Can Tube Heat Melt Solder? Question for Amp techs

[MetalManiac]

Let me preface this by saying I am the worst solderer in the world, but I'v gotten a smidgeon better over the years from so much trial and error... mostly error, and not trying to do too much.

I am putting new Metal Oxide 470K 1 watt grid stopper resistors in my '66 Bassman in place of the old original carbon comps, just to be safe( not certain if you can see whether a old Carbon Comp is still good or not by simple visual inspection..the ones I had looked good still, although one looked a littel worn, and of course your amp techs will tell you carbon Comps on the grid stoppers have the best tone )) and especially to preserve this amp for future posterity..to someone or some thing that will have this amp after I am gone.

I dropped a globule of solder down by the tube base by using somewhat too much solder on one of the welds ( on a side note, it seems to have actually stabalized the wobbly tube socket lug somewhat).

This amp has some of the greatest vintage crunch ever( think old Marshall), while not having the cleans of a old Super Reverb or Deluxe Reverb at all.


So I am wondering if the tube heat when its being played could actually melt this solder and cause an issue? I'm not about to try and resolder it (By the way, I actually solder better in a state of moderate alcohol intoxication).

What do you think of the Chocolate drops Caps( Brown Turds) on this amp. My amp has two or three. I am considering replacing them with NOS Orange drops ).

[Demanic]

Re: Can Tube Heat Melt Solder? Question for Amp techs

I would not think that the tube would get hot enough to melt solder, otherwise it would melt the solder holding the socket to the board, or wires. As long as it doesn't short anything, it should be OK.

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[MetalManiac]

Re: Can Tube Heat Melt Solder? Question for Amp techs

Heres eome pics. The Sprague Atome filter Caps were put in by a real amp tech. The next to last picture you' see the two Grid Stop resistors I installed today. One of the pics is with the original chocolate drops I am thinking of changing to old stock Orange drops..but will probably leave it be.

Look at all those beautiful original Blue caps!

I installed Dale 1K 5Watt Marshall resistors as the Tube Screen Caps [EDIT- I MEANT SCREEN GRID RESISTORS], although some recommend using the original value caps as a "fuse", this is not recommended strongly by others even Kevin O'Conner, as these were not meant to be fuses. I am going to have installed a HT fuse , and probably a Bias cap protection down the road.



[IMG] [/IMG]

[Myaccount876]

Re: Can Tube Heat Melt Solder? Question for Amp techs

1) If you have any electrolytic capacitors that are original (from 1966 - for the record, every single electrolytic cap from my "younger" '77 Bassman was out of spec), FFS replace them already! I can guarantee you from halfway across the country that they are all either out of spec, leaking, bulging, or any combination of the three. Don't use bad filter caps - that can introduce a ton of AC ripple (that's supposed to be filtered out) and wreck the power transformer. The value of those amps plummet if any of the transformers are not original or damaged.

2) Do not listen to anyone that says to use a resistor like a fuse. Use the correct screen resistors (tube screen cap?) as specified in the schematic - not what just any bozo said on another forum. Keep to the 470 ohm screen resistor, but you could (probably should) up the maximum wattage to something safer than 1 watt - go for the biggest one that fits (a 10W fireproof resistor would be ideal, but it won't fit directly on the tube socket).

3) It is possible for solder joints to be at least weakened inside a tube amp - especially if the amp overheats. Cold solder joints are obviously going to be the most vulnerable/problematic, but in usual operating conditions, good solder joints (a strong mechanical connection, and then a good soldering job) should be fine. Just gently shake the amp around a bit to see if the solder blob falls out. If you really want to ensure the blob doesn't cause any problems down the road, remove the socket and get the blob out. And just test your carbon comp resistors with a multimeter - if they're in spec, they're good for now, just don't overheat them and make sure they don't see too much voltage.

[zzmoore]

Re: Can Tube Heat Melt Solder? Question for Amp techs

Do not think I have ever seen a mix of Blue Molded and Brown Blob caps like that.....but Fender did a lot of "mix and match" if it saved them a dime.
Anyway.....replace the Brown ones if you want...they did not typically have leakage problems, but it is your amp, do what you want.
There is no advantage to using Carbon Comp in any position IMO. The argument CAN be made for plate resistors.....but that is NOT what amp building and guitar playing is about. Your choice of resistors is perfectly fine.
The tube will not generate enough heat to melt the solder, but.....can't you just Wick/Suck/Knock the solder off.?
good luck

[Scott_F]

Re: Can Tube Heat Melt Solder? Question for Amp techs

Those big blue Spragues sitting next to that 22ug smaller cap? Well now days those big blue actually house smaller more modern caps. It's aesthetics. I've been going with smaller better rated e-caps like the ones TAD sells. Also the ones Nik at Ceriatone private orange labeled are really good too.

