Bottlehead crack resistance is wacky?

[Paul Birkeland]

This might be a case where it's just best to purchase a fresh set of hardware and electronics from us. 

Very little in your build resembles what's in the manual in terms of layout, placement, lead lengths, and soldering.  Consequently, when looking at your build for where the problem might be, it just ends up looking like it's everywhere. 

We haven't seen the wiring around the 8 pin socket, but I would suspect that the keyway is not facing the front of the chassis.

-PB

[Doc B.]

Don't plug that amp in yet. For one thing you have a white rectangular 270 ohm resistor across the top of the power tranformer that is dangerously close to touching the transformer terminal that is connected to AC mains neutral. Also I think your filter capacitor and the other 270 ohm resistor are not soldered at terminal 15. Also, your RCA jacks look they they are shorted between the center pin and the outer shell, with solder. They will need to be reheated enough to get the solder from the center pin so it doesn't touch the outer shell/threads. You can use solder wick or a solder pump for that.

All of the excess leads need to be trimmed, and several of the solder joints look like they need more heat to properly flow the solder into the joint. Getting it to look more like the pictures in the manual will be worthwhile. If you go back over each terminal strip, straightening the wire dress, reheating any blobby looking joints and making sure things that shouldn't touch are properly separated you should have an easier time of getting it up and running. I will also suggest that you give us some photos of the areas that we can't see in the images you have posted so far.

[kong288]

I rotated the place where the big tube goes so it's pointing in the right direction, resoldered, and tried to take as much solder as I could. I moved the 270 ohm away from the a/c wire. And I do have the black cable coming from center to L3. Here's some closer pictures:

http://imgur.com/a/szTAx

To be honest to me it does look like the end product. I really don't think I need to buy it from you again. At least in the Manuel I'm using. There is a lot of solder, however. But i've taken a lot off from before.

I also fixed the rca jacks and retested the ohms. They're both grounded right, and their grounds are 0.

While cleaning up the bottom area of the amp I broke an LED. what's the best way to get a new one?

[Doc B.]

You can get a replacement LED by emailing [email protected].

[kong288]

Thanks, I sent an email. Do you see anything wrong from the pictures?

[Paul Birkeland]

Thanks, I sent an email. Do you see anything wrong from the pictures?

The 3.3K resistors are improperly mounted.  I can't tell if the left one is going to T7 or T8, but if it touches both, expect smoke.

Straighten out the leads on the 270 Ohm 5W resistors.

The 270K and 270 Ohm resistors on the left 6 lug strip aren't properly mounted.

The nuts are missing from the power transformer.

The black wire going from the power supply to the headphone jack is too long (well in excess of what's in the manual).

There is some kind of disturbing material coming out of terminal 7 and going to?

The input wiring isn't braided.

The 22K resistor between T4 and T5 is improperly mounted.

The 22K resistor between T1 and T2 is also improperly mounted.

The red wire to A7 is improperly run.

The jumper between T2 and T4 is not the correct length, and improperly installed.

The black wire going to A9 has too much insulation removed.

T9 has long leads poking through it, they need to be trimmed.  (If they touch the chassis, you will smoke the power supply)

The connections on B7 aren't at all wrapped around the tube socket pins, and will slip out pretty easily.  They also won't contact well enough to heat the 6080 without being properly soldered.

The wire from T7 to B3 is longer than the manual specifies.

One of the screws mounting the octal socket is supposed to be on the 9 pin socket.

The solder joints on the power switch are very cold.  If you take your pliers and pull on those wires a bit, they will pop off.

I can't tell, but I don't think you have the jumper that needs to be installed on the volume control (see the manual).

The twisted end of the pair of 3.3K resistors isn't slipped through 3U, but instead 3U has been bent out of the way. 

The wire to B3 has too much insulation stripped on the socket end.  If that bare wire touches the socket ring, you'll smoke the power supply.

The red/black twisted pair of wires on the 6.3V winding on the power transformer aren't really soldered.  The black jumper also appears not to be soldered on one end.



I would still recommend new electronics, hardware, and wire.

-PB

[kong288]

Thank you SO much for the detailed response! I sadly do not have another $300 to give you, but I really value you guys on holding my hand.

[grausch]

Remember, PB is not advising you to purchase new parts because he wants a bigger Christmas bonus. You chose to build differently than the instructions in the manual. With the current build, even if you get the resistance and voltage checks right, you still have a risk of shorts, will most like have hum due to the insufficient braiding and could have other issues due to flaky solder joints. For you, this will be the easiest, but most expensive solution.

My 2c, but you basically have 3 options to fix your amp, and these are listed in order of the best chances to get a working amp.

If you start with a blank slate, build everything according the manual, and get your solder joints right you have a good chance of getting a working, and great sounding amp. Plus, you already have the base, so it will be $279 less the cost of the base. This option will be easiest by far.

2nd option would be to remove everything from your amp and leave all the chassis parts (transformers, terminal strips, tube sockets, etc.). You can then restart from the soldering section in the manual and build everything according to the instructions. If you damage nothing else during the removal process, then you just need buy some additional wire. The other parts (caps, resistors, rectifiers, LEDs) can be ordered from Bottlehead or online. That would be more difficult than starting from a clean slate, and it assumes that you have not damaged the transformer.

3rd option would be to implement all of PB recommendations. I would redo all of the solder joints on your amp. Since you need to remove several components, you could also consider starting afresh. You may also need some additional wire and you still run the risk of damaging some parts. Since you are not building from scratch, there may well be other unresolved issues, but once you have done all of this you will be a lot closer to a working amp. Because of the potential other issues, I can understand PB advising you to order new parts and start from scratch.

Other questions:

• Have you watched Tyll's video? http://bottlehead.com/smf/index.php?topic=3340.0 It is essential that you watch this to see proper soldering technique.
• What soldering iron / station are you using? It may be worthwhile to invest in a proper soldering station. If you don't wish to, see if you can borrow one from a friend. Building the Crack was pretty daunting for me. I am glad I had a proper soldering station. Having proper tools makes your life a lot easier
• What temp are you soldering at? Everybody is different in what they use, but I like 375 Celcius. Takes longer to heat up, but I have less risk of damaging parts and melting insulation on the wires.
• What solder are you using? Cardas Quad is surprisingly cheap from this vendor http://www.ebay.de/itm/CARDAS-QUAD-EUTECTIC-SOLDER-5m-LENGTH-17-5gm-BETTER-VALUE-/400764029293?pt=UK_Sound_Vision_Other&hash=item5d4f65c96d. It is very easy to work with and gives good joints.
• http://bottlehead.com/smf/index.php?topic=173.0 You don't need all the tools here, but give this thread a good read.

[fullheadofnothing]

Paul was not suggesting buying a kit, he was saying you need to everything except the most expensive parts (base, chassis, transformer). We have done this many times for Crack builders. I don't know what the cost is, but replacement hardware, electronics, and wire will be much less than the cost of the full kit. E-mail queen [squirrely a] bottlehead [stop] com for cost information