Author Topic: Getting butt kicked by a Seeburg jukebox  (Read 610 times)

Skylabs

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Getting butt kicked by a Seeburg jukebox
« on: October 30, 2016, 08:04:20 PM »
Finally got this guy up and running. Just adding bluetooth so I can get it on the sales floor. I have added bluetooth to an AMI and Rockola in the past with no issues, this Seeburg is a different beast though.

Ok, so I started off as usually splicing my bluetooth receiver into the phono input of the jukebox amplifier. I add a DPDT switch so both the bluetooth and phono are not active at the same time (same thing I do on vintage consoles with no "tape" inputs).

As with the AMI and Rockola jukeboxes they mute the Amplifier when the phono is not in use, usually a simple switch located around the tonearm which is easy to bypass. This is where this Seeburg gets interesting. They tied the Mute switch to the eject button on the record player (see diagram). So now I had to add a triple pole double throw switch in between the bluetooth and the phono so when the user goes back to phono it again mutes the amp when not in use AND allows the record to eject. Got this problem solved, now on to the next.

I bet I have installed at least 20+ bluetooth receivers to consoles and jukeboxes that didn't have an aux input this very same method- no issues. For some crazy reason when I plug the 3.5 jack into the back of the bluetooth receiver I get really bad distortion. If i plug the same 3.5 jack into my phone- no distortion. To try and narrow things down I used a different bluetooth receiver from a different manufacturer and plugged the Bluetooth reciever into a different 110 outlet- got the same results. I know that phono inputs have a built in pre-amp boost, but I have never encountered this much distortion at low or high levels. So today I brought a 20 db pad and a Hi-z to Lo-z attenuator. Guess what? Didn't help.

Here is my theory. The bluetooth receiver in this case is acting like a wide open amplifier, my phone being the pre-amp.

So this thursday I am going to bring a Sonos Connect with me and see if it acts the same. Even though a Sonos Connect is similar to a bluetooth receiver I think they are different enough, in that, with the Sonos connect it is the pre-amp and I am just adjusting its volume with my phone rather than sending the music source from my phone.

Only other option would be a potentiameter in between the bluetooth and the amplifier input- but I would think that would be the same as the 20 DB pad.

ANY suggestions would be very appreciated! I know this is a vintage console forum, so sorry about that, I just figure you folks might have a solution.








 

TC Chris

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Re: Getting butt kicked by a Seeburg jukebox
« Reply #1 on: October 30, 2016, 10:57:19 PM »
What are those L & R gain controls shown on the diagram?  They seem to go to some sort of "top cont."--another volume control, governed by these?

Chris Campbell

Skylabs

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Re: Getting butt kicked by a Seeburg jukebox
« Reply #2 on: October 31, 2016, 12:07:46 AM »
What are those L & R gain controls shown on the diagram?  They seem to go to some sort of "top cont."--another volume control, governed by these?

Chris Campbell

I'll check that out on Thursday Chris. Maybe there are some resest pots I over looked on the amp itself. I think in my blinded stupor I saw "optional" on the schematic and didn't think any further.

I think you might have something there. Thank you!

Skylabs

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Re: Getting butt kicked by a Seeburg jukebox
« Reply #3 on: November 04, 2016, 01:57:23 PM »
Well I found the gain controls on the amplifier. Adjusting them only boosted or attenuated the distorted signal from the bluetooth receiver. I then plugged the Sonos Connect in- same results.

I pulled out my multimeter and measured the output on my phone and the bluetooth receiver. Turns out the phone was giving around .3v and the bluetooth receiver was outputting 1.5v. So I think my next step would be to either try a potentiometer or adding some resistors to the cable from the bluetooth receiver to the amp.

Skylabs

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Re: Getting butt kicked by a Seeburg jukebox
« Reply #4 on: November 10, 2016, 09:49:36 PM »
SOLVED!

I had given up on adding bluetooth to this jukebox 3-4 times. Last night it hit me to try a direct box.

I have a theory on why this worked, but It's a theory at best, and is probably wrong so I wont embarrass myself. I am just stoked it worked.