New 18W Superlite TMB/Arc Welder for a minute

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ViperDoc
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New 18W Superlite TMB/Arc Welder for a minute

Post by ViperDoc »

SO, I just finished wiring up a new 18W Superlite TMB with a modified front panel and parallel component layout.

Image

I passed my bulb limiter tests with flying colors, put the tubes in and lit up the amp. Power string voltages looked good. I probed all pins on V3 and all looked good. 11.87VDC on the PT cathodes, NICE. ...

Then I probed the V4 plate pin 7 and started to arc weld my socket pin to the chassis. Never a f^cking dull moment.

Image

I assume I carelessly pushed the socket pin against the chassis or I had a solder glob on the backside I didn't see. Since I had no shorts on the limiter tests, I feel like I pushed it too hard when I probed it, and now the pin looks like a church BBQ shingle.

I'll check the tube, but unless I can adequately deoxidize that pin, I figure a socket replacement is in order with plenty of pin clearance against the chassis. Anything else you'd recommend, please let me know. Thanks!
Last edited by ViperDoc on Fri 02/05/21 4:18 pm, edited 1 time in total.
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Re: New 18W Superlite TMB/Arc Welder!

Post by JMPGuitars »

ViperDoc wrote:
Thu 02/04/21 8:01 pm
Anything else you'd recommend, please let me know. Thanks!
I would definitely replace the socket. Use heat shrink tubing on the pins, and make sure you don't bend the pins backwards. Many of the pins look very close to things they shouldn't be, and many also look bent.

The board looks really nice, but you should clean off all that excess flux. For future builds, I recommend using some good "no clean" solder.

Thanks,
Josh
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Re: New 18W Superlite TMB/Arc Welder!

Post by ViperDoc »

On further inspection, it had to be some rogue schmutz. I've got the OT primaries tack-soldered to confirm the correct orientation, so there's no way I could have bent the pin enough to touch chassis metal. Time to shake that baby out again! New socket indeed. And yes, that picture makes the heater wire look flat to the chassis, although it isn't.

Yes, I've got flux rosin on the board, need to clean that off. I've been using Kester 44. What "no clean" solder do you like to use?
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Re: New 18W Superlite TMB/Arc Welder!

Post by JMPGuitars »

ViperDoc wrote:
Thu 02/04/21 8:40 pm
On further inspection, it had to be some rogue schmutz. I've got the OT primaries tack-soldered to confirm the correct orientation, so there's no way I could have bent the pin enough to touch chassis metal. Time to shake that baby out again! New socket indeed. And yes, that picture makes the heater wire look flat to the chassis, although it isn't.

Yes, I've got flux rosin on the board, need to clean that off. I've been using Kester 44. What "no clean" solder do you like to use?
This is what I use:
Kester 24-6337-8800 No-Clean, 63/37 Alloy, 0.031" Diameter
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Re: New 18W Superlite TMB/Arc Welder!

Post by geoff 1965 »

2A7C4216-C0E3-4530-80C5-FA723B306353.jpeg
Let me know if you need these ViperDoc!
at least you caught it, nice build & good luck sorting that out.
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Re: New 18W Superlite TMB/Arc Welder!

Post by ViperDoc »

Ha, thanks for the bro back up. Although you’d have to be blind to miss such a spectacle. It looked like a firework. Smelled like one, too.
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Re: New 18W Superlite TMB/Arc Welder!

Post by geoff 1965 »

Main thing is you are okay,could have been a lot worse!
I had a duff mosfet that grounded and fried a 12W wirewound resistor in seconds,luckily I did’nt have my hand on the chassis.
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Re: New 18W Superlite TMB/Arc Welder!

Post by ViperDoc »

The first thing I did was pull the AC cord out of the power module. It definitely makes me want to wire up a shut-off box on my bench, and perhaps never use hardwired power cables. And always double-check/clean your chassis before going hot.
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Re: New 18W Superlite TMB/Arc Welder!

Post by ViperDoc »

Well, she sounds great! I replaced the burned socket and fixed an error I made in wiring the input/EQ bypass switch. I loaded this amp up with 7189 power tubes and it sounds great. My previous 18W TMB needed a lot of noise reduction, this one not so much. I designed my board with room for the PR mod in case I wanted to add it, but I don't think I will.

I do have a faint high pitched tremor sound that goes away the further I am from the amp. you can only hear it when I'm not playing. Will need to sort that out.

Now to decide if I want to go for the effects loop or not...
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Re: New 18W Superlite TMB/Arc Welder!

