I am trying to track down a schematic for Greg Ball's SKA SKPre (preamp) and the SKOptivol module that works with it. I've searched the web to the best of my ability but keep getting to a dead end. Any help will be appreciated. I believe Greg is out of touch these days but if anyone knows how to contact him, perhaps that would help. Thanks.
Last edited:
I didn't readily find anything on the SKPre or SKOptivol either.
The designer, Greg Ball, used to post here as 'amplifierguru', so you can search for his past comments. I haven't noticed any posts by him for quite some time, come to think of it.
The designer, Greg Ball, used to post here as 'amplifierguru', so you can search for his past comments. I haven't noticed any posts by him for quite some time, come to think of it.
I think Greg is out of commission or at least he was for a while. I could not find anything in the GB150 thread. I've built the 150 and it's a nice amp. I have the SKpre and Optivol kits but the PCBs don't give component values, so I need a schematic or bill of materials.
I'll try searching for "amplifierguru" threads. That could be the trick.
I'll try searching for "amplifierguru" threads. That could be the trick.
Here's what a friend got at the time and I mounted both kits for him without any issue. It's still in his main system and working fine.
I found an old email from Greg on just the optivol - I think it is the same as the material in the SKpre anyway.
I think there was an error in this version - the LED was the wrong way around "have another look at your instructions because it says to put the anode of the LED to C1, but I reckon it should be away from C1."
I think he corrected it afterwards. He also mentioned to make sure to ground the centre hole as it helped reduce hum pickup.
I think there was an error in this version - the LED was the wrong way around "have another look at your instructions because it says to put the anode of the LED to C1, but I reckon it should be away from C1."
I think he corrected it afterwards. He also mentioned to make sure to ground the centre hole as it helped reduce hum pickup.