Bruce,
I am finally getting time to build this preamp. I just wanted to verify that schematic in the post below from April 2017 is the most recent, updated schematic.
I recently downloaded and read your article in the Feb 2018 audioxpress magazine regarding the GrooveWatt. Excellent article - thanks again for all that you give to the community.
Regards,
Phil
gofar99 wrote:
8-) It is a great phono preamp. Use the newest schematics though. The keys to making it as good as it can be are good power supply filtering, very careful grounding and layout. If you are going to use LOMC with it (I do) then you will need to use step up transformers (most major companies do as it is like free gain without noise). There are a few that I really like. First is Silk Audio's SAC1 (about $200 a pair and available in a nice case assembled for about $100 more - a bargain), then comes Softone PLC-1, after that either Lundahl 1678 ot 9226. I like to kee the SUTs external so I can move them around and try new things. If you are not going to do that you can put them inside the case for the preamp. Be aware that they need to be away from the power transformer and I put an extra steel shield around them. Copper and aluminum will not do. I find the steel to complement the Mu metal that they already have, but a second level of Mu metal doesn't seem as good as the steel. If they are in an external small steel case you can physically move them away from hum sources. Mine sit about 1 meter away from both the turntable and the preamp. I have not found cable length to be an issue with SUTs and LOMC.
Good listening
Bruce
EDIT: The black shield in the middle has been removed (didn't do anything). And yes it is headed for an article in Audio Express in a month or so.