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Item: FS: StereoKnight Magnetic Enigma Pre-amp and Matching StereoKnight M100 Monobloc Valve Amps
Location: Melbourne - Endeavour Hills
Price: $6,500 for the lot (Preamp $3K, Monoblocs $4K - will only split if confirmed buyers for both)
Item Condition: Excellent - see below for more details
Reason for selling: Moving house - smaller room means I need to combine stereo and HT systems
Payment Method: Pickup - Cash, Bank transfer, Paypal (+3%)
Extra Info: I don't have the original boxes - buyer can arrange shipping at their own expense and risk (see below for more info)
I thought these would be my forever system, but we've decided to move to a smaller property. In the new house I don't have room to run separate stereo and HT systems so need a set-up with HT bypass. I'd be open to a trade for an Elektra Pnyx and HD300 or a Parasound P5 and A21 - probably not interested in much else but feel welcome to test the waters if it's got decent grunt and HT bypass.
Some background - after trialing a number of options to drive my Osborn Reference Eclipse Towers, Greg Osborn persuaded me to try his StereoKnight pre and monobloc combo. I had absolutely no intention of spending so far over my budget, but listening to these loosened the purse strings - even Mrs Q was mightily impressed and gave me no grief for overspending - and that's saying something.
The really outstanding aspect of the StereoKnight gear in my opinion is that it sounds so good at low to middling volumes, but is also crankable. Also, these are very quiet, especially for valve gear - I've heard a lot of solid state gear that's produced more background hiss. If you have a search on SNA I think you'll find that the StereoKnight Enigma and M100s are highly regarded and very few have come up for sale.
The Enigma pre-amp is built like a tank and weighs as much (22Kg) as many power amps. The balanced and unbalanced outputs are both active at any time so you can output to the monoblocs and a sub (as I do). The monoblocs are similarly built like a couple of brick outhouses.
The pre has had the standard ElectroHarmonix 6922 valves replaced with equivalent UK IEC Mullards - these provided a huge improvement across the board - better bass, sweeter treble and mids. The monoblocs have had the ElectroHarmonix 6922 valves replaced with Tesla gold pin / gold grid valves for improved reliability (EH went through a period of truly woeful reliability). The original power valves were initially replaced with some SED Winged C KT88s (great sound, but no longer in production) and more recently I've used Tung-Sol KT120s which have given further improvement in tightening the bass. In the interests of full disclosure, one of the SED Winged C KT88s lived up to their reputation of going out with a bang and took out one of the sacrificial resistors on one monobloc. I had the monobloc fixed by Greg's usual repairer, who replaced the resistor and gave the amp a clean bill of health. It's been rock solid since then. Also, these are early production M100s and are labelled as M75s (I understand the only significant change was a modest upgrade to the output transformers).
The pre and monoblocs are one owner and have always been kept in a non-smoking environment. Both the Enigma and the M100s are in good cosmetic condition but have a few minor scuffs and fine scratches - I've tried to show these in the photos but they're not easy to capture. The Enigma also has some burring around one screw on the top where I had trouble loosening and overtightened screw - see photo.
As you may know, StereoKnight didn't survive the GFC and the two partners went their separate ways. The partner responsible for the engineering design has since founded AM Audio and some of their products draw on the same principles as StereoKnight, albeit at higher price points. Greg Osborn sells AM Audio and the RT-1 pre that is based on the Enigma pre costs $5890 (ouch!) and misses out on a remote.
Serious buyers are welcome to an audition, but please don't waste both our time by expecting a low-ball offer will be accepted.
For interstate buyers, as mentioned above I don't have the original boxes. I am OK with you arranging shipping and insurance at your expense, but would ask that you have a trusted contact inspect the gear first and confirm that it's cosmetically as described and in full working order. I could also deliver to a local shipper like Pack and Send after inspection by your trusted contact.
StereoKnight was always about engineering and production - marketing wasn't their strong point, so there's not a whole lot of information about on the web and what does exist isn't the slick, polished stuff you get from professional marketing. Some extracts from Greg Osborn's then website below.
Magnetic Enigma-1.0R Pre-amp
The unique design of this all new tube preamp, the "Magnetic Enigma-1.0R" can be implied from the term "magnetic", which indicates its direct origin from the StereoKnight magnetic passive preamp. Not only does the Enigma-1.0R use 4 transformers for volume attenuation, but also another 2 transformers for signal output, and two more for power supplies.
