Seeburg MA1-L6 amp trouble

[fwdstuck]

I just recapped the amp (MA1-L6 goes in the seeburg trashcan). All my tubes check good. But it has low sound and distortion. Like a blown speaker. The speaker is has 6.5 ohms across the voice coil and 4500 ohms across the field coil. The service manual says 8 and 5400 ohms. I guess that good. And it has a new cartridge in it. It sounds half way decent with the volume turned almost all the way down, were you can bearly hear it. But the more more you turn it up the worse it gets. Any help thanks.

 

[KenLayton]

Did you replace the electrolytic capacitors AND the wax paper tubular capacitors?

Have you checked the resistors for any out-of-tolerance ones?

 

[fwdstuck]

Yes, I have replaced all the caps, wax and electrolytic. I haven't checked all the resistors. I checked a few and some were a little bit on the high side. But I figured it they would be okay.

 

[KenLayton]

When you measured the field coil and the voice coil, did you use an impedance meter or just a common ohm meter?

 

[fwdstuck]

Common ohm meter

 

[KenLayton]

That would explain the readings you got. You were just getting DC resistance readings and not actual AC impedance readings. The field coil and voice coil are probably fine.

I would still scrutinize very closely the resistors for any that are off value (out of tolerance). Pay close attention to the the ones in the mute section, Automatic Volume Control section, and in the output tube section. Naturally, you will also want to check the resistors in the power supply section.

 

[fwdstuck]

The output section, your talking about the two 6l6s ain't you?

 

[KenLayton]

Yes that's correct.

 

[fwdstuck]

I've checked about 8 or 9 resistors from different parts of the amp. And all of them check on the high side. Like 3 39k resistors across the treble control all check 41k, 45k, and 48k. Its like that on all the resistors I have checked. I think i'll replace all the resistors too.

 

[fwdstuck]

With all the resistors being on the high side (out of tolerance) cause to to have low sound and distortion?