# Quick questions about new pcbs/builds



## mekrob69 (Mar 1, 2022)

I just received new boards for a Duo Cast and Carmine Drive.

First question: On the back of the Duo Cast are two small rectangular pads (looks like the pause symbol), what are these? It looks like I may be a solder jumper if I were to forgo that component.

Second question: Above the J201 on the Carmine Drive is what I guess is a place to solder a SMD J201, if I bought a standard J201 would I just install it and ignore the SMD pads?

Last question: How do you socket Transistors?
I bought a socket strip to make my own transistor sockets, so for the J201 I’ll just break a line of 3 sockets, for the OC71 and BC549C I plan on breaking 3 pins of and adhere them in the right configuration (probably super glue, or sticky tack). Then solder them in. Do you just push the transistor in, or if the transistor sounds good do you have to solder it in the socket?

Thank you for any help


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## Feral Feline (Mar 2, 2022)

1. Yes, probably a place to put a solder bridge (I’ve not looked at the doc/schem to see what it is)
[edit: see Temol’s post below ]

2. Use one or the other, not both.
If you are unable to get THD-trans I’d recommend getting some wee daughter-boards with pre-soldered SMD trans, that way you can still socket the main board and install and swap different transistors to get a feel for how they each sound. Some builders don’t like sockets, but I’ve never had a problem with socketed trans and thus never overcooked a trans from soldering it.

3. Don’t use superglue, use the sticky tack (sparingly) and once the sockets are soldered in place remove the sticky tack — too much tack or too close to the solder-area = a hot sticky mess (this is the voice of experience talking).
For transistors with legs in a triangle formation, try to get your sockets to be 2+1, which will be more stable than three individually cut SIP sockets.

Once sockets are soldered, you can push the trans-legs in (consult the manufacturer’s trans’ datasheet to make sure of the correct pinout).

If you’re happy with the completed functioning circuit, then you may consider soldering the trans into the socket, but if it’s not loose and making good contact why bother? If it dies or you want to try other trans down the road ...


I like to trim my transistor-legs quite short ( space constraints and I socket), but if you’re going to solder them then keep them longer and use an alligator clip as a heat-sink on the leg between the trans and solder-iron.


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## temol (Mar 2, 2022)

Feral Feline said:


> 1. Yes, probably a place to put a solder bridge (I’ve not looked at the doc/schem to see what it is)


It's a jumper (surface mounted). It's located between pin 1 and 8 of the charge pump.


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## zgrav (Mar 2, 2022)

there is also an in-between option on whether to solder a transistor into a socket -- if you have good connections on the three leads, just solder in one of the leads (probably the middle).  that keeps the transistor in place but is much easier to remove if you want to replace it with something else later.


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## mekrob69 (Mar 2, 2022)

temol said:


> It's a jumper (surface mounted). It's located between pin 1 and 8 of the charge pump.


So is this an optional thing or something I need to do as part of the build? I don’t see anything about it in the build doc


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## zgrav (Mar 2, 2022)

what charge pump are you using?   solder the jumper for a MAX1044S (or a 7660, I think).  Do not solder the jumper for a LT1054


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## mekrob69 (Mar 2, 2022)

Feral Feline said:


> 1. Yes, probably a place to put a solder bridge (I’ve not looked at the doc/schem to see what it is)
> 
> 2. Use one or the other, not both.
> If you are unable to get THD-trans I’d recommend getting some wee daughter-boards with pre-soldered SMD trans, that way you can still socket the main board and install and swap different transistors to get a feel for how they each sound. Some builders don’t like sockets, but I’ve never had a problem with socketed trans and thus never overcooked a trans from soldering it.
> ...


Thank you so much for the detailed answers!

Great idea to socket the daughter boards so I can still build to my taste. Also thanks for the note about super glue, I figured the sticky tac would be messier, but now I know

I’m excited to begin my first two Germanium builds, with your insight hopefully things go a little smoother


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## mekrob69 (Mar 2, 2022)

zgrav said:


> there is also an in-between option on whether to solder a transistor into a socket -- if you have good connections on the three leads, just solder in one of the leads (probably the middle).  that keeps the transistor in place but is much easier to remove if you want to replace it with something else later


I will keep this in mind, especially if it’s giving me trouble or not wanting to socket


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## mekrob69 (Mar 2, 2022)

zgrav said:


> what charge pump are you using?   solder the jumper for a MAX1044S (or a 7660, I think).  Do not solder the jumper for a LT1054


I got the LT1054, it’s cool that little stuff like that makes it able to accept similar pieces


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## WheatAndBarley (Mar 2, 2022)

I used to break apart the line of sockets and place them individually but lately I've started ordering these from digikey: https://www.digikey.ca/en/products/detail/mill-max-manufacturing-corp/917-47-103-41-005000/7364145

They're really pricey for what they are but I haven't found anything else that does the same thing.


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## Barry (Mar 2, 2022)

WheatAndBarley said:


> I used to break apart the line of sockets and place them individually but lately I've started ordering these from digikey: https://www.digikey.ca/en/products/detail/mill-max-manufacturing-corp/917-47-103-41-005000/7364145
> 
> They're really pricey for what they are but I haven't found anything else that does the same thing.


I've got a few of those around here somewhere


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## Feral Feline (Mar 2, 2022)

Pricey little hockey-pucks indeed!
Thats what I want, but I can’t bring myself to buy ‘m.


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## Fishbonetabby (Mar 5, 2022)

Barry said:


> I've got a few of those around here somewhere


Pricey buy so convenient! I used them on my War Scythe build and I'm really glad I did. I don't remember where I got them but I paid about the same. The old town electronics shop near me sells has them at $9 for 2 😫😫😫


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