Post by JMPGuitars »

ViperDoc wrote:
Fri 02/05/21 1:47 pm
Well, she sounds great! I replaced the burned socket and fixed an error I made in wiring the input/EQ bypass switch. I loaded this amp up with 7189 power tubes and it sounds great. My previous 18W TMB needed a lot of noise reduction, this one not so much. I designed my board with room for the PR mod in case I wanted to add it, but I don't think I will.

I do have a faint high pitched tremor sound that goes away the further I am from the amp. you can only hear it when I'm not playing. Will need to sort that out.

Now to decide if I want to go for the effects loop or not...
When you're ready, I'd love to hear a demo. I want to try some 7189 tubes eventually.
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Re: New 18W Superlite TMB/Arc Welder!

Post by TriodeLuvr »

ViperDoc wrote:
Thu 02/04/21 8:40 pm

Yes, I've got flux rosin on the board, need to clean that off. I've been using Kester 44. What "no clean" solder do you like to use?
You couldn't pay me to use "no clean" solder in this type of gear. After 15 years of using it at work, I can tell you there's a huge difference in the ability to flow solder between "no clean" and rosin core. If every single component and part you use is brand new and no more than a few months old, "no clean" will get the job done. But anyone with NOS parts or vintage gear should absolutely steer clear. LOL, they don't call it "no clean" for nothing. Just TRY to clean an oxidized component lead with it.

About the flux - unless you're passing microwave frequencies through that amplifier, don't worry about it. The benefits of cleaning will be cosmetic only.

Jack
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Re: New 18W Superlite TMB/Arc Welder!

Post by JMPGuitars »

TriodeLuvr wrote:
Fri 02/05/21 8:41 pm
You couldn't pay me to use "no clean" solder in this type of gear. After 15 years of using it at work, I can tell you there's a huge difference in the ability to flow solder between "no clean" and rosin core. If every single component and part you use is brand new and no more than a few months old, "no clean" will get the job done. But anyone with NOS parts or vintage gear should absolutely steer clear. LOL, they don't call it "no clean" for nothing. Just TRY to clean an oxidized component lead with it.

About the flux - unless you're passing microwave frequencies through that amplifier, don't worry about it. The benefits of cleaning will be cosmetic only.

Jack
I disagree.

I haven't had any trouble with the Kester no-clean, regardless of the age or type of parts. If you have issues, you can always use extra flux, or maybe try cleaning parts once in a while. ;)

Cleaning flux isn't just superficial. Joints being cleaned at the very least helps you see the quality of the solder joints. Obviously amps aren't as sensitive to the mess as microphones are, but the one thing we know for sure is that clean joints are less likely to cause issues than dirty joints.
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Re: New 18W Superlite TMB/Arc Welder!

Post by ViperDoc »

JMPGuitars wrote:
Fri 02/05/21 7:34 pm
When you're ready, I'd love to hear a demo. I want to try some 7189 tubes eventually.
This is an amp of many personal firsts: first 18W.com-based build, first Superlite TMB build, first use of 7189 tubes, first GDS transformer set, first build with Synergy Mustard caps, and many other details. All together, this amp sounds way more open and smooth than my other two TMBs from other source documents. With a PRS 594, this amp is absolute rock heaven. I based it off of the 18W Superlite TMB with a very few modifications.

The fat switch is wonderful. I also wired in a EQ-bypass boost on a foot switch, and it sounds awesome, if only a bit too bass-y. I also used an SPST to short the 100R 10W sag resistor on the back panel, and I like both options. The power entry module made the AC wiring incredibly easy and much cleaner. And it's dead quiet.

I'll iron out a few details and then maybe I can squeeze out a sound sample...
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Re: New 18W Superlite TMB/Arc Welder!

Post by TriodeLuvr »

JMPGuitars wrote:
Fri 02/05/21 9:58 pm
TriodeLuvr wrote:
Fri 02/05/21 8:41 pm
You couldn't pay me to use "no clean" solder in this type of gear. After 15 years of using it at work, I can tell you there's a huge difference in the ability to flow solder between "no clean" and rosin core. If every single component and part you use is brand new and no more than a few months old, "no clean" will get the job done. But anyone with NOS parts or vintage gear should absolutely steer clear. LOL, they don't call it "no clean" for nothing. Just TRY to clean an oxidized component lead with it.

About the flux - unless you're passing microwave frequencies through that amplifier, don't worry about it. The benefits of cleaning will be cosmetic only.

Jack
I disagree.

