# The Leben CS-600 ~ An Introduction to Leben Tube Amplifiers *November 20, 2025 — Kasper Bergholt* This blog post, focusing on the Leben CS-600 and CS-600X tube amplifiers, began as a thorough introduction to vintage tubes after I bought a Leben CS-600 in 2024. It expanded to cover other Leben Hi-Fi Stereo Company amplifiers, from early models to their latest tube-based products, with a focus on integrated amplifier designs. In addition, it turned out to be the beginning of the[Objects for an Ideal Home series](). ![Black-and-white photo: four Russian 6P3S-E \(6П3С-Е\) vacuum tubes lying on their sides, pins facing the camera, beside CD editions of Bill Evans's 'The Paris Concert II.]() *Four Russian 6P3S-E (6П3С-Е) output tubes lying next to three different CD editions of[‘Bill Evans: The Paris Concerc II’]()album from 1984 (the concert was recorded in 1979).* ## Key features of the Leben CS-600 - Excellent build quality – I expected a lot, but the amp exceeded those expectations: substantial weight, robust build, refined finish, and exceptionally smooth, precise controls - Aesthetically superior - A completely silent background, regardless of the input source - Numerous inputs supporting a wide range of configurations - The option to connect a dedicated preamplifier via the ‘pre-amp in’ inputs - Tape out, which I use to connect a USB sound card to do sampling from vinyl records - High resale value. - Balance and bass boost function (which I don’t use) - Headphones output - Compatible with a wide range of output tubes - 6CS7 input tubes very reasonably priced when I got it - Sufficient power output for a wide range of speakers (28 watts with EL34 family and 32 watts with 6L6 family) of output tubes - Heavy-duty power transformers - Wide range of impedance settings to match different speakers - Possibility of bypassing several circuits using the tape-in connections - Rock-solid stability and flawless operation - Differences between the Leben CS-600 and CS-600X ## Input and output tubes in the Leben CS-600 vs CS-600X Both the Leben CS-600 and CS-600X have four driver tubes facing the listener – behind these are four output tubes. In the driver stage of the CS-600X there are two 12AU7A and two 12BH7A tubes; in the Leben CS-600 all driver tubes are of the[6CS7 variety](). In the CS-600X the distribution of driver/preamplifier tubes is: 12AU7A; 12HB7A; 12AU7A and 12BH7A. In addition, there’s a 6CJ3 damper tube in the CS-600 and a 6CM3/6DN3 damper tube in the CS-600X. ![Quad of Sovtek 5881 / 6L6WGCoutput tubes for the Leben CS-600. These are the tubes my amplifier came with installed from the factory.]() *Quad of Russian-made Sovtek 5881 / 6L6WEGC output tubes. These are the tubes my amplifier came with – along with four Raytheon tubes for the driver stage.* ## A word of warning on changing tubes From the Leben CS-600 manual:*“Before removing a top cover for replacing tubes, please confirm the power cable is disconnected and the tubes are cooled down”.* ![Box of four 6CJ3 tubes from General Electric. My Leben amplifier came with a 6CJ3 damper tube from General Electric from the factory.]() *Box of four 6CJ3 rectifier tubes from General Electric.* ## Yoshi Hontani on tube placements I’ve corresponded with Yoshi Hontani, Leben’s Japanese distributor and general contact for the English-speaking world, who explained tube positions this way: The two left tubes are for the left channel; and the two right tubes are for the right channel. This gives us:*Tube 1 (from the left) is the first stage for the left channel;**Tube 2 (from the left) is the second stage for the left channel;**Tube 3 (from the left) is the first stage for the right channel;**Tube 4 (from the left) is the second stage for the right channel.* The selection of driver tubes for the CS-600X is much broader, offering both the option of NOS (New Old Stock) tubes and modern production tubes. Many seem to prefer the sonic signature of the older brother because it’s more transparent, precise, airy with a wide sound stage, whereas the CS-600X is more lush, warm and what could be termed tube-like in character. Another difference between the two is the choice of damper tube used in the amplifier design. One uses a 6CJ3 damper tube, while the other uses a 6DN3 damper tube. ![6CJ3/6DN3 damper tube in Leben tube amplifier sitting next to the cathode switch on the one side and an EL34 RFT output tube on the other.]