This is a rare Croft Twinstar I amp. This is a hybrid Tube/Transistor amp. It has barely been used. I'd guess less than 100 hours, maybe less than 50.I am sadly letting it go, as it did not enough usage in my living room - my kids have taken over the room with their musical instruments, and adults have been banned from it. I am therefore selling off the wonderful system I had built for it. All Glenn Croft amps are handbuilt, point to point wired, with extensive listening involved with the selection of every part (resistor, capacitor, tube, wire, solder, etc) that goes into the amp. It is a very rare product of one man's obsession! Here is a review: http://www.croftacoustics.co.uk/reviews/26_rev.html
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NOTE: THIS IS SET FOR US VOLTAGE, IN SPITE OF WHAT THE CASE HAS PRINTED ON IT. NO NEED FOR ANY TRANSFORMERS. I DO NOT KNOW WHAT WILL NEED TO BE DONE TO CONVERT IT BACK TO 220v. ------------
I found the following information on a German site, and had google translate it. I'm assuming the prices are in Euros. CROFT TWINSTAR amplifier TRANS VALVE DESIGN ™ amplifier OUT OF PRODUCTION Croft Twinstar amps are the result of decades of continuous development with the aim of the quality of music reproduction from amplifiers to optimize extreme.
For many years, Glen Croft his tube amplifier technology successfully developed (he was one of the few manufacturers that the legendary "Futterman" circuit concept in which tube-end amplifiers do without output transformers, employed) - what was eventually a reputation as an English "tube guru" einbachte.
The amplifier section is Glenn Croft for some years to a combination of tubes and transistors (hybrid) passed, so he is not only the fine detail, the tonal richness and fine dynamics of the tube circuit takes advantage of, but also the specific performance requirements of the speaker better meet can be.
rec. Selling prices:
TSI - 2400, -
TSII - 3950, -
TSIII - 4725, -
TSIV - 6200 - to 7795 - depending on version
TEC - 12 450, -
Tsvi - 9450, -
TSVII - 11.000, - Croft has this special circuit (input and driver tubes, the MOSFET transistors "work") can be protected as TRANS VALVE ™ design. Basically, the selected MOSFET transistors, which take over only the final amplification, while the circuitry - used as "single ended" tubes - as far as possible. The whole circuit needs no negative feedback, and for each model with the most sought-built components (Glen Croft is a true component-fetishist!). The different models of the Twin Star series differ not only in the power amplifier performance, but also in their musical ability through drawing, strength of tone color, dynamics, and thereby increased the intensity of the reproduced music will reach the listener. The intensity of the Play Music, Croft reach the amplifier is very difficult to describe, but if this music is heard, directly and beguiling good experience! Twinstar amplifiers are to be ordered as an additional mono amplifiers and converted as such with the appropriate performance doubling. Technical data: Performance (simplified): TSI: 45/55 Watt - 4 / 8 ohms (2 x ECC83 double triodes and rectifiers-tube power supplies)
TSII: 50/100 Watt - 4 / 8 ohms (as above and additionally stabilized voltage)
TSIII: 90 / 55 Watt - 4 / 8 ohms (as above + with 4 tubes controlled input stage)
TSIV-1: 80/60 Watt - 4 / 8 ohms (as above + with 4 tubes stabilized output level)
TSIV-2: 300 / 350 Watt - 4 / 8 ohms (high power version without regulation and stabilization - Large Chassis) Frequency range: 0.15 Hz - 120kHz-1dB
Input Sensitivity: 0.5 - 0.7 V
Input impedance: 470 Kohm
Dimensions: 100 x 400 x 300 mm (H.xBr.xT.) Download Twin Star brochures, English "Inner Ear Report" CharismaX with TSI Croft philosophy amplifier Updated on: 16 March 2009 - BH http://translate.google.com/translate?hl=en&sl=de&u=http://www.inputaudio.de/inhalt/deutsch/p_croft/005_croft_twinstar.shtml&ei=X8wlT-ntD4bi0QHipY3-CA&sa=X&oi=translate&ct=result&resnum=4&ved=0CEMQ7gEwAw&prev=/search%3Fq%3Dcroft%2Btsi%2Btwin%2Bstar%26hl%3Den%26client%3Dfirefox-a%26hs%3DUHz%26rls%3Dorg.mozilla:en-US:official%26biw%3D1431%26bih%3D814%26prmd%3Dimvns ------------------ Here is a review I found: Beyond the Frontier Croft Reviews Listener Review
VOLUME15, #3 2003
AMPLIFIERS Croft Twinstar Amplifier & Charisma II Preamplifier Review
Croft is a British design and manufacturing company operating under the name of eminent
audio uk, and is named for Glenn Croft who has been active in his business for about 30 years.
