B1 preamp build thread

Member
Joined 2016
Paid Member
B1 Selector Switch

Hello All,
While I'm waiting on my chassis to come in I'm now thinking that I'd like to add a selector switch so that I can have more than 2 inputs. I've read in some of the first posts that selectors have been sourced from Hifi Collective and PartsConnexion. I found this one locally and it's also sold on Mouser. Would it be ok?
56D36-01-2-AJN Grayhill | Mouser Canada

I'm not sure exactly the type I need and would like some help and suggestions for a reasonably priced non exotic switch.

Thank You!
 
Hi All,

i am thinking to add :
input selector,
balance Pot,
Pot attenuator,

any obvious mistake in my sketch?
thank in advance guys!

Balance attenuator — imgbb.com
 

Attachments

  • Balance + attenuator.png
    Balance + attenuator.png
    87 KB · Views: 422
Last edited:
Official Court Jester
Joined 2003
Paid Member
that's idiot proof part , Papa put there as protection , taking in account that B1 was commercial product , with all possible consequennces

however , when I'm making some gadget , I'm only idiot going to use it , so why not optimize it ...... :)

you can omit that resistor completely , meaning - you can put short instead
 
i'm currently gathering parts to build a B1 buffer. now i'm trying to find out which DPDT switch to order for input switching. NKK makes nice toggles. there's the normal version rated at 6A and the "fancy" one rated at 0.4VA with gold plated contacts. would it make any difference witch one i use for input switching?

here's the pdf with the NKK toggle switches: NKK Toggles
 
B1 selector switches

Characteristics to look for in a switch for line-level work include:

Silver plated contacts. Yes, gold is prettier and doesn't oxidize as quickly, however silver has always sounded a lot better than gold, and its' oxide is very soft and designed to be displaced by the action of the switch contacts.

Douglass Sax, of The Mastering Lab, says he can always hear a gold contact in an audio signal chain! I'm not sure I can, but Doug has done some really fine work in his day. It has always amused me to see all of the gold in use nowadays, just another example of manufacturers' fashion statements at work.

Secondly, switches should preferably be make-before-break, to avoid the possibility of a nasty pop occurring at the moment of switching. You can probably get away with break-before-make if your sources are free of any trace of DC on the outputs.
 
Last edited:
Use the smaller one. Don't worry about contact material. The smaller one will be easier to use, nicer to touch, and more appropriate for the teeny signals of sources.

well, the size would be the same. just the rating and the contact material are different. maybe it's smaller or more delicate on the inside since it's rating is so much lower. the data sheet says one is for power level and the other for logic level ..... whatever that means (can you tell i'm a newbie? :D)