() *6DN3 damper tube in the Leben CS-600 tube amplifier sitting next to the cathode switch on one side and an EL34 RFT output tube on the other.* ## Tube upgrade set for Leben CS-600 ![Four twin-triode 6CS7 tubes and one 6CJ3 damper tube from American producer General Electric.]() *Four twin-triode tubes for the driver stage of my Leben amplifier and one 6CJ3 damper tube produced by General Electric. All tubes New Old Stock and New in Box.* ## Bypassing the input selector in the 600 and 600X In a recent review of the CS-600X it’s suggested to use the tape-in input to bypass the input selector for improved sound by a shorter signal chain: “Incidentally, you’ll get better sound from the CS600X using the tape monitor input rather than the regular line inputs. Why? Because the tape monitor bypasses the main selector, resulting in a shorter more direct signal path. Try it!” With a setup of this caliber, and considering the price of the amplifier, I thought it wise to ask Leben directly if this was a safe and recommended way of connecting things. “In a recent review in (Stereonet) it’s suggested to use the tape-in input to bypass the input selector for better sound, see below. Is this considered safe / beneficial use of the function if no recording device is connected to the tape-out? Yoshi Hontani replied quickly: “Yes, this is true. You can use the TAPE MONITOR directly to receive a Phono input (for example).” “I’m planning some comparative listening sessions to hear whether this setup makes a meaningful difference. ![Leben CS-600 tube amplifier. Cameras use: Pentax K10D.]() *Leben CS-600 tube amplifier. Camera: Vintage[Pentax K10D]()and Pentax SMC-A 50mm f/1.2 lens.* ## On tube-rolling / tweaking: Blessing and curse Of course these characteristics change with different tube combinations, and that’s one of the charms that attracts some people to tube amplifiers. Over time our hearing evolves, our preferences shift, our speakers can change, our RIAAs and DACs, the synergy of which can be tuned by different choices of preamplifier and driver tubes. Admittedly, this can also be a curse, an ongoing tweaking and split testing potentially leading to an overemphasis on voicing at the expense of the actual listening experience. In a sense, I think Leben’s motto ‘A Motion Sound’ is an attempt to transcend the more analytical layers of the Hi-Fi experience – I find people usually reflect on a movie before and after watching it, not during. ![The three heavy-duty transformers in the Leben CS-600 with the text: 'Leben' - Leben Hi-Fi Stereo Company, 'A motion sound'. These contribute to CS-600's weight of 22.5 kilos.]() *The three heavy-duty transformers with the text: ‘Leben’ – Leben Hi-Fi Stereo Company, ‘A motion sound’. These contribute to the amplifier’s weight of 22.5 kg.* ## Supplies of 6CS7 tubes have dried up lately The supply of NOS (New Old Stock) 6CS7 tubes has quickly been depleted during the last couple of years. “The Tube Store,” the American reseller of vacuum tubes has addressed this issue on their website, providing a notice stating that their supply is extremely limited in comparison to earlier, and as a result they are no longer able to offer matched pairs or quads of 6CS7. “Note to Leben \[CS-600\] amplifier owners, we do not have matched sets at this time. These tubes are very difficult to find. Only odds and ends of various brands available,” The Tube Store, August, 2023. In general this phenomenon is called “Vacuum Tube Extinction” and is something one should be aware of when investing in a tube amplifier. The CS-600X manual has a section on why 12AU7A and 12BH7A tubes were chosen for the new first stage of amplification: A huge quantity of these tubes (12AU7A and 12BH7A) were produced by many manufacturers in the past and many high quality NOS tubes are available on market, therefore, you have a chance to try several different NOS tubes by replacement. Apart from it, these tubes are still being produced for musical instruments and for audio amplifiers