problems with my first build

[Bob-I]

I just looked close up to the pictures. There's several solder joints that I'd question. Use your own meter and measure from the component lead to the final connection to make sure there's 0 ohms, plus yank on the joint with plyers to try to break it loose.

Especially with symptom of voltages changing after a few minutes, as temp changes a questionable solder joint will change in resistance.

[analogjunkie]

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?

The were lit at first, then they were not. I may not have the filaments wired correctly? I have pin 8 straight grounded on the power tubes, no resistor. Is this wrong? I'd like to get this done tonite so I can try this amp out at my gig tomorrow

[analogjunkie]

I did get the voltage thing situated and all the voltages run smoothly when testing. I just can't get sound. there is a low volume hum oscillation still. The hum changes pitch when I check the voltage on the phase inverters, and when I change the setting on the trim pot. a short possibly? I'll check that.

Now that I think of it there was a grey wire for the OT that I did not connect anywhere that was rated 2ohm load. that is the only thing I can think of that I did not connect anywhere.

[Bob-I]

I did get the voltage thing situated and all the voltages run smoothly when testing. I just can't get sound. there is a low volume hum oscillation still. The hum changes pitch when I check the voltage on the phase inverters, and when I change the setting on the trim pot. a short possibly? I'll check that.

Again, get the probe and test the way I described above, it's your best way to find where the problem is. What you're describing sounds like the signal isn't getting to the PI so there's a mistake somewhere in the preamp.

Now that I think of it there was a grey wire for the OT that I did not connect anywhere that was rated 2ohm load. that is the only thing I can think of that I did not connect anywhere.

As long as it's not making contact with anything that's fine.

[Structo]

Yeah, your lead dress ain't the best in the world.
You should look at other D'lite's and try to copy their wiring.

A common mistake people made when building the D'lite was failure to connect the ground wires from the cathodes of the preamp tubes to the ground buss.

On some drawings these wires are omitted for clarity to other items.

So make sure your cap/resistor pairs on the two preamp tube cathodes go to ground. That is the cap/resistor pair on pin 3 and 8.

I hate to say it but that is pretty much a fire hazard as it is right now.
You should really try to neaten up that wiring before you get too much farther along.
Besides not looking very good, it is an invitation for noise and oscillations due to excessive lengths and poor routing.

It's hard to trace the wiring when it's going all over the place and it is a good idea to use different colors to keep track of the different elements of the tubes.
Such as red for plates, yellow for cathodes and blue for grids.
They don't have to be those colors as long as you use three or four different colors and keep them the same throughout.

Good luck, I know you have pride in your amp and you want it to look as good as it sounds.

[67plexi]

Your first build. Tom is 100% you need to clean up the mess.
Not a good pick for the first build. Most start out with a fender 5F2 Princeton.
Before you strip it down chart your voltages from the chart I posted. get solid core wire rated @ 600v to rewire.
use the layout to the tee,

http://brownnote.net/shared/images/D-Li ... laysV3.jpg

[analogjunkie]

I spent all night taking everything apart and rewiring. The hum has seemed to disappear but I am still getting zero signal coming through. I know for a fact everything is wired up like the layout. Everything is grounded correctly, tubes all getting the proper voltage, I even rebuilt the phase inverter section. No shortages or anything like that from visual observation and testing. I am completely stumped. Anyone else have any advice?

[bluesfendermanblues]

No insult intended, but you should take it to a tech.

There are lethal voltages in a tube amp and frankly you have been given a lot of sound advise in the posts above, but you don't seem to have the needed experience with tube amps. Therefore, don't take the risk upon yourself. Take it to a qualified tech.

[Guitarman18]

bluesfendermanblues is right, and I always find that working all night to solve issues doesn't help. I always need a clear head and to take my time, to avoid making mistakes.

Have you checked to see if the speaker jack sockets and any other jack grounds, like the signal access chassis ground (also used for Presence ground point in some layouts) are grounding to the chassis correctly by removing any paint that may prevent a good contact.

Be careful!

Paul.

[odourboy]

Debugging a problem/mistake is often the most challenging aspect of amp building and is where experience can really help. Where are you located? There are probably several builders here who would be willing to take a look at your amp. I know I would if you're in the GTA.

[mcrracer]

I spent all night taking everything apart and rewiring. The hum has seemed to disappear but I am still getting zero signal coming through. I know for a fact everything is wired up like the layout. Everything is grounded correctly, tubes all getting the proper voltage, I even rebuilt the phase inverter section. No shortages or anything like that from visual observation and testing. I am completely stumped. Anyone else have any advice?

IF everything was wired properly the amp would be working! I second the suggestion to take it to someone qualified. You are not the first person to complete a build and find that it does not work right away. The difference between you and many of us is That it appears you do not know enough about electronics and amps to know what to do next...OR follow the instructions of those who do know. There is no shame in asking someone to help you who can put the amp on their bench in front of them. Just continue to learn and you will do alright eventually. If you insist on trying to do it yourself, BE CAREFUL, take the schematic (not the layout) and a highlighter marker. Start at the input jack and highlight each connection on the schematic as you check it and resolder it on the amp. Measure EACH resistor with your ohm meter to make sure the value is correct. Go thru one connection at a time and you should find your problem. Good luck.

[Structo]

Try this,
With the amp on and a speaker connected, ground the black probe of your DC volt meter.
With one hand touch the red probe to the plate resistors, starting with the V3 phase inverter plates.
You should hear a pop in the speaker each time you touch the resistor.

So touch the red probe to the two plate resistors on V3.
Hear a pop? That stage is probably OK.
Now move to V2 plates.
Hear a pop? If not, your problem may be in that section.
If you hear a pop on all the resistors, your problem may be the way the input is wired.
Good luck.

[Drumslinger]

I know everyone has their own way about checking things and what i like to do is:

1. grab a highlighter (yellow, blue, green, whatever color you like)
2. print out both schematic and layout.
3. check each point and mark it off with the highlighter. (amp unplugged and drained) (i do this with my builds before i turn it on and have found a mistake here and there)
4. like a couple of the memebers have said "step away from the amp for a day or two and then approach it with a clear head".

hope this helps.

[BobW]

Try this,
With the amp on and a speaker connected, ground the black probe of your DC volt meter.
With one hand touch the red probe to the plate resistors, starting with the V3 phase inverter plates.
You should hear a pop in the speaker each time you touch the resistor.

So touch the red probe to the two plate resistors on V3.
Hear a pop? That stage is probably OK.
Now move to V2 plates.
Hear a pop? If not, your problem may be in that section.
If you hear a pop on all the resistors, your problem may be the way the input is wired.
Good luck.

Tom, this is a quick and excellent method for finding a stage problem.
I learned this method a long time ago after buying Jack Darr's "Electric Guitar Amplifier Handbook" back in the mid 70s. It's still a good reference.

[angelodp]

Please re-post your pics so we can see the solder re-flows. As Bob-I pointed out you have numerous junctures that are not properly soldered. No sound - no signal. It might just be a very simple dead joint. Do you know how to drain the caps before you mess around in there. 500v DC, be real careful and or get some tech input locally.