Stocked Valves

We stock a range of triodes and pentodes that we recommend and have tested in our amplifiers and pre-amps.

All valves are new, old (or original) stock (NOS), not re-released valves and were purchased from Russian government surplus stores and auctions. Most were bought and supplied in their original factory boxes. Some older valves are marked with the Cyrillic CCCP logo (SSSR; Soyuz Sovietskikh Sotsialisticheskikh Republik, the former Union of Soviet Socialist Republics or USSR). Many of the Military or MIL grade valves bear the OTK stamp from military quality inspection. Some, typically rarer, more expensive valves, were bought in lots/quads when they could be found.

All of the valves we stock sound fantastic and the differences between the sound produced by each type are very subtle. In the input stage we have also tested NOS Tesla and Siemens E88CC and brand new ElectroHarmonix 6922EH Gold valve - which are very similar (identical?) to the 6N23P-EV. In the outputs we have tested successfully with original Mullard EL84s, original Cossor 6BQ5s and new Bugera and ElectroHarmonix EL84s.

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Picture of a main board


Ordering Valves

If a valve we stock is available in its original individual box, the listing will state NIB, otherwise the valves will be supplied individually wrapped for protection. (New boxes are available, if requested, for non NIB valves). All valves are thoroughly tested before dispatch to ensure they perform as expected (for their type and age) both in bespoke test equipment for comparison with their datasheet and in our products, for their sound quality.

If valves are bought in pairs/quads for use in our amplifiers then they will be supplied with basic matching to work with our amplifier. This means they will be matched, for current gain or signal gain (depending on their application and where it matters) to within 10% of each other. Premium matching is available at extra cost if matching accuracy of 5% or less is desired. Platinum mathcing (3% maximum variation) is also availabe. Please do talk to us about valve choice and matching.

Datasheets are available for all stocked valves on request. The following is the list of valves we stock and their price (each). Valves are available in small quantities and are intended for use with and are tested for use in our products.

Prices are inclusive of VAT which will be charged at the rate applicable at the date of sale, currently 20%. Postage and packing will be charged depending on the number of valves purchased and the service required, e.g. First or Second Class, Signed for, Parcel Force Tracked 48hr etc.


Triodes

(Click on image thumbnails to view a larger picture)

Getter Supports: S (Non-MIL version Single), D (MIL ruggedized Double), T (MIL ruggedized Triple)
Pins: S (Silver colour - plated), G (Grey)

Image Valve/Tube Cyrillic/OEM Brand Date Codes OTK MIL Getter Support Pins Box Comments/Description/Observations
6N1P 6N1P 6H1П Russian Various S G Bulk These are Voskhod but no rocket logo, great sounding valves. 3000 hr life.
6N1P 6N1P 6H1П Voskhod '81 & '86 S G Bulk The classic 6N1P tube from Voskhod, Kaluga, great sound. 3000 hr life.
6N1P-EV 6N1P-EV 6H1П-EB Voskhod '84, '88 & '90 Yes D S Bulk MIL ruggedized version of the 6N1P, a great valve. Extended life 5000hr.
6N1P-EV 6N1P-EV 6H1П-EB Nevz '72 Yes D S Bulk Nevz version of the 6N1P-EV.
6N1P-VI 6N1P-VI 6H1П-BИ Nevz '88 & '90 Yes D S NIB The 6N1P-VI version is optimised for pulse operation, i.e. high peak current. Great for a driver or low power triode output stage; impeccable as your input gain stage. MIL ruggedized, 3000hr.
6N6P 6N6P 6H6П Nevz '80 to '87 S G Bulk Taller tube, higher power, lower gain, double triode, designed for audio. Great as an input gain stage, driver or triode output. Sounds similar to the 6N23P-EV i.e. excellent! 2000hr.
6N6P 6N6P 6H6П Nevz '86 Yes D S Bulk If you have plenty of input signal amplitude, the 6N6P is a great valve for your input gain stage. With a power rating of 4.8W/triode (8W total) the 6N6P is also prefect as a driver or triode output. 2000hr. These are all MIL OTK inspection stamped.
6N23P 6N23P 6H23П Voskhod '80 08 '83 01 '93 01   S G Bulk