as well, and there is no fear of replacement tubes in future as well. To sum up, only 6CS7 tubes can be used in the CS-600 , and only 12AU7A (ECC82) and 12BH7A tubes can be used in the CS-600X. ## Circuitry in the CS-600X from the CS-600X manual “After the first stage amplification by SRPP through the first triode unit of 12AU7A and 12BH7A, make a phase reverse by Mullard type cathode connection through the second triode units, then transmit to the last stage. Self-biasing circuit (Auto-biasing circuit) will protect the output tubes EL34 (or 6L6) from damage. A characteristic of the damper tube(6CM3/6DN3) is to raise a high voltage gradually, which will affect very much to extend a life of the output tubes.(6DW4B also can take place of 6CJ3). The Bass Booster of CS600X is controlled by capacitors arranged on the “NFB loop”, that is a very rare method. Bass(or treble) control is normally controlled by a tone control circuit, however, the above method makes the circuit much simpler. Furthermore, in order to cut a negative influence of the Bass booster to the middle frequency, 15Kohm resistor(filter) is arranged in the circuit.” Text quoted from Leben CS-600X manual. ![Three Russian output tubes in the same family: 63PS, 63PS-E and Sovtek 5881/6L6WGB.]() *Three Russian output tubes in the same family: 6P3S, 6P3S-E and Sovtek 5881/6L6WGB.* ## Leben CS-600 factory specifications *Tubes employed:* 4 X 6L6GC (5881) (output tubes) 4 X 6CS7 (input / driver tubes) 1 X 6CJ3 (6CM3) *Output power: 32W X 2 (6L6GC)**Frequency response: 10 Hz – 100 kHz (-0.1 dB). THD: 0.7% -(1KHz/10W)**Input sensitivity: 900 mV at 20 W.**Output impedance: 4/6/8/16 ohms (selectable)**Headphone output: 1000 mW.**Dimensions/size: 450 (W) x 360 (D) x 142 (H) mm. Weight: 22.5 kg.* As far as I know, there haven’t been any changes to these specifications. ![Russian 6P3S-E output tubes, 80s made by Refletor. The Both the Leben CS-600 & CS-600X are compatible with this Soviet 5881 equivalent. See the settings table for optimal settings. I run with both switches up \(both diodes showing red when the amp is on\).]() *Russian 6P3S-E output tubes, 80s made by Reflector. Both the Leben CS-600 and CS-600X are compatible with this Soviet 5881 equivalent. See the settings table for optimal settings. I use both switches in the up position (both diodes showing red when the amp is on).* ![Linlai KT88 tube in the front - cathode/resistor toggle to the left. Four 6CS7 Sylvania tubes to the left - of which the last is only slightly seen.]() ## Tube settings table / overview of output tubes ![Leben CS-600 cathode and resistor selectors making it possible to use both out tubes in the EL34 and the 6L6 family.]() *Leben CS-600 cathode and resistor selectors making it possible to use both output tubes in the EL34 and the 6L6 family.* ![Chart showing the recommended settings for 6L6, EL34, 6CA7, 5881, KT77, 6L6GB, 350B, KT66, KT88 and 6550A output tubes, which can all be used in the CS-600 \(and CS-600X\). Note that the tubes marked with \* can only be used with the amplifier's lid removed. The chart is copied from an original Leben CS-600 manual.]() *Chart showing the recommended settings for 6L6, EL34, 6CA7, 5881, KT77, 6L6GB, 350B, KT66, KT88 and 6550A output tubes, which can all be used in the CS-600 (and CS-600X). Note that the tubes marked with \* can only be used with the amplifier’s lid removed. The chart is copied from an original Leben CS-600 manual.* ## 6L6, KT77, 6L6GB, 350B, KT66, KT88, 6550A There is a wide selection of tubes currently in production from different manufacturers. In addition to the 6L6/5881 and EL34, both amplifiers are compatible with KT77, 6L6GB, 350B, KT66, KT88 and 6550A tubes. Some of the tubes are considerably taller than the classic 6L6/5881 and EL34, so you’ll need to remove the lid to use these. In this way, the design accommodates both tube collectors who were lucky (or clever) to buy NOS tubes when the prices were at a completely different level from what they are now for the best tubes from the best brands. ![Quad of EL34 outputs produced by German RFT marked 'Philips' on both the tubes and the boxes.]() *Four EL34 output tubes produced by German RFT and marked ‘Philips’.