Audio Research I/50

I was thinking of buying one as well but then I read that it needs to be biased by a trained technician. That really has made me consider not buying it. It makes no sense that a product in this price range, made by a manufacture with such a long history of making tube amps, would offer their latest product like this. Audio Research needs to clarify this. There are some points/questions I'd like to bring up.

1) Why can't Audio Research offer either automatic bias or user adjustable manual bias? Prima Luna offers automatic bias. Rogue and most other companies at least offer user adjustable manual bias. Trim pots next to each tube. Companies like Rogue even include a multimeter readout dial on the amp. Very easy. Four words: User Adjustable Trim Pots. Why not AR? 

2) I've owned tube amplifiers before with manual user bias. I usually checked the bias at least once every 3 months. I can tell you they were always a little off and I always had to readjust the bias to get it back to the optimal bias level. Not all tubes are equal. Some fade out over time quicker and some can even stop working. For AR to basically say the bias is fine for 2000 hours or about 2 years is odd to say the least. Is Audio Research certain the tubes won't drift out of bias within 2000 hours or about 2 years? 

3) Where to send it in to get the new tubes biased? Does AR do it or do we need to find our own "qualified technician"? Some of us may live far away from one and need to box it up and ship it off to one. Very inconvenient. Not to mention the extra cost for the user and possible shipping damage each time. What if a tube goes bad early? More hassle.

As I write this I am more convinced than before that I'm not buying one. It's a shame because I'm sure it sounds great, it does look awesome and it's made in the USA. Perhaps the biasing issue won't matter to some of you. Especially if you have an AR dealer close by with a technician. However, for others I think it will be an issue. 

@runwell

I wish I could answer your question correctly. I’m not a technician just an audiophile. I’m not 100% sure why tube amps drift out of bias. If it is just about the tube or if it also about the amplifier? I believe the bias can change at anytime during the life of the tube. I don’t think there is a period where it preforms at exactly the same level over a long period of time. This change is not necessarily an indication that a tube is nearing the end of its life. This is just my best guess. I am sure someone else on this thread can clarify it better than I can.

Also, thanks for asking Audio Research directly and posting their response. I’m confident now this amplifier is not for me. Why are the trim pots hidden on the bottom of the amp? Turning over the amp, taking off the bottom cover and then we can check the bias? I suppose anyone could do that but who really wants to? I thought Audio Research said that a trained technician is supposed do that? Or is that only when the tubes are replaced? But why? If the tubes need adjustment then why can’t the owner also adjust the new tubes themselves? Makes no sense. The bottom line is that Audio Research should have designed this brand new amplifier with the trim pots on the top of the amp poking through the top plate. Make it easy for the user. Just like 90% of all other tube amps do.

To answer your last question. I assume that after unplugging the amp, turning it over, then opening up the bottom plate that you’ll have to plug it back into an electrical outlet again. It’s the only way to check the bias. Why AR didn’t mention that in their reply to you? Odd. Furthermore, the fact that the bottom plate is opened up and the unit is plugged into a wall outlet is a warning. Especially to new users. Can you say potential lethal voltages? 

@ Transience 

That's great. Let us know how you like the I/50. The Graham LS6 speakers are very nice. My assumption is that the two should be a good match. I agree with you on the Octave amps. They have implemented a unique and easy way for all users to bias the tubes.