The basic 6N23P valve from Voskhod all with the rocket logo - the earlier ones also bear the CCCP (SSSR) logo. Very open frame anode, heated cathode and grid clearly visible - very attractive valve with a fantastic sound. 3000hr.
6N23P 6N23P 6H23П Reflektor '67 to '74 Yes D G Bulk

A rare, MIL ruggedized, version of the basic 6N23P valve. Fully boxed anode, fantastic sound. (These are older valves; some of the logos and stamps are worn). Originally rated for 5000hrs.
6N23P-EV 6N23P-EV 6H23П-EB Reflektor '73 to '90 Yes D S New/ NIB Best of the bunch. Military ruggedized, extended life version. Stunning sound, real clarity and depth of sound. 5000hr.
6N23P-EV 6N2P-EV 6H2П-EB Voskhod '83 Yes D S Bulk Higher gain for lower input signal applications. Impeccable sound, Military ruggedized, extended life, in a factory box. 5000hr
6N23P-EV 6N2P-EV 6H2П-EB Voskhod '82 Yes D S NIB Higher gain, for lower input signal applications. Impeccable sound, Military ruggedized, extended life, in original boxes. 5000hr.




Pentodes

(Click on image thumbnails to view a larger picture)

Image Valve/Tube Cyrillic/OEM Brand Date Codes OTK MIL Getter Support Pins Box Comments/Description/Observations
6P14P 6P14P 6П14П Reflektor '80 to '91 S G Bulk The 6P14P is a great equivalent to the 6BQ5/EL84 pentode but with higher power capability, (14W not 12W anode power). 3000hr
6P14P-EV 6P14P-EV 6П14П-EB Reflektor '83, '84, & '89 Yes T S NIB/ Bulk Extended life, ruggedized version of this great pentode. Often re-branded as a premium EL84 or 7189 tube. 5000h.
6P14P-ER 6P14P-ER 6П14П-EP Reflektor '90s and 91-11 Yes T S NIB/ New Box The ultimate 6P14P/EL84/6BQ5 valve, only ever available for military use, 10,000hr rated. Simply the best of its type available. Like the 6P14P-EB - these are often re-branded. These are the original Reflektor 6P14P-ER valves.
6P3S 6P3S 6П6C Reflektor 1982 & 89/90 Yes N/A S NIB/ Bulk Russian Military output beam tetrode- not to be confused with the -E variant which has much lower Anode and second grid voltage. This is a solid, good valve. Near Equivalents; 6L6, 6L6GT, 6L6GC, 5881.
6P3P-J 6P3P-J Guigang 95 N/A S NIB Big bottle Chinese output beam tetrode from the factory that was (allegedly) bought by PSVANE. A beautiful valve to look at - and it sounds good too. All are tested thoroughly. Near Equivalent; 6L6GC. The -J denotes a higher level of quality screening.


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More information

We stock high quality commercial and MIL grade, ruggedised valves. In addition to an increased level of testing and quality inspection during production, MIL grade valves employ a number of techniques to make them more resistant to vibration in service. This is not essential for domestic audio use but there are advantages which include: higher quality, often an extended rated useful life as well as lower microphonics. 'Microphonics' is the term used to describe what happens when external vibrations, including loud music, are transferred mechanically to the internal components of the valve so it acts like a microphone, adversely affecting audio quality. We have not experienced any microphony problems with any of the valves we stock for use with our products.

