My "Stupendous" PPP 6P1P build

[kodabmx]

At least it goes eventually... I wouldn't run them at 100% though. I think they will fail rather quickly, but then again I'm basing that on larger models. I usually derate to 40% but again, they run inside a 75°C box. YMMV.

 

[Bas Horneman]

Ok..in that case I'll build them with the 5A supply right away.

 

[Bas Horneman]

Bummer as I bought the 2A critters specifically for this. First time using switching supplies. Did not know these things should be derated....

Maybe I should just use good old AC. Have 3,6A 12,6VAC transformers.

 

[Lingwendil]

I use AC on everything, simple and easy to implement correctly.

 

[Bas Horneman]

I use AC on everything, simple and easy to implement correctly.

Come to think about it....I ordered power transformers that have a pair of 6,3V windings. Could tie them up to supply 12,6V...and Bob's your uncle.

 

[kodabmx]

You can, but there might be hum - I didn't do anything fancy with the heater traces as I designed it for DC. I think they are independent though but one side might be tied to ground.

 

[Bas Horneman]

Mood

 

[Wavebourn]

I used SMPS in Gubernator-71 amp, to power filaments of GK-71 tubes. The SMPS was rated properly for hot filaments, but could not start. So I used 12.6V winding from the transformer, and with a diode bridge connected it in parallel to filaments. The problem solved! 12.6V rectified heated up filaments, their temperature increased, resistance increased, then SMPS started and took over!

 

[Bas Horneman]

Interesting... Did you have some circuitry that tuned off the ac after the DC 'took over'?

 

[Wavebourn]

Sure, a diode bridge.
As soon as SMPS provided 20V, diodes had no even a chance to open.

 

[Bas Horneman]

Ahaaa.

 

[Bas Horneman]

For those wondering where to get the bamboo cases: Bamboe wandboxen | Action.com

 

[Demonkleaner]

I just googled "bamboo wall boxes" and there's ton's of options out there.
Thanks Bas!

 

[Bas Horneman]

Thanks Bas!

You are welcome!

 

[Francois G]

I just googled "bamboo wall boxes" and there's ton's of options out there.
Thanks Bas!

Demonkleaner,

I googled and didn’t spot anything in the NA market like the boxes Bas posted above. What specific link(s) did you find useful?

 

[Bas Horneman]

Feet glued to chassis. Feet made from "Action" broomstick. Bezemsteel | Action.com 94 eurocents. Won't get a "dowel" for that price from your local builders supply.

Boards also completed and cleaned. Now just waiting for the power transformers to arrive. Before I start mocking it up.

 

[kodabmx]

Looking nice

 

[bayermar]

Hi Bas,

looks great so far!
Thanks for the idea of bamboo box shelves.
I might have to try this in the future, too.

I am very comfortable with metal working. I also like working with wood in principal, but I am usually not very happy with the result at the end. Last chassis took me many weeks of painting, sanding, painting, sanding, polishing, painting, sanding, polishing...(I think you get it).
Only finally I was kind of happy with the result.

Cheers,
Martin

 

[Bas Horneman]

I am very comfortable with metal working

Hi Martin,

To me it is a chore. Things have gotten better with my age and experience as I have more patience. But again I made and error with my 2a3 amp top chassis. Drilled one hole in the wrong place. But luckily I will probably be able to mask it with a big washer of some sort. Not so much a chore as it is daunting...I'm always holding off starting. That's why I love wood...its much more forgiving.

Kind regards,
Bas

 

[Bas Horneman]

Power transformers in the house.