16A8

[RicharD]

When I first started getting back into electronics, a circuit I was copying used a 16A8 tube.  I later discovered this is the 16V version of the 6BM8.  The quandary with this first project was the 16V filament supply.  The original circuit used 3 of these tubes with the filaments tied in series from a primary tap.  Not exactly cool these days + I was only using the 1 tube.  I remember talking with DL on the phone as I was driving and he said, "all I can think of is to use a doorbell transformer."  The funny thang was at that moment in time, I had a doorbell kit under my seat.  Anyway.... this weekend I've been toying with little low watt amps.  I built a little 6CL6 amp that my wife actually slept through.  The down side of this tube is it only takes 3V of audio signal input to hit full power.  This means the circuit is pretty much a clipper, end of story.  I've been trying to use up these old MR16 12V lighting transformers.  I realized today that with a bridge recto, 12VAC puts me right at 16VDC.  It all came back to me so I doodled up this circuit.  The pentode needs about 16V to hit full output.  The triode is making 100V.  This might actually work.  I haven't built the circuit yet.  This is about a $10.00 tube.  Reverb transformers are less than $20.00.  I've probably thrown away 100 MR16 transformers in the past.  9 resistors, 8 caps, a box, and the usual brica-bracka.  Easily built for under a C note.

[DummyLoad]

stick a 6AU6 or 6AV6 in front... use a series drop R to get ~6V for 6AU6/6AV6. guaranteed you won't have enough gain to your liking.

meh! for 6AU6 or 6AV6 @ 300mA- drop 10V @ 300mA = 33R - 3Wdiss - use 33R 5W

6AU6/6AV6 tube and R r cheep cheep; like us. :D

--DL

[DummyLoad]

you may be interested in 6BA8 as well... triode section is similar to 12AU7

[RicharD]

>guaranteed you won't have enough gain to your liking.


OK Fine. 

[DummyLoad]

you're taunting me, aren't you? there's a special place in hell for folks like you... ;)

wimp! betcha can't do it with a diff pair.. :p

--DL