Kaidee's Simple SE Build Thread

[rknize]

What kind do you have? The heaters on the Chinese ones are bright because they always seem to stick out the bottom a quarter inch or more. The Sovteks are comparatively dim with their narrower cathodes and tucked-away heaters. JJ is somewhere in between.

You are certain that you don't have the 5V and 6.3V heater winding swapped, right?

 

[nukaidee]

these are the chinese ones.. which pin is supposed to be 5v and which one is 6v? I'm at 2 hrs run time now.. seems to be okay, relatively stable. surprisingly weaker than i expected though! i'm running at close to max power, but man... does it sound nice!

 

[nukaidee]

ok.. i'll take it that it works.. however i get a loud hum when the amp is on.. even with the volume all the way down.. will this be rectified with a choke? or a motor run cap?

 

[urmoo]

Choke will do the trick, but wires have to be sorted as well. Motor run cap wil give you a massive improvement in sound.

 

[nukaidee]

I already split the wires, all the power is together and all the signal is together as far apart as possible.. is it possible to wire this amp with balanced inputs?

 

[budmaestro]

Circuit breaker as on/ off

I bought 5 of these on fleabay. Is this too cheezy to use as an switch and fuse in one for my Simple SE?

Allen Bradley 1492-CB1G020 Breaker 2 Amp
Allen Bradley 1492-CB1G020 Breaker 2 Amp - eBay (item 320436647668 end time May-14-10 06:58:18 PDT)
I got the idea from a Ty_Bower post (#60 this thread)
My experience with the SSE has shown this amp puts stress on current production 5AR4's and ends up burning though more than a few 2 amp fuses in the process.
Mounting will be a challenge. Other than aesthetics, these are Swiss made and likely good for 10,000 throws.
Thoughts?

 

[Ty_Bower]

My experience with the SSE has shown this amp puts stress on current production 5AR4's and ends up burning though more than a few 2 amp fuses

Yup, the circuit breakers are ugly and mounting is tricky. They want to snap onto a DIN rail, not get bolted to the back side of a chassis. I've found the tactile feel of a circuit breaker isn't as pleasant as switch, but I suppose that's an aesthetic thing. I guess it would work just fine. There will be a temptation to simply reset the breaker for the seventh time it trips, and that's probably not a good thing.

If you are finding the rectifier tube is stressed, you need to try one (or more) of the following things:

1) Get a better quality rectifier. Blackburn Mullards seem to come highly recommended (and have an asking price to match).

2) Put some solid state rectifier diodes (UF4007) in series with the plates of the rectifier tube. There's a thread around which discusses the topic.

3) Reduce the capacitance of the first cap (the one immediately after the rectifier). The Simple SE schematic calls for a 47 uF part, which is at the upper limit for a good 5AR4. Try a 33 uF (or lower) cap instead. A smaller cap increases the conduction angle (?) presented to the power transformer, which makes it happier too.