Hi guys,
I´m in the process of modifying some channels on my SSL to have the black E EQ instead of the pink G EQ.
While I´m at it I thought it´d be nice to document the process and share the instructions here.
While the EQ card itself has the same format and is a simple swap (unscrew from the back), there are two small mods that need to be made for it to work: A) one pot needs to be modified and B) the wires from two more pots rerouted.
A) modification of the HF frequency potentiometer
The G EQ uses two wafers of the pot in parallel, while the E EQ uses only one. So if you go from G to E you can simply disonnect one wafer of the pot. Remove the pot from the frontpanel, carefully slide it out the back, cut open the insulation with a sharp knife and remove it. Then rewire the connections as shown in the picture. You need to cut the three connections between the potwafers and then reconnect two connections on the single bottom wafer. Do not change any cables going to the pot. Do not put the pot back in yet, as we need to get to some connection points on the mainboard beneath it.
B) rerouting pot connections
the HF and LF frequency pots of the G EQ do not connect to the mainboard, but to 10-pin headers directly on the EQ card.
For using the E EQ these connections need to be rerouted to the mainboard. For each pot there is a small terminal on the mainboard, which does not have connections right now. The easiest way is to solder an opposite (male) side of the pin connectors to these terminals and keep using the original (female) pin connectors, just not connect them to the EQ card, but to the new connectors. Use a solder sucker/desoldering iron first to clear all solder from the terminals from the back of the mainboard, then solder the wires to them. I found a multicolored ribbon cable and it was easiest to use the corresponding colors.
The pin assignement for the connectors is as follows:
SM1 (HF Frequency pot):
1 Be
2 Y/G
3 Bk/R
4 W
SM2 (LF Frequency pot):
1 W
2 Bk/R
3 Y/G
4 Be
Here is how you count the pin connector pins:
https://dl6gl.de/media/images/pfostenstecker-schematisch.jpgThe letters are color codes: Be Blue, Y/G Yellow/Green, Bk/R Black/Red, W White.
Y/G and Bk/R are connected in parallel. It doesn´t matter which hole is being used to solder the connection.
Once it´s soldered in, connect it with the original ribbon cables and put back the modified HF freq pot as well.
This should give you E EQ in your G channel.
I hope you´ll get some use out of these instructions. Let me know if there are any questions.
I have already modified 4 channels according to them and they all work perfectly.
If some of you have experience with the mod and want to add something to these instructions, please feel free!
Best,
Christian
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