Morpheus

Morpheus, who could shape shift into anyone's appearance and give people dreams of heroes or kings. Or that dude from the Matrix....  OK, a little presumptuous, but it's a cool name right? 

 

I've been playing with the 6E6P-DR and it's shorter-lived brother the 6E5P and wanted to use this tube as a preamp or driver stage. I'd already dreamt up a spud amp with it in the Spudsky project, but that will have to wait a bit as I need to stop day-dreaming and start building something to play music.

So playing with some ideas of a spud, driver, even preamp stage for this tube, I started to look for some iron. What would I need though, as each task would require different windings. Line-out would need 2:1 or 4:1 step-down, an SE IT would need 1:1, or should I use it in the future PP amps it would need to be 2:1+1 so it can act as phase-splitter, and finally a 6K:16R ratio as a spud amp. These ratios can never all be combined, but with a little luck I could at least check all the driver boxes. I already have a set of 5K/30mA and 7K/25mA OPTs, so that is not a priority.

Combing through all the Lundah PDF files I could not really find anything that would do 30-40mA, have ±35-40H on the primary and also get 4:1 or 1:1 ratios. They were all meant for 10-20mA and when they did meet the 40-50mA DC current they would be completely different ratios. I emailed Benny Glass as AquaBlue (at 12am) explaining what I was looking for and jokingly said that the LL2763 in 40mA would check all the boxes. The next morning I wake up and see an answer from Benny...

Yesssss!!!!
Me after receiving an email saying "I'll just order the 2763 in 40mA then".

 

The 2763 has a 4+4:1+1+1+1 winding scheme and should hit the induction I need at around 40mA. This would allow all sorts of combinations, some of which I wimong them are the 4:1, 4:4 and 4:2+2 that I would need for the line-out, SE interstage and PP phase splitter. This would allow me to:

1.) Tinker with the 6E6P in a line-out configuration, like testing filament bias with voltage and current sources, check the transformer volume control, test the 6E6P in-circuit.

2.) Use this line-out in a preamp to feed the ArtAudio Quintet amps while I wait for parts and build up the 801A output stage.

3.) Use the 1:1 ratio to drive the 801A when I have the power-supplies for it finished and work on the 10Y driver stage.

4.) Use the 4:1 ratio again to feed the 10Y:801A poweramps while I build up the Usagi 26 preamp and supplies.

5.) Use it for all sorts of gain/drive stages in projects like the EL84 SE amp, the 4P1L Ultra-linear amp.

6.) Finally use it as a phase-splitter in the planned PP UL amp to drive the output tubes. (maybe in 2025?  ;) )

 

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Here are the three modes and their gain/signal levels.

 

My DAC outputs 1-2Vrms depending on if it is DSD or PCM, so let's say 3Vpp to be on the safe side. This should allow it to have plenty of gain for the Line-out and SE Interstage rolls, but needing some extra gain when used as a driver cq phase-splitter; there will be a preamp at that point, so this should be no problem.