Moko's DIY 834 Phono Stage Build

[ZZMoko]

So the package turned up from Germany I went with the kit containing all the caps,resistors etc as it wasn't much more expensive than the bare board.



The caps contained are these





So that's what I've got does anyone have any suggestions before I start to any upgrades I should make before I start soldering....Different Capacitors etc?

[williamsunique]

Watching with interest.

Paul

[willbewill]

I see you bought the Cricklewood approved model

[Phil Y]

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.

[ZZMoko]

That's a good point Phil I was just thinking if it saved the hassle of taking the board apart and attempting to resolder components it might be an idea to upgrade it now, but only if previous builders had experience of improvements made by changing the caps etc.

Hopefully one of the guys who have already built this stage will see this and make some suggestions

[itskeith]

Watching with interest. 

[ZZMoko]

Remembered I had this old Indian aluminuim lunch box knocking around looks the perfect size for the power supply to go in



Quick question how do you separate two parts of a PCB board easily and more importantly successfully
 

[niclaspa]

I have no direct experience of this kit, but looking at the PCB it appears that provisions have been made to allow separation of the power supply from the amplifier.

Putting the power supply in a separate box has the advantage that you don't need to worry about it introducing hum into the phono stage.  But, there is extra cost and work involved.  You need a connector with at least five poles: 2 for high tension, 2 for heater supply and one for earth.  From a safety aspect, it important that the power supply chassis and the amplifier chassis are connected with an earth cord.  The connector and the cable needs to be rated for the high tension voltage.  Make sure that you choose a combination of male/female connector that don't leave high tension on any pin that can be touched.  Amphenol make good connectors, which I have used for this purpose:





Unfortunately, not very cheap.

I think that the easiest and cheapest option is to get a enclosure that is big enough to keep the transformer at a good distance from the amplifier.

Good luck with your build!   

[Chris65]

Quick question how do you separate two parts of a PCB board easily and more importantly successfully.

There is a 'break' line between the two (the row of small holes). I'd suggest you remove all the components (bit of a pain) & then separate them.
Just a matter of applying pressure to one side - put the circuit board on a table with the break line on the table edge, gently but firmly apply pressure on the overhanging PSU board and they will eventually separate.
This PCB is quite thick, so takes a bit more than some, flip it over every now & then as you apply pressure.

That's a good point Phil I was just thinking if it saved the hassle of taking the board apart and attempting to resolder components it might be an idea to upgrade it now, but only if previous builders had experience of improvements made by changing the caps etc.

Hopefully one of the guys who have already built this stage will see this and make some suggestions

Like I said in the other thread, I don't think anyone got the full kit (they didn't have those at the time), so we had to supply the caps.
I like Phil's advice.

[awty]

Nice looking board David.

Are the vacuum tubes going to stick out the lid?

You could use Aluminum plate or even ply wood to strengthen the box.

[ZZMoko]

The aluminuim box isn't big enough for the valve board so I was thinking of using it for the power supply section.....I still need to find a case the right size for the valve board the search continues....

[awty]

The aluminuim box isn't big enough for the valve board so I was thinking of using it for the power supply section.....I still need to find a case the right size for the valve board the search continues....

Make one.

[ZZMoko]

I might   but I'm going to see if I can find an old CD player case or something similar from my local HiFi place as they always have loads of discarded stuff laying around.

Returning to power supply and separating it from the signal board would this type of connector do the job....?

http://www.ebay.co.uk/itm/WD19-Plug-Socket-Connectors-Boat-deck-Camper-Caravan-Waterproofing-Kit-/151559529513?var=450773687758&hash=item2349a6e429:m:ms7f7i7szZ9A7rxWsNX4XNw

Or there's this one

http://www.ebay.co.uk/itm/SP13-and-SP17-Series-IP68-Circular-Multipole-Plug-Socket-Connector-set/161568085294?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D20140122125356%26meid%3D2e39b53832f0485fac157a4ec8231efd%26pid%3D100005%26rk%3D2%26rkt%3D6%26mehot%3Dpp%26sd%3D151559529513

Apparently you can specify the number of pins required and it seems to handle upto 25A.

At the other end I would use a fused IEC for the input to the Power Supply board

[ZZMoko]

Possible change of plan the recycling pile turned up this case...it was an old tuner which has a hefty shield separating the power section from the rest of the electronics which I can use to the same ends in my build

 



I will have to fashion a front and a lid but plenty of bits laying around for that...does anyone know if having the valves poking out the top of the case would cause any problems as in the confined space this is all going to have to fit in it may allow a bit more cooling?

[niclaspa]

The connector in the first link is for 12V.  You need a connector that is rated for the high tension.  I am not sure what it is in your case, but I guess that it is in the region of 200-300V.

The five pin version of the connector in the second link is rated for 180V which is on the low side.

But, that tuner case looks good!     You can fill unwanted holes with chemical metal.  With a bit of sanding and a touch of spray paint it will look great!