Bottlehead Forum

Bottlehead Kits => Crack => Topic started by: henrywvy on January 12, 2021, 07:47:25 PM

Title: Resistence test - 22 is more than 1 ohm
Post by: henrywvy on January 12, 2021, 07:47:25 PM
Just got the kit assembled and it passes most resistance check except one - I've got 7.6 ohm - 80 ohm over several re-test (after referring to an old thread where gbennn got 'infinity' on 22, I've since checked through the ground lug, RCA jacks and did some touch up) here's the current measurements I've got:

1. *
2. *
3. 0.6 (my cheap multimeter won't got any lower than that, even with red and black pins touching each other directly 0.6 is the lowest possible)
4. *
5. *
6. 0.6
7. 2.96k
8. 0.6
9. 2.96k
10. 0.6

12. 0.6
13. *
14. 0.6

20. 0.6
22. 15.6 << abnormal

B3. 2.96k
B6. 2.96k

RCA
L - ~100k
R - ~97k
GRN - 0.6

* I have initially painted both side of the transformer bell (was rather careless for not reading through the manual before that), but have since scrapped off the 4 corners where washers are placed, pretty sure it has got clean contact to the bell.

Any pointer to check is very much appreciated, thanks!
Title: Re: Resistence test - 22 is more than 1 ohm
Post by: Paul Birkeland on January 13, 2021, 04:01:56 AM
That reading at 22 means your transformer screws should be tightened a bit more.
Title: Re: Resistence test - 22 is more than 1 ohm
Post by: henrywvy on January 13, 2021, 05:30:37 PM
Thanks Paul! turns out it's the ground lug that needs to be tightened! wouldn't have guessed that without your expert help, just completed DC check and seems good to go, now I'm excited :D

1. 80V
2. 180V
3. 0
4. 180V
5. 80V

6. 0
7. 107.7V
8. 0
9. 106.5V
10. 0

And just one more question please - when testing wall plug voltage, i've noticed that most wall plugs in my house reads 243-244, except 1 which reads 246V - should I avoid using that wall plug or it would be fine? my transformer is wired for 235-245 per instruction.
Title: Re: Resistence test - 22 is more than 1 ohm
Post by: kGlerup on January 13, 2021, 07:42:08 PM
As long as you ensure to wire your transformer for 240V input, then the 246V will not cause any issue.
Line voltage can vary hugely in some countries and I'm sure the amp can handle this.
Title: Re: Resistence test - 22 is more than 1 ohm
Post by: henrywvy on January 14, 2021, 12:27:57 AM
Thanks for the good info kGlerup!

I know I really shouldn't but I ran the voltage test over lunch (working from home) and next thing I know, 1.5 hours had past XD, this does sounds so beautiful with HD6XX/650!

Next I'm looking to treat the wood with boiled linseed oil.
Title: Re: Resistence test - 22 is more than 1 ohm
Post by: kgoss on January 14, 2021, 03:13:55 AM
Nice work.  Enjoy!
Title: Re: Resistence test - 22 is more than 1 ohm
Post by: kGlerup on January 14, 2021, 10:26:49 PM
Looks like a very clean and tidy build!

Yes, the non-SB Crack sounds VERY pleasing with the HD600/650's  ;)
Title: Re: Resistence test - 22 is more than 1 ohm
Post by: johnsonad on January 15, 2021, 03:47:38 AM
Nice looking build!
Title: Re: Resistence test - 22 is more than 1 ohm
Post by: henrywvy on January 15, 2021, 05:54:51 PM
Thanks a lot for your kind words! was rather nervous as this is the first electronic project for me - only experience with soldering were during high school and that was really a long time ago. This have certainly opened up my mind more and thanks for this wonderful community it's been a very pleasant experience  ;D

Also purchased the SB together, will give the non SB Crack a good time, at least half a year or so before putting that together, though opinions on SB seems to be rather polarized but I guess it deserves a try.
Title: Re: Resistence test - 22 is more than 1 ohm
Post by: njfairbanks on January 17, 2021, 02:11:28 PM
Great looking build! I went the boiled linseed oil route myself and am very pleased with the result. Finished it with Minwax Paste Finishing Wax


Thanks for the good info kGlerup!

I know I really shouldn't but I ran the voltage test over lunch (working from home) and next thing I know, 1.5 hours had past XD, this does sounds so beautiful with HD6XX/650!

Next I'm looking to treat the wood with boiled linseed oil.