SEEBURG JUKE TO HOME STEREO

Q&A about all types of jukeboxes: Wurlitzer, Seeburg, Rock-Ola, AMI, and more.



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scott1124
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SEEBURG JUKE TO HOME STEREO

by scott1124 » Fri May 02, 2014 6:17 pm

I have a Seeburg 222 with a SHFA-5 amp. I would like to hook it up to my whole home audio system. Can anyone tell me how to make this happen?
Thanks in advance....


Ron Rich
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Re: SEEBURG JUKE TO HOME STEREO

by Ron Rich » Fri May 02, 2014 6:30 pm

Hi Scott,
IMHO, the "best way" to do that would be to tap off the the volume control, or, if you wish, you might investigate an "impeadence matching transformer", and tap off the speaker out-put, on the amp. Ron Rich


Topic author
scott1124
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Re: SEEBURG JUKE TO HOME STEREO

by scott1124 » Fri May 02, 2014 7:01 pm

Thanks for the fast reply, are you referring to the "automatic volume control" or the or the master volume control?
-Scott


Ron Rich
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Re: SEEBURG JUKE TO HOME STEREO

by Ron Rich » Fri May 02, 2014 7:04 pm

"Master"--depending if you want "independent volume control", hook to either the "in or "out" side--


Topic author
scott1124
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Re: SEEBURG JUKE TO HOME STEREO

by scott1124 » Fri May 02, 2014 7:08 pm

Thanks. I will probably have more questions once I have a look at it later today.
I may require hand holding to get it figured out. - Scott


Ron Rich
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Re: SEEBURG JUKE TO HOME STEREO

by Ron Rich » Fri May 02, 2014 7:16 pm

Scott,
Sorry, "hand holding"" s'not my yob !!" (unless you are a great looking Gal !! :lol: )
Ron Rich


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scott1124
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Re: SEEBURG JUKE TO HOME STEREO

by scott1124 » Sat May 03, 2014 12:27 am

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I have attached a couple pictures (hopefully) showing wiring to the volume control and I have the following questions:
Which is the input side and which is the output side?

Which terminals do I connect to?

How do I convert to an RCA type plug to plug into whole home audio amp?


OK no hand holding.....just patience :wink:


Ron Rich
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Re: SEEBURG JUKE TO HOME STEREO

by Ron Rich » Sat May 03, 2014 1:17 am

Scott,
I suggest you not proceed any further--one must be able to read schematics, and have some understanding of electronics, in order to safely accomplish this. There is too great a risk, both to you, ( or anyone who might touch either unit), and risk of damage/ruin, to either the jukebox, or your system. Ron Rich


Rob-NYC
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Re: SEEBURG JUKE TO HOME STEREO

by Rob-NYC » Sat May 03, 2014 3:57 am

scott1124 wrote:I have a Seeburg 222 with a SHFA-5 amp. I would like to hook it up to my whole home audio system. Can anyone tell me how to make this happen?
Thanks in advance....



Scott, normally connecting a machine of this vintage to external amplification would be a simple matter, the amp in yours present two problems.

The original two versions of the tube stereo amps used a cathode follower (low impedance output) and external remote volume control option. On the last three versions the circuit was greatly simplified (cheaper) and the audio is never intended to leave the chassis at the low level stages -only the speaker (power) level.

The internal impedance is very high and because of this the length of external cable must be short and should have low capacitance. This is to avoid attenuating high frequencies due to cable capacitance.

The second obstacle is the input impedance of what you wish to connect it to. Looking at the circuit and parts I can see that the signal from it's volume control sees at least 340,000 ohms. The average input impedance of a typical home receiver is 40,000 to 100,000 ohms. This is a bit low and might cause a reduction of the bass response due to reactance in the capacitors ahead of the new connection.

All of these can be dealt with, but it requires some degree of understanding of electronics to slightly modify the circuits or build a simple outboard cathode follower.

Taking the signal from the speaker outputs on the amp is much simpler involving only two new resistors for each channel, but it means the power amp + volume control is in the circuit and it's shortcomings are imposed on the output.

Either way, I suggest you download the schematics/parts lists for your amp here:
http://www.verntisdale.com/Seeburgschem.htm print them out and then look for a local technician to help you accomplish this project.

BTW: Has that amp been rebuilt. If not it is past time to do so. The technician can do some simple mods to facilitate adding an external amp while rebuilding it.

