[MartyMart]

Hi,
I thought this may be useful and a fun thing to do, document my D-LA2A build :-)

This will be ongoing whenever I have time to continue, it may take a few weeks to complete.

So we begin with some parts :




And here is the blank PCB from Volker = thanks :-)



The first items to fit are all the resistors and diodes - going for lowest level first is always better.
I checked everything with my DMM and used matched values for the left and right channels.



And here is a longer shot of my working area, I made sure that the larger 3w resistors had some
"air space" below them, same for the diodes too, that's my new RS solder station which is really good BTW.



Here I needed to make up some 2k7 resistors as I didn't have that value.
It ended up as 2k6 but should be close enough, once again matched the four sets.




Next all the smaller caps, orange drop, solen fast, the poly's & Mica's



Next comes the valve and TB4 sockets and high voltage electro's
I left the heater connections off for wiring up, which will be the next step.



And bottom of the board ....


And here is a little "Arty" closeup :-)




That's all for now, more next week when I'm back from weekend shows.

Marty.

[braeden]

Always love a good photo build, good job! 

[Gustav]

When I had a studio, the La2A was my main gear-crush, and Volker's design is just great.

Will enjoy watching you document it. And if you don't mind having it added to a separate DIY blog, let me know.

Gustav

[flaheu]

Cool !

This thread is an inspiration for me to build mine.
I got my boards for years and never found the time (motivation) to start.

By the way great photos 

[MartyMart]

So folks, time for some additional shots and a little more progress :-)
I have tried to improve the photo's by using 'HI DEF' and then reducing the size afterwards, I think this
time it's better, with only one slight focus problem.

Here is where I ended last time, missing shot of the installed screw terminals>



Here i solve the issue of fitting the Relays, they are expensive and any mistakes would be a real
PITA to solve / remove them, so I decided to use sockets.



Carefully clip from an 18pin DIL socket, the 2/4/6/7th pins and this will fit on the board like so:



It allows for a snug fitting relay AND the 1n4148 diode also, here they are taped down :



Then I solder opposite corners first just to centre it :



Then add a dab of solder to all the remaining pins:



Carefully line up the relay with the pins and push home:



Leaving the front pair free for the 1N4148 diode - I would fit these first and do check orientation !



and here they are all fitted and ready to rock :



AND ,,,, a few close ups of the procedure :







Next I decided to try and tackle the "Heater wiring" ---- AARRGGHHH !!!!

.... no really don't panic, it's not so hard if you just take your time ... measure twice and cut once
and all that stuff.

I have done heater wiring before on a couple of tube amps but i am NO expert !

I chose two colours for the H1/H2 wires, measure up AND include a few extra cm's for the twists
and VOILA !!



Here's where I twist and "tin" the wires with some "helping hands"



Once you start to move on from the first connection, it gets a little tough to insert 2 x wires
into the H1 connections, so after tinning the wires I made a little "hook" with one wire end.
So one H1 lead tucks into the board up against the tube socket lead and one "wraps" around that, as
it's now a little "hook" shaped end ... seems to work for me, no way I could get 2 x H1 leads
into the hole in the board.
Here is one such connection, with tape helping keep it all steady once again
you can see the "hook" on the yellow lead before I solder:



And with one side done, this is where I sign off for today :-)
More soon as I can ... and when I buy some more valves since I lost the whole lot in my move !! :-(



BAH ... that's the blurred pic, think i got the twists nice and tight though :-)

Marty.

EDIT :
Final pics of the heater wiring and top with large Solen Fast caps added>

[Piedwagtail]

You could

twist the wires with a vice and an electric drill, lean back and get instant wonder grade twists that don't unravel.

clean the flux off with a toothbrush and some white spirit; makes it look awfully clean and wouldn't be sticky anymore.


Robert

[MartyMart]

You could

twist the wires with a vice and an electric drill, lean back and get instant wonder grade twists that don't unravel.

clean the flux off with a toothbrush and some white spirit; makes it look awfully clean and wouldn't be sticky anymore.


Robert

Thanks, my electric drill would rip my hand off .... two speeds, fast and VERY fast !! - the hand twisted leads
are quite happy where they are.

Flux cleanup comes when I'm finished "Fluxing"  :-)

[Piedwagtail]

True you need a variable speed drill.

Never used to clean got a bad habit from synth diy.

Recently I tried a chinese 5V 5A SMPS box with a variable pot turned to 6V, so small it's changed my heater habits. Bit weird having no hum or really hot resistors.Recommend.

Robert

[MartyMart]

Slight delay, waiting for the valves to arrive from the UK so I can continue.

I will get there !!

Marty.

[jplebre]

Marty, which case are you going to use? 3u?
You need to trim the valve sockets for 2u :S

[MartyMart]

3U case from Parusha, had it since 2009 !!

It's a bit "clean and white" so I might try distressing it a bit :-)

I like gear that looks old and used.

Just got the valves in the post but working for a few days and off to the UK to see my folks.

Will continue the week after next.

MM.

[jplebre]

Looks good keep on posting Marty!

Cheers

[desol]

3U case from Parusha, had it since 2009 !!

It's a bit "clean and white" so I might try distressing it a bit :-)

I have the same case.  At first i wasn't sure if I'd like it...but after having it for a bit,
i don't hate it!

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