chefducuisine
Well-known member
darkcharly,
from your description i am assuming you are using the LM394 in a 6 Pin metal case.
Please keep in mind that the SSL9k is a differential amp (check Google for the Cohen design).
As a first step please check if a signal appears on pin 6 of IC 29 and IC 22 together with the gain set to the mid position of the switch and a 1kHz sine applied at the input. In a second step try moving the gain switch around to see if the amplification changes.
If you want to exclude your gain switch from the equation simply replace the switch by adding a resistor instead of the switch - something in the 1kilohm region should be enough. You will need two resistors to replace both decks of one switch.
If this works apply the same procedure on pin 6 of IC 30 and IC 23.
It is always a good idea to check the solder joints. Visually and by using an Ohm-Meter.
from your description i am assuming you are using the LM394 in a 6 Pin metal case.
Please keep in mind that the SSL9k is a differential amp (check Google for the Cohen design).
As a first step please check if a signal appears on pin 6 of IC 29 and IC 22 together with the gain set to the mid position of the switch and a 1kHz sine applied at the input. In a second step try moving the gain switch around to see if the amplification changes.
If you want to exclude your gain switch from the equation simply replace the switch by adding a resistor instead of the switch - something in the 1kilohm region should be enough. You will need two resistors to replace both decks of one switch.
If this works apply the same procedure on pin 6 of IC 30 and IC 23.
It is always a good idea to check the solder joints. Visually and by using an Ohm-Meter.