* ## 6CJ3 damper tubes in Leben amplifiers The Leben CS-600 and the Leben CS-600X both employ so-called damper tubes in their designs. The CS-600 utilizes a 6CJ3 tube, and the CS-600X uses a 6CM3. ![6CJ3 damper tube, used in amongst others the Leben CS-600 amplifier. Beautiful writing on the silvery background of the tube. Photo: Kasper Bergholt.]() *NOS (New Old Stock) 6CJ3damper (used in the Leben CS-600 amplifier) tube from Lindahl.* ![6CJ3 NOS tubes from General Electric. The Leben CS-600 design uses one of these for a damper tube function. Photo: Kasper Bergholt.]() *6CJ3 NOS tubes from General Electric. The Leben CS-600 design uses one of these for a damper tube function.* ## EL34 RFT tubes including measurements on Roetest V10 tester My first experiment with another type of output tubes is four New Old Stock EL34 tubes by the German manufacturer RFT marked ‘Philips’. The tubes are now on their way from Croatia. Testing them out is a project for the near future. RFT stands for Rundfunk- und Fernmelde-Technik. Below are the measurements for each EL34 tube performed by a professional on a Roetest V10 tube tester. I’m looking forward to listening to these and compare them to the stock 6L6 Sovtek tubes the amplifier came with from the factory. ## Current setup ***Leben CS-600:**Sylvania, General Electric, Raytheon, Dumont, Tung Sol 6CS7 tubes, black and gray plates+ Russian 6P3S-E output tubes (Reflector, New Old stock), Philips EL34, Sovtek 6L6GC / 5881. 6CJ3-family damper tube (General Electric, Sylvania, Raytheon).* **Speakers:***Harbeth M30.1 speakers. I use Snell K II speakers for reference.* ***Tonearm cable:**Yannis Tomé Audio Cables, Coppercord, Silverord Duo24.* ***Interconnect:**Yannis Tomé Audio Cables, Clio silver, Coppercord, Silvercord Duo 24. For reference: Belden 8402.* ***RIAA:**Leben RS30-EQ RIIA (Hytron 6X5GT rectifier tube + two Telefunken ECC81s)* ***Turntable:**Project X2, with upgraded RCA connectors* ***Cartridge:**Goldring 2400* ***Speaker cables:**Mogami 3103. Pearl Street Station speaker cables (Duelund-inspired), solid-core copper in cotton and linseed oil.* --- ## A Short History of Japanese Leben Hi-Fi Stereo Company *Leben Hi-Fi Stereo Company, established in 1995, is a Japanese manufacturer of high-end tube-based preamplifiers, power amplifiers and integrated amplifiers, and, so far, a single tube-based RIAA, the Leben RS30-EQ.* Leben is a German loan-word that translates to ‘to live’, ‘to be alive’, ‘lively’ or simply ‘to exist’. Newer models contain the tag-line ‘*A motion sound*‘ adding a feeling of experiencing music in a Haruki Murakami-like atmosphere. ![Transformers in a Leben tube amplifier with the text: Leben. Leben Hi-Fi Stereo Company. A Motion Sound.]() *Transformers in a Leben tube amplifier with the text: Leben. Leben Hi-Fi Stereo Company. A Motion Sound.* ## Taku Hyodo, Leben’s founder Taku Hyodo, an experienced audio engineer with a past working for Luxman, is a collector of new old stock vacuum tubes, for example 6X5GT, 3CSS, 12AT7, E288CC and 6L6GCs, in addition to being a music lover with a professional background playing the guitar. At 60, Hyodo left Luxman in 1979 to establish his own company, “Kouri Denki Corporation”. He kept designing and constructing amplifiers under the ‘KFH’ brand name – primarily custom-made products for café, bars and restaurants, also a somewhat Haruki Murakami-like project. ## The first product to hit the market, the ‘Triode 33’ Mr. Taku Hyodo’s first commercial product to see a broader market was the ‘Triode 33’ power amplifier released in 1991 followed by the RS-35A 6L6GC tube-based power amplifier under the Leben brand in 1995. ![U.S. Arny production of 6X5GT/G tubes from Sylvania Electric Products INnc. Production date: June 1945.]() *U.S. Army production of 6X5GT/G tubes from Sylvania Electric Products Inc. Production date: June 1945.