Speedball upgrade done - large board voltages over a little bit, is it okay?

[cddc]

Just completed the Speedball upgrade.

Resistance check is OK.

The small board voltages are also within ranges.

However, large board OA&OB voltages are around 15V above the upper band.

Here are my Speedball voltage measures:

Small board:
OA = 85V
IA = 179V
B-A/B = 0
IB=179V
OB=82V


Large board:
OA = 115V (15V above the 75-100V range, which is a little bit over 10%)
OB = 117V (17V above the 75-100V range, which is a little bit over 10%)
G = 0
B+ = 187V

So, are the large board OA and OB voltages okay?

Really appreciate it if someone could help!

 

[cddc]

Just for references, below are my stock voltage measures. Some of them are a little bit over 110% of the given values/ranges, the ones highlighted in red.

Stock Crack voltage readings:

1=90V (right at the 75-90 upper band)
2=180V (10V over 170V, but within 10%)
3=0
4=180V (10V over 170V, but within 10%)
5=87V (within 75-90)
6=0
7=115V (15V over 100, also over 10%)
8=0
9=113V (13V over 100, also over 10%)
10=0
11=0
12=0
13=180V (10V over 170, but within 10%)
14=0
15=203V (18V over 185, right at 10%)
20=0
21=226V (20V over 206, right at 10%)

A1=87V
A2=0
A4=0
A5=0
A6=90
A7=0
A9=0

B1=89V
B2=180V (10V over 170, but within 10%)
B3=115V (15V over 100, over 10%)
B4=86V
B5=180V (10V over 170, but whtin 10%)
B6=112V (12V over 100, over 10%)
B7=0
B8=0

Are these voltages in red okay?

PS: for the stock Crack, tolerance is 10%-15%, so I think all the stock Crack voltages are within range.

 

[cddc]

What are the possible reasons that caused some of the voltages to exceed the 10% tolerance?

Is it possible that the grid voltage in my area is higher than other areas?

 

[Tom-s]

I think your on the right way of thought. Your B+ voltage is higher as specified right out of the transformer.
You could measure your socket voltages (but be very careful when doing this!!).

Edit: Overall i think you're ok with these measurements. Your tubes are running within range. Hows the sound?

 

[cddc]

Thanks Tom.

Sound-wise, it's okay and sounds great. The Crack with Speedball is fully functional - all tubes and LED's are on.

Just trying to identify the sounding difference between the stock Crack and Crack+Speedball now.




-------------------
PS:

Just measured the voltage from my wall jacket. It's measured at 126V AC (a little bit over 110V).

Not sure if the high input voltage from my wall jacket caused the high voltage values in my Crack and/or Speedball?

 

[Paul Birkeland]

Yeah, your voltages are slightly high, but still acceptable.

-PB

 

[cddc]

Thanks very much, Paul.

Do you think the high grid voltage (126V in my area vs 110V in the manual) could be the reason for these high voltages in my Crack?

 

[Paul Birkeland]

Wall voltage affects B+ first, which trickles down.  Since this is a directly coupled circuit, the operation of the 12AU7 influences the voltages that you see at the 6080.

When the 12AU7 plate voltages (terminals 1 and 5) creep up, so do the cathode voltages of the 6080 (7 and 9). 

If you end up rolling tubes, you will notice that these voltages move around a bit.

-PB

 

[cddc]

Wall voltage affects B+ first, which trickles down.  Since this is a directly coupled circuit, the operation of the 12AU7 influences the voltages that you see at the 6080.

When the 12AU7 plate voltages (terminals 1 and 5) creep up, so do the cathode voltages of the 6080 (7 and 9). 

If you end up rolling tubes, you will notice that these voltages move around a bit.

-PB

Cool, it seems the high wall voltage in my area justifies the high voltage values in my Crack.

Thank you very much for your explanation. Much appreciate it!