2. amps-preamps
  3. 180714-178160

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?

 

 

 

willmarchant

Showing 3 responses by willmarchant

willmarchant OP
11 posts
 

Thanks all. And when connecting the multimeter Does it matter which lead goes to which point (yellow & black points on the ARC)?

willmarchant OP
11 posts
 

Great!  Many thanks

willmarchant OP
11 posts
 

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?

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