First Time Build Problems

[nosaj]

How about some closer pics of the pots and the board?

Thanks,
nosaj

[dwilliamsaudio]

I gave this a shot. It didn't make any difference. I don't think it should though since the NFB is jumpered in and out.

[dwilliamsaudio]

I don't know how much you'll be able to tell from these. The more I add and remove components, the sloppier it is starting to look. I am getting close to ordering a new PCB and starting over. Or going full turret board from Mojotone or somebody.






Here's one from before installing it. A bunch of things are blank for possible modifications.

[nosaj]

I'm not going to say that these are your issues but to me It looks like there may be some cold joints, some joints with not enough solder, and some that just look funny.
Also the back of the tone pot the cap soldered to it doest quite look bonded to the case(I've had some that looked like that and a little force and they popped off.

There/s no reason to start with a new board unless you have some lifted traces but even though can be fixed for little to nothing, just don't expect perfection that comes with tons of experience just look at this as a steeping point and each amp after this will look better. You will get it there are some the best and brightest that help us out here everyday.

Go MEF!!
Thanks,
nosaj

[dwilliamsaudio]

I really do appreciate the help. I don't have any pads that are lifted, but I do have some that are pitted. Are these just dirty? Is there a way to fix them?

[nosaj]

Can you post a pic of one you are talking about? I used skitch to add arrow to the photo I posted. I would first off reflow every solder joint on the board and add solder if needed. Basically to me a good joint will have sides like a skateboard wall ramp. Nice smooth curve.

Thanks,
nosaj

[dwilliamsaudio]

Alright. I re-touched all the solder joints on the PCB, as well as everywhere else. Then I started over with TubeDepot's testing sequence. My B+ was normal as well as my DC voltage on the bypass caps (C3 and C6). When I got to the part where the preamp tubes and rectifier are in without power tubes, the instructions say to test the bottom of R14. It is a 1.5k resistor.

"Move the red meter lead to the lower lead of resistor R14. The voltage here should read +63V +/- 2.0V volts."

My voltage here was incorrect. It was more than a minor discrepancy. It is 340V DC. I then replaced a few of the coupling caps, which made no difference. I have marked R14 and the replaced coupling caps on the diagram below.

So, rather than fix my problem, I inadvertently caused a different one. I will probably just keep redoing things one at a time unless someone has an idea as to why this voltage would be so high.

[ThermionicScott]

Quit blindly replacing parts or redoing things. Trace the wire connected to R14 and see if it leads where it should. Without the 6V6s, 340V sounds like what you'd see on a power supply node. Make sure you didn't inadvertently swap the wires to "n" and "r" or something like that.

Whenever there's a problem, there's a reason for it.

[dwilliamsaudio]

I don't know exactly what it was specifically. I didn't seen anything soldered in the wrong place. But I no longer have a voltage problem at R14. I am now getting some distortion, but at around 5 on the volume. If I am not there yet, I believe I am close. I just need a place to play it loudly to test everything out. My DC voltage everywhere looks good. With a 5Y3, my B+ is now at 366.

There is something that still seems off about the volume pots. I don't get any sound at all until I am at around 2. I have CTS pots in now because I prefer how they feel. The kit came with Alphas. Is the taper on CTS pots different enough to cause that?

[ThermionicScott]

I don't know exactly what it was specifically. I didn't seen anything soldered in the wrong place. But I no longer have a voltage problem at R14. I am now getting some distortion, but at around 5 on the volume. If I am not there yet, I believe I am close. I just need a place to play it loudly to test everything out. My DC voltage everywhere looks good. With a 5Y3, my B+ is now at 366.

There is something that still seems off about the volume pots. I don't get any sound at all until I am at around 2. I have CTS pots in now because I prefer how they feel. The kit came with Alphas. Is the taper on CTS pots different enough to cause that?

Sounds like it's working normally. From 0, you'll turn the volume knob a bit, hear nothing, turn the knob a little more, and then BAM! you're at close to full volume. And from there it's kind of a narrow window before the amp starts clipping (congrats, there's your 12 watts!) Plugging into the #2 inputs gives you the ability to fine-tune things a little better, at the cost of some overall gain.

I'm pretty sure Leo expected guitar players to ride the volume and tone controls on their guitars, and given the numbers that tweed Deluxes sold in, players must not have minded doing that.

[dwilliamsaudio]

That's great to hear! I will have to take it somewhere where I can be loud. I really appreciate all of your help, as well as everyone else from the forum who contributed. Thank you.