Hi,
I,m interested in bias levels for ref 600(mk2,3 )and ref 300(mkII) used by others in their amps.The factory level is 65ma and I do use this(6550,but will go kt88 as rec) but even the factory approved tech (only 1 in oz ) when he visits always rebias down to 55ma / each tube.He states that for reliabity/longer tube life etc this is recommended.(note I rebias back to 65ma sounds better)
Ref 600 had/have a bad reputation which I suspect is low quality tubes,heat, overbiasing (accidently ,I saw 100ma when adjusting 1 day) and the DUST which caused most of my troubles and bad tubes.
Why I posted for other,s opinion and experiences is I spoke to another amp designer/builder and he said very unreliable amps and must rebias down also.
My amps now that I clean dust out every 3mths and run lower fan speed have been very reliable and with tubes tested can provide many yrs of trouble free operation.Vacuuming amps today.
http://www.audioresearch.com/ref600.html
Look forward to your reply,s (1st post)
Regards Victor.
I,m interested in bias levels for ref 600(mk2,3 )and ref 300(mkII) used by others in their amps.The factory level is 65ma and I do use this(6550,but will go kt88 as rec) but even the factory approved tech (only 1 in oz ) when he visits always rebias down to 55ma / each tube.He states that for reliabity/longer tube life etc this is recommended.(note I rebias back to 65ma sounds better)
Ref 600 had/have a bad reputation which I suspect is low quality tubes,heat, overbiasing (accidently ,I saw 100ma when adjusting 1 day) and the DUST which caused most of my troubles and bad tubes.
Why I posted for other,s opinion and experiences is I spoke to another amp designer/builder and he said very unreliable amps and must rebias down also.
My amps now that I clean dust out every 3mths and run lower fan speed have been very reliable and with tubes tested can provide many yrs of trouble free operation.Vacuuming amps today.
http://www.audioresearch.com/ref600.html
Look forward to your reply,s (1st post)
Regards Victor.