* Leben released the RS-28C preamplifier (equipped with E288CC tubes) in 1998. To cater to a wider range of audiophiles, Leben subsequently introduced a series of more affordable amplifiers: the CS-200, CS-250, CS-300, and CS-300X, released in 2001, 2002, 2003, and 2005, respectively. ## Broader access to the products from Leben These amplifiers allowed a broader audience to experience the unique sound quality associated with Leben products. In 2005 Leben released the Leben CS-600 amplifier featuring four 6CS7 tubes for the driver stage and four 5881 or EL34 output tubes. The CS-600 was succeeded by the CS-600X in 2019, with the design remaining mostly the same, except for the type of driver tubes. ![Four Sylvania tubes - New Old stock - 6CS7 variety]() *Four Sylvania 6CS7 tubes.* Point-to-point wired tube amplifiers are rarely seen nowadays, as they require a skill set few modern workers have in the world of general mass production. Leben is one of few amplifier manufacturers that feature amplifier designs of this type thanks to a small number of highly skilled employees working in the company’s quarters in Nishi-Koya in Amagasaki City, Japan. --- ## The Leben RS30-EQ RIAA, 6X5GT & ECC81 Tubes ![Leben RS30-EQ RIAA next to aLeben integrated tube amplifier.]() In addition to a Leben tube amplifier, I’m also satisfied owner of Leben’s only RIAA so far, the Leben RS-30EQ, which both looks and sounds stunningly well. ![Goldring 2400 cartridge mountedon Project X2 tonearm, which feeds into the Leben RS300-EQ RIAA.]() *Goldring 2400 cartridge mounted on a Pro-Ject X2 tonearm, which feeds into the Leben RS30-EQ RIAA. Pentax SMC-A 50mm lens on Pentax \*istD S.* The RS-30EQ RIAA is based on a circuit including a single 6X5GT rectifier tube and two 12AT7s Jan Philips tubes. The European designation for the 12AT7 is ECC81. ![Jan CHS 6X5XT/G / VT-126B - U.S. Army / U.S. Navy. Acceptance date June 1945. Produced by Sylvania Electric Products.]() *Jan CHS 6X5XT/G – U.S. Army / U.S. Navy. Acceptance date June 1945. Produced by Sylvania Electric Products for the US Navy & Army. Co-designated 6X5GT/G & VT-126B.* ## 6X5GT rectifier tubes ![Vintage 6X5GT rectifier tube from RCA \(Radio Corporation of America\). For use in for example Lebens' RS30-EQ RIAA.]() *Beautiful vintage 6X5GT rectifier tube from RCA (Radio Corporation of America). For use in for example Lebens’ RS30-EQ RIAA.* The image shows a vintage 6X5GT rectifier tube from the American manufacturer RCA, Radio Corporation of America. The 6X5GT is used in a rectifier role in a range of high-end audio designs, for example Leben and Audio Note UK (not to be confused with Japanese Audio Note Kondo, which I briefly introduce in this[blogpost on the a Sunbuck Kondo Audio Note KSL-M7 clone](). ![Leben RS30-EQ RIAA with ECC81 & 6X5GT tubes. The ECC81s are from Telefunken and was an upgade I made from the Electro Harmonix ECC81 the RIAA came with. The 6XGT5 is the Hytron rectifier tube the RIAA came with originally.]() *Leben RS30-EQ Riaa with ECC81 & 6X5GT tubes. The ECC81s are from Telefunken and was an upgrade I made from the Electro Harmonix ECC81 the RIAA came with. The 6X5GT is the Hytron rectifier tube the RIAA came with originally.* ## Substituting 6X5GT tubes with Bendix 5852 tubes – not a good idea! In different fora (and by certain vendors) it’s suggested to use a Bendix 5852 as drop-in replacement for the 6X5 or 6X5GT, and, in addition, that the Bendix 5852 should be the holy grail of tube rectification (e.g. in Audio Note DACs). A word of warning though: The Bendix 5852 draws 1.2 ampere, whereas the 6X5GT draws half of that (0.6 ampere). This means that the Bendix 5852 presumably will sound different (and better to some), but might be too heavy a load for the equipment’s transformer. ![Ambience black & white photo of four EL34 tubes in the front and three transformers behind the EL34 tubes in a Leben CS-600 integrated amplifier.]() *Ambience shot of Leben tube amplifier showing of four EL34 tubes in the front and three transformers behind the EL34 tubes.* ## 12AT7Ts/ECC81s in the RS30-EQ I was of the impression that Jan Philips 12AT7 (ECC81) tubes were installed from the factory in my Leben RIAA, which I bought about a year ago. I detected a general over-leanness in my setup (*Leben CS-600*, Leben RS-30EQ RIAA, Pro-Ject X2 Carbon, Goldring 2400 cartridge & silver cables from Yannis Tomé Analogue Audio Cables). ![Goldring 2400 pickup hovering over acryllic platter on a Project X2 Carbon turntable.]() *Goldring 2400 cartrdige hovering over acrylic platter on a Pro-Ject X2 Carbon turntable.