Starting a 2204 build

FourT6and2 said:
The vast majority of your solder joints are cold. Don't mean to be harsh. But... gotta work on your soldering skills a bit more. When there's a hard transition, for example, from a blob of solder on a turret, to the turret itself, that's a cold joint. It hasn't "wetted" properly. Not to toot my own horn, but this is what joints need to look like.

If you fix all the cold joints, it will help your noise floor. Might not cure it 100%, but it will help.

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What temperature do you set your iron?
 
ledvedder said:
What temperature do you set your iron?
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Well, I use a high-frequency induction iron that has no temp setting. But I'd say 750F is a good all-around temp.

If you are going to do more amp building, I recommend something like the Hakko FX-888D. It certainly makes soldering easier (I use the FX-100). For solder, I prefer Kester "44" 63/37 eutectic, rosin core.
 
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I currently have this. I usually set it between 350-400C. I have a roll of 63/37, but I haven't tried it yet. Still going through my 60/40.
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FourT6and2 said:
Well, I use a high-frequency induction iron that has no temp setting. But I'd say 750F is a good all-around temp.

If you are going to do more amp building, I recommend something like the Hakko FX-888D. It certainly makes soldering easier (I use the FX-100). For solder, I prefer Kester "44" 63/37 eutectic, rosin core.
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I also use kester 63/37. I also have it in 3 different sizes.

750 is also good. The more stuff I’m soldering in a solder joint the warmer I’ll make it. Soldering relays and such lately I have it turned down to 650.
 
glpg80 said:
Doesn’t solidify as fast, flows a little easier.
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63/37 should melt and solidify faster than 60/40 (and at a lower temp), that's why I use it. Or I should say... the window is smaller since it melts/solidifies at one specific temp, rather than over a range of temps like 60/40. It goes from liquid straight to solid. So it has no plastic state and less chance for a cold/contaminated joint. 60/40 goes from liquid to plastic, to solid. So any movement of the joint/components will cause a cold joint.
 
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FourT6and2 said:
63/37 should melt and solidify faster than 60/40 (and at a lower temp), that's why I use it. Or I should say... the window is smaller since it melts/solidifies at one specific temp, rather than over a range of temps like 60/40. It goes from liquid straight to solid. So it has no plastic state and less chance for a cold/contaminated joint. 60/40 goes from liquid to plastic, to solid. So any movement of the joint/components will cause a cold joint.
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I find it’s still slow to solidify, but that’s just me.
 
glpg80 said:
I find it’s still slow to solidify, but that’s just me.
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That's exactly why 63/37 is better.

As the joint cools, 60/40 begins to solidify sooner, at 190C. But it enters a plastic state and doesn't fully solidify until 183C. 63/37 waits. And waits. And then boom... instantly solidifies at 183C. So it might appear as though 60/40 solidifies faster because you're seeing it start sooner. But that plastic state is an illusion. And if you disturb the joint before it fully hardens, you've got a cold one. If you timed two joints that started at the same temp to see how long it takes, they would both solidify at the same time. 60/40 would start the race sooner but they both cross the finish line at 183C.

Anyway... if you have good technique with either one, it's not a problem :)
 
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FourT6and2 said:
That's exactly why 63/37 is better.

As the joint cools, 60/40 begins to solidify sooner, at 190C. But it enters a plastic state and doesn't fully solidify until 183C. 63/37 waits. And waits. And then boom... instantly solidifies at 183C. So it might appear as though 60/40 solidifies faster because you're seeing it start sooner. But that plastic state is an illusion. And if you disturb the joint before it fully hardens, you've got a cold one. If you timed two joints that started at the same temp to see how long it takes, they would both solidify at the same time. 60/40 would start the race sooner but they both cross the finish line at 183C.

Anyway... if you have good technique with either one, it's not a problem :)
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Then we are saying the same thing all along 😂

Yes I actually go one step further, I’ll PM you what I actually use.
 
glpg80 said:
Then we are saying the same thing all along 😂

Yes I actually go one step further, I’ll PM you what I actually use.
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I covered the chassis with a metal sheet pan. It didn't make much difference. It's actually fairly quiet with nothing plugged in. But as soon as I plug my guitar in, it's buzz city! Lights on or off makes no difference. It can't be the guitar. This is my Suhr guitar that I play all the time with all my other amps.

I'm really close to just ordering another board and starting over. I've tried reflowing every connection, moving wires around, trying different ground points.
 
Possibly stupid question and not meant to be a dig at you, but what flux are you using. Some of those joints kinda look like they’re either light on flux or some residual oil was leftover on the metal parts.

Edit: for the purposes of isolating the noise, I’ve found running a long grid wire above the board and moving it around will help identify the issue and adding additional shielding.
 
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ledvedder said:
I covered the chassis with a metal sheet pan. It didn't make much difference. It's actually fairly quiet with nothing plugged in. But as soon as I plug my guitar in, it's buzz city! Lights on or off makes no difference. It can't be the guitar. This is my Suhr guitar that I play all the time with all my other amps.

I'm really close to just ordering another board and starting over. I've tried reflowing every connection, moving wires around, trying different ground points.
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Solder a 0.02uF cap from the ground of the input jack to chassis ground and see what it does.

Have you tried putting a small shield around the input jacks? Do you have them both connected or only one?

Don’t do the board. I believe you’ll find after all of that work you’ll still have the buzz. We need to isolate this problem first.

Does this chassis have a coating for rust prevention? Did you scrape or scrub all of your ground connections before you bolted the tabs down so that you’re getting good ground?
 
glpg80 said:
Solder a 0.02uF cap from the ground of the input jack to chassis ground and see what it does.

Have you tried putting a small shield around the input jacks? Do you have them both connected or only one?

Don’t do the board. I believe you’ll find after all of that work you’ll still have the buzz. We need to isolate this problem first.
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Oh, I forgot to mention... It only happens when plugged into the high input.
 
ledvedder said:
Oh, I forgot to mention... It only happens when plugged into the high input.
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I think your problem is related to coupling around the input jacks or EMI on the guitar cable making it’s way into your circuit. How much have you converted to coax so far?
 
Putting a 0.02 cap from the input jack to ground made no change. Since the buzzing stops when I plug into the low input, I tried replacing the high input jack. But it still happens.

 
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ledvedder said:
Putting a 0.02 cap from the input jack to ground made no change. Since the buzzing stops when I plug into the low input, I tried replacing the high input jack. But it still happens.

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This is progress. This tells me it’s something coupling in or around the first gain stage.

Back to the coax, do you use regular wire from the 68k grid stopper to the first stage?

If you clip a cap across the 68k grid stopper, does the frequency change?
 
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