The remarkable performance of this Preamp has been achieved with an all new audio and power supply circuit design. The circuit is pure tube, Class-A, with zero feedback, utilising a total of four long-life tubes (2 6H30 as the drivers and 2 6922 as the amplifiers); and further, it is a true balance circuit design in both the input and output stage, with the support of 4 volume control transformers. For balanced input signal, each channel has two opposite signals, a positive and a negative one. Theoretically, it needs 4 transformers to attenuate 4 separate input signals for a two channel source. StereoKnight had implemented this theory into the design of the magnetic passive preamp, resulting in exceptional performance.
The Magnetic Enigma-1.0R is a direct upgrade from StereoKnight's reference version of the magnetic passive preamp. By utilising both tube amplifiers and output transformers. One great advantage of this magnetic feature, is its capability for optimal matching with any amps and interconnects, while accepting any sources input at various impedance levels.
In the interests of achieving the least possible interference to the audio signal, the power supply is divided into two separate parts: The main power transformer, which is used to power the audio circuit, and a smaller power transformer, which is designed to support the remote control, and LED display functions. MOSFETS are used for both voltage stabilisation and supplying a constant current, which enhances the reliability and makes the tube amplification as linear as possible.
With its great build quality, audiophile grade components, versatility and the ability to musically transform every system, the result is, that not only does the Enigma-1.0R deliver striking clarity and detail, that presents instrumental timbres and textures in an amazingly lifelike way, and also represents great value and reliability.
Feature summary of the Magnetic Enigma-1.0R line stage preamplifier.
* Fully differential circuit with balanced in and out.
* 4 transformers for volume attenuation with 33 steps.
* Transformer output.
* Pure tube, Class-A, with a Zero feedback audio circuit.
* The Versatility to match all kinds of amplifiers and interconnects, based on full magnetic
or transformer implement designs.
* The capable to drive two amplifiers or one amp + one subwoofer at same time either
through the two balanced or RCA outputs.
* Full remote control on volume, source selection, output selection, balance adjustment,
* MOSFETS for voltage stabilisation, and supplying constant a current.
* Hovland musicap capacitors in the signal path.
* Detachable IEC power cord. High quality gold-plated StereoKnight custom binding posts and RCA jacks, TEFLON insulated wire and Japanese made POCC rectangular solid core copper wire throughout.
* Full machined aluminium alloy chassis and remote control for best possible build quality and appearance.
Tube complement: Two 6H30 as the drivers, two 6922 as the amplifiers.
Frequency response: 8 Hz ~ 80 KHz , -1 ~ +1 dB.
Input Impedance: 20k ~ 300k ohms, a great feature favoured by the Magnetic Enigma volume control function.
Volume control: 4 transformers at balance input, 2 transformers at RCA input, used to attenuate, with 33 steps which are connected to 33 digital relays. The relays are controlled by a CPU that receives the signal from a digital stepper, which is either the consequence of turning the volume knob or by instruction from the remote control.
Output Impedance: 600 ohms balanced. The Enigma is of pure balanced circuit design, so the 2 RCA output is converted from the balanced output.
Gain: 20 dB
Output voltage: 20v RMS balanced at 2v RMS input at less than 1% THD at 1kHz
S / N: > 100 dB at 1KHz
Input selections: 4 pairs RCA single-ended ; 3 pairs balanced / XLR
Output selections: 2 pairs balanced / XLR ; 2 pairs RCA ( two amplifiers or one amplifier and one subwoofer can be connected same time, either by balanced output, or RCA output )
Remote control functions: Source select, output select, volume up /down, mute, dimmer, balance adjust +/-
Power consumption: 45 watts
Dimensions: (W x D x H) 430 x 400 x 140mm or 17 x 15.5 x 5.5 inches
Weight: 48 lbs (22 Kg) net weight, 61 lbs (28 Kg) shipping weight
StereoKnight M-100 Monobloc Amplifiers
The fully balanced design M-100
These are astonishing. Fantastic power, control, detail, transparency, openness and sheer musicality. I have never heard a KT88 amp, or in fact any amplifier short of the CAT that even goes close to these amps.
