Harma Valves / 5881-HARMA

5881-HARMA 5881-HARMA Click on image(s) above to view larger

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A test report is available click here to view

Harma valves consist of a selected range of valves that are chosen after meeting stringent standards for sound quality and reliability. These valves are sourced from current production as well as some of the finest Nos valves available. Unlike our competitors no Harma valves, past or present has been made in China. Harma valves represent the finest available items of their type available.

Harma valves are tested using a range of custom designed and built test rigs which are unique to Watford valves.These unique tests are not offered by any other valve supplier in the world.

All Harma pre amp valves undergo the drive rating system; the valve undergoes a series of through tests under full operational conditions. This involves a controlled burn in process to ensure perfect stability and correct ageing. A shock and vibration test, microphoney, hum, and a balance and symmetry test.

All Harma output valves undergo our own unique real world burst testing. No other supplier tests valves this way. The burst testing process involves a series of varying timed electrical signal bursts. This runs the valves under the same stress conditions that they will meet in your amplifier especially when overdriven. All out put valves are then dual matched by us on anode current and gain. This will ensure that you get the best selected valves available anywhere in the world.
The Harma 5881 is the original button based Russian military valve that powered the Marshall and Mesa Boogie amps (STR 425) in the late eighties. This valve has bullet proof reliability and proven track record over decades of use in Russian military applications.

This valve was designed to withstand 3G as it was used in the servo motors of Russian fighter Jets. The valves are made with highest quality military grade plate material for extended life in the most serve working conditions. Therefore they have a reputation for clarity and reliability. So when used in Guitar amplifier applications this valve is vibration and rattle free and will give many years of excellent service.

This is why Mesa and Marshall used this valve to power their high gain designs thought the 1980's and 1990's.

This valve produces a very tight and focused sound with immense attack.
When used in high gain circuits the valve produces a tight crunchy wall of sound which suits rock players.

If the valve is pushed with the pedals at the front end the 5881treble is forward and nicely aggressive without any fuzz. If you scoop out the mids then you still retain the punch and clarity unlike many other 6L6GC types.
For any extreme Metal, Hard Rock, Grunge or Fusion styles this is an ideal choice as this valve does not go thin and tinny like many other 6L6GC when pushed.

Here is Guitarist Paul Bacon email on fitting the Harma 5881

"I just want to say how pleased I am with the Harma 5881 valves.

I have had problems with the Mesa branded valves ever since I bought my Mesa Express 5:50 Amp. All the Mesa branded STR440 valves developed a rattle and added an annoying harmonic hum to the amplified guitar sound after a short time.
I replaced the Mesa valves each time but the problem would repeat.

I spoke to Watford valves who were very helpful, and suggested some Harma 5881 valves as a replacement.
I have used the new Harma 5881 valves in my amp for many months now and the amp remains free of any tube rattle and harmonic interference. ****Problem solved.****"

Thank you

Paul Bacon

All Harma Output valves are Dynamically Burst tested and undergo our own unique real world burst testing under real working conditions. The valve undergoes full drive testing which involves a series of varying timed electrical signal bursts that replicate the same stress conditions that the valve will encounter in your amplifier. Note No other supplier tests valves this way and why Harma valves have been used by the top Professionals. This is designed to ensure the ultimate reliability. The Harma valves have passed all the following tests:

Gain (m/A) Drive Tested)
Variable Signal Burst(Burst tested)
Transconductance (gm) Drive Tested
Output Drive Tested
Noise 1 (signal to noise)
Noise 2 (Aural)
Microphonics Test 1(Ambient)
Microphonic Test 2 (Shock)
Cathode Test
Grid Leakage Test

All output valves are then dual matched by us on anode current and gain. This will ensure that you get the best selected valves available anywhere in the world.



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