Build Report and Basic Questions

[TubeTim]

Greetings All,

Since Doc and Co. were kind enough to give status updates I thought I would send a builders status back their way. 
"The package" arrived in good order and timely.  The front panels and woodwork look really good.  I started by gluing up the wood chassis.  A practice run using a nylon web belt was tried to align and lock the 4 sides.  That seemed to work very well so that is the way it was glued together.  Next day it was solid like a single piece and the mitered corners seams disappeared with a little bit of sanding.  The first task done and it is extremely impressive how well the wood had been cut.  The top cover fits perfect also.

A couple basic questions:

Can one use a rubbed oil finish after a light staining?  Will the oil finish be a good approach?

The instruction manual is very clear and well written.  In reviewing it one could tell someone took a lot of consideration into producing it.

Referring the photograph of the assembled circuits in the chassis:  Is this considered a top class wiring?  I am curious and don't want to insult the build.  Some of the wire leads could be squared off more for a clean look.  Then again maybe if one does this it compromises the sound.  This is why the inquiry.

For the wire tie points.  I learned decades ago while making Eico & Heathkits that one should use the loop above the bakelite and wrap the wire around it twice.  Twice is a bit much as one can't easily undue a mistake.  The photos show many times the hole in the tie point is instead used.  I'd rather use this method as once soldered it should be as secure as a wire with a single wrapped hook.

Solder: OK, read some past posts about the 4% Au solder, which I had intended to use.  The 60/40 is no problem.  My skill level with a solder iron is very high, so I may go with the 4%Au.  Maybe stick with 60/40 for the PWBs.  Any comments about that are most welcome.

Thanks,

Tim

 

[2wo]

Ill go,

1, Oil finish is my favored, easy to apply and a nice glow. I like tung oil myself.

2, Do a search for Wardsweb on this forum, or maybe the old one on AA, get an idea just how neat it can be. I like to make my wiring neat and workman like.

3, Terminals have changed a bit. Have a look at them, plan ahead, see how many connections need to end up there. Then use your best judgement. Sounds like you have done this before.

4, You say you are an experienced solder slinger, use what you like. Me I like 2% Ag, as the stuff I have is just as easy to use, as good  60/40. Or I would use that. Actually it 63/37 or something like that. I think 4% is too much...John 
     

 

[Paul Birkeland]

Referring the photograph of the assembled circuits in the chassis:  Is this considered a top class wiring?  I am curious and don't want to insult the build.  Some of the wire leads could be squared off more for a clean look.  Then again maybe if one does this it compromises the sound.  This is why the inquiry.

For the wire tie points.  I learned decades ago while making Eico & Heathkits that one should use the loop above the bakelite and wrap the wire around it twice.  Twice is a bit much as one can't easily undue a mistake.  The photos show many times the hole in the tie point is instead used.  I'd rather use this method as once soldered it should be as secure as a wire with a single wrapped hook.

Hello Tim,

Putting a sharp, 90 degree bend in solid core wire is said to be detrimental to the interior crystalline structure, which potentially could be an issue.  Additionally, running the circuit wires like this would require a fair amount of additional wire, and we would have to specify in the manual where the wire should be bent, then which end goes where (notice how many wires are given a length and an additional jacket stripping instruction for both ends).

You can certainly wire up your Mainline as you like, and you will find a few spots where tight bends are used for components placed close together.

On the terminal strips, taking two wraps around the top terminal will give a very good connection, but it will be very difficult to remove if you make a mistake.  Generally, half a wrap is more than adequate on the top hole, and on the bottom hole we suggest bending a bit of the lead poking through the hole 90 degrees to keep it in place.

-PB

 

[hopeful]

Good idea to consolidate these sorts of inquiries in a single thread!

I've completed my basic hardware assembly and finished stuffing and soldering my C4S boards last night.  Quick question - is it okay if the clip on heat sinks touch the C4S boards at the bottom, or does there need to be physical clearance? 

I hadn't ever worked with these sorts of heat sinks before and had to fight them a bit (eventually realizing I needed to pull them open from the sides) to slide them on.  I'm slightly concerned that I may have put too much force on the transistors/solder joints in the process - so I already plan to rewet them.  But do I need to try and pull the sinks back up a bit so there is clearance? 

Otherwise - it has been smooth sailing and lots of fun so far!  Many thanks to team bottlehead for another outstanding kit    I posted a couple of progress pics over in the HF thread (post #39) in the event that anyone is interested in taking a look: https://www.head-fi.org/t/662240/mainline-new-bottlehead-premium-headphone-amp/30#post_9724139

 

[Paul Birkeland]

Yes, the heats inks can contact the board, as there is solder mask over the traces to prevent contact. Letting the heats inks rest on the pc board will also stabilize them a bit.

