Aikido Heater PSU help

[Bengali]

Hi,

I have the Aikido ALL in One 9 pin board. I'm using a LM1084 5A V.Reg.
The trafo is an antek 1T250 which has dual secondary 6.3V 3A. I wired them in series for 12.6V going into the FWB to the V.Reg.

On the aikido board, I've jumpered J2 and J5 to use it as series parallel heaters. The issue is when I plug in ALL 4 tubes, the heater voltage is only 0.920V!

If I plug in a pair of tubes at a time, either one pair in the input or output, the heater voltage comes up properly at 12V. I see the heater tube glow.

Thinking maybe I have a defective V. Reg., I've pulled it out and replaced it with another V. Reg and still getting the 0.920V.

Since the 6N1P tubes are working as a pair, I don't think there is an issue with the tubes. Any ideas?

Thanks for your help!

[ultrachrome]

I have the octal all-in-one board. Do you have a heatsink on the regulator?

[rotaspec]

I'm doing my Aikido point-point, but I'm looking at the Aikido filament schedule and for a 12v PS and all 6v tubes (if yours are 6N1P in all positions) then you should use J1 and J4.

J2 and J5 will put 12v on the 6v heater, and cause the 1084 to shut down as you've seen.

The 6N1P cannot be run on 12v, unlike a 12a*7 which can be strapped for either 6 or 12v heaters.

Gary

[Bengali]

I have the octal all-in-one board. Do you have a heatsink on the regulator?

yes, most definately, big to-220 heatsink on board.

I'm doing my Aikido point-point, but I'm looking at the Aikido filament schedule and for a 12v PS and all 6v tubes (if yours are 6N1P in all positions) then you should use J1 and J4.

J2 and J5 will put 12v on the 6v heater, and cause the 1084 to shut down as you've seen.

The 6N1P cannot be run on 12v, unlike a 12a*7 which can be strapped for either 6 or 12v heaters.

Gary

J2 and J5 puts out 12V, that is correct, J2 ties V1 and V2 heaters in series, J5ties V3&V4 in series so it should be fine.

the curious thing is if I only plug in one pair of tubes, it works just fine.
I see 12V at the heater and the tubes glow fine. The problem is when all 4 tubes are plugged in. I don't get it.

[Bengali]

Hi,

I rewired for 6.3V, change the V.Reg. R19 to output 6V.
Works now. I still don't know why it would not work with series parallel
with J2 and J5.

Thanks.

[rotaspec]

On the diagrams I have (Rev A and C), J2 puts PS voltage directly across V1, and J5 put PS voltage directly across V2. V3 and V4 would not receive heater PS at all unless other jumpers were installed as well.
Maybe the all-in-one PCB has different jumper numbers than the standard 9-pin PCB

[Bengali]

On the diagrams I have (Rev A and C), J2 puts PS voltage directly across V1, and J5 put PS voltage directly across V2. V3 and V4 would not receive heater PS at all unless other jumpers were installed as well.
Maybe the all-in-one PCB has different jumper numbers than the standard 9-pin PCB

yes, I believe all in one board has different wiring then standard board.

It's working now, been listening for about 40minutes until it started smelling bad. the trafo is really hot to the touch. not sure if this is normal. maybe it needs to cook some more to burn off the smell?

[Bengali]

The 6N1P cannot be run on 12v, unlike a 12a*7 which can be strapped for either 6 or 12v heaters.

Gary

Thanks again Gary. I over read your comment. So the 6N1P cannot be strapped for 12V heaters, too bad. I wanted to have the flexibility of
trying other tubes. not a big deal though.

what tubes are you using?

[rotaspec]

Originally Posted by Bengali

yes, I believe all in one board has different wiring then standard board.

It's working now, been listening for about 40minutes until it started smelling bad. the trafo is really hot to the touch. not sure if this is normal. maybe it needs to cook some more to burn off the smell?

NOT NORMAL!
There is excessive current being consumed somewhere.
Transformers should run no more than warm to the touch.
Double check your component placement and polarity (in the case of electrolytic capacitors.

I haven't looked yet at the all-in-one board, so I can't be of much more help until I see the schematic.

[rotaspec]

Originally Posted by Bengali

Thanks again Gary. I over read your comment. So the 6N1P cannot be strapped for 12V heaters, too bad. I wanted to have the flexibility of
trying other tubes. not a big deal though.

what tubes are you using?

I have a reasonably wide range of Russian tubes to choose from, but 6N1P-EV for input tubes and 12AU7A for output tubes is one combo I really want to try. I will probably start up with 6N1P-EV all round.
One reason I didn't opt for a PCB (aside from the fact that it has to come to New Zealand from the US), is so that I could try some tubes not supported.
The other reason is that I already had a console chassis that suited the 4-tube Aikido design, and already had the power supply (EZ80 tube rectifier) mounted.
One of the PCB-unsupported tubes I have had some luck with in my little SE amps is the 6N3P-EV driving EL84/6BQ5 outputs. It's the easiest to get low distortion at B+ less than 300v, out of all the 6N1, 6N2, 6N3 variants I have tried. It's not compatible with the PCB only because of the strange pinout, but it's a nice sounding tube.
I'm a fairly newbie at this BTW. The Aikido is only my 3rd build.

Gary