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Harma Valves / 6GK5/6FQ5-HARMA STR
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All prices contained on this page are exclusive of VAT. This is currently charged at 20% and is payable by the UK only.
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.
The Harma 6GK5 been selected for use in Conrad Johnson amplifiers. 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.
These valves offered a number of sonic benefits over the GE 6GK5.
The valve has a supported structure which makes then very low in microphonics. They provide better low end definition than the GE and they provide more detailed midrange clarity. The standout feature is the valve smooth treble response. They provide a warmer smoother sound when compared to the standard GE 6GK5.
We have limited Stocks on this valve, we also have available a Cryo treated 6GK5 due to many requests for this from our customers.
Here is what one of our German customers said in an actual email after fitting the Cryo Harma 6GK5
Thank you Tubes arrived yesterday.
I`ve put them right into my CJ Premier 14.
What a sound!! What a performance!! What a soundstage. These are the best tubes for this Pre-amp, I`ve ever had!!
kind regards
Ulrich Szesniak
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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