Finished my SEX but got some strange values on some terminals

[rbruinsma]

All terminals have the correct resistance values except for the ones where you need to use the volume knob:

Terminal:	Resistance volume set to min:	Resistance volume set to max:
Center pin - input jacks	100.2K ohm	100.2K ohm
19	1.6K ohm	100.6K ohm
39	1.6K ohm	100.1K ohm
A4	226K ohm	100.3K ohm
B4	223K ohm	100.3K ohm

I did a search on the forum and found this post: http://www.bottlehead.com/smf/index.php/topic,1509.0.html that exclude my strange reading for the Center pin.

A quote from Grainger49:

The manual is wrong, the reading from the center pin of the RCA should read ~100k (+/- 10%) regardless of the volume pot position.

That still leaves the strange reading on A4 and B4, what went wrong here?

 

[Grainger49]

A quick look at the schematic says that regardless of the pot setting the input jack center should read about 100k ohms to ground.  So your first measurement is exactly what you expect.

Your readings at A4 and B4 indicate that you have the wrong resistors attached to A4 and B4.  It is possible that you got the wrong resistors.  Do they look like the resistor attached to tube pin 4 in the picture on page 39?

If not this also changes the reading you will get on terminal 39.

 

[rbruinsma]

Your readings at A4 and B4 indicate that you have the wrong resistors attached to A4 and B4.  It is possible that you got the wrong resistors.  Do they look like the resistor attached to tube pin 4 in the picture on page 39?

I think I have found the problem: almost sure it is the right resistor but I did solder it to the upper hole instead of de lower hole of the terminals 19 & 39.

Could that give me the strange readings on A4 and B4?

 

[Maxwell_E]

Based on that picture you have the correct resistor, also in the correct orientation. The top or bottom hole doesn't matter on these terminal strips because they are connected.

 

[Maxwell_E]

I would check the wiring on the C4S board too, as the wire running from 135K resistor runs to the same ground post as the volume pot. I don't see how this could affect the volume pots reading, but being in the same neighborhood makes it suspicious to me. Worth a check.

 

[Doc B]

Are you sure you were reading 223K and 226K ohms? Possibly 223 and 226 ohms?

 

[Maxwell_E]

Also, the 1.6K measurements with the volume to minimum. I get about 1.5 Ohms from 39/19 to ground on my amp. This could be explained with misplaced K's.

 

[rbruinsma]

Are you sure you were reading 223K and 226K ohms? Possibly 223 and 226 ohms?

Oooohhhh, I just rechecked and it reads 223 and 226 ohms instead of 223K and 226K ohms!

Thank you all for helping me out and next time I will pay more attention.

 

[rbruinsma]

My sex is up and running and I am amazed by the quality!  For now listening with my iphone and senns hd800 to test. Tomorrow going to connect the sex to my pre amp and rega turntable. Will post the results on that and some pics.

For now, going to enjoy the music and thank you bottlehead for this great product!