Rob/NYC
"If we believe absurdities, we shall commit atrocities" -- Voltaire

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MattTech
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Re: SEEBURG JUKE TO HOME STEREO

by MattTech » Sat May 03, 2014 5:32 am

As was mentioned, impedences are of importance here, and in order to have success, compatability has to be considered as well.

Something like this needs to be done by an experienced tech, not dabbled over through the internet.
Safety is a factor, both for the user, and the equipment involved.

I'd most likely use blocking/isolation capacitors, and a reasonably simple voltage dividing network to get the job done - but a novice with no training certainly wouldn't understand such things.
The Internet is a marvelous thing, however it's not a good substitute for actually being there.


Topic author
scott1124
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Re: SEEBURG JUKE TO HOME STEREO

by scott1124 » Sat May 03, 2014 7:07 pm

Rob-NYC wrote:
scott1124 wrote:I have a Seeburg 222 with a SHFA-5 amp. I would like to hook it up to my whole home audio system. Can anyone tell me how to make this happen?
Thanks in advance....



Scott, normally connecting a machine of this vintage to external amplification would be a simple matter, the amp in yours present two problems.

The original two versions of the tube stereo amps used a cathode follower (low impedance output) and external remote volume control option. On the last three versions the circuit was greatly simplified (cheaper) and the audio is never intended to leave the chassis at the low level stages -only the speaker (power) level.

The internal impedance is very high and because of this the length of external cable must be short and should have low capacitance. This is to avoid attenuating high frequencies due to cable capacitance.

The second obstacle is the input impedance of what you wish to connect it to. Looking at the circuit and parts I can see that the signal from it's volume control sees at least 340,000 ohms. The average input impedance of a typical home receiver is 40,000 to 100,000 ohms. This is a bit low and might cause a reduction of the bass response due to reactance in the capacitors ahead of the new connection.

All of these can be dealt with, but it requires some degree of understanding of electronics to slightly modify the circuits or build a simple outboard cathode follower.

Taking the signal from the speaker outputs on the amp is much simpler involving only two new resistors for each channel, but it means the power amp + volume control is in the circuit and it's shortcomings are imposed on the output.

Either way, I suggest you download the schematics/parts lists for your amp here:
http://www.verntisdale.com/Seeburgschem.htm print them out and then look for a local technician to help you accomplish this project.

BTW: Has that amp been rebuilt. If not it is past time to do so. The technician can do some simple mods to facilitate adding an external amp while rebuilding it.

Rob/NYC



Rob

Thank you for the detailed explanation!
I can now understand why the other gentlemen were a tad concerned about me tackling that kind of modification....Have no fear! I am well aware of my limititations :wink:

It appears that coming off the speaker output would be the easiest solution. I see various types of speaker output to line level converters out there (some are made for tube guitar amps) and I wonder if any of these products would work.

Which speaker outputs would be best to tap into?

Thanks again for your input
P.S. The amp was rebuilt about 5 years ago and still functions perfectly.


Rob-NYC
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Re: SEEBURG JUKE TO HOME STEREO

by Rob-NYC » Sun May 04, 2014 9:30 am

Scott, glad to hear that the amp was rebuilt.

There are a lot of attenuators available. I've never actually bought one -just made them using what I had.

Looking at these two:

http://www.parts-express.com/axxess-ax- ... mpaign=pla

http://www.parts-express.com/boss-b65n- ... mpaign=pla

I see no mention of whether an internal dummy load is present, but given their size and price I guess not. A dummy is not desirable here because the amp is already loaded by it's speakers. Without a dummy it will be OK to connect the new box to the 4-8-16 watt taps.

Again, you will have to set the machine's volume control to some convenient level and it's tone shaping will also be present in the new line output. I suggest turning off any bass boost or "loudness" control in the external amp, otherwise the sound will probably get muddy.

Good luck.

Rob
"If we believe absurdities, we shall commit atrocities" -- Voltaire


Topic author
scott1124
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Joined: Fri May 02, 2014 6:08 pm
Location: Winnipeg, MB, Canada

Re: SEEBURG JUKE TO HOME STEREO

by scott1124 » Mon May 05, 2014 4:13 am

Thanks for the help.
I will go with the line converter for now. If I can find a local tech, I will look at some of the other options.----Scott

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