He became a force to be reckoned, as he produced amps and preamps for the proverbial “song”
with a high-end sound. Croft sold them via word-of-mouth, as marketing seems to have been
unimportant to him. More recently, croft has designed and produced truly high-end electronics
and improved visibility with more advanced marketing procedures. The components under
review are second from top of the line of four amps and four preamps currently available, which
bring us to the.... APPEARANCE:
The Charisma II preamplifier is a true vacuum tube unit with few bells and whistles. The main
features include a tube regulated external power supply with a 500Va dual capacity toroidal
transformer. The output stage is directly coupled to the inputs thus using bare minimum components in the
signal path. Where applicable, wire wound resistors are employed and hand wiring is
accomplished d with high purity copper conductors. The vacuum tube complement includes five 6SL7GTs, one ECC83, one 6080 and one 85A2.
Everything inside is hand-and-hard wired providing an immaculate layout and a straightforward
signal path arrangement. We understand that this unit is available with dual volume controls for left and right channels.
Here we have an amplifier design which, in its basic layout, varies somewhat from the
Futterman OTL’s of years past The preamplifier’s original design sports a wooden face-plate, which actually looked quite
attractive. However, the face plate has been redesigned and now offers the much snazzier look
of polished steel. Nothing interferes with the components’ immaculate frontal layout which
accommodates two small brass knobs in the centre which operate the selector switch on the
left and the volume on the right. The company logo is located under the two knobs. Also on the
(far) right a small toggle serves as the on/off switch. The external power supply is connected to the main unit and, strangely, doesn’t include the
AC cord which is attached to the main unit. The rear of the unit accommodates only four inputs
(including phono) which reflect Croft’s minimalist outlook: less is more (than enough to provide
a connection for a cd player, a tuner, a spare and a mute control). The amplifier matches the appearance of the preamplifier and sports only the on/off toggle on
the unit’s right front and the company logo in the centre. The relatively new look of these
components will appeal to refined taste as they are quite attractive with a touch of urbanity.
Technology: The Twinstar power amplifier is what croft calls a transvalve design, which hints at the hybrid
topology employed here. It features a unique input stage powered by two 6sl7 tubes and solid
state Mosfet output devices. The se are hard wired directly to the amplifier’s output stage,
omitting transformers, capacitors and resistors resulting in what is known as OTL (Output
Transformer-Less) and OCL (Output Capacitor-Less) design. The amplifier features a pure class
A input stage and zero feedback. Where necessary in the input stages, croft employs paper in
oil coupling capacitors. The Mosfets are carefully selected for tight tolerances and according
to the designer, provide similar sonic characteristics to those achieved with excellent vacuum
tubes. The amplifier delivers 46 watts/channel, enough power to drive medium efficiency
loudspeakers with sonic finesse of a good single ended tube design as we shall see when we
get to.... THE SOUND:
For our auditioning sessions, we used the Gershman GAP’s, as well as the Mead Song Lab
ribbons (both reviewed in this issue). The Audio Aero Capitole CD player (reviewed in our last
issue) served as our component and wiring was done with the XLO Limited Edition (reviewed in
our last issue) as well as the Nordost Valhalla cables. All peripheral components had been
previously auditioned and their sonic character was well known to our listening panel. To
ascertain compatibility and/or synergy with additional electronics, we connected the amplifier
to our in-house amplifiers - the Bryston 7B SSTS (reviewed in vol. 15#1) and the Wytech Labs
Onyx monoblocks (reviewed in vol. 13 #4) for some of our sessions. For other auditions, we
connected the croft amplifier to our in-house Wytech Labs Opal preamplifier, as well as the
Audio Aero Capitole player which sports its own preamplifier section. First, we used the amplifier with our in-house Opal preamplifier which quickly established the
“sonic signature” of the Croft power amp. The first and foremost sonic element of this
amplifier is its ability to “charm” listeners, as its musical proficiency far outshines its
unpretentious appearance. Though we expected smooth flowing highs, we didn’t anticipate the
effortless blossoming of high frequencies combined with perspicuity. Pure midrange
information, while demonstrating similar sonic attributes to the highs, did short fall of
perfection as it “romanticized” the sound of the brass and other hard sounding instruments.
