Tag Archives | cryo valves

Cryo Valves

Watford Valves was the first company in the world to offer a cryogenically treated valve brand range showing huge commitment to the proven scientific cryogenic process.


What are Cryo valves?
Cryogenic treatment involves putting components into a chamber that is slowly filled with liquid  nitrogen, reducing the temperature to a very frosty minus 195 degrees Centigrade over a period of approximately 12 hours. Having reached this temperature, treated items are then held for what’s called the ‘soak phase’, which is about another 12 hours at minus 195C, before being slowly returned to room temperature over yet another 12 hour period.

Why use Cryogenic process?
Cryogenic treatment re-aligns a material’s crystalline structure to a more uniform state, removing the stresses introduced during the manufacturing process.

Watford Valves deep cryogenically treated valve range offers the musician and audiophile valves which are not only specially selected and tested, but are cryogenically treated for the ultimate performance. We also offer a full range of cryogenically treated valves made by the great factories of the past, such as Mullard, Telefunken, Philips as well as modern brands such as Groove Tubes, Tube Amp Doctor, JJ Electronic (formally Tesla), Electro Harmonix and Sovtek. So whatever is your preferred make Watford Valves will have a cryogenically treated version in stock.

What are the benefits of using cryogenically treated Valves?
The cryogenic process offers permanent change to the metals microstructure. The reduction in electronic noise improves the valves noise floor leading to lower microphonics. Until now clear note definition, musical complexity and rich harmonic content was only attainable by using rare and expensive new old stock classics.

Many guitarists have found the dramatic effect cryogenic treatment has on the way the valve performs not only in clean applications but also when overdriven. The cryogenic process removes the harshness from the valves tone and imaging has more focus and bite. It has a warmer sound which is pleasing to listen to, providing a clear and musical distortion. In short, many musicians, engineers and audiophiles have found that by using cryogenically treated valves it is a proven way of obtaining NOS sound quality with a great difference, an affordable price!

Watford Valves offers a full range of cryogenically treated valves – high quality at an affordable price.

The Harma ECC83-STR Cryo has the most neutral and warmest sounding with the Classic vintage tone when compared to all the current production ECC83/12AX7 types. This is our most popular valves as it has provides medium to high gain with a warm balanced vintage tone.

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The Harma ECC83 Retro CRYO is a true sounding recreation of the famous Mullard ECC83.

Unlike many tube suppliers, we are not interested is a look alike copy we are interested in the sound.

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EL34/HARMA-RETRO-CRYOEL34 Harma Retro Cryo   

The Harma EL34-Retro is based on the famous Mullard EL34 and has a number of important features over standard EL34 types. The grids of the tube use a block construction this enables the valve to provide smoother output and eliminating odd order harmonics.

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The Harma 6L6GC Retro is a re issue of the famous Sylvania STR 387 that was produced for Fender in the early 1970s.This was one of the most famous 6L6GC and sought after for it balanced and clear sound. The valve features thick mica spacers and internal bracing which reduces vibrations and microphonics.

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EL34-SVETLANA/WINGED C CRYOEL34 Svetlana Winged C Cryo
The Svetlana EL34 has become standard equipment in Marshall Amplifiers for many years now. The design is based on the famous Mullard EL34. The constructions see a laminated alloy used for the plate construction which helps heat transfer under overload conditions.

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The Svetlana 6L6GC was designed based on the famous Sylvania STR 387 6L6GC and manufactured in the JSC Svetlana factory in St. Petersburg, Russia. These are the Original Svetlana 6L6GC which are also known as Winged C due to the company’s original trade mark logo that is on the valve.

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These Cryo Groove tube 6L6GC GE reissues offer a considerable improvement over the standard item. This makes this one of the best modern made 6L6GC available today as you simply get more of the good things this valve has to offer. All out put valves are then dual matched by us on current and gain. This will ensure that you get the best selected GT valves available anywhere in the world

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Marshall Original Superlead 1959 100 watt head Classic EL34 Retro Cryo full upgrade kitMarshall Original Superlead 1959 100 watt head Classic EL34 Retro Cryo full upgrade kit

The Marshall Original Superlead 1959 Classic Retro full revalve kit is specially selected for Marshall 1959, 1959S, 1959X & 1959 SLP 100 watt Heads. The Classic Marshall kits are designed to give your Marshall as close to the old Mullard tone as possible. This is done by using modern day production valves that are traditionally voiced and then getting the sonic improvement that Cryogenic treatment brings to the valve. The cryo treated valves have a smoother distortion with more detail and clarity. The valve has more bite and better focus and they produce a sound that is only attainable by using very expensive new old stock valves.

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Orange AD30 Classic/Retro Cryo full revalve KitOrange AD30 Classic/Retro Cryo full revalve kit

Orange AD30 Classic Retro Cryo full revalve upgrade kit covers both the AD30 combo and AD30 Head. It is designed to give your AD30 as close to the old Mullard tone as possible.

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This Classic Cryo upgrade kit covers the Black Star HT CLUB 40 combo and is designed to provide the ideal combination for those who demand a tight driving rock sound with plenty of rich sustain. This combination designed to give you the classic British sound with more top end bite.

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Find out more information on the Guitar Buyer review which was published in 2006 (prices are not applicable) – http://www.watfordvalves.com/pdfs/guitarbuyer_Watford_4mt.pdf

The cryo-treated tubes definately sound different; that’s to say somewhat glassier, more edgy and with more punch and definition. – Guitar Buyer


Just wanted to say thanks for the advice on choosing the Harma Retro Cryo revalve kit for my Blackstar HT60 Soloist. It has made a decent sounding amp into a fantastic sounding amp – much clearer, more open and just generally bigger sounding. Best valves I’ve had in the amp by miles.

Andrew Johnstone

Thank you Derek. The last matched pair are in a Copland CSA-14 (6922 Harma Cryo Feb ’14). They are used as phase splitters between the preamp and power amp stages. In my opinion they are the best sounding valves I have heard in this amp. The sound is highly detailed and incredibly smooth in the upper frequency’s, breath taking in the vocal range and tight, punchy and very rhythmic in the bass. Thank you for a great product. Kind regards

Martin McCabe

Hi Derek!

Your Harma Cryo valves compare extremely well to Mullard EL34 Xf2’s and GEC KT66.

Having shelled out for sets of Nos valves in the past for comparison i know what i’d buy now.

These were used in a Plexi Superlead clone i built and a JTM45 Bluesbreaker of my own layout & spec with Danbury transformers.

Also put Harma 6L6’s in a Peavy Deuce combo for keys (piano and synth) and they were great.

Best Regards

Andy Mazur, Guitarist & Amp Tech