Page 1 of 1
Bad Tubes Or Good Tubes?
Posted: Fri Sep 12, 2008 6:44 pm
by edisonsclone
my 1965 rockola starlet does not sound bad,(not perfect, but good) however I have come to realize that when I adjust the base and treble I only hear a slight difference, Would this be caused by the tubes or bad caps? Or something elts?
Re: Bad Tubes Or Good Tubes?
Posted: Fri Sep 12, 2008 7:37 pm
by Radiokub
On the jukes that i've worked on, bass and treble issues were mostly caused by caps but if you have a tube tester, go ahead and test the tubes anyway to be on the safe side. The other problem i've found in several that i've done is that someone had been into it before and made circuit changes or did a hack job working on the amp. Find you a manual for your juke and check to make sure the circuits match up with the schematic. If everything looks ok, go ahead and do a recap and you'll really enjoy the difference. Only in rare instances have i found where resistors have drifted badly. Also make sure all your connections and controls are squeaky clean as if this juke has been put into commercial service at some point it will be filled with smoke residue. Also make sure your cartridge is correct for your model as some put in anything to get them to play again. Those old Rockola amps are capable of putting out room filling sound with lots of bass and treble so anything you do will definately make an improvement. Let us know what you find and if you run into trouble we may be able to walk you through it.
-Tony
Re: Bad Tubes Or Good Tubes?
Posted: Sun Jun 07, 2009 8:22 pm
by Ken Layton
Generally bad capacitors can be a source of your "lack of tone" control, but more often too is that there are some resistors in the tone control section that may have drifted "off value" and need to be replaced.
Re: Bad Tubes Or Good Tubes?
Posted: Mon Jun 08, 2009 2:01 am
by Ron Rich
Everything written above is true, but there is one other thing that is often "overlooked". Check that there are no "remote" (extra) speakers on the speaker taps--including old wires--then set the cabinet speakers up as per the service manual for that model phonograph. Can make a "Big difference"-- Ron Rich