ECC83-HARMA STR BALANCED ECC83-HARMA STR BALANCED 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.
Special balanced item with matched sections for use in phase inverter position, tube microphones or input positions where balanced operation is required.

The Harma ECC83 STR 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. This valve also has a low noise floor so it is ideal in high gain circuits if you want more clarity or simply calm down harsh circuit. This have also has some important features such as an internally rugged construction which is based around a frame grid design. The valve is made with thick mica supports. This has a number of advantages such as reduced microphonics and better isolation from vibration. The grids windings are all gold plated as were the original Telefunken valves.
This translates to excellent sonic and mechanical performance in high volume and guitar combo applications

This makes it a great choice for clear Fender sounds or warming up a harsh modern amp or taming a high gain circuit. This is one of the best modern ECC83. These valves are all selected for low noise, low microphoney and are drive tested with a gain rating of between 229 and 249 digital points give rich even sound.

All Harma preamp valves are Dynamically Drive tested under real working condition have passed the following tests:

Gain (db) Drive 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



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