Bottlehead Forum

Bottlehead Kits => S.E.X. Kit => Topic started by: smog on March 28, 2018, 02:02:29 PM

Title: S.E.X 3.0 Voltage reading question. Power transformer heat concern.
Post by: smog on March 28, 2018, 02:02:29 PM

Hi

Just finished my s.e.x 3.0 stock build, 4 ohm and 120v.  All resistance checks were withing spec, except the H1-H7 were fluctuating around 190 ohm range.  H8 was 0.

Edit: just read another thread and learned the “lower”  H1 through H7 readings is normal.

Also curious/concerned about my H4, H7 Voltage readings being negative.

Here are the Voltage readings, which were all within 10%

2.   87
3.   20
4.   0
5.   0
6.   416
7.   435
10. 409

16.  90
17.  20
18.  0
19.  0
20.  417
21.  435
24.  409

H2, H5.  3.6,  3.6
H4, H7. -3.4, -3.4

I assumed from the +/- the H4, H7 being negative was OK..So, I powered on and using headphones played music through without any sort of issue, dead quiet background and beautiful music.  However, when I powered down I noticed the Power Transformer stack and bell cover were quite hot to the touch, even after some time after powering down.  Is that normal??

Thanks for any help,

I just went through the amp and cleaned up some solder joints.

Title: Re: S.E.X 3.0 Voltage reading question. Power transformer heat concern.
Post by: Paul Birkeland on March 28, 2018, 03:26:03 PM

The power transformer should be nice and toasty to the touch.  In order to overheat the power transformer, you'd have to draw excessive current from it, and this will manifest as very low voltages and stinky resistors.  Your voltages look great, so we can conclude that the power transformer is operating at the proper temperature.

Title: Re: S.E.X 3.0 Voltage reading question. Power transformer heat concern.
Post by: smog on March 28, 2018, 03:31:46 PM

Thanks for the quick reply.  Just wasn’t expecting it to be so hot.  Thanks again.