kostalex
Headphoneus Supremus
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- Dec 23, 2006
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Please, recommend some tubes for SOHA II > W5000 combo. Music are blues, jazz, jazz vocal.
Originally Posted by kostalex /img/forum/go_quote.gif Please, recommend some tubes for SOHA II > W5000 combo. Music are blues, jazz, jazz vocal. |
Originally Posted by dBel84 /img/forum/go_quote.gif Well I did more than mull and I have to say that the 6FQ7 has now surpassed all tubes in this amp - I imagine with a little tweaking to get more current on the cathode, this would be even better. It is still not up to the level of my former amp but it is almost there. an analogy might help - SOHA II with 6FQ7 = High Def iMax imaging, former amp with 6FQ7 = iMax 3D I can now enjoy my music once again..dB |
Originally Posted by regal /img/forum/go_quote.gif Does the stock heater supply handle this much current the 6FQ7 requires? |
Originally Posted by dBel84 /img/forum/go_quote.gif The reg is a 1.5A regulator , mine has a larger heatsink but I don't think this will make much difference. In normal operation, you are running most tubes at 12.6V in parallel - ie 12.6V with 300mA + 300mA = 12.6V and 600mA. The 6.3V tubes run in series and thus the voltage is additive but the current remains the same - still 600mA. That is if I am thinking about this logically..dB @DoomzDayz : the 6680 is the closest to the 6FQ7 of the tubes that I have tried - Tungsol 12AU7, philips 5814, amperex 8416, sylvania 5963 |
Originally Posted by dBel84 /img/forum/go_quote.gif much appreciated, my math was correct just the current draw of a regular 12.6V tube was off. My amp does not have R3P and has beefier heatsinks, thus the ability to use these tubes in my amp..dB |
Originally Posted by regal /img/forum/go_quote.gif Does this negate your ability to run 150 mA 12.6V tubes like the 12AU7's? |
Originally Posted by regal /img/forum/go_quote.gif Here's how to get the most of your tubes on the SOHA II. The issue I was hearing on some of the 12AU7s and 6DJ8's was a slight weakness or thinness. So here is how you can safely get more current thru the tube: 1. Set B+ to 85V 2. Add another 18k ohm resistor on top (parallel) of R4L&R (makes it 9k ohm) 3. Add another 200 ohm resistor on top (parallel) of R6L&R (makes it 100 ohm) Adjust P1L&R to give .550 V across R6L&R Check to make sure you have at least a 19V drop across the top CCS (adjust P1 until you do) This gives 2.75 mA thru each tube section. . |