You are correct. Now, you just need to time travel back to 2012 and tell that to the ebay seller. 😉
jeff
6P15 neither is an EL83 nor an EL84. I think this is the reason why Svetlana once marketed their 6P15 as SV83 instead of EL83.
Btw, do the prices for 6P14-EV's really have skyrocketed these days? Once they were resonably cheap...
Best regards!
Btw, do the prices for 6P14-EV's really have skyrocketed these days? Once they were resonably cheap...
Best regards!
Hi Brian,
Do you remember what the screen voltage and screen current were at <1.5 watt dissipation with your Baby Huey 300V plate voltage? Have you tried to run them at above 1.5 watts screen dissipation, and if so, what happened.
I’m asking because I’m interested in defining practical upper limits for 6P15P-EV and I’m currently building a PP amplifier using Toroidy EL84 8k output transformers, with adjustable grid bias and screen voltage, to explore this.
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Since I am using a Toroidy OT the screen voltage is about the same as the plate voltage due to the low DCr of the windings. I simply calculated screen power by measuring Voltage across the series screen resistor to calculate current and multiplying by screen voltage. I’ m running regulated supplies so I could come up close to 1.5w without exceeding the rating due to high line voltage considerations. So for example at 295volts 1.5w would be about 5ma. The tubes I have are Soviet military surplus and should run at the 1.5w limit and still have a good lifespan. Not sure how they will work if pushed past the ratings. I did measure a slightly lower output impedance than for the 6bQ5s that I had on hand. I have a lot of used 6BQ5s and only 1 pair of new ones so I have not compared sound.
Thanks! I did not realize your Baby Huey is using the UL taps for the screens. In my experiment I plan to start with 330v from plate to cathode, and use the regulated supply to vary the screen voltage (not UL connected) while monitoring the screen current.
Thanks to OP and sorry for the slight diversion, but it is all about figuring out what is permissible with 6P15P tubes.
Thanks to OP and sorry for the slight diversion, but it is all about figuring out what is permissible with 6P15P tubes.
FYI Francois - when I tried using a zener to lower the screen voltage I did not get good results. I did not pursue it further deciding to sacrifice a couple of watts to preserve tube life. In pentode mode you are in a different realm. The high output impedance will be an issue unless you are aiming for a current source amp or are going to use some form of feedback to lower it.