This was more apparent when we used the Gershman speakers and, in all fairness, didn’t
detract from the amplifier’s “musical” quality. In other words, hard-sounding instruments
didn’t sound severe enough to be labelled as realistic, but were gratifying enough to provide
listening pleasure. THE CHARISMA II PREAMPLIFIER IS A GREAT COMPONENT ALLOWS FIRST-RATE
REPRODUCTION
Without a doubt, the most difficult test for the amplifier was with the meadow song lab
speakers, when we used it first to drive the subwoofers and later the ribbons. Attached to the
sub, the amp demonstrated surprisingly rich and low resolute low bass without, however,
allowing even minute slacking of control by the drivers - proof of excellent bass. The stability of
the amplifier was challenged by the ribbons, which tend to reveal shortcomings throughout the
midrange and high frequencies. However, none of these potential problems were evident as the
ribbons reflected the amplifiers mid-range bloom, smoothness and sophisticated high
frequency information. All in all, this is a superb amplifier with considerable musical
proficiency coupled with technology which brings its performance to a satisfactory and natural
conclusion. The preamplifier offers a phono stage which we didn’t test, although we heard it in operation at
the spring audio show in Montreal. There we listened to a couple of cuts of an lp and noted the
quiet, naturally flowing information that is what a good turntable/cartridge combination does
best. Back in our listening studio we tested the preamplifier with in-house power amps,
including the Bryston 7B SST monoblocks, the Wyetch labs onyx monoblocs as well as the
sibling Croft Twinstar. With our in-house amplifiers, the Charisma II quickly revealed its
strength and its weakness. The strength was its musically gratifying disposition which
included ripe, sonorous lower midrange and bass. Pure midrange had that undeniable vacuum
tube quality with blossoming information achieved without masking the program materials
inner detail, indeed revealing instruments texture and gradation. The highs were accomplished, finishing upper extremes very well, but failed to conclude with
maximal resolution. Some panellists felt this to be characteristic of vacuum tube designs and
quite pleasing to the ear. Others thought that, although not being a big issue, the highs were
“too polite”. The editor stated that this attribute will match well with many loudspeakers and
should not really be considered a weakness; rather, it should be viewed as the unit’s
personality which will please many listeners. As this trait doesn’t diminish the unit’s musical
proficiency, on which we all agreed, the solution for potential buyers is, as always, to listen
before you buy. Imaging, focus, detail, rhythm and time/space elements combined with attributes of superb
design make the Charisma II a high-end contender quite compatible with amplifiers of different
makes. SYNOPSIS & COMMENTARY:
In business, far too many consumers are worried about the science of audio, its technology.
While science is interesting, it is perhaps more intriguing to learn why audio designers are
predisposed towards a particular technique, a method which results in the interpretation of
music via electronics. It is safe to assume that, while all designers have the same goal, they
may choose quite different techniques to reach it. Here we have an amplifier design which, in
its basic layout, varies somewhat from the Futterman OTL’s of years past. It works extremely
well, and we dare say, is much more reliable and affordable. Most of the OTL’s we have
examined are much more expensive as one of the problems is matching parts and tubes - a
time consuming chore. Croft’s Twinstar amps perform beyond expectations and far above the
run of the mill amplifiers currently available. Additionally the Charisma II is a great component that allows first rate reproduction and,
ultimately, a view into the art form itself - the music. The Charisma/Twinstar combination won
the respect of everyone who listened to the system as synergy was achieved and the
loudspeakers we used acted as though the electronics were made for them. It is obvious that
Glenn Croft is a gifted designer - an old dog with new tricks - who has taken the audio
industry’s standards up by a few notches – Good Job.
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