Joule-Electra Info Page!
Introduction | What's a OTL? | Refine It - Not Redesign It | Links & Lit | Retail Price List
Joule-Electra Info Page!
Introduction |
What's a OTL? |
Refine It - Not Redesign It |
Links & Lit |
Retail Price List
Welcome to our Joule-Electra info page!
Joule-Electra Links & Literature Joule-Electra is not much for very fancy or slick literature, but I have a collection from over the years which Jud Barber has put out. Some of it is not current (as noted), but I have included it because of there are some nice pics which still represent what the products look like and some of the text has some neat details about the design (much of which applies to current products). All the links below open up into a new window.
Joule Electra Retail Price Info ALL PRICES ARE MANUFACTURER'S SUGGESTED RETAIL PRICES AS OF AUGUST 2009 AND ARE SUBJECT TO CHANGE. ALL PRICES ARE IN U.S. DOLLARS FOR U.S.115VAC/60HZ LINE VOLTAGE PRODUCTS ONLY. AS ALWAYS, PLEASE CALL OR E_MAIL FOR OUR SALE PRICE ON ANY JOULE-ELECTRA PRODUCT! Preamplifiers and Phono Stages
OTL Power Amplifiers
Options for OTL Power Amplifiers include: 220 or 240 volt power supplies - $1,000; Solid Wood (Musicwood) chassis - Price On Request. All Joule-Electra OTL power amplifiers are built to order - a 50% down payment is required when a order is placed for them with final payment due at delivery. Musicwood chassis are available in a variety of woods (straight grain Sitka Spruce, straight grain Western Red Cedar and Maple) finished in with premium automotive clear coat finishes.
|
[Main] [Picture
of the Month] [What's New & HiFi
Blog!] [Demo
& Used Gear] [Product Lines]
[Who Are We?] [Our Facilities] [How We Do Business] [Where Are We?]
[]
Signature Sound
8409B Shallowcreek Road, Liverpool, NY 13090 USA
Phone: (315) 622-4137 Fax: (315) 622-2993
Hours: Noon to 8:00pm - Monday to Saturday
Demos By Appointment
I
have been a big fan of Joule-Electra gear for many years. I have been
captured by the dimensionality, purity, and musicality of their products
since I first heard them some ten years ago. Over the years I have come to know the talented southern
gentleman and his lovely wife (Jud and Marianne Barber) who are
Joule-Electra quite well. Here is
a guy who in his younger years, eschewed pursuing a education in electrical
engineering because he did not want to make
his love and passion for music
and vacuum tube circuits his daily work. Instead he pursued a degree chemical engineering (acing all his electrical engineering elective courses
of course) followed by successful career in chemical and plant engineering.
Towards the end of his career he took his thoughts and ideas from many years
into products and started Joule-Electra. The LA-100 preamp quickly garnered
a reputation for its ability to portray a palpable soundstage and a
wonderfully natural sounding tone and their OTL amplifiers started changing
minds about the resolution and purity of tone capable by tube power
amplifiers.
Since
picking up the product line about 10 years ago, the Barbers have become like family
to me. The Joule Electra preamp (first a LA-100, now a LAP-150) has long
been the heart of our reference system here at Signature Sound. The crown
joule (pun intended) of the Joule-Electra line up is their marvelous OTL
(Output Transformer Less) tube power amplifiers which are quite frankly, in my
estimation, the finest audio amplifiers on the planet. Signature Sound has a
wealth of experience with the wonderful VZN series of amplifiers from
Joule-Electra. We have sold and delivered many pairs (including the first
pair of VZN-220 "Right of Passage" monoblocks) of them over the years
and I have received personal training from Jud Barber on the design and
manufacturer of their products during my visits to their company/home. While
some dealer(s) may have "sold" more Joule-Electra products than Signature
Sound over the years, you will find no other dealer as knowledgeable as us
when it comes to the sound, operation, maintenance, fabrication, and design
of Joule-Electra products! - Rich Brkich, Owner, Signature Sound
While vacuum tubes are a fairly old
technology and are pretty much missing in modern everyday life because
of the compactness and high efficiencies capable of solid state devices,
that does not mean they have no value or use. In fact, many enthusiasts have
have praised and still enjoy the sound qualities of vacuum tube based power
amplifiers in this day and age. Vacuum tube based power amplifiers enjoy great popularity in the
specialty (hi-end) HiFi marketplace and pro-audio marketplace (just ask any
serious electric guitar player!). Since vacuum tubes are mostly great
voltage amplification devices, traditional vacuum tube based amplifiers need
a way to convert the relatively high voltage and low current output to the
(generally) lower voltage and higher current needed to power a loudspeaker.
