Harma Valves / ECC83-HARMA STR DR250 High Gain

ECC83-HARMA STR DR250 High Gain ECC83-HARMA STR DR250 High Gain Click on image(s) above to view larger

All prices contained on this page are exclusive of VAT. This is currently charged at 20% and is payable by the UK only.

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.
A specially selected version of the Harma of the Harma ECC83 STR valve which has a slightly earlier break up than our standard ECC83-STR.

The Harma ECC83 STR features an internally rugged construction with thick mica supports. This has a number of advantages such as reduced microphonics and better isolation from vibration. This is particularly useful in guitar combo applications.
The grids windings are all gold plated as were the original Telefunken valves and the Harma ECC83 STR provides one of the most neutral and warmest vintage tone of all the current production ECC83/12AX7 types.

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 a high gain rating of 250 plus digital points.

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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