Bottlehead Forum

Bottlehead Kits => Crack => Topic started by: keithpgdrb on November 03, 2013, 09:14:00 PM

Title: Confusion on speedball final voltage check at headphone jack
Post by: keithpgdrb on November 03, 2013, 09:14:00 PM: Finished my speedball upgrade, checked all the voltages and they seem fine. went to the last step of checking the voltage at the headphone plug tip. instructions say that it shouldn't go past 9V. I swear mine is going to like 20+volts. its only for a split second, but its going there. how can this be when everything else checks out ok? To show what I'm seeing, I've included a video of me turning on the crack with the probes in place. also, here are my voltage readings, just in case I've gotten it wrong. Help!!!

Video, that hopefully works.
https://www.facebook.com/photo.php?v=10151931966335660&l=329683658070573642

Voltage checks:

1. 87
2. 173
3. 0.8mv
4. 173
5. 89
6. 0
7. 110
8. 0
9. 109
10. 0
11. 0
12. 0
13. 172
14. 0
15. 192
16-
17-
18-
19. 80!!!! ok
20. 0
21. 210
A1. 88.6
A2. 0
A3. 1.53
A4. 0
A5. 0
A6. 86
A7. 0
A8. 1.5
A9. 0.9
B1 86
B2 172
B3 110
B4 88
B5 172
B6 109
B7 0
B8 0
Title: Re: Confusion on speedball final voltage check at headphone jack
Post by: Chris65 on November 03, 2013, 10:50:39 PM: I think you're fine, if everything else checks out. With Speedball the mV reading tends to be higher on the TRS jack check.
Or just do the mod: http://www.bottlehead.com/smf/index.php/topic,2946.0.html (http://www.bottlehead.com/smf/index.php/topic,2946.0.html)
Title: Re: Confusion on speedball final voltage check at headphone jack
Post by: keithpgdrb on November 04, 2013, 03:57:33 AM: I was going to do that modification anyway. that would solve my spike problem then?
Title: Re: Confusion on speedball final voltage check at headphone jack
Post by: Doc B. on November 04, 2013, 04:58:17 AM: It's OK. Those numbers aren't what really the headphones see. A 300 ohm headphone's impedance will lower the voltage by about a factor of 10.
Title: Re: Confusion on speedball final voltage check at headphone jack
Post by: keithpgdrb on November 04, 2013, 05:28:57 AM: So I can start listening to TUNES!!??!! Sweet! Thank you Doc.
Title: Re: Confusion on speedball final voltage check at headphone jack
Post by: Doc B. on November 04, 2013, 08:30:32 AM: Yeah, and if you are still concerned just turn the amp on first without headphones plugged in, wait a few seconds, then plug headphones in.
Title: Re: Confusion on speedball final voltage check at headphone jack
Post by: keithpgdrb on November 04, 2013, 09:20:23 AM: As long as you thnk the numbers are ok, I won't worry. Gonna add a few of your mods anyway n the week. Looking forward to the tunes.