Monday, October 26, 2015

Can The Type 85 Vacuum Tube Be Used As An Audiophile Grade Fuzz Unit?

Even though it dates back from the 1930s Golden Age of Radio, but can the Type 85 vacuum tube work as a heart of an audiophile grade fuzz unit? 

By: Ringo Bones 

To some, an “audiophile grade fuzz unit” may sound oxymoronic because after all they are primarily designed to produce harmonic distortion at relatively low volumes in electric guitar amplifiers. But given that vacuum tubes and electric guitar electronics had been going hand-in-hand for over 60 years with exceedingly good sounding results, should electric guitar electronic effects designers explore underutilized vacuum tubes for possible use in the hopes of designing one that offers both versatility and good sound quality? 

Fuzz units or fuzz pedals as they are originally known were originally introduced back in the 1960s and were readily embraced by rock and Blues electric guitar players. It makes use of germanium signal diodes to clip the electric guitar signal originally produced by the magnetic pickups to produce a chainsaw-type distortion. Germanium semiconductor diodes have a lower voltage drop, Vf = 0.2 volts, in comparison to silicon semiconductor diodes at Vf = 0.6 volts. This means that the signal is clipped at a much lower level. The sound produced by this electric guitar effect / processor is quite versatile. It can sound warm and fuzzy to nasal and grainy. The most famous example of this effects unit is the Dallas Arbiter Fuzz Face. Originally, they are composed of solid-state semiconductor parts – i.e. germanium signal diodes and germanium transistors during the 1960s to operational amplifiers by the start of the 1980s, but will a better-sounding one be made around the Type 85 vacuum tube? 

The Type 85 vacuum tube is a duo-diode triode vacuum tube in a single enclosure designed for use as the first-stage detector, automatic voltage control and first stage audio amplifier in 1930s AM radios / AC line operated receivers. It was also used as the phase inverter in several 1930s era public address amplifier designs. It is electrically identical to the octal base 6V7. The Type 85S is a spray shield type made by Majestic. The Type 85 vacuum tube has a maximum plate voltage rating of 250 volts DC but it is typically run at 135 volts, a maximum plate current of 8-milliamperes but typically it is run at 3.7-milliamperes, a maximum grid voltage of -20 volts but it is typically run at -10.5 volts, a filament or heater voltage of 6.3 volts and a filament current of 300-milliamperes. The Type 85 vacuum tube has an amplification factor or mu of 8.3 and a transconductance or gm at 750 and it has a plate resistance of 11,000-ohms. 

The Type 85 vacuum tube is a multiunit vacuum tube that is it is a vacuum tube containing several independently acting tubes in one envelope. The electron stream is divided into several parts, each part being acted upon by one set of electrodes. The top metal cap is electrically connected to the ground and therefore does not represent a high voltage electric shock hazard. But can the two vacuum tube signal diodes enclosed in the Type 85 vacuum tube be used as “clipping diodes” for it to be used as an “audiophile grade fuzz unit”?
Even though hobbyists and DIY-ers well versed on how the Type 85 vacuum tube works are still relatively rare, Kara Chaffee of deHavilland managed to design and produced one in current commercial production called the deHavilland Mercury preamplifier. Although she didn’t use the two built in vacuum tube diodes and left them unconnected. But given the Type 85 vacuum tube’s robust tone and crystalline clarity, would it be a great vacuum tube not just for electric guitar preamplification and distortion work, but also for acoustic guitar amplification given its robust tone can make a typical acoustic guitar’s built in piezoelectric Fishman Transducers sound as if they were 3,000 US dollar Condenser Tube Microphones? 

Even if the Type 85 vacuum tube’s big size might intimidate the contemporary 21st Century guitarists, there are now pack-of-gum-sized lithium polymer rechargeable batteries with nanostructured anodes sold in Airsoft shops that can hold enough juice to power a Vietnam War era AN / PVS-2 starlight scope with its 15,000 volt photomultiplier tube for 15 hours straight before recharging, so battery operated fuzz pedal units using the Type 85 vacuum tube is technically feasible this day and age. And given that the Type 85 vacuum tube was used as a automatic voltage control unit in AM radios during the 1930s Golden Age of Radio, with its built in vacuum tube diodes, it could also be useful as a gold channel or audiophile grade compressor-sustainer unit, noise gate and limiter. 

Sunday, October 18, 2015

8-String Electric Guitars: The Ultimate Heavy Metal Music Guitars?

Though the idea is as old as the traditional 6-string guitar itself, does adding extra strings for expanded range the makings of the ultimate guitar for heavy metal music?

