In 1906, American physicist Lee DeForest invents the audio tube, which is a three-electrode version of John A. Fleming’s electronic valve. The audio tube was often referred to as the DeForest valve, but today is known to audio enthusiasts as the triode. The patent for the audion tube was sold to AT&T, and in 1907 DeForest founded the DeForest Radio Telephone Company. In the years that followed, Lee DeForest broadcast radio events from exotic venues such as the Eiffel tower, and the New York Metropolitan Opera House. By the 1920’s audio tubes had made the transmitting of radio signals and home radio receivers a common item in the American household.
Specifications: 13 wpc at full output 1.4 volts for full output freq response 10hz to 40khz distortion .5% at mid power Output tube 300B Driver tube 6an4
The very first tube amplifier designs were quite simple, and used a single output tube to amplify the input signal. This circuit design was the mainstay of home electronics for many years. In 1947 the Williamson circuit was invented, and became the dominant circuit for commercial and home audio amplifiers. But in the 1990’s an interesting event happened. A small group of tube enthusiasts rediscovered this early amplifier circuit, and started to tout the benefits of this design. Amplifiers based on this circuit are now known as single ended triodes, or by the acronym of SET. Eventually through the efforts of fanatics such as Harvey “Gizmo” Rosenburg SET amplifiers came out of the shadows and have taken their place in the audio landscape. Because of this audio renaissance we have seen many older tube types come back into production. For example, today we can purchase 300B, 2A3, and PX 25 output tubes from a wide variety of manufacturers.
The strength of SET amplifiers comes from the simplicity of the circuit design. These amps contain fewer parts, have a shorter signal path, and are quite often hand built with point to point wiring. Since fewer parts are used, each one will have a significant input on the overall sound of the amplifier. It is generally agreed upon that the most important parts in a tube amplifier are the output and power transformers. These transformers are literally the foundation for everything that will occur in a tube amplifier. If you are lucky enough to be around a grizzled veteran of tube amplifier construction, you will have to listen to him go on and on about how important “good iron” is for an amplifier.
Over the years the have been several companies that have excelled at the black art of winding transformers. If you get a group of amplifier builders together, I can guarantee you they will go on all night discussing the merits of transformers from companies such as Hammond, Magnequest, ElectraPrint,Sowter, and Tamura. Electra-Print Audio was founded by Jack Elliano, and over the years has gained a reputation of being one of the premier winders of transformers. Apparently this is not a well kept secret, because companies such as DeHavilland,Wellborne Labs, Cyrus Brennan, and Modwright use Jack’s transformers in their products. But Electra-Print produces more than transformers. They offer custom built amps that are based on Elliano’s Direct Reactance Drive circuit. For the last few months I have been listening to a pair of Jacks 300DRD amplifiers, and want to relay to you my experiences with these amps.
The 300DRD amplifiers occupy a good deal of real estate in my listening room. Each amplifier has an 18-inch by 12-inch footprint, and weighs approximately 40 pounds. The up side of having such a large chassis is the amount of room the designer has to lay out parts and minimize electrical interactions. The frames are built out of solid black walnut, and the steel top plate, transformers, and capacitor are finished in gloss black. There are only 2 tubes in each amplifier. Output duties are handled by a TJ 300B Meshplate, and the pre driver tube is a Sylvania 6AN4. The overall appearance of the 300DRD is very pleasing; with a classical look to them that all tube aficionados would appreciate. I asked Jack Elliano to give me a simple explanation of the benefits of the design choices he made in this amp. Jack touted the benefits of direct coupling of the output tube. Also that solid state rectification in the power supply results in the lowest amount of voltage variation during bass notes. Finally, the Ultrapath circuit eliminates any audio path through the power supply, and is responsible of the amplifiers ability to reproduce a high level of musical detail. Since I have an extremely limited knowledge of electrical design, I believe it is safe to say that I could not recognize a DRD or Ultrapath circuit if it bit me on the leg. But I can judge an amplifiers overall performance, and will take Jacks word on why his amplifiers sound the way they do.
Now that the preliminaries are out of the way, it is time for the main event. The Electra Print amplifiers are fed from an Electra Print PVA pre amp. Source duties are taken care of by a Sony SCD-CE595, which has been modified by Tube Research Labs. A pair of Cain & Cain Abbey’s fills the speaker slot. Finally, Tara Labs Air 3 and Master cables connect everything together.
