Hi
i have been building the following layout:
http://www.turretboards.com/layouts_schematics/vjr/stock_mod.pdf
today i powered it up for the first time... after some waiting... nothing.. no sound.. no buzzing or humming... nothing... and then some smoke 🙂
i then replaced the burned resistor.
(first resistor 1K over the first cap. 22uf 450v.)
i have checked everything again, for the 15th time and the i noticed i had the ground of the OT connected to the green wires... so i cut the wire and powered up the amp.
no smoke, still no sound.
very careful i felt the 1K resistor, it was hot, but not burning.
the i switched the amp off and accidentally i bumped my guitar, and then i heart sound slowly fading out.
now what did i miss?
i really could use some suggestions...
i have been building the following layout:
http://www.turretboards.com/layouts_schematics/vjr/stock_mod.pdf
today i powered it up for the first time... after some waiting... nothing.. no sound.. no buzzing or humming... nothing... and then some smoke 🙂
i then replaced the burned resistor.
(first resistor 1K over the first cap. 22uf 450v.)
i have checked everything again, for the 15th time and the i noticed i had the ground of the OT connected to the green wires... so i cut the wire and powered up the amp.
no smoke, still no sound.
very careful i felt the 1K resistor, it was hot, but not burning.
the i switched the amp off and accidentally i bumped my guitar, and then i heart sound slowly fading out.
now what did i miss?
i really could use some suggestions...
You need to post really clear pictures of your build.
Plenty of them, that shows everything.
You have a mistake somewhere that produces a short circuit.
You should not have replaced the resistor, and turned it on again. Not until you find the mistake.
You have another part burned out and it could be the transformer.
DO NOT operate the unit, until all the connections have been verified.
PHOTOS? PHOTOS?
You can make this much worse than it is, by turning it on again.
Operating the amp without a speaker load will blow the output transformer, bingo.
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The caps in the layout do not show any polarity symbols. How did you orient them?
Do you have any kind of Volt meter?
Do you have any kind of Volt meter?
soundguruman thanks for your reply, but i really can't take good photos of this build. it's all soldered to the tube sockets.
i'll order a turretboard and start over just to be on the safe side.
i'll order a turretboard and start over just to be on the safe side.
@loudthud
most of the parts came from the original PCB.
i looked at the polarity and matched it to the layout drawing.
and yes, i do have a volt meter.
most of the parts came from the original PCB.
i looked at the polarity and matched it to the layout drawing.
and yes, i do have a volt meter.
There are no polarity makings on the layout. I have marked polarity on the attached layout.
Voltages at the tube socket pins would go a long way towards revealing where the problem is, but you may do damage to the amp while taking the readings. Check the polarities against the diagram. If any caps were installed backwards, they are damaged now, replace them with new ones.
Voltages at the tube socket pins would go a long way towards revealing where the problem is, but you may do damage to the amp while taking the readings. Check the polarities against the diagram. If any caps were installed backwards, they are damaged now, replace them with new ones.
Attachments
ok i've checked everything twice. all de caps are in the right place with the correct polarity.
but still the same thing... i wait nothing happens.. i turn of the power, and then it briefly comes to life.
but still the same thing... i wait nothing happens.. i turn of the power, and then it briefly comes to life.
You have something wrong in the bias supply. When you turn it off the bias supply is dropping faster then the B+. at some point the voltages are right for the tube's to conduct and you get sound.
i measured the red wires 360volts! the etiquette on the transform says red should be 260...
where do those 100volts come from?
for input i choose the blue wire with has to be for 230 input.
the orange are 6.4volts this should of course be 6.3.
link to transformer information
where do those 100volts come from?
for input i choose the blue wire with has to be for 230 input.
the orange are 6.4volts this should of course be 6.3.
link to transformer information
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Are you measuring between the two red wires, or measuring each to ground? Measuring them to ground may not give an accurate reading (depending on your meter) becasue of the bridge rectifier.
Ok i measured again, 283volts. So I now used the brown wire for 240volt input and the. Measured again. It then gave me 261volts. The orange wires only gave 6.1volts.
Then I looked over the layout again. I noticed the gray wire, from 1uf cap to The volume potmeter. It is the ground to the chassis. The input jack is grounded to the chassis, so then I directly solderded a wire from the input ground to the 1uF cap. And the whole thing came to life... Seems the ground to the chassis is not ok. It still has a bit of a 50hz hum but this is ok for now.
Still I wonder, why did I get sound when switching of the amp?
Then I looked over the layout again. I noticed the gray wire, from 1uf cap to The volume potmeter. It is the ground to the chassis. The input jack is grounded to the chassis, so then I directly solderded a wire from the input ground to the 1uF cap. And the whole thing came to life... Seems the ground to the chassis is not ok. It still has a bit of a 50hz hum but this is ok for now.
Still I wonder, why did I get sound when switching of the amp?
The generally accepted tolerance for heater voltage is +/- 10% so you are ok.
Single ended amps always have a little bit of hum. Hard to say why you got sound when the amp was switched off.
Single ended amps always have a little bit of hum. Hard to say why you got sound when the amp was switched off.
Ok thats good to know but ive spend some more time playing guitar and the hum is to much. And gets louder when turning up the volume?
Ive added a second bridge rectifier for the 6.3 volts orange wires but doesnt change anything..
Also i did get a reply from the website owner provider of the diagram he said i should replace the first 1k resistor with a 3watt resistor, i only had one 5 watt resistor so i added the 1k 5 watt resistor but it stll get to hot to touch!
Ive added a second bridge rectifier for the 6.3 volts orange wires but doesnt change anything..
Also i did get a reply from the website owner provider of the diagram he said i should replace the first 1k resistor with a 3watt resistor, i only had one 5 watt resistor so i added the 1k 5 watt resistor but it stll get to hot to touch!
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