I'm thinking of doing this upgrade on my jukebox. This may be able to someone who would like to upgrade an old console as well.
First, this started out in the shout box. As there was some good info there, I'm pasting it here to save for future searches or reference.
(21:08:29) scorpio333: Been thinking of upgrading the jukebox cartridge from ceramic to magnetic. Key here is the tracking is about 4.5 grams which rules out most carts. Stanton 500 and Shure m44 are two recommendations. If anyone has one of these collecting dust, I'm looking for one on the cheap. If I do it, I'll be rewiring the tonearm with new leads and rca's. Not looking to go hifi with this, but improve the sound a little.
(21:16:42) Sir_Thrift-a-Lot: Keep in mind that a jukebox is far more physically coupled to the speakers than most turntables. Given the amount of amplification required for magnetic carts, I really wonder if this wouldn't end up turning it into a feedback machine.My advice would be to just use the best conical stylus you can find and keep it clean.
(21:17:51) OldiesButGoodies: @scorpio - not so simple I am afraid. The magnetic cart will req a diff phono amp, it has higher gain, and the RIAA curve is baked in differently for ceramic.
(21:18:40) OldiesButGoodies: but very doable if you bypass the ceramic cart circuitry and and add something for a mag cart
(21:19:04) OldiesButGoodies: please correct me if wrong everyone else
(21:20:01) Sir_Thrift-a-Lot: OBG, I believe all of those considerations are correct too, they are just different ones than what I pointed out.
(21:21:19) Sir_Thrift-a-Lot: IIRC, most ceramics didn't have an RIAA curve at all on the amp end. The cart was so short on high frequency response that it sort of had a "built in" curve.
(21:22:12) Sir_Thrift-a-Lot: The RIAA curve was decided in part as the null curve to the typical ceramic cart.
(21:23:41) Sir_Thrift-a-Lot: Oh, and the reason I said to use a conical stylus is because many 45s are made of styrene and elipticals and especially line contacts will chew them up. Only use an eliptical if you plan to only use vinyl 45s.
(21:24:29) Sir_Thrift-a-Lot: I do think these kind of tech discussions would be better in a thread where they can be referred back to rather than in the shout box where they disappear.
(21:45:03) scorpio333: Great idea on the thread, I'll start one later. For now, you're both right. I left out the fact I'm not using the internal amp or speakers. Upgrading to use those is counter productive. I'm using an external amp, so rewiring the arm into rca's which will go into the phono input. I'll add all this to a thread when I get home later tonight.
Let me state my plans with the jukebox as it changes what is above. The amp in the box needs recapped, however some of the caps are not commonly available and some mods need to be done. I'm not really up for that, especially when all is said and done I'm not too sure the amp and speakers are going to sound all that great. For now, I've been running the RCA's into an old Pioneer SX-1000TW in the garage, this receiver has a ceramic input (and it's a loud little amp). Once the insides are cleaned up and painted, I'll be able to roll it into the basement and run it into the tubes. As it stands now, no preamp is needed.
It's a jukebox, it was never really made to sound great. Its purpose was to be loud enough that people kept feeding it quarters. Don't hassle me about this, I like the machinery and the nostalgia and I'm keeping this damn thing out of landfill, I should be getting a tax break!
STaL makes a good point of a magnetic cart being sensitive to other influences inside the jukebox and creating bad output. Since I'm not using the internal speakers, feedback isn't the concern, it's more motor noise I'm worried about. I've googled a bunch and there's not a lot of info. The info that is there is split, some get noise others don't. With that in mind, I'm thinking of testing this first before removing wires and modding. Using a busted up old turntable as a donor, get the tonearm wiring out. Remove current cart on the jukebox. Install new cart and run the wires temporarily so they don't get snagged or in the way. Give it a listen and decide which way to go.
From googling a few carts are recommended: Stanton 500, Shure M44, and Pickering P-AC-1. The tracking force of the cart needs to be around 4.5g. A more modern 1.5g cart would just cause thing to flop around, fixing that will drive the cart into the record. I'm looking for one of those or similar on the cheap to try this out.
I've got about a 40 year range of 45's, from the 50's to the early 90's. So that's a concern as well. Best workaround I can see is to buy another jukebox - one old school, one modernized!
