Bell Clarillon 75 watt Ultra Linear Tube PA Amp

The tetiary wire is red and the 8 ohm spkr is orange. You were correct on the colors being differant.
Thought so. What resistance do you measure between the red tertiary wire and the orange 8-ohm speaker tap when both tertiary wires aren't connected to anything?
 
That indicates the tertiary winding is not a separate winding, but simply designated taps on the same secondary as the speaker taps. That means you should not ground either of the (formerly tertiary) floating taps. You can use one of them to provide negative feedback. Try both (but not at the same time! I.e., try one, then try the other) connected to the 80ohm feedback resistor on the final preamp / phase splitter 12AX7, and listen for which one sounds best.
 
I think I will think about it for awhile
That indicates the tertiary winding is not a separate winding, but simply designated taps on the same secondary as the speaker taps. That means you should not ground either of the (formerly tertiary) floating taps. You can use one of them to provide negative feedback. Try both (but not at the same time! I.e., try one, then try the other) connected to the 80ohm feedback resistor on the final preamp / phase splitter 12AX7, and listen for which one sounds best.
The Amp volume cuts out if I connect either one to the splitter grid pin 7 nfb , the humm is still too loud to use it also , the tone is incredable when I turn it up loud on the Marshall spkr cabinet. I wont have my ear drums for very long if I keep on playing it that loud indoors . I just cant use it like it is. It has a 60 mfd filter cap on it and I would expext it to be pretty quiet. Seems like either the OT or Can has to be making all the noise to me. Maybe the JJ E can cap is defective. But wouldent a bad cap distort worse at higher volumes ? Would my scope help me any on this if I hook it up ?
 
The cap cans are ; 200 mfd @300 v , 60 ,20,20 @500v. I read 470 volts on the can so 500v should be ok. The 470v is on 20 not 60 mfd, maybe that is why it humms ? Shouldent it have more than 20 mfd on 470 vdc ? The 470 feeds the splitter at 460v. and second 1/2 of stage 2's 12ax7, then a drop resistor down to 200v. goes to the other 20 mfd and powers the first 12ax7 and first 1/2 of stage 2. Im thinking that the primary and secondary are ok now and it is a filtering issue that needs to be addressed. If the OT is good.
 
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I think I will think about it for awhile

The Amp volume cuts out if I connect either one to the splitter grid pin 7 nfb , the humm is still too loud to use it also , the tone is incredable when I turn it up loud on the Marshall spkr cabinet. I wont have my ear drums for very long if I keep on playing it that loud indoors . I just cant use it like it is. It has a 60 mfd filter cap on it and I would expext it to be pretty quiet. Seems like either the OT or Can has to be making all the noise to me. Maybe the JJ E can cap is defective. But wouldent a bad cap distort worse at higher volumes ? Would my scope help me any on this if I hook it up ?
The output transformer won't produce a 60hz hum on its own; that has to come from somewhere else. Try putting a known good electrolytic cap of appropriate voltage rating in parallel with the 60 mfd filter cap and see if the hum diminishes. If it diminishes significantly, the existing 60mfd cap is probably defective.

There are various ways you can use your scope to identify distortion, set output tube bias for minimum distortion, determine the amount of ripple in the power supply, etc., but most troubleshooting can be done without it.

As I mentioned before, you may need more resistance than 80 ohms between the negative feedback tap on the output transformer and the final preamp / phase inverter 12AX7.
 
The cap cans are ; 200 mfd @300 v , 60 ,20,20 @500v. I read 470 volts on the can so 500v should be ok. The 470v is on 20 not 60 mfd, maybe that is why it humms ? Shouldent it have more than 20 mfd on 470 vdc ?
Put another known-good cap of appropriate voltage rating in parallel with it. If the hum diminishes significantly, replace the original.

470 volts on a 500v cap is cutting it very close. It will almost certainly shorten the lifetime of the cap.
 
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