Momentary high V reading on Headphone after Speedball

[hjc]

Howdy,

I built my Crack a couple weeks ago, with all voltages and resistances checking OK.

I’ve just installed the Speedball upgrade and all circuit voltages checked OK.

However the Headphone Tip/Ring voltage does swing higher than 9V, getting around 20v and up to about 30v on one test, albeit extremely briefly (a split second only). It does return to zero though. Before the Speedball, the tip/ring voltage only got to about 7.5v.

I do wonder at the accuracy of my meter, which does tend to swing around a bit before settling on a voltage (or an ohm reading when checking R values). It’s an auto range DMM.

I did plug in a sacrificial pair of headphones after the Crack had been powered on for a minute, and it sounds fine.

Is the momentary high voltage reading a serious problem, if so what could be causing it ?

I’m on 240V mains here.
My voltage checks are:

T  Should be  Actual reading
1 75-90 77
2 170 181
3 0 0
4 170 181
5 75-90 80
6 0 0
7 100 105
8 0 0
9 100 108
10 0 0
11 0 0
12 0 0
13 170 180
14 0 0
15 185 200
20 0 0
21 206 220

thanks for any help !

cheers Howard

 

[Chris65]

The TRS voltage is a little higher with Speedball, so no problem. Search 'TRS Speedball' on the forum & you'll find some info.

 

[hjc]

Hey thanks Chris, good to know. Thanks very much, I figured it wasn't a big deal since I don't plug the headphones in anyway until about 1 minute after powering on. And the amp sounds great. cheers