-cab output like the open back. Electrosonic offers a half-and-half option for speaker cabs using two or more drivers.

What is the difference between alnico and ceramic magnets when used on speakers?:

I'll refer this to the Q&A page at WeberVST...lots of detail describing the pros/cons of each:

http://www.webervst.com/sptalk.html

Why port an enclosure?:

Porting increases the speaker cab's bass response. This is for players who want to maximize the depth of the bass frequencies. However, some of the cab's punchiness(attack) and focus is lost.

How does the Tone Ring port differ from a regular port?:

The Tone Ring is a special offset baffle design that allows output from the rear of the speaker to be projected out the front of the cab, in the same opening that front speaker output is being projected from. It also has the benefit of being completly hidden beneath the grill cloth.

What is the Weber Beam Blocker?:

It is a free floating device that gets installed between the speaker and the baffle. Its design blocks Icepick-like point source treble frequencies, which allows a smother blend of sound radiating from the speaker.

What is the projection spacer?:

It is a spacer that goes between the speaker and the baffle. This has the effect of increasing projection and depth of the driver it is used with. The spacer is made of the same baltic birch plywood that the baffle is, which results in an incredible 28-ply thick nearly indestructable baffle structure.

What is a 'Detuned' cab?:

A detuned cab design is one where there is a large oversized port on the front on the cab. It is not tuned to any particular frequency. This port is typically the same diameter as the speaker being used. The cab usually looks as though it is a multiple driver cab, even though it may only be a single or dual driver cab. This has the effect of greater depth and lighter weight. Downside is the large size.

Why oversize a cab?:

Usually, the larger you can build the speaker enclosure, the better it will sound in terms of resonance and depth. Downsides are that you have a larger box to contend with, and sometimes the punchiness and the attack of the driver will be deminished.