Dutch Crack

[daantjuh44]

Hi all,

I received my crack a few days ago and figured I would make a build log here.

While I was waiting for the crack to arrive I had a bit of fun modeling the crack in 3D modeling software and working out a color combination.
Finally decided on staining the wood in white, anodizing the plate black, painting the transformer bell end black and painting the transformer platters white as can be seen in the rendering.

(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fs9.postimage.org%2Fqrqlwlt3z%2Fcrack.png&hash=27ff64568e4115740274f5c24de6035f09c80896)

I asked the company that will handle the anodizing about how it will affect the electrical conduction, they said the metal wont conduct electricity anymore.
If I remove the finish from the plate near the mounting holes will this suffice or should I look at painting it instead of anodizing?

I will glue the base tomorrow and maybe start the staining process. I also have two interconnects I need to make to practice soldering on as this will be my first time soldering electronics.

I got a nice 48W temperature controlled soldering station, some 60/40 solder and a wire stripper as an early Christmas present so I think I'm all set.

[Paul Birkeland]

For the safety ground connection, we supply toothed washers that will poke through the anodizing (it's a very thin layer).

For the terminal strip on the 9 pin socket, move the lock washer so that it's touching the chassis plate instead of the nut, and you should be good to go.

-PB

[daantjuh44]

That's great!

I will take the plate to the anodiser on monday then.

The interconnects are finished and the glue of the wooden base is drying at the moment.

I will take some pictures tomorrow when I have some good lighting.

Edit: Here are the pictures I promised

First the interconnects:
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fs18.postimage.org%2Fuvjt71oqx%2FIMG_1019_1.jpg&hash=4ee9fe9e964ea680e2065faf1f9b1c59af4ce8f5)

And the glued up wooden base:
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fs15.postimage.org%2Fsni18roxn%2FIMG_1020_1.jpg&hash=ccee41468f2e8d66d425254d6cc5b6c7d16ef9bf)

Daniel.

[daantjuh44]

Built the crack today, started in the morning thinking I would build half of the amp today. Turned out to be so much fun that I just couldn't stop myself soldering.

I attached some pictures of the finished crack, only need to stain the wooden base.

The underside:
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fs16.postimage.org%2F3r2a0b5tx%2FIMG_1061_1.jpg&hash=dcef00426e2b576bf1d01e3d950d73652e93e614)

And the top:
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fs12.postimage.org%2Fwgxnp0s4t%2FIMG_1062_1.jpg&hash=ebd81a262ed2b550122cb86a0b8692cd0fb11618)

Hopefully going to do the measurements tomorrow, might be Monday before I get the chance.
Only ran into 1 problem during the building process, the leads of the 270ohm resistor weren't long enough to make it from one terminal strip to the other, bending the upper lips of the terminal strips solved this.

Can't wait to finally try the amp.

Daniel.

[Paul Birkeland]

Hello Daniel,

The build is looking good!

With that 270K resistor, leaving the leads that long will potentially allow it to contact other parts of the circuit (it is close to the 150V AC winding, contact here will blow your fuse).

I'd leave no more than 5mm of lead length there. 

We apologize for the green 270 Ohm resistors.  The normal supply of our 270 Ohm resistors dried up, and rather than waiting six weeks to ship kits, we substituted a resistor of higher quality that has marginally shorter leads. 

Are you still planning to go with a white base?

-PB

[daantjuh44]

I will shorten the leads of that resistor, had trouble fitting it in there but wasn't aware of the danger of the leads being too long, thanks for that pointer!

Also no need to apologize for the green transistor, I just figured I'd tell how I solved it for other people potentially having this problem.

Yes I'm still planning to go with a white base, I'm buying the stain Monday.
Hope it will look like I want to.

Daniel.

[daantjuh44]

Just did the resistance check, l have two measurements that are not panning out.
It's terminal 6 and 10 where te striped sides of the 160v capacitors are attached, they measure 0 ohms instead of the 2.4kohm they should be measuring.

What could be the problem here?

Edit: could this be because I bridged the outer terminals of the jack to keep the startup voltage down?

Daniel.

[Paul Birkeland]

Edit: could this be because I bridged the outer terminals of the jack to keep the startup voltage down?

Daniel.

Yes, that will alter that reading accordingly.

[daantjuh44]

Great, so it is safe to do the voltage checks now?

Will any of the voltage reading be different because of this mod?

Daniel.

[daantjuh44]

Just did the voltage test and found out the hard way I had soldered the capacitor at terminal 14 and 15 on with the stripe on the wrong side. Checked and double checked for ages but still managed to overlook it.

This broke the 270 ohm resistor because it got too hot, actually cracked the ceramic coating and discolored the wires.

What parts do I need to replace, the 270 ohm resistor doesn't conduct anymore and while reflowing the solder joint I also nicked the capacitor I soldered on the wring way burning the outside a bit.

I think I just need to replace the resistor and the cap I nicked or could this have done damage elsewhere in the system?

Daniel.

[Paul Birkeland]

Yes, you can replace the cap and resistor.

You can e-mail queen(at)bottlehead(dot)com and we can send you replacements.

Otherwise, a 270 or 250 ohm 5 watt resistor is a suitable replacement, along with a 220uF/250V cap (don't change the cap value).

-PB

[daantjuh44]

Sorry, I forgot to reply to this thread,

I have since ordered the new components from Eileen and am eagerly awaiting their delivery.

Daniel.

[ashneel]

Hello Daniel,

The build is looking good!

With that 270K resistor, leaving the leads that long will potentially allow it to contact other parts of the circuit (it is close to the 150V AC winding, contact here will blow your fuse).

I'd leave no more than 5mm of lead length there. 

We apologize for the green 270 Ohm resistors.  The normal supply of our 270 Ohm resistors dried up, and rather than waiting six weeks to ship kits, we substituted a resistor of higher quality that has marginally shorter leads. 

Are you still planning to go with a white base?

-PB

Some advice regarding the green 270Ohm resistor..I cannot connect the parallel terminals as it is shorter. How should I proceed? My apologies for posting here, and for my English. I am French. Kind regards

[Doc B.]

Yes, sometimes the green 270 ohm resistors are all that we can get and the leads are shorter. The easiest thing to do is bend the terminals slightly or slightly tilt the entire terminal strip before soldering the resistor

[daantjuh44]

Finally had the chance to finish my crack today, went on a trip to Austria for 2 weeks.

My my does this thing sound good!
I just can't stop listening to it.

I do have a weird noise in the left channel sometimes, its like someone is pulling a plastic bag over my head, a rustling sound. Sometimes I get a quick humm in there too.
Is this something that will go away over time?

Daniel.