I bought the Roland TD-7's back when they came out, around 35 years ago. I haven't played for quite a few years. I started again when I got the V-drums a few years back. I have been interested in adding V-drums ever since they came out. I have been looking for a used set for a long time. I found a set that worked perfectly due to the stand he had. He had all the extra parts I needed to put both sets together. I am running two brains because the TD-9 brain that came with the Vdrums has a wiring harness, so there isn't any flexibility. I found a used TD- 10 brain to run the rest, but it doesn't have enough inputs to run all the drums. I don't want to give up the TD-9 anyway because it has a built in MP3 player that works great. I don't understand why every brain doesn't have an MP3 player baked in. The TD-9 brain is severely limited in sounds though. It's crazy that there are only a few high hat sounds, and minimal cymbal sounds, but 50 rim shot sounds. I hope to find a used TD-20 brain.