I haven't had any trouble with the Kester no-clean, regardless of the age or type of parts. If you have issues, you can always use extra flux, or maybe try cleaning parts once in a while. ;)

Cleaning flux isn't just superficial. Joints being cleaned at the very least helps you see the quality of the solder joints. Obviously amps aren't as sensitive to the mess as microphones are, but the one thing we know for sure is that clean joints are less likely to cause issues than dirty joints.
Well, that was my point - rosin flux is much superior in terms of cleaning the joint. The sole reason "no-clean" was invented was to eliminate the need for factory assemblers to remove residual flux on the outside. Manufacturing employees in lower-volume applications, such as QA and repair, still often use rosin flux because it removes oxide more aggressively (i.e. cleans the joint) and flows solder better. Rosin flux also doesn't vaporize as rapidly as "no-clean," and that helps lesser-skilled workers produce good, shiny joints.

It's great that you're not having problems with "no-clean." Nevertheless, the differences between the two types and the purposes they're best suited to are facts well-understood by industry. There simply isn't a reason in this type of work to use anything other than rosin core solder.

Jack
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Re: New 18W Superlite TMB/Arc Welder for a minute

Post by crgfrench »

I've been using MG Chemical 60/40 rosin core, .031".

I'm picking up some Kester 63/37 rosin core, .031" (Kester part 2463370027).

I love the smell of rosin in the morning. Smells like...

Victory.
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Re: New 18W Superlite TMB/Arc Welder!

Post by JMPGuitars »

TriodeLuvr wrote:
Fri 02/05/21 11:29 pm
Well, that was my point - rosin flux is much superior in terms of cleaning the joint. The sole reason "no-clean" was invented was to eliminate the need for factory assemblers to remove residual flux on the outside. Manufacturing employees in lower-volume applications, such as QA and repair, still often use rosin flux because it removes oxide more aggressively (i.e. cleans the joint) and flows solder better. Rosin flux also doesn't vaporize as rapidly as "no-clean," and that helps lesser-skilled workers produce good, shiny joints.

It's great that you're not having problems with "no-clean." Nevertheless, the differences between the two types and the purposes they're best suited to are facts well-understood by industry. There simply isn't a reason in this type of work to use anything other than rosin core solder.

Jack
Right, the separate flux is good for cleaning things that need it. In those cases, I use it to pre-clean / re-tin stuff outside and away from the build to avoid any mess. I usually use a rosin paste flux I can dip stuff into prior to dunking in my solder pot.

Some types of flux can be corrosive, and can potentially carry signals across them. Rosin core doesn't have that issue, but it still can hide the joint, making proper circuit inspection difficult or impossible. Of course rosin core isn't universally useful either.

If you or anybody else feels their soldering skills are inadequate to fully benefit from using no-clean solder (or any other type), I suggest watching and rewatching the soldering technique videos linked in my signature. Solder technique is always more important than most other things going into a build.
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Re: New 18W Superlite TMB/Arc Welder for a minute

Post by ViperDoc »

Problem noted:

When playing through this amp with single coils on any guitar, there is a very faint, fast ticking sound happening. When I switch to a humbucker, it completely disappears. It's not the guitar. Otherwise the amp sounds great. This ticking seems to accompany tremolo circuits, which I don't have. Bad cap or solder joint?
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Re: New 18W Superlite TMB/Arc Welder for a minute

Post by JMPGuitars »

Is your cellphone close by? Move it farther away if it is.
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Re: New 18W Superlite TMB/Arc Welder for a minute

Post by Bieworm »

ViperDoc wrote:
Sun 02/07/21 3:14 pm
Problem noted:

When playing through this amp with single coils on any guitar, there is a very faint, fast ticking sound happening. When I switch to a humbucker, it completely disappears. It's not the guitar. Otherwise the amp sounds great. This ticking seems to accompany tremolo circuits, which I don't have. Bad cap or solder joint?
I have that too sometimes. It is definitely the internet router. It's typical...
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Re: New 18W Superlite TMB/Arc Welder for a minute

Post by JMPGuitars »

Bieworm wrote:
Sun 02/07/21 5:06 pm
ViperDoc wrote:
Sun 02/07/21 3:14 pm
Problem noted:

When playing through this amp with single coils on any guitar, there is a very faint, fast ticking sound happening. When I switch to a humbucker, it completely disappears. It's not the guitar. Otherwise the amp sounds great. This ticking seems to accompany tremolo circuits, which I don't have. Bad cap or solder joint?
I have that too sometimes. It is definitely the internet router. It's typical...
Could be cellphone, wifi router, bluetooth, watch, etc...

Do you have copper shielding properly installed in your guitars?
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