2. amps-preamps
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new tubes on auto-bias amp,can be done by anyone?

could i just simply put NEW tubes on an AUTO-BIAS amps? as long as the PAIR/QUAD tubes are matched?!? right? 'coz every time i called-up the manufacturer,,,they always recommended sending the amps to them,,,SO HASSLE,,, physically & emotionally,,,i can't get a straight answer from them,,,was it just their another marketing strategy? or they were being SOO...HONEST,,,my objective is TUBE ROLLING,,not for a repair,,,,thanks
allanxxxoooxxx_18
atmasphere's avatar
atmasphere
11,656 posts
 
short answer: yes. If you have to ship the amp back, doesn't sound like auto bias to me!
facten
2,782 posts
 
What amp do you have? Does the manual state or on the manufacturers web site does it state that the amp is auto bias? If it does than enjoy yourself. I have 2 auto biased amps and have gotten into rolling.
allanxxxoooxxx_18 OP
4 posts
 
i just purchased a sophia 845 mono-block,it consist of (1) 845, (1) 6sn7, (1) 3a5,,,thanks guys for some inputs
washington_highend_audio
41 posts
 
The 6SN7 tubes in your amplifier are in self bias.
So, you can tube rolling 6SN7 tubes in your 6SN7 drive 845 amplifier.

845 tube rolling may require to rebias 845 and re-set hum pot--it is the standard procedule for most 845 amplifiers. Many users are not capable to do the 845 tube re-bias(high voltage and high current involved).

I would recommend you do not touch 845 for tube rolling. Plus there is no better sounding 845 from vintage time unless you pay $2000 for one pair of used RCA 845.
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