I like carbon comp resistors in the preamp portion for the most part. Again mostly aesthetics. But players buying Amps still like them and I try to build what people want.

[Myaccount876]

Re: Can Tube Heat Melt Solder? Question for Amp techs

I use F&T caps. High quality, and not nearly as overpriced as Sprague Atom caps.

Also, Jerry I looked at the picture of your filter caps; did your tech seriously just cut the old leads and solder the new capacitors to the cut leads? That's amateur work - when you heat up the cut lead to solder the new lead to it, not only do you get a crap mechanical connection (which you absolutely need - amps experience a lot of vibration when you're playing loud), but you also slightly heat the solder joint at the board eyelet. The entire joint isn't fully heated which makes a weak connection/cold solder joint much more likely. It's not even hard to do the job properly - use a $2 solder sucker (any amp tech should have at least one), quickly melt the solder without damaging the board, quickly suck it all up, remove the old lead, put the new lead in *making sure it makes physical contact with the eyelet), solder it, and you're done. The tech is straight up lazy and doesn't care about his work if he's making amateur mistakes like that; hope he didn't charge much. I'd be embarrassed to return someone's amp to them like that.

[Fresh_Start]

Re: Can Tube Heat Melt Solder? Question for Amp techs

I use F&T caps. High quality, and not nearly as overpriced as Sprague Atom caps.

Also, Jerry I looked at the picture of your filter caps; did your tech seriously just cut the old leads and solder the new capacitors to the cut leads? That's amateur work - when you heat up the cut lead to solder the new lead to it, not only do you get a crap mechanical connection (which you absolutely need - amps experience a lot of vibration when you're playing loud), but you also slightly heat the solder joint at the board eyelet. The entire joint isn't fully heated which makes a weak connection/cold solder joint much more likely. It's not even hard to do the job properly - use a $2 solder sucker (any amp tech should have at least one), quickly melt the solder without damaging the board, quickly suck it all up, remove the old lead, put the new lead in *making sure it makes physical contact with the eyelet), solder it, and you're done. The tech is straight up lazy and doesn't care about his work if he's making amateur mistakes like that; hope he didn't charge much. I'd be embarrassed to return someone's amp to them like that.

Splicing the leads on the electrolytic filter caps is beyond lazy and headed toward negligent if not worse.

There is no point to using new "Sprague" electrolytics. Scott is correct about it being a pretty package around a new, crappy cap.

I like and use the F&T electrolytic caps too sometimes.

Respectfully, I would leave the amp alone unless you're willing to work on it sober. High voltage and impaired judgement are not a good mix.

Half watt carbon comp resistors in spots where there are large voltage swings may add some mojo. Anywhere else they just add hiss in my experience. Randall Aiken has a lot more credibility that I do though:

http://www.aikenamps.com/index.php/resistor-types-does-it-matter

A 10 watt screen grid resistor is overkill unless you're using some hellishly high voltage tube.

Chip

[MetalManiac]

Re: Can Tube Heat Melt Solder? Question for Amp techs

Splicing the leads on the electrolytic filter caps is beyond lazy and headed toward negligent if not worse.

There is no point to using new "Sprague" electrolytics. Scott is correct about it being a pretty package around a new, crappy cap.

I like and use the F&T electrolytic caps too sometimes.

Respectfully, I would leave the amp alone unless you're willing to work on it sober. High voltage and impaired judgement are not a good mix.

Half watt carbon comp resistors in spots where there are large voltage swings may add some mojo. Anywhere else they just add hiss in my experience. Randall Aiken has a lot more credibility that I do though:

http://www.aikenamps.com/index.php/resistor-types-does-it-matter

A 10 watt screen grid resistor is overkill unless you're using some hellishly high voltage tube.

Chip

I sucked the blob of solder out...well, with a solder sucker that is.

The 5 watt Dale resistors I'll leave in, because I am going to put an HT fuse, so if a tube blows, it won't take out the PT.

The recap work is solid, although I'm sure it isn't optimal.

AND, my days of doing anything but minimal stuff to an amp are over. Thats why a tech is gonna do my Hiwatt. Already have all the necessary caps and resistors, and they weren't cheap. F&T Filter caps .

BTW, I appreciate everyones interest. Thanks.