* Tubes: 1 X 6H30, 2 X 6922 4 X KT88
* Power output: 2×100W (8ohms ULTRALINEAR); 2x 140W (4ohms ULTRALINEAR)
* Input: 1 x RCA, 1 x XLR
* Frequency response: 10Hz~60kHz
* THD: 1%(1kHz)
* Input sensitivity: 2 V
* Input impedance: 50 Kohms
* Output impedance: 8ohms, 4ohms
* S/N ratio: > 90 dB
* Dimensions: 500×330×240mm
* Net weight: 35Kg x 2
* Power consumption: 550W maximum
The M-100 paired monobloc amplifiers are designed for those who seek superb performance based on high power and a fully balance design, where the reliability and easy maintenance are assured for years to come. The M-75 is mainly designed for full balance input, thus gaining the ultimate performance possible, supported by the transformer assembly, including power, input, output, and balance, newly designed and manufactured by StereoKnight. Two 6922 tubes are used for amplification when XLR input is selected. A 600 ohm input transformer was designed to split phase for balanced amplification when RCA input is used.
High power with excellent drive & control: transformer and KT88
Four matched pairs of KT88s, driven by a 600W ultra wide bandwidth, C-core type output transformer, conservatively designed for an output of 100WPC at 8 ohms, or 140W at 4 ohms, where two important factors were concerned:
* Power is not the single bench mark of performance. The ability to drive and control the most difficult loads, in any situation is more critical;
* Achieving exceptionally high power output, by pushing the tubes to their maximum capabilities will easily damage them in the short term, and can affect the stability and reliability of the unit.
At 100WPC output the M-100 provides excellent drive and control, as well as plenty of power, which easily makes it a winner in any situation.
With four KT88s, we could easily achieve an output of over 125WPC, which may look impressive, but we care more about the reliability of our products, as well as our customer's long term satisfaction. Sacrificing some power does not mean we compromise the performance.
KT88s or 6550s are used for power amplifying, which are the power tubes preferred by StereoKnight. We value the KT88 based on the following considerations:
* Properly designed and engineered, and assisted by high quality transformers, KT88s can produce all typical 'tube sound' usually associated with 300Bs, 2A3s or 845s.
* KT88s are stable, reliable and have a long tube life.
* They are easily obtainable, and reasonably priced.
As for the noise, which has annoyed tube equipment for decades, it will never be a conern any more. ZERO noise concern will be the basic promise that StereoKnight brings to your musical enjoyment. Another ZERO is about negative feedback: ZERO-NEGATIVE-FEEDBACK concept and technology are fully applied in both the preamp and poweramp stages in the S-40's design and engineering. This unique feature brings single ended class A sonic characteristics to the S-40's push-pull based design.
MOSFET technology is used to stabilize voltage most precisely, which offers faster rectification, and has the ability to address a much higher capacitance than the older tube rectifiers. Tube rectifiers are designed to handle only 50 microfarads (mf) at maximum, while MOSFET rectifiers can handle capacitances greater than 4000 mf. MOSFET also offer far better reliability and don't age as quickly as tube rectifiers. Tube rectifiers age and eventually short out the power supply cap, which is an expensive repair. It can also help to reduce electro-magnetic noise (dead silent background?) and operate unit more stably and reliably.
Technology & parts
MOSFET technology is used to stabilize the voltage precisely, which offers faster rectification, and has the ability to address a much higher capacitance than the older tube rectifiers. Tube rectifiers are designed to handle only 50 microfarads (mf) at maximum, while MOSFET rectifiers can handle capacitances greater than 4000 mf. MOSFETs also offer far better reliability, and don't age as quickly as tube rectifiers. Tube rectifiers age, and eventually short out the power supply cap, which is an expensive repair. It can also help to reduce electro-magnetic noise ( dead silent background) and allow the unit to operate with more stability and reliably.
All components and each measurement which may improve sound performance or enhance the reliability of the unit have been carefully considered. StereoKnight designs and manufactures their units in a way to satisfy the most picky and ambitious audiophiles. For example, most wires connecting parts inside chassis are covered by TEFLON insulation --- (Teflon insulated wires are more suited to the higher working voltages. High voltages run on separate wires to avoid copper crystallization (whiskers, due to high voltage) --- between layers of fiberglass when high voltage is run on PC board traces. Teflon wire also has better thermic stability and can withstand higher current for a short time).
In addition, critical wires are hand made by compositing several kinds of selected enamelled wires in optimal proportions. We also use Japanese made POCC rectangular solid core copper wire as the wire in the signal path. This type of wire which is often used by the big brands to make high cost interconnect cables.
