Bottlehead Forum

Bottlehead Kits => Crack => Topic started by: skeeb234 on September 18, 2022, 11:13:53 AM

Title: Finished Crack build - Voltage Check needed! [resolved]
Post by: skeeb234 on September 18, 2022, 11:13:53 AM

Good afternoon everyone,

This is my first Crack build and my first time ever soldering period.  I did practice on other small things before I started the Crack.  I read through the instructions carefully and took my time with this...I was going well till the part with the LEDs and then things got a bit more difficult for me.  Thankfully I got through all of it and did the resistance checks this morning.  Everything checked out within spec! 

However, my voltage check is not within spec.  It's consistent at least...but enough cause for caution to post here.  Here were my numbers:

Terminal 1 - 140v should be 50-100 +/- 10%
Terminal 2 - 155v should be 170v +/- 10% good here!
Terminal 3 - 0 and should be 0 - good!
Terminal 4 - 155v should be 170v +/- 10% good here!
Terminal 5 - 140v should be 50-100 +/- 10%

Terminal 6 - 0 and should be 0 good!
Terminal 7 - 140v should be 90-115 +/- 10%
Terminal 8 - 0 and should be 0 good!
Terminal 9 - 140v should be 90-115 +/- 10%
Terminal 10 - 0 and should be 0

As you can see in Red, terminals 1, 5, 7 and 9 are high.  The manual did say some deviation is possible but I defintely want to check that!  I will post pictures of my build on a reply to this post next.  The Tubes did all glow just fine when it was powered on so thankfully no issue there.  My biggest concern is plugging a headphone into this!  The only high OHM HP I have is my ZMF Atrium.  No way in hell I want to blow a 3k headphone. 

Thank you in advance for any advice here!

Title: Re: Finished Crack build - Voltage Check needed!
Post by: skeeb234 on September 18, 2022, 11:21:06 AM

Here are the pictures:

Title: Re: Finished Crack build - Voltage Check needed!
Post by: Doc B. on September 18, 2022, 11:33:04 AM

You are missing the black wire from the volume pot terminal to the center terminal of the strip right behind the nine pin socket.

Title: Re: Finished Crack build - Voltage Check needed!
Post by: skeeb234 on September 18, 2022, 11:37:15 AM

Wow, no idea how I missed a darn step, but thank you Doc!  I'll post an update once I correct this!

Title: Re: Finished Crack build - Voltage Check needed!
Post by: skeeb234 on September 18, 2022, 12:46:28 PM

That was it!  LEDs lit right up and all voltages are within spec now.  The only thing left to do is plug in some headphones.  I admit I'm a bit nervous to plug in my Atriums, but if all things are within spec I cant imagine I would do any damage to them.

Title: Re: Finished Crack build - Voltage Check needed! [resolved]
Post by: Paul Joppa on September 18, 2022, 06:17:45 PM

If you have a cheap pair of headphones, use them for the first test. Low impedance is fine for testing - it won't hurt anything.