Tommi Myöhänen’s Ibanez SR505 Conversion

Tommi Myöhänen of Kuopio, Finland converted this Ibanez bass to a 12-string. He writes, “Here's a quick rundown of my 12-string Ibanez SR505. I don't remember when I got the hankering for a twelve, though I do remember that Amy Humphrey and Doug Pinnick had a significant role in that. I looked at different options on acquiring my own 12 and after much consideration I decided to find a suitable 4-string or 5-string bass to be converted. I studied the different options for conversion and required parts from this very website and other online sources. I asked guitar builder Jarkko Jokinen to take the project.”

“I started by buying a new Ibanez SR505 from a local music store. New because I wasn't patient enough to wait for a used one and I reasoned I could sell the neck and other unnecessary bits once the conversion was done. I also bought a Schaller 471 8-string bridge and Schaller BML Light tuners for the fundamental strings and Schaller Mini Locking tuners for octave strings. For strings I got sets from D'Addario and SIT.”

“I went with a 5-string as I found out that usual 4-string necks are not wide enough for the Schaller bridge's string spacing. The average 5-string neck, on the other hand, is just about perfect. If you are planning a similar conversion make sure that the pickups are bar magnet type, 5-string pickups with pole pieces probably wouldn't work too well.”

“The conversion itself was quite simple once we had worked out the details. Jarkko made a new neck and installed the bridge in place of the original Ibanez part and did the basic setup. Neck is maple, fingerboard, headstock veneer and laminated strip in the neck are an African wood called Mwule. This wood it is very hard and fairly light, and light is generally a good thing when it comes to 12-string necks. Neck dimensions are basically the same as the original 5-string neck except the new one is a lot thicker - 22 mm at first fret compared to 19.5 mm SR5 neck. Two truss rods, as that seems to be the preference for 12’s.”

“The neck is exactly what you would expect from a custom builder, perfect in every way. There's some light flame figure in the maple but nothing too flashy. The fingerboard wood matches quite nicely with the stock body and I quite like that little peek of maple at the neck root. Also, check out the mucho cool XII inlay action at 12th fret. Neck is attached with four screws, just as standard SR’s. Now that I think of it, an extra screw or two would not have hurt anything though I haven't noticed any issues so far.”

“On the bridge side, Jarkko had to enlarge the bridge rout a bit toward the back to fit the new bridge and add some filler blocks to the sides. Fillers seem to be ebony although I'm not completely sure.”

“Only real problem is when strapped on, the bass settles to pretty much horizontal attitude. I prefer a more erect posture so I fixed that by adding a bag of lead shot to the back end of the strap. I'll have to figure out a more elegant balance solution later. It seems that the thin and light SR series body is not quite ideal for a 12 and it might be good to go to a thicker, heavier body, with more meat in the back. One factor on the slight neck heaviness of course is the thicker than standard neck profile.”

“Another slight issue are the tuners. I got the Schaller BML light tuners because I wanted to keep the headstock as light as possible. However, the large diameter string posts limit tuner placement to some degree so it might be better to go with thinner posted tuners for easier headstock packaging. I don't think the weight difference of four tuners is going to be that big of a deal.”

“Still, I'm happy with the result. Sure, the biggest limiting factor so far is my playing ability but as it goes with projects of this sort I had a few ideas for a new one even before this one was finished. I'll keep playing My Little Twelve for now and see what, if anything needs fixing. Once I have that figured that out it might be time for a new one.”