Seeburg C Low Volume

Hi All,

I have started a restoration project on a Seeburg C. Early days yet.

I sent the amp away to be repaired/recapped before starting the restoration as it obviously needed work. I now have the amp installed and the juke is working, it requires much more work and adjustment yet.

The technician who carried out the recap has taken ill and is not available. My juke is the least of his problems. I was not able to speak with him and he left a message for me to pick-up the amp. His message said that he attached the amp to his Seeburg B, and it sounded great with lots of base and volume.

My problem is that the juke sounds clear with good base, but, low volume. I am guessing that I am receiving about half the volume I should. I have replaced the needles, but have the original redhead cartridge. I have checked and cleaned the connection of all the plugs and wires including from the pick-up. The amp is MRA1-L6.

I am confused as the technician said it had lots of volume when connected to his juke. From this, I assume the volume control, mute switch, and tubes are all good.

Can anyone give me any direction where to start looking? I don't believe this juke has been used in many years.

Any advice greatly appreciated.

Regards

Gordon.

Gordon,
Two questions--
1. Did you check to see if the "squelch" switch is working ?
2. Which needles/cartridge are you using ?
Ron Rich
edit--one more question--
Which amp model ?

Hi Ron,

Thanks for your reply.

Answers....

1. I don't know about the squelch switch. Where do I find it and how can I check it? The manual does not seem to cover this.

2. I am using the redhead cartridge with new needles from Victory Glass. They are for stereo use and the package says that are replacements for the Pickering. Sorry, not much to go on.

3. The amp is MRA1-L6. I don't think this is the original amp. My juke is a model C.

Kind Regards

Gordon..

Hi Gordo,
The problem is most likely the needles--can't find good ones today -- all are around 30 % lower in volume then originals.
The squelch switch is covered in the Service Manual--however, in your case, since a MRA-1 is installed, it is not used. The model C should have a MRA-3 installed, which had the built in AVC.
If by chance, you have the "optional" AVC box installed in that -1 amp, it would be "the same" as a MRA-3, for squelch operation.
Ron Rich

Hi Gordo: I had similar problem with my LPC1, after amp recapped. It took cleaning with aerosol cleaner on the volume pot. It did not have problem before the rebuild. I guess had carbon build up inside. Now have have huge volume. Mark

Hi Ron and mb9513,

Thanks for taking the time to respond.

Ron, can I bypass the AVC in the mechanism? Will this make any difference?

Also, are replacement cartridges available (that take needles that are also available)? Will this help?

mb9513, What is the aerosol cleaner called? Is it a contact cleaner? I will try to purchase some and try it. or, should I replace the volume pot as it's a very scratchy when I turn the volume key anyway.

Regards

Gordo.

Gordo,
As I done rit before--you ainna got's no stiknkin AVC in that amp, unless you have the optional "add-on" AVC box. MRA-1's and MRA-2's, did not have it--
I would use "Deoxit" to clean the VC--your "re-builder" should have done it when he "rebuilt" the amp---
Ron Rich

Gordo, I agree with Ron, use Deoxit. I din't have the can when I posted. that is what I used to get my LPC1 volume control cleaned. I would not recommend replacing the pot. They are not going to easy to find, and Seeburg built them real good so it should be ok if cleaned. Hope this helps. Mark

Hi, I cleaned the volume control, however no improvement.

I am thinking the problem may be the speaker, however, I have no way to check.

I wired in a (modern) auxilary amp and speakers. Wow, great volume and good sound. This is why I am suspecting the speaker.

As my amp is from an earlier model (probably a model B, MRA1-L6) and my juke (and speaker) are a model C, could this be an issue?

Looking at the net, it appears that the model B has 2 wires that plug into the amp, whereas my model 3 has 3 wires.

Any ideas?

Regards

Gordon.

Gordo,
Want to re-read what you wrote ? I can't make sense out of the last line ?
Ron Rich

Ron,

I guess my question is ....'is there a difference in the model B speaker and a model C speaker'? or can they swap?

Regards

Gordon..

Replace the needles with the older ones...if you can find a set. The new ones have much lower volume. The C speaker will plug in directly and will work with your B amplifier.
If you think the speaker is at fault you can substitute a high wattage resistor with the same value of the field coil and test it with a modern PM speaker. Be careful as
you have high B+ voltage running through the field coil. The problem still can be in the amplifier and the only way to tell is to swap out the amp/speaker with a known good
working one or do a bench test. The B amplifier will work fine in your C but won't have AVC. You can get an AVC adapter that plugs into the 6SN7 (I believe) spot if you want AVC.
The B amp uses four 6V6 tubes for output where the C amp uses two 6L6's.

The speaker for the B or C are the same. The speaker has two wires for the field and two for the voice coil.

Gordon, on the speaker plug (all of the 50's era field coil speakers that Seeburg used) pins 4-5 are the field coil. You should measure around 5600 ohms.

Pins 2-6 are the 8 ohm voice coil (should measure around 6 ohms).

Rob/NYC

Thanks everyone for taking the time to offer help.

At present I am looking for 'old' needles or a NOS cartridge. These are quite expensive, however, I think it may solve my problem taking note of what you have all said.

Also, I am looking for a replacement speaker. The original speaker had some old cloth wrapt around it, so I don't think it is very good anyway.

I have located a speaker for sale from a model B. However, it appears to only have 2 wires leading from the speaker to the amp. I thought it should have 3?

How does this wire into my existing plug?

Thanks again,

Gordon.

Gordo,
If it only has two wires--it is not the correct speaker for your amp. See the amplifier schematic-- Ron Rich