I have one of those. Actually I like solder wicks even better, at least for small joints. I ordered a whole bottle of flux now. Flux on the wick, should do the trick =) I have some joints that are perfect on one side, but lack a bit of solder on the other side. I see some of 6L6s joints are like this, so I guess no biggie. But if I do them over, would you just reheat and add solder, or desolder first? Another alternative is adding flux to the side with little solder, then reheat and add solder.
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I had one of those cheapie ebay solder puller and even that worked ok for a while.
But you have to work quickly. For run of the mills pins parts, the coolest tool
I've seen is a Hakko vacuum desoldering gun.
I personally wouldn't worry too much that the solder hasn't flowed completely to
the other side if it's good on your main solder side (nice shiny volcano dome and
not a round blob) But a quick reheat and reflow should solve it should you
want to pursue it. (Just make sure you don't overdo the heating; you can
kill parts that way.)
The one time flux residue really gave me problem was with the SMD jfets
for the BA2018 preamp and I was not able to control the dc offset of
one channel. Eventually tracked it down to some residue around one jfet
and it was all fine after cleaning it (with a bit of alcohol and wooden toothpick)
But you have to work quickly. For run of the mills pins parts, the coolest tool
I've seen is a Hakko vacuum desoldering gun.
I personally wouldn't worry too much that the solder hasn't flowed completely to
the other side if it's good on your main solder side (nice shiny volcano dome and
not a round blob) But a quick reheat and reflow should solve it should you
want to pursue it. (Just make sure you don't overdo the heating; you can
kill parts that way.)
The one time flux residue really gave me problem was with the SMD jfets
for the BA2018 preamp and I was not able to control the dc offset of
one channel. Eventually tracked it down to some residue around one jfet
and it was all fine after cleaning it (with a bit of alcohol and wooden toothpick)
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Thanks Dennis, as usual!
I think all the joints are good. And there is no residue. There is so little flux i. The solder (Interflux), that almost everything evaporates. I think the main problem I have, is assessing HOW MUCH solder to apply, and therefore the joints come out differently. I just tried applying a bit of extra solder to the other side of a few joints. And it came out nicely. I will go over the rest of the joints tonight.
On another note, today a shipment arrived from Modushop, including my new back plate. So finally I can start assembling the PSU from inlet to transformer. The PSU board has been reordered and I will do it from scratch, as I inherited some crappy work buying a half finished dysfunctional F5T.
I actually ordered a few riser panels, and had enough brass standoffs to put a 150x180mm panel 12 cm above the PSU board. This means extremely short signal cables, as well as very short distances for all other cables. I can post a pic later.
This means 15-16 cm distance from FE front to transformer, and around 20 cm from the JFETs. As opposed to 22 cm from the whole board to closest point on transformer if I mount the FE on the back plate. Are distances OK, or should I mount on back plate?
This posistioning really gives easy access to biasing the FE, as well as good ventilation for it. Probably no stress anyways, but I had hoped to make use of the UMS, and this solution looks neat and also makes drilling in the chassis unnescessary.
I think all the joints are good. And there is no residue. There is so little flux i. The solder (Interflux), that almost everything evaporates. I think the main problem I have, is assessing HOW MUCH solder to apply, and therefore the joints come out differently. I just tried applying a bit of extra solder to the other side of a few joints. And it came out nicely. I will go over the rest of the joints tonight.
On another note, today a shipment arrived from Modushop, including my new back plate. So finally I can start assembling the PSU from inlet to transformer. The PSU board has been reordered and I will do it from scratch, as I inherited some crappy work buying a half finished dysfunctional F5T.
I actually ordered a few riser panels, and had enough brass standoffs to put a 150x180mm panel 12 cm above the PSU board. This means extremely short signal cables, as well as very short distances for all other cables. I can post a pic later.
This means 15-16 cm distance from FE front to transformer, and around 20 cm from the JFETs. As opposed to 22 cm from the whole board to closest point on transformer if I mount the FE on the back plate. Are distances OK, or should I mount on back plate?
This posistioning really gives easy access to biasing the FE, as well as good ventilation for it. Probably no stress anyways, but I had hoped to make use of the UMS, and this solution looks neat and also makes drilling in the chassis unnescessary.
Thanks. I agree. So to the bias boards. I have plenty of room to put them in front of the gain stage, and at the same time fairly close to the output boards. This gives the advantage of biasing them very easily from the top. Also, I don’t get the hassle of soldering wires through both boards. On the other hand, this means longer wires. What’s your take on it?
