Moko's DIY 834 Phono Stage Build

[ecosprog]

This I probably a very embarrassing question to ask but here goes.....

Which side of the PCB are you supposed to put the solder joint when soldering the components.....The same side as the components (the top side) or the side where the legs come through the PCB (the bottom side)?

Solder from the bottom and a good joint should flow through to the top side.

[ZZMoko]

Good that's what I did but looking at some other photos it looked like they had been soldered from the top..

[willbewill]

I'd love to see someone soldering those big caps from the top

[Sk8Ter]

One thing I would mention just as an aside.
It depends on your attitude, but if you upgrade the kit before you build it, you will have no idea what difference the better capacitors have made. I know that with a PCB build there is some risk in swapping components, but how about building it 'as is' then after a few months, when you have really got used to how it sounds, swap some caps. That way, you will learn for yourself what difference hifi grade caps can make. You will then be much better informed for any further upgrades to this, or any other gear you have.

It is always good to ask others for their experience/advice but nothing compares to finding out first hand.

Regards, Phil.

+1

[ZZMoko]

Just thought I'd try and get this back on track.....Any ideas?

Ok more questions as I'm fairly clueless when it comes to electronics......

I'm intending to have two inputs on this phono stage one for my regular Stereo tonearm and one for my Mono GE VRII arm will I need a selector switch to choose between the two inputs or will it be ok to just wire up both inputs to the board?

If a switch is required what sort should I be looking for?

Something like this http://www.cricklewoodelectronics.com/RTY2.html? Or does anyone have any other suggestions?

I was thinking of keeping the length of the signal wires as short as possible and as I would need to be able to switch between the two Tonearms and going with an extension bar arrangement like in this photo below..

[niclaspa]

David, that switch suites your purpose. 

I could be wrong, but if you take the trouble to have an extension bar for the switch to keep the signal wires as short as possible, maybe you should invest in a switch with a little better quality?  For example: http://www.hificollective.co.uk/switches/selectors-switches.html

[williamsunique]

Ok more questions as I'm fairly clueless when it comes to electronics......

I'm intending to have two inputs on this phono stage one for my regular Stereo tonearm and one for my Mono GE VRII arm will I need a selector switch to choose between the two inputs or will it be ok to just wire up both inputs to the board?

If a switch is required what sort should I be looking for?
Something like this http://www.cricklewoodelectronics.com/RTY2.html? Or does anyone have any other suggestions?

My point of view is to not switch such a small signal. Bad!
I would rather just unplug and plug depending on which arm I was using.  A better alternative is to have two phono stages and then have the switch attached to their o/p.  Take it even one step further and use ldrs for switching.

Paul

[ZZMoko]

Thanks for the answers regarding the switch.....

But I'm stuck on something else now.....which way to put in capacitors The Four caps I have left over tow of which are sat in the valve holder so you can see the types I mean.



I have the yellow cap which is marked 103J which I think should go in the holes marked on the PCB 100UF/10V but there is also + and -ve signs marked and I have no idea which way around to put the cap in, the same problem also apply a to the Blue Caps marked .012J

So does anyone have an idea on how to proceed?

Thanks in advance

[ropie]

Those caps aren't polarised, David, meaning they can go either way around.  That said, I have no idea where they should sit on your board.

[Phil Y]

No, those caps don't go there. Those positions require electrolytic caps, also the yellow cap is 0.01uF and the blue one is 0.012uF so are orders of magnitude too small in value. Another clue is that with caps, bigger value and higher voltage both make caps physically bigger. The PCB says 10v but the two you show are marked as 630v.

The ones to go in that position should be this style:



Phil.

[ZZMoko]

The blue one came with the kit and is shown in the finished board photo (you can buy a fully populated board) so I think that one should definitely go in the 0.1UF box marked on the board)




The yellow pair I bought as there appeared to be two caps missing

[Phil Y]

Hello David,

Small capacitors are often marked in pico farads (pF)as the yellow one you are asking about.
103 means, in pico farads, 10 followed by another 3 zeros ie 10,000 pico farad.
As this is a science thing, the next range up is 1000 times bigger which is nano farads(nF). Your yellow cap is 10nF.
The next range up is micro farads (uF). Your yellow cap is 0.01 uF.

I hope that helps, Phil.

[Phil Y]

Mmmm, that blue cap does seem to be fitted in the position marked 0.1uf on the finished board. The only thing is, it looks to be marked .012 which suggests that it is 0.012uF. One tenth the size required by the board markings. It could be the board marking is wrong, I have seen that more than once.

Phil.

[ZZMoko]

Panic over part 1.....found the electrolytic caps hidden under some stuff when I moved to take photo so now soldered into place.



So now which do I use the yellow caps marked 103J or the blue caps marked .012J which came with the kit.....the board at that point says 0.1uF/250V?

[ropie]

Erm, didn't you buy the yellow ones yourself?  I'd use the blues as they are shown on the completed photo