You audio geeks out there know that a (output) transformer is used to accomplish this
task. Transformers work pretty well (as a great number of fine sounding vacuum tube amps
prove), but they do have their limitations: they are bandwidth limited;
heavy (lots of metal laminations with coils of wire wrapped around them);
have phase distortion out towards their top and bottom response limits; and
need to be operated within the linear region of their magnetic circuit.
While it is not easy or particularly
efficient, a vacuum tube can directly drive a loudspeaker. There are a few
tubes out there that have enough current output capability (especially when
teamed up with several other tubes of the same type) to directly drive a
loudspeaker - completely doing away with the voltage to current transforming
device. This is where the term OTL comes from... as these special amps are
Output TransformerLess. Now for those of you who want
to get technical/clever... yes, just about all solid state amps are "OTLs" but
traditionally OTL amplifiers are amplifiers that are vacuum tube based with
the tubes directly coupled to the load/speaker (no inductors, transforming
devices/circuits, transformers or capacitors in the output path of the amp).
The benefits yielded in a OTL amp is that mainly there is no phase
distortion or bandwidth limitations. The tube amplification circuit is
allowed to be heard in all its glory without interference between it and the
speaker. Are there trade-offs with the OTL amplifier? Yes. They are not
typically efficient. OTL amplifier topologies generally use Class A triode
output stages and require more tubes than conventional transformer coupled
tube amps that use more efficient (generally not pure class A) circuits to
generate the same amount of output power. Also, OTL amps are not well
suited for driving speakers with very low resistance (impedance) as they
loose power as the speaker impedance drops to very low levels unless the OTL
amplifier is made very large (and hence very expensive) in power output
capability.
Now, not all OTLs are alike. There are a
couple of different OTL circuit topologies used over the years (one of which
had a reputation for poor reliability). Joule-Electra uses the most reliable
and stable OTL topology which is generally called the Circletron. These are
not easy (or inexpensive) to build though... differential input stage and
floating power supplies require good engineering and execution to deliver
great results. We believe Joule-Electra's VZN series of OTL amps are the
best OTL design out there. Thier selection of the extremely rugged Russian
6C33 triode tube provides great sound and ensures many thousands of hours of
reliable operation (two or three times of that of conventional output
tubes). The use of wood based non magnetic chasses, top quality parts
chosen for the best sonic characteristics, point to point wiring, use of
damping & isolation materials on chassis and circuit boards,
continuously adjustable feedback controls, easy to use and adjust individual
bias controls, and use of a variac in part of the power supply to
carefully maintain the optimal filament string voltage for the output tubes
are just some of the things that make the Joule-Electra VZN series of OTL
amp's so special. The proof is in the listening of course and that is were
these amps deliver the goods like no other amplifier can.
A quick note or two about the Joule-Electra design
philosophy as I have learned it from Jud Barber over many conversations
during the past years. The core circuits of Joule-Electra gear (the Mu
follower used in the preamp and the class A triode based circletron topology
used in the amps) have remained constant ever since the amp and preamps
introduction. Instead of trying to reinvent the wheel every few years as
many other manufactures do, Jud Barber has regularly evolved the workings
around the core circuit topology to make the OTL amp and preamp perform better
while maintaining the fundamental harmonic integrity which their products
are famous for.
This does not mean that Jud Barber has not investigated other circuit topologies.
Jud has shown me pictures of several different prototype gain stages he has
tried.... only to reject them because they simply do not work or sound as
good as the designs he currently uses.
Some examples of the refinements made over the years
include: The Music Wood OTL amplifier enclosures; shunt to ground volume
control; and improvements to the power supplies of the amplifiers and
preamps. A number of the improvements are discussed in the literature we
have listed below for your review (there is not enough space or time for me
to get into a discussion of those details here) so feel free to peruse that
info at your pleasure! The new Marianne Electra Memorial Edition
preamps incorporate even further refinements with custom made wiring and
some extremely good sounding passive parts (unfortunately these parts
and wire are very expensive so these preamps are new models made in addition
to the existing products) to take the pre-amps sound to a even higher level
(again, you can find details in the literature and info links listed below).