DcibeL said:
Cool. That's good to know. I was worried about increasing the potential for failure by having the leads under tension so I soldered them as close as they would naturally sit.
Dcibel, what sort of solder do you use and recomend? I've just been using 60/40 in .7mm and it handles nicely (temp controlled iron at 300c) I've noticed that some folks here are using more exotic solders, and there is lead-free available too.
My son came back from school with a project he built there, and managed to blow up a BC548 on it. While we were repairing the PCB, I noticed the solder they used seemed to have a lower melting point than mine.
I guess, unless there are health, sonic or handling benefits, I'll stay with what I have...
Thanks,
Michael
Member
Joined 2003
The tension will be quite small so it is not a problem.
Personally I think the type of solder has little effect on electrical characteristics, although there is some fancy solder with silver in it that is sold for audio purposes. To me, it seems a little excessive and maybe a bit of a waste of money. I use eutectic no-clean solder because I get it free from work
. Eutectic is best for surface mount or tempurature sensitive parts because it has the lowest melting point and changes from solid to liquid very quickly so there is a reduced chance of a disturbed solder joint when using it. Soon at work we will be moving to Lead Free, for health benefits I believe. Lead Free melts at a relatively high tempurature, and doesn't make quite as smooth of a solder joint.
For those small transistors, there is a special heatsink tool you can buy to clip onto them to prevent from burning them when you solder them. Really though attaching something metal to them will do the trick, such as wrapping some tin foil around them.
If there is ever a problem getting solder to stick to a surface, there is liquid flux that you can paint onto the surface. Watch for what type you are using because some are corrosive if they are not washed off thoroughly. I use a water soluble type of flux which works very well, but I can't remember it's exact name off the top of my head.
Personally I think the type of solder has little effect on electrical characteristics, although there is some fancy solder with silver in it that is sold for audio purposes. To me, it seems a little excessive and maybe a bit of a waste of money. I use eutectic no-clean solder because I get it free from work
. Eutectic is best for surface mount or tempurature sensitive parts because it has the lowest melting point and changes from solid to liquid very quickly so there is a reduced chance of a disturbed solder joint when using it. Soon at work we will be moving to Lead Free, for health benefits I believe. Lead Free melts at a relatively high tempurature, and doesn't make quite as smooth of a solder joint.For those small transistors, there is a special heatsink tool you can buy to clip onto them to prevent from burning them when you solder them. Really though attaching something metal to them will do the trick, such as wrapping some tin foil around them.
If there is ever a problem getting solder to stick to a surface, there is liquid flux that you can paint onto the surface. Watch for what type you are using because some are corrosive if they are not washed off thoroughly. I use a water soluble type of flux which works very well, but I can't remember it's exact name off the top of my head.
kmj said:
How are those boards comming along? I thought i might ask so this thread doesn't sink back to far
Hi things are going fine. I just have some other PCB purchases happening at the same time as this and I am trying to get everything worked out. It won't be long now. Brian and I will be offering these as PCBs and complete kits.
BTW, thanks for asking.
Cheers!
Russ
Member
Joined 2003
As you probably already know Russ, I've hooked up your Freebird preamp to my Mauro "My_Ref" amplifier today and it works just great. I should have really tried connecting my input directly to the amp and then feed it through your preamp to see the difference it makes, but sorry I got exited and just hooked it all up. It would be easy for me to test if I hadn't soldered the wires directly to the board.
Other than my previous suggestion of spacing parts out a bit more, my other suggestion would be for the power supply board. It would probably be a good idea to have two holes for the center tap transformer input to accomodate transformers with dual secondary wiring.
Keep up the good work!
[Edit: forgot also to mention that I have the output of the preamp going to my subwoofer and there is a small thump when I turn it off. nothing major or annoying though. Just thought I'd mention it]
Other than my previous suggestion of spacing parts out a bit more, my other suggestion would be for the power supply board. It would probably be a good idea to have two holes for the center tap transformer input to accomodate transformers with dual secondary wiring.
Keep up the good work!
[Edit: forgot also to mention that I have the output of the preamp going to my subwoofer and there is a small thump when I turn it off. nothing major or annoying though. Just thought I'd mention it]
DcibeL said:
Ah yes, the dreaded turn off thump. Well here is something to try, for 110 mains I use a 4.7R 1/2W resistor with a .1uf 200V film cap in parallel with mains the switch contacts. The will suppress the large voltage transient when you throw the switch. The is a simple RC snubber accross the switch. The same value would probably work for 220 but I would increase the voltage rating of the cap to 400V at least.
Cheers!
Russ
I have come up with what I would consider the successor to the FreeBird, you can read about it here:
http://www.diyaudio.com/forums/showthread.php?postid=735878#post735878
Cheers!
Russ
http://www.diyaudio.com/forums/showthread.php?postid=735878#post735878
Cheers!
Russ
Well, here is why I used make before break, if you use break before make then (in most designs) you will leave the input open for a brief moment while you change sources which could cause a pop or click. Mine switch is smooth, no pop, no click. I am not sure what the downside to using make before break would be.
Member
Joined 2003
I also used break before make in my preamp. There is no pops or clicks when switching between inputs, but who knows in a few years when the switch starts to wear out. I used a rather cheap 2 pole, 6 pos switch from Mode Electronics.
I chose this type of switch because I did not want to cause problems with having 2 sources connected to each other, even for the small moment while the switch switches.
I chose this type of switch because I did not want to cause problems with having 2 sources connected to each other, even for the small moment while the switch switches.
Never had any problems with a break before make switch and are all as quiet as, and that's with el cheapo switches. The main thing AFAIK is you only break the hot wires and the grounds are always connected (all connected together) for a noiseless operation.
With the make before break, is there a problem with the output voltage coming from one source into the output of the other source, even if the second source is not powered up? In other words, 2 sources on the 1 input with one powered and the other not.
With the make before break, is there a problem with the output voltage coming from one source into the output of the other source, even if the second source is not powered up? In other words, 2 sources on the 1 input with one powered and the other not.
how long before we can order... ?
I need a preamp badly as I have no volume control for my inverted GC, don't want to do the pot messing with the gain thing....
Don't want to go back through the 12 pages to find out if its a stereo PCB or mono design, and what the dimensions are (busy planning case size to house the giant transformer I have with the amp and pre in 1 minihifi style cube)
I need a preamp badly as I have no volume control for my inverted GC, don't want to do the pot messing with the gain thing....
Don't want to go back through the 12 pages to find out if its a stereo PCB or mono design, and what the dimensions are (busy planning case size to house the giant transformer I have with the amp and pre in 1 minihifi style cube)
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