Fender 600 champion reissue complete rebuild

[Mikante]

I have just built the bulb current limiter but i have one question. The bulb i have it is only 22 watt rated, i need to find a bigger one i know. I was only curious to try it, i plugged in my cellphone power charger and the bulb started flahing like crazy, why?
The little charger is only 9v, why would it draw enough power to light up the bulb and make it flash like Christmas
Did I wire the device in the wrong way?
Ground and Common are going straight from plug to plug, the hot wire from the power cord is connected to one lug of the lamp socket and then from the other lug goes to the power plug hot lug.

[martin manning]

A 22W incandescent bulb will be fine for initial testing of this low power amp. Not sure what is going on with the phone charger, but it's something to do with its internal circuitry.

[Mikante]

It does the same with my little solder pen which is rated 18w

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[sluckey]

Maybe your bulb is a CFL or LED. Those will not work. Bulb must be incandescent.

[Mikante]

It might be, I bought this bulb so long ago I don t remember.

[martin manning]

Ground and Common are going straight from plug to plug, the hot wire from the power cord is connected to one lug of the lamp socket and then from the other lug goes to the power plug hot lug.

Your current limiter sounds like it is wired correctly, but you need an incandescent bulb. That may be hard to find now, but perhaps you can get one that is intended to be used inside an oven, with a clear glass envelope and tungsten filament?

Do you mean the layout of the components?
The schematic is exactly as original, i just bypassed the tone stack and added a choke.

I would like to see exactly what you think you have wired up, with your modifications included, before commenting on the result you get when you apply power.

[Mikante]

Ok I gey it, I will draw my build schematic and post it here.
Meanwhile I was able to find an old 60watt incandescent bulb and the device now work properly.
I decided to plug the amp without tubes and speaker.
I m reading 416 dcv coming out the choke, which would be the first node. Across the voltage dropping line, the reading does not change significantly, I m always reading over 400 dc volts. Is that normal without tubes?

[sluckey]

Across the voltage dropping line, the reading does not change significantly, I m always reading over 400 dc volts. Is that normal without tubes?

yes

[martin manning]

Ok I gey it, I will draw my build schematic and post it here.
Meanwhile I was able to find an old 60watt incandescent bulb and the device now work properly.

Great!

I decided to plug the amp without tubes and speaker.
I m reading 416 dcv coming out the choke, which would be the first node. Across the voltage dropping line, the reading does not change significantly, I m always reading over 400 dc volts. Is that normal without tubes?

If you are connected through the bulb limiter, there will be some overall voltage reduction, but when operating on the full AC voltage, you can expect to see the voltage at the first node drop ~10% when the tubes are installed.

[Mikante]

If the voltage drop will b around 10% with tubes and speaker connected, I can expect 360/380 dc volt, that would be right on the spot.

[Mikante]

This is coming from the actual work, I didn't look at the schematic, with this I can actually know for sure that everything I did was right. Simple but effective, I never thought of that.

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I hope this sketch doesn't t look like I think it looks, messy
Ps. I forgot to add the wiring of the output transformer but it is correct.
Red primary first node,
Blue primary pin 3 6v6gt.
Secondary black and yellow to output socket.
I didn t add the feedback loop rotary switch in the sketch, simple, 3 way rotary switch, 2,2k or 22k or nothing.

[sluckey]

If the voltage drop will b around 10% with tubes and speaker connected, I can expect 360/380 dc volt, that would be right on the spot.

But you have wired the choke for a choke input filter. So, when you put the tubes in B+ at the first filter cap will be much lower than you might think. Your PT puts out 280VAC. 280 x .9 = 252 and that means you will only have 252 at the first filter cap. Edited...

The solution is to make a cap input filter by putting one more filter cap between the diodes and the choke. Then your voltages will be as expected.

[Mikante]

Hey, isn t the choke in the right place?
Today the b+ was around 410vdc. On the fender schematic you have 360 there, no tubes or speaker were connected when i did the reading.
Should i move the filter cap right after the choke to the front?
I don t want to add another filter cap.

[sluckey]

Today the b+ was around 410vdc. On the fender schematic you have 360 there

Yes and there is a filter cap connected directly to the rectifier diodes on the orig schematic.

You need a cap on each side of the choke. I edited my previous post to show correct voltage.

[Mikante]

Yes there is a cap before on the schematic but i didn t mount it.
I have another 22uf 450v i could add.