5e3 clone

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fixer2
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5e3 clone

Post by fixer2 » Fri Feb 12, 2021 1:09 pm

I just recently built a 5e3 clone and in the stages of testing it I got to the point of putting in the tubes all of them started first with the rectifier tube then the pre amp tubes then the power tubes I’m getting way high voltage on the big resistor by the rectifier I should be getting 50 to 65 volts I am getting 175 volts so I must have something wiring wrong because the kit had me use only yellow wire it is tuff to trace is there a way that I can do a resistance test with my multi. Meter after I drain all voltage from the caps of course and find it this way or is there a area to look like the tube sockets and trace it out there this is a tube depot clone so it’s on a pc board not point to point I will have to get some pictures on I just reestablishedmy access to this forum my computer crashed so I have been wanting to get back to reading and learning from you guys.

danman
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Re: 5e3 clone

Post by danman » Fri Feb 12, 2021 7:40 pm

You will need to post a pic or at least a link to the layout that you used. I have built several 5e3's and I don't know of any resistor near the rectifier that would have normally have 50-65v on it. Most of the resistors in the B+ rail will have about 400vdc on them and the cathode resistor for the 6v6's will have about 20vdc or so across it. It's possible that TubeDepot has made some changes to the standard schematic so we would need some pics to be able to give a better answer.

Does the amp sound and play properly or have you not tried to use it yet?

fixer2
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Re: 5e3 clone

Post by fixer2 » Sun Feb 14, 2021 10:00 am

Ok here is a layout I used.

fixer2
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Re: 5e3 clone

Post by fixer2 » Sun Feb 14, 2021 11:07 am

Ok here are some pictures of my build I know it’s messy but here it is I should have used different colors of wire not like how they supplied me with only a couple of colors too hard to trace I’m wandering if I can do a resistance check like I’m checking out the transformer but here I’m going to see if I have something that is hooked up to power that shouldn’t be?

fixer2
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Re: 5e3 clone

Post by fixer2 » Tue Feb 16, 2021 5:08 pm

I have not been able to play it I havent gotten that far this resistor burnt up while I was doing the powering up part from , low voltage slowly increasing to full wall voltage. I see my pictures didnt make it .

danman
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Re: 5e3 clone

Post by danman » Tue Feb 16, 2021 6:55 pm

Since I can't see the pics or the layout, I will suggest that you build and use a "lightbulb current limiter" for further testing. A variac does nothing to limit current and will allow a new build to fry if you don't shut things off quickly. A LBCL will limit current to a very safe level in the event of a short. Once you get past the testing phase with it, you remove it and power up normally. Every new build should be started up on a limiter until the circuit is proven safe.

Here is a great read on first startups and troubleshooting.

https://robrobinette.com/Tube_Amp_Startup.htm

https://robrobinette.com/Tube_Guitar_Am ... ooting.htm

Rob's whole site is a wealth of good info, layouts and mods for popular amps.

fixer2
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Re: 5e3 clone

Post by fixer2 » Fri Feb 26, 2021 3:56 pm

How can I get the pictures of my build and TubeDepots 5E3layout on I tried to attach it? I think I’m too old for computers ok just joking ok tell me how to attach the pictures and I will do you really know your stuff and help me out a lot in the pass thanks again

danman
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Re: 5e3 clone

Post by danman » Fri Feb 26, 2021 6:57 pm

I took a look at the TubeDepot layout and the only big resistor near the rectifier that I see is the 250 ohm flameproof resistor on the end of the board. This is the cathode resistor for the power tubes and it controls the bias for the 6v6 tubes. If this resistor is smoking then it's only two possibilities. You have a bad power tube drawing excessive current or you have wired the 6v6 sockets wrong. If you take a resistance reading from pin 8 of each 6v6 to ground you should see somewhere in the neighborhood of 250 ohms. Take this reading with the power off and the caps drained. If you don't see this reading then there is a wiring problem at the sockets.

I left you a PM about posting pics also.

fixer2
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Re: 5e3 clone

Post by fixer2 » Sat Feb 27, 2021 6:58 pm

Ok thanks for going the extra mile and looking at tube depot web site for the layout . I will do the testing for the resistant like you said .

fixer2
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Re: 5e3 clone

Post by fixer2 » Sat Feb 27, 2021 7:03 pm

Here is another attempt at posting pictures

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