Although not true of house wiring, on your amp black is ground and yellow is DC and likewise you will use your black Fluke probe to black and the Fluke red probe on yellow.
Re-tubing my Audio Research Ref 110
After taking advice here I've ordered 8 matched KT120 valves and 4 6H30 (getting difficult to get as can't import from Russia now!)
I've read the ARC instructions but want to make sure I've understood correctly - don't want to blow it (or me) up.
I turn it on for 15-20 with the speakers connected but no signal going through (so disconnect the source or mute?)
The I attach the multimeter, one to the yellow and one to the black beside each pair of tubes/valves. Does it matter which wire goes to which?
Then I turn the blue screw (guess the one adjacent to each set of the two tubes is the one?) The manual says I need to adjust to get 0.65V DC on the meter but that's for the original spec 6550 tubes. Is it the same for KT120 tubes?
And do I just stick the other 4 x 6H30 tubes in - do they need anything?
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Problem with retubing on ARC Ref 110! New matched tubes installed and starting biasing (after waiting 15 mins with amp on, speakers connected but no source selected. First tube set at 65mv, slaved unit measured 66 second tube set, first at 65mv, slaved at 67 third set, first at 65mv, slaved at 73 fourth set, first showed up as -73. Adjusted to -65 (wouldn't adjust below -20), slaved unit created error on Fluke ('OL' and little red triangle with a lightning symbol lights up) Any idea what's wrong? Am I doing it wrong or faulty tube, faulty amp? BTW, is the slave tube the one nearest the front of the amp or nearest the back or is this irrelevant? |
In reverse order, the slaved tube is behind the adjusted tube, and per the manual will have the higher V number so from left to right your output tubers are numbered V5 with it's slaved tube V7 behind it, V9 with it's slaved tube V11 behind it, V6 with it's slaved tube V8 behind it, and V10 with it's slaved tube V12 behind it. Remember what I told you above, you have some badly mismatched tubes and likely a faulty tube. My advice would be to try to return the KT120's and stick with 6550's from a reliable source-I recommend Jim McShane, Upscale and TC Tubes in that order. I am sorry you are having so much trouble. I would never recommend that a newbie to tube amps buy an amp like the ARC 110 without some brick and mortar support, a local friend who knows, or a local reliable tech. |
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