By: Ringo Bones 

Even though the idea of adding some extra strings to the instrument to expand its range is as old as the traditional 6-string guitar itself – indeed it is, in fact, much older than the one cobbled up by Andres Segovia. Renaissance and Baroque era lutenists often added extra bass courses to their advanced lessons to facilitate a more ambitious musical counterpoint. More recently, George Van Eps conceived a 7-string Gretsch in hopes of rivaling the piano’s harmonic richness. During the mid-1980s, Steve Vai created a 7-string Ibanez so that he could “shred” unimpeded across five-and-a-half octaves and Jazz guitarist Charlie Hunter employed 7-string and 8-string Novax guitars to play simultaneous bass and guitar lines. 

But the more recent 7-string and 8-string solid-body electric guitar mania springs fourth from a more visceral desire – to play heavy metal guitar riffs so low in pitch and lethal they make your fillings rattle. Ever since rap hip-hop and hardcore punk metal hybrid bands like Korn and Limp Bizkit got lucky enough to get regular mainstream FM radio airplay during the late 1990s, guitar companies have ever since issuing an unprecedented number of electric guitars with low B-strings (61.7 Hz). During the heyday of hair-metal, 7-string and 8-string solid-body electric guitars was usually an expensive custom item, but ever since the Y2K scare came and went, 7-string and even 8-string solid-body electric guitars in the 500 US dollar to 1,500 US dollar price range suddenly became something that any self-respecting progressive avant-garde 21st Century era heavy metal band can’t do without. 

The most popular 8-string solid-body electric guitar in current manufacture is by Ibanez – as in their Ibanez RG8 8-string electric guitar, though the first mass-produced 8-string guitar was made by Ibanez Guitars in Japan – as in the Ibanez RG228 – primarily as a toe-in-the-water exercise to capitalize on the low-frequency-guitar-riffs mania of the late 1990s. And ever since, the 8-string solid-body electric guitar has been in widespread use by modern heavy metal guitarists who first got their major record label deals back in the mid-1990s. Such as Fredrik Thordendal and Mårten Hagström of Meshuggah, Dino Cazares of Fear Factory, Stephen Carpenter of Deftones, Justin Lowe and Trent Hafdahl of After the Burial and others. The 8-string solid-body electric guitar is particularly associated with the “djent” sound popularized by Meshuggah and other contemporary metal artists. 

The 8-string guitar’s standard tuning, from low to high, is F#, B, E, A, D, G, B, E. Other alternative tuning interpolations are available and, more often than not, 8-string guitar users chose other tuning permutations to suit according to his or her playing style. Many prefer to tune the low F# string to a low E (41.2 Hz) which gives the 8-string guitar the same range as a 4-string bass guitar and to provide the 8-string guitar with a fuller sound three different E-strings were used as “sympathetic resonance strings”. While some progressive metal and alternative metal guitarists tend to tune their 8-string guitars in either open-D tuning or a more exotic Jazz-based major-thirds tuning. 

Sunday, October 11, 2015

Tweed Electric Guitar Amplifiers: The Ideal Electric Guitar Amplifier?

Even though heavy metal guitarists may beg to differ but are tweed electric guitar amplifiers the ideal electric guitar amplifiers when it comes to tone? 

By: Ringo Bones 

A full Marshall stack may be visually impressive to look at from the perspective of kids of all ages but seasoned electric guitar players more often than not that when it comes to “purity of tone” – at least from an electric guitar player’s perspective – tweed amps, or combo amps from the 1950s is where its at. But do seasoned electric guitar players know something that the rest of us don’t? 

Since they hit the market during the 1950s, tweed electric guitar amps – especially ones manufactured by Fender – had been sought after even before Ronald Reagan became president. They had been traditionally used by Blues and Country musicians and before the advent of those Marshall heads and stacks, also by rock n’ roll guitarists as well. Acoustically, tweed amps have a sharp treble roll off above 5,000 Hz and a bass roll off between 60Hz to 100Hz depending on the diameter of the loudspeaker used. The nickname tweed originally refers to the lacquered beige light brown fabric covering these combo style amplifiers but there are younger guitar players out there who think that tweed is short for traditional. 

Even though the timbral roar of Marshall heads and stacks was the dominant electric guitar tone of 1980s era MTV, some iconic MTV music videos had tweed electric guitar tones during the main guitar solo. An excellent example of which is the main guitar solo by Eddie Van Halen on Michael Jackson’s Beat It. And believe it or not, most stadium rock / metal guitarist of the 1980s and present want their stadium filling Marshall stacks to have a timbre of a mid 1950s Fender tweed combo amp which is easier said than done form a technical perspective. At least it keeps us vacuum tube electronic technicians gainfully employed since the late 1980s.