Lightspeed Attenuator a new passive preamp

[udailey]

Hi Richard. Can you post a pic or send one to me of your set up? I wonder if you have one of two possible problems
1: Put shunt LDRs in series spot
2: Wired 5k pot in wrong.
Uriah

[udailey]

I dont think the calibration of shunt has anything to do with it at all. As soon as you turn the volume up a little bit that 200R trimmer stops having any effect on centering the image as it becomes a minor percentage of your position on the 100k pot.
Uriah

[udailey]

When I say series in shunt spot basically what I mean is this
We have across the board 4 LDRs. Lets call them ABCD and they are in that order. A is shunt, B is series, C is shunt, D is series. So if we took a pair out of the bag and put them in the board the proper way would be that the pair would either go in A and C or in B and D but NOT AB or CD.
Uriah

[Tripmaster]

Hi Uriah

I didn't take a note of the LDR numbers I inserted in series or shunt. They were inserted in pairs and I believe I soldered the lower resistance pair in to shunt location.

[udailey]

Richard, Have you seen this?
https://docs.google.com/fileview?id=...OTNjMzdm&hl=en

[Tripmaster]

Originally Posted by udailey

When I say series in shunt spot basically what I mean is this
We have across the board 4 LDRs. Lets call them ABCD and they are in that order. A is shunt, B is series, C is shunt, D is series. So if we took a pair out of the bag and put them in the board the proper way would be that the pair would either go in A and C or in B and D but NOT AB or CD.
Uriah

Yes I soldered them in the correct location. 1 and 3, 2 and 4

[Tripmaster]

Originally Posted by udailey

Richard, Have you seen this?
https://docs.google.com/fileview?id=...OTNjMzdm&hl=en

Yep

[udailey]

Okay, from the top it looks fine. Thank you for the pics.
I would look to your balance pot and see if it is wired correctly. The Wiper should be the middle hole in the 'series balance' spot. If you switch the outer wires from the 5k pot around then the balance will work in the opposite direction.
Uriah

[Tripmaster]

Originally Posted by udailey

Okay, from the top it looks fine. Thank you for the pics.
I would look to your balance pot and see if it is wired correctly. The Wiper should be the middle hole in the 'series balance' spot. If you switch the outer wires from the 5k pot around then the balance will work in the opposite direction.
Uriah

Yes the pot is fine

[udailey]

Richard, When I search for "richard's" who have bought from me there is only one so I am assuming its you. You have built a few of these. I trust you have done everything correctly and maybe I am the one who made a mistake. If you send it back to me I will test it and either fix it or send you a new kit.
Uriah