'Military' grade valves

How are MIL spec valves made more rugged? We'll start with the 'cage'. The cage is the internal body of the valve where the components of the valve (anode plates, heated cathode, heaters and grids) are supported between the top and bottom Mica supports. It is quite delicate. MIL grade valves tend to have higher quality connections between the pins in the base of the valve and the components in the cage and don't just rely on these connections to support the cage but have additional supports to the pins.
MIL grade valves often use double or even triple layers of Mica for the top and bottom of the cage.

These Mica plates hold the valve components in place, maintaining the small gaps between the anode, cathode and grid and isolate them from the glass envelope, or tube. The heated cathode and plates of the anode will have more support, often being completely 'boxed' in so the grids and cathodes are barely visible and the getter ring/plate will have more than one mechanical support. The 'getter' is the very thin layer of reactive metal deposited on the inside of the valve glass body (by induction heating the getter material). The getter's appearance varies, is usually silver, like a mirror, on the inside of the valve and darker looking from outside the valve. The reactive metal of the getter traps atoms of reactive gas left behind in the vacuum in the valve improving (or hardening) the vacuum and so life and performance of the valve. If the getter is transparent, blotchy or white, it's a sure sign of a broken vacuum and if the valve is still working, it may not be for long!
Note that even if the getter looks perfect, the vacuum in the glass tube is never perfect (that's very hard to achieve, even in space!) and over time smaller atom size gasses can leak in past the vacuum seals. In extreme cases valves can become 'gassy' as the vacuum gets weaker - this can cause an abnormal amount of blue luminescence to be generated in the valve when its working (some blue luminescence is not a problem and can look very attractive!)

(As to whether or not Military grade valves sound better - this is a very subjective topic and again there are a lot of fact based theories and even more opinions on this. All we are prepared to comment is that they should last considerably longer than a commercial equivalent (and they are quite a lot harder to break if you drop one by mistake!)

Valve Operational Life

Valves are very similar to old-style tungsten filament lamps - they have a finite life - they are a consumable. (The Russian for a valve is Lamp!).
The rated 'life' of the valve is VERY dependent of how hard they are driven (typically how close to maximum power and/or heater voltage) and is the minimum rated operational life of the valve specified by the manufacturer.
It varies as to whether this is specified at normal operating conditions, or at maximum power, maximum heater volts and worst case operating conditions (more applicable to MIL valves). Over a long time (i.e. decades) the performance of the valve can degrade - even (especially!) if it's never switched on and the rate of degradation depends, to a degree, on how well the valve has been stored (constant temperature and humidity) before we got them. This is usually seen on test, by a valve having a lower emission than specified, i.e. it conducts less current for a given anode and grid voltage than specified and exhibits a lower transconductance (mA/V) - Ia and S (or gm). We have also seen higher anode resistance (Ra) - this can also mean that the valve generates a higher voltage gain and may produce more noise (hiss). This is why we test all of our valves and why the rated life cannot be guaranteed.

One of the ways that MIL spec valves can achieve an exrtended operational life is to limit the range of acceptable heater voltages that can be used. Typically a MIL spec valve will state a heater voltage in the range 6.0 to 6.6V where a commercial equivalent is rated for 5.7 to 7.0V. This only really has an impact on the importance of selecting the correct mains transformer input tap for the amplifier's mains supply. Higher heater voltages mean higher current gains, but lower valve life!

This is less of a problem for input and driver valves, which, provided the heater volts are correct, are hardly stressed and will last for many years.
The life of the output valves will depend on how the amplifier is configured. If the amplifier is set for pure Class A push-pull, for example, the valves spend the entire time they are switched on at close to maximum power; this reduces their effective life. This is one of the reasons our default configuration is Class A, with the output valves biased to about 55% of maximum valve power, reducing the stress on the valves so they last longer. It also wastes less energy. (The nature of the amplifier output stage means it operates in Class A Push-Pull for lower volumes, migrating seamlessly to class AB at higher volumes).

If you think your input valves are getting tired and noisy or lacklustre - it's probably time to try a new pair. (Why not take the opportunity to try a different type or upgrade?)