Pulling on the MJE5731A's shouldn't hurt them unless you can see broken leads, if any of the legs have slipped out, I would closely inspect all of your solder joints.

-PB

 

[hopeful]

Thanks for the confirmation and explanation PB!  The leads and solder joints on my MJE5731A's all look fine, so I imagine I'm still in good shape.  I just don't really have a clear sense as to how much force or stress a solder joint can really take.  I assume at a certain point physical stress can result in an unreliable connection akin to a cold or dry joint? 

 

[Grainger49]

Here is a link to WardsWeb Bottlehead build.  Pretty and knowing him, awesome sounding.

http://wardsweb.org/audio/sexamp.html

 

[TubeTim]

Tung oil it will be.  The solder 62/36/2.  Pointing out 63/37 was very helpful and a google search lead to an interesting article about this Vs. 60/40.    Thanks  John

PB & G  Thanks for the link and the info about the wiring.  Since the wiring shown in the instruction manual is more to my liking I will go that route.

So far progress consists of glued wood joints.  :-(  DubMike is smokin' this build, great job DM !


Best Regards All,

Tim

 

[TubeTim]

Greetings,

In the manual, page 21 and 22 it says to set both attenuator switches to 6 positions.  On the front plate for one of the switches there is only 5 labelled positions.  In looking at the pictorial wiring diagram there does appear to be one switch with 5 wired positions and the other with 6 positions.
Can someone kindly clarify?

Thanks,

Tim

 

[fullheadofnothing]

Not fully following here. The ID panels that shipped are from a different batch than the one shot for the manual, but they should be identical. There are clearly 6 positions shown on the ID plate in the manual (i.e. top of page 19).

The attenuator is not shown in the schematic, so I'm not quite clear what you're referring to here. The resistors on the two switches are configured differently, so they do look different visually. Is that what you mean?

Regardless, set the switches for 6 stops. The instruction is correct.

 

[TubeTim]

Hey Joshua,

First, my compliments on an very well written manual.  Also thanks for the prompt response. 

Thanks for pointing out the manual has a picture of the front plate, I should have looked for that.  Be that as it may, the manuals front plate does not match the one here, please see attached image.  It is missing the 0-db position or the coarse.  This is NOT a big deal as the 0-Db position will not be used so the difference will never be apparent.

By pictorial, I meant the photo on page 71.  There one of the attenuators has what looks like 2 diametrically opposed terminals unused compared to the other (1 O'clock and 7 O'clock position).

I'll leave the switches both set for 6 positions and "solder on".

Best Regards,

Tim

 

[Grainger49]

A picture is worth... you know.

Tim seems to be spot on.  Maybe the ID panels shipped were wrong?

 

[fullheadofnothing]

Huh. Well, I guess the file got botched. I'm blaming PB, mostly because he's on vacation right now. Next time I'm in the office I'll check if they're all like that. Also, for what it's worth, the switch with the blank spots is the switch that has all 6 positions identified. If that confused you, welcome to the brain rot of switching back and forth between the top and the bottom sides of the chassis...

As for why there are empty spots, I think it would be because all the resistors on that switch go to ground, so one position is not grounded to give full output. Note as always that when I am talking about anything electrical, it should be taken with a major grain of salt, and hopefully a smart person will come along soon enough to correct any mistakes and make fun of me.

 

[Grainger49]

Joshua,

I thought it was a rule to blame the guy who just left.  This is probably not applicable in the case of Bottlehead.

 

[bernieclub]

Just unpacked my kit.  I got the same attenuator plate....it appears to be missing the 0db mark on the course adjuster.

 

[isldkid]

Yes, the heats inks can contact the board, as there is solder mask over the traces to prevent contact. Letting the heats inks rest on the pc board will also stabilize them a bit.

Pulling on the MJE5731A's shouldn't hurt them unless you can see broken leads, if any of the legs have slipped out, I would closely inspect all of your solder joints.

-PB

 

[Grainger49]

To help those giving you assistance, just post the voltages that are out of spec.  To keep them from having to search back and fourth in the manual also post the expected.  This will save time and bandwidth.  So something like this:

Expected 100V, Measured 125V

 

[isldkid]

Grainger, ok got it thanks. Will do that the next time around.
Best,
FC

 

[Grainger49]