* I thought the output tubes in the amplifier were to blame, or the silver cables or the Goldring 2400, which made me start looking for a set of NOS EL34 tubes instead of the 6L6/5881 Sovtek tubes the amplifier came with from the factory. ![Tube box for vintage Telefunken ECC81 tube for use in my Leben RS30EQ RIAA.]() *Tube box for vintage Telefunken ECC81 (US designation: 12AT7) tube for use in my Leben RS-30EQ.* ## Comparative listening: the Leben RIAA vs Marantz 65CD-II To calibrate my listening experience, I got a cheap Marantz CD65II CD player on eBay. After a couple of hours warm-up time it sounds astonishingly good despite being, or perhaps because of, being 35 years old. I used the same interconnect cable (Gaia series) that I use for the RIAA, which leaves three things to affect the sound: the tonearm cable, the cartridge and the Leben RS30-EQ itself. ![Three semi-rare Telefunken ECC81 / 12AT7 NOS \(New Old Stock\) tubes for use in Leben RS30-EQ Riaa. Two for use and one spare.]() *12AT7 NOS (New Old Stock) tubes for use in Leben RS30-EQ Riaa. Two for use and one spare.* ## Electro Harmonix 12AT7EH/ECC81 vs New Old Stock Leben has recently switched from Jan Philips military grade tubes to RFT Germany 12AT7 tubes in the RS30-EQ RIAA thought. But when I took off the cover to look at the tube compliments, they were from modern Electro Harmonix (type: 12AT7-EH ) tubes made in Russia, and not NOS / vintage GE’s as I had expected. By all means fine tubes, I don’t know much about them, but definitely calls for some experiments. ![12AT7EH tube from Russian manufacturer Electro-Harmonix. Present-day production in my Leben RS30-EQ \(which aquired around a year ago\).]() *12AT7EH tube from Russian manufacturer Electro-Harmonix. Present-day production in my Leben RS30-EQ (which I acquired around a year ago). I think this indicates that NOS/NIB tubes are getting scarcer and more expensive – especially if the setup requires a closely matched pair.* On my wish & to-do list is trying New Old Stock Siemens Halske triple-mica tubes for the RIAA, as I’ve had good results with this producer in my old tube-based preamplifier (an Audio Note M1). ![Tung-Sol 6X5GT- rectifier tube for use in Leben RIAA. Photo: Ksaper Bergholt.]() ## JAN CHS 6X5GT/G from June 1945 ![6X5GT rectifier tube. Marked Jan CH '6X5GT/G VT-126B. Acceptance date 6-45. US Army. Rarely seen in pairs with identical serial numbers. For use in e.g. the Leben RS-30EQ and some Audio Note DAC's too. Photo: Kasper Bergholt.]() *6X5GT rectifier tubes in original boxes. Marked Jan CH ‘6X5GT/G VT-126B. Acceptance date 6-45. US Army. They are rarely seen in pairs with identical serial numbers. For use in for example the Leben RS-30EQ and some tube-based DACs from Audio Note UK.* ## Tubes in the RS-28CX preamplifier with inbuilt RIAA In the Facebook Leben Hi-Fi group tubes are often debated as they have an influence on sound, some tubes in some positions more than others. Recently, there was a thread mentioning that Leben seems to have switched to newly produced tubes in the RS-28CX dedicated preamplifier. ![Project X2 Turntable]() *Sunlit corner of a Pro-Ject X2 turntable* Instead of New Old Stock General Electric J.A.N 6CG7 tubes in the line stage, new tubes from Electro-Harmonix. The phono stage, that is identical as I understand it to the RS-28CX uses two ECC81/12AT7 tubes. Here there’s been some recent changes too, where Leben has changed from General Electric ECC81/12AT7 tubes to ones from the German produced RFT. I can recommend the group for anyone seeking advice on all things related to Leben range of products, and Leben’s distributor towards Western countries, distributor, Yoshi Hontani, participates occasionally. ![Four Telefunken ECC81 & Siemens E81CC tubes for use in Leben RS30-EQ RIAA.]() *Four Telefunken ECC81 &¨¨ Siemens E81CC tubes for use in Leben RS30-EQ RIAA.* ## Leben RS30-EQ specifications *Tubes: JAN 12AT7A (General Electric) X 2. 6X5GT (General Electric).* *Gain: 23.5dB* *RIAA curve: less than+/-0.2%* *Input impedance: 47Kohm* *Max input: 400mV (2Khz.)* *Output voltage: 175mV* *Power consumption: 17W* *Weight: 6 kilos**Dimensions: 340(W) x 140(H) x 240 (d) mm* ---