As a general rule, single ended triodes are known to excel in the areas of midrange reproduction and the ability to put performers in a believable acoustic space. I can tell you that the Electra Print amps have the magical ability to create the illusion of a musical performance. Most importantly, these amps also have a very even tonal balance that has just a hint of extra warmth to it. The 300DRD are capable of reproducing all of the midrange detail in a recording, but do it in such an easy and relaxed manner. It can be a bit of a mind altering experience when you first encounter a good SET amp, and experience this dichotomy of detail and smoothness. A 1994 recording released by John Gorka, entitled “Out of the Valley” is an excellent disc for illustrating this point. Gorka has a distinctive baritone voice that is capable of being rich and resonant, and at other times has a surprising ability to convey the emotional content of a ballad. A good amplifier will highlight his vocal abilities, while an average one will lose the little details and smooth the sound over. Well the Electra Prints are good amplifiers, matter of fact they are one of the most capable amplifiers I have heard for reproducing a performers voice. The title track “Out of the Valley” is an emotional ballad that portrays the struggle of young people living in a small town, and attempting to leave it for a better life. It is a song that contains poignant lyrics, expressive guitar playing, and a vocal performance that lets all the emotion of the writer flow through. The 300 DRD amps let you experience this in a manner that few traditional amplifiers are capable of. This is the primary strength of a single ended triode amplifier, its unique ability to portray all of the music in a manner that lets the listener experience a performance and not just a song. Another cut; “Flying Red Horse” features Mary Chapin Carpenter as a guest vocalist. Her dark and smokey vocal style is an excellent addition to Johns, and their individual styles highlight and compliment each other’s strengths. The 300DRD amp does a stunning job of letting each vocalist’s performance stand on its own merit. The amps have the rare ability to present the individuality of both vocalists, and to contrast their different vocal gifts. At the same time these amps can show how smoothly their voices blend together and harmonize, creating a unique auditory experience. This level of vocal realism is very difficult to achieve, and is what makes these amps worth owning.
Single ended triodes have the ability to create the illusion of acoustic space in a manner that few solid state or conventional tube amplifiers are capable of. In more than one instance I have heard various SET amps coupled with high quality horn speaker systems that had all the speed and trans parency of electrostatic, or ribbon speakers. And they had dynamic range, and extended bass response that dipole speaker could only dream of. The Electra-Print amps have this ability to create a believable soundstage, and to properly place the performers within it. These amplifiers are present a wide stable soundstage, and have very good front to back depth. On Ellis Paul’s release “Say Something” the track “Thin Man” highlights the Electra-Print amps capabilities in regards to creating a believable soundstage. This is a minimalist recording that consists only of Ellis Paul, his acoustic guitar, and you the listener. The Electra-Print amps not only create the ilusion of Ellis Paul in your listening room, but they also allow you to hear the acoustics of the recording venue. It becomes very easy for the listener to close his eyes, and imagine being seated in a small, dark club, just a few feet off of the stage. When paired with the right speakers, the 300DRD amps can be holographic in its ability to recreate performers and their instruments. The high frequency performance of the 300DRD amps portrays a classic tube heritage. The treble reproduction is smooth and refined without any hint of glare or harshness. Although the amplifiers sound relaxed in the upper registers, they do not artificially roll off the high end frequency response. Sony has released several songs on SACD by The Bangles, including “The Hazy Shade of Winter” The opening tambourine sequence is so clearly reproduced that I felt that if I tried hard enough, I could count the exact number of metal cymbals in the tambourine. The accompanying guitar work was so quick and precise, with the decay of individual notes occurring so quickly that they appeared to just vanish. But most importantly, the Electra-Prints did not alter or cover up the tonal balance of the recording. It still remains obvious that this is a commercial recording, and it has a distinctive sound that is often associated with pop music. Bass performance and dynamic range are the two main areas that people find fault with single ended triode amps. This is quite understandable since the majority of SET amps bring less than 15 watts to the table. The 300DRD has competent, but not exceptional performance in the lower registers. These amps have quick and tuneful bass, that never gives the impression of being bloated or euphonic. But the champion of deep bass response in the 13 wpc weight class is the Art Audio Diavolo. The Diavolo has an iron fisted control over a speaker’s woofer, and is capable of creating bass that drive other SET amps green with envy. Quite simply, the Electra Print cannot match the Diavolo in this category. But that’s understandable, because I have yet to hear another amp based on 300B tubes that could. I found that acoustical bass instruments, such as cellos, tubas, or kettledrums were reproduced with plenty of weight and extension. On Aaron Copeland’s “Fanfare for the Common Man” the opening percussion lines had substantial weight and authority. But when you changed genres to modern electronic music such as techno or trance, the 300 DRD tended to run out of steam before the music could reach dance club levels. Although, with careful selection of speakers, any perceived bass response issues could be minimized.
At the end of the day it is time to tally up the scorecard for the Electra-Prints and determine if they are worth your hard earned money. With a retail of $2500 these amps are not inexpensive by any stretch of the imagination. Although this pair of amps were acquired from the used market for approximately $1100. Objectively speaking, these amps have an excellent tonal balance, the ability to extract large amounts of inner detail, and throw a wide and deep soundstage. But there is more to the single ended triode experience. The 300DRD amps allow the emotional experience of the music to flow through your speakers, and take up residence in the listening room. When people encounter a properly matched SET system for the first time, quite often they are literally blown away by intense connection they get to the music. And that is what these amps are capable of. The Electra-Print 300DRD amps are inherently musical, and can be the cornerstone to a very satisfying audio system.