problems with my first build

[analogjunkie]

I built off the dlite layout and double triple checked everything in the build. the tubes light up but the only sound i get is a consistent low volume hum from the speakers. i know this is vague but i checked for shorts and bad connections and cant find anything. is there something i am missing? anyone care to help?

[talbany]

1st Check all the voltages

[Bob-I]

I built off the dlite layout and double triple checked everything in the build. the tubes light up but the only sound i get is a consistent low volume hum from the speakers. i know this is vague but i checked for shorts and bad connections and cant find anything. is there something i am missing? anyone care to help?

Happy to help. Start with posting close up pics of the build.

Another good troubleshooting method is to build a probe like this one from BYOC http://buildyourownclone.com/probe.html . Inject a signal, like an iPod, at the input and listen using the probe at the various stages. First listen at the input jack, then the grid of V1a, the plate of V1a and on through the circuit. Chances are you'll lose the signal somewhere in the early stages and you'll be able to locate it with the probe.

[mlp-mx6]

To expand on Tony's suggestion -

Measure the voltages on each preamp triode - plate, grid, and cathode. (no need to measure the heater pins)

Also measure the voltages on each power tube pin - cathode, grid, screen, and plate. (no need to measure the heater pins)

Tell us what you find.

[analogjunkie]

I want to test out the voltages but should I test them with the tubes in or out? is there any tutorials for this testing/trouble shooting on amp garage?

I disconnected the loop because I figured it may be that, but it wasn't. I know it is very messy but it is my project amp

I did a few things different from the dlite layout like used a choke, relay switches, etc as per mods on layouts by members here.

[talbany]

Measure with tubes in..

Tony

[analogjunkie]

After warming up for 5 mins I tested everything across the board and all the voltages were in proper range. Then I went back to test it again after it warmed up a bit and all the voltages sky rocketed. power tubes went from 430 to 500, pre amp tubes all jumped to around 450 which I know is way too high. All the tubes went from glowing properly to burning out.

I would imagine there is something wrong with my power filtering? I want to find the problem but I dont want to fry the PT. Any suggestions?

[ChrisM]

What kind of board material is that for the filter cap board?

[analogjunkie]

What kind of board material is that for the filter cap board?

It's a flooring material. 100% non flammable and non conductive. I've used it in lower voltage applications before like fuzz and boost pedals. I can't imagine that would be the problem.

[ampdork]

I am betting you have something wrong with the filament wiring.

You said they weren't lit? If the heaters aren't working you'll get big volts.

Check your filament grounding scheme. Did you use resistors or a true CT?

[ChrisM]

What kind of board material is that for the filter cap board?

It's a flooring material. 100% non flammable and non conductive. I've used it in lower voltage applications before like fuzz and boost pedals. I can't imagine that would be the problem.

Thanks, was just wondering.

[sergio]

Hi , here there are many guys can help you , but I think you should rewired a bit your lead-dress , for a more simple search of problem.
I can't tell anything from this photos! sorry if I'm not to big helper , start from your PT and go step-by-step.
what is your scheme of reference?

Sergio

[67plexi]

Voltage chart.

[Bob-I]

After warming up for 5 mins I tested everything across the board and all the voltages were in proper range. Then I went back to test it again after it warmed up a bit and all the voltages sky rocketed. power tubes went from 430 to 500, pre amp tubes all jumped to around 450 which I know is way too high. All the tubes went from glowing properly to burning out.

I would imagine there is something wrong with my power filtering? I want to find the problem but I dont want to fry the PT. Any suggestions?

First off, with this problem take the tubes out just to make sure you don't kill them.

Next disconnect the leads from the PS board to the preamp board and test voltages again. Double check all the wiring on the PS board including grounding, balance resistors, polarity of the caps.

Slow and steady wins this race.

Did you make a test probe? This will be important once you get past this issue?

[Bob-I]

... but I think you should rewired a bit your lead-dress , for a more simple search of problem.

Sergio has a good point. There are a lot of long loops in the wiring. Shorten the leads and dress them out like you see in the pictures posted. Neatness is critical.