The only time I would worry about solder not flowing all the way through to the other side would be if the through hole is getting trashed or if you had to drill the through hole slightly larger wiping out the connection between top and bottom.
Russellc
Good to know. But i still find myself OCD’ing over good joints that are not fully soldered through. Leave or fix? Hmmm
Wrt output boards: what is the best sequence for doing this? Do you guys fix the MOSFETs to the sink prior to soldering, or after soldering? I am thinking the best way to ensure good fixing to the sink, is first bending the legs, then mounting them to the sink, put on the board, center the pins, tighten the FETs, and then soldering them to the board. Thoughts? I ask a lot. That is because I think a lot. Apologies.
Wrt output boards: what is the best sequence for doing this? Do you guys fix the MOSFETs to the sink prior to soldering, or after soldering? I am thinking the best way to ensure good fixing to the sink, is first bending the legs, then mounting them to the sink, put on the board, center the pins, tighten the FETs, and then soldering them to the board. Thoughts? I ask a lot. That is because I think a lot. Apologies.
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Use good solder. Everyting you have talked about with yours makes me think it’s not very good at all. Fire-Metall from the store is absolutely incredible (though currently out of stock), as is WBT and Cardas Quad. Even something like 63/37 Kester 44 Will make it much, much easier to solder.
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If its still apart, fix them, it only takes a few seconds each, if top is good, don't worry.
Russellc
Another thing, I notice solder joints rarely look as good in photos than they do in person...
Russellc
Agree. Mine look better in real life. Probably something to do with reflexted light. Considering ordering a photographer.
I don't know...next thing you know you'll have light stands and a Zeiss macro
just so you can get those beauty shots of solder joints.
Thanks for all the good advice and answers to my questions, really, to everyone!
Just redid all joints I weren’t happy with. It is acutally a really good, and very expensive solder. It’s just not very forgiving if you don’t heat the solder pad and part enough, or if you use too little solder. It is a one chance type of solder. Remember, the guy who recommended it, is the head honcho of high end amp servicing in Norway. At least I do not know of anyone as experienced as him. He does ML, Krell, Primare and Hegel over here. There are others, but I trust the guy.
Nevertheless, I ordered some Weller solder alpng with some new tips the other day. It has three and a half times as much flux, so I will get to compare. Fire Metall is on the short list btw.
Along everything that went smoothly today, some things did not go as well. I kinda broke the new EMI/RFI filtered inlet. Well, didn’t completely break it. But it is not possible to use one fuse with it anymore, a part proke. Is it possible to use two fuses with BA-3 with only one transformer, or do I need to reorder?
Also, the soft starts that came with the amp, look like crap, meaning there are burnt traces on the PCB. It is still intact, but needs testing. So kinda tempted to just use a thermistor, like in Nelsons PSU, and as 6L6 has advised me to.
Just redid all joints I weren’t happy with. It is acutally a really good, and very expensive solder. It’s just not very forgiving if you don’t heat the solder pad and part enough, or if you use too little solder. It is a one chance type of solder. Remember, the guy who recommended it, is the head honcho of high end amp servicing in Norway. At least I do not know of anyone as experienced as him. He does ML, Krell, Primare and Hegel over here. There are others, but I trust the guy.
Nevertheless, I ordered some Weller solder alpng with some new tips the other day. It has three and a half times as much flux, so I will get to compare. Fire Metall is on the short list btw.
Along everything that went smoothly today, some things did not go as well. I kinda broke the new EMI/RFI filtered inlet. Well, didn’t completely break it. But it is not possible to use one fuse with it anymore, a part proke. Is it possible to use two fuses with BA-3 with only one transformer, or do I need to reorder?
Also, the soft starts that came with the amp, look like crap, meaning there are burnt traces on the PCB. It is still intact, but needs testing. So kinda tempted to just use a thermistor, like in Nelsons PSU, and as 6L6 has advised me to.
So I encountered my first problem, and it has to so with soldering. So I have worked on my technique. And joints come out nice now. But I am really struggling with the MOSFETs solder pads on the front end. I find them very small and narrow. Perhaps I need a tip activator or something. But am I the only one experiencing difficulty with these joints, or have others similat experiences? Soldering the JFETs was easy conpared to this.
Tips and hints appreciated. Could not find anything on this searching the threads.
Andreas
Tips and hints appreciated. Could not find anything on this searching the threads.
Andreas