* Full balance design.
* High grade 600W EI type power transformer, extra wide band C-core output transformers (StereoKnight signature).
* High end components (Nichicon and Hovland capacitors), parts (StereoKnight designed heavy duty gold-plated binding post) and wire (TEFLON insulated wire and Japanese made POCC rectangular solid core copper wire) through the signal path.
* ZERO-NEGATIVE-FEEDBACK technology.
* ZERO noise: dead silence background.
* MOSFET voltage stabilisation.
* High control power (100WPC or 140W at 4 ohms), capable of driving a wide range of loudspeakers.
* Easily accessible individual output tube bias measurement, and adjustment points on the side of the chassis.
* Detachable IEC power cord, high quality gold-plated StereoKnight custom binding posts and RCA jacks.
* Full high quality aluminium alloy body construction, power meter in faceplate and acrylic enclosure cover design: sturdily and artistically built.
Item: Cambridge Audio 540P "Special" MM Phono Stage
Price: 150 (including postage anywhere in Australia)
Item Condition: Excellent like new
Reason for selling: Funding for fixing a vintage amp that just bougth
Payment Method: Pickup - Cash, Paypal, COD Only
Bought this amp on last November from here. I'm including the information provided on the previous post as it's pretty much on the same condition:
This is the special upgraded version of the popular 540P which takes it far beyond entry level and competes with more expensive units. The power supply capacitors have been professionally upgraded to Panasonic FC and coupling capacitors to Elna Silmic. Op amps are upgraded too. This is based on the "Hypnotoad" recipe with the removal and upgrade of cheap Chinese parts to audiophile standards. The result is a much more open, articulate and dynamic sound. This is a great phono stage for the money.
Here is a link to the forum which the modded Cambridge Audio phono stage was tried and shows how much of an improvement it made. http://audiokarma.org/forums/index.php?threads/modded-640p-giant-killer-phono-stage.346388/
I'm selling it for the same price I paid, the price include postage anywhere in Australia
By Red MacKay
Item: Cambridge Audio Azur 640P-B, mm/mc phono
Location: Box Hill South, VIC
Item Condition: Excellent
Reason for selling: Upgraded
Payment Method: Pickup - Cash, DD, Paypal to Friends. Can post at cost.
I bought this here about two years back and used it for a bit on my old Pioneer deck.
I can't help myself though and replaced it with many other phono units along the way spending lots of dollars!
It works a treat and is a great little unit.
It does both MM AND MC. Just a flick of the switch on the back of the unit to select either.
So you can have two arms on your deck attached at the same time if you want.
It also has a handy subsonic filter you can switch in or out on the back of the unit too.
Comes with original wallwart power supply too.
The current new replacement for this unit is around $350.
I also have the original box and am happy to post at cost.
Item: Matched pair of TJ Full Music 45/n mesh-plate SET tubes - Near New!
Item Condition: Near new, perfect.
Reason for selling: Not used, downsizing valve collection.
Payment Method: Pickup - Cash, Paypal, COD Only
These TJ Full Music 45/n mesh-plate SET tubes came stock with my tube pre-amp. They are great sounding tubes, and look super great too with their large balloon shaped glass envelopes and the way the filaments light up the plates.
I have since amassed a large collection of other 45 (and other) tubes and am now wanting to downsize the collection.
These TJs have at most 150 hours on them (light use a couple of times a week for first ~6 months of owning the pre-amp). So these tubes are pretty much still brand new. They've been stored safely in their original boxes for the last few years, unused. I just plugged them in now to make sure they still work , which they do perfectly ! (see pics attached).
Come with their original boxes and paperwork (again, see pics attached)
I will post to anywhere in Australia using Express Post with tracking and extra cover. Buyer to pay shipping costs.
SOLD: FS: (Perth) Electro Harmonix 6H30Pi EB Gold Pin Cryo Certified Matched Pair (for Audio Research preamp)By MAXXX
Item: Electro Harmonix 6H30Pi EB Gold Pin Cryo Certified Matched Pair (for Audio Research preamps)
Location: Perth, WA
Item Condition: Used less than 50 hours
Reason for selling: Not needed, sold my AR LS17 preamp with factory tubes.
Payment Method: Pickup - Cash, PayPal, COD Only
Extra Info: Cryoset Certified MATCHED PAIR of 6H30Pi (for Audio Research preamp). FREE postage for Australia.