Question For Those In The Know About Audio Research Power Amps

@rooze 

I know this thread is aged quite a bit but wanted to comment on your post about Audio Research stating the KT150 was safe to run in the REF 110.  I’m pretty sure whoever it was at Audio Research responded to your inquiry about using this tube was having a bad day or somehow misinformed on the specs of the transformer in the REF 110.  To safely run the KT150 you’d need to do a pretty extensive overhaul of the amplifier.  Not only would you need to replace the transformer, but you’d need to also need to replace several components on the board itself.  I double checked with Audio Research and they confirmed this. 
 

Unfortunately now when someone Google searches REF 110 and tube options, they often land on your audioresurgence review and this thread, and are led to believe with your review and the response you received that the KT150 will work.  It’s scary because a perfectly usable REF110 could be bound for it’s eventual demise if someone takes this as the gospel truth, invests $1100 in a set of KT150’s and then destroys a perfectly good $3,000 power amp.  
 

This is the response I got from AR.  
 

“Hello Andrew, 

We do not recommend using the KT150 in the REF110 amplifier. The current draw from those tubes is more than the power transformer was designed to handle and using those tubes will shorten the life of that transformer. It is ok to use 6550’s, KT88’s, or KT120’s but we do not recommend other tube types for this amplifier. 

Thanks,
Greg

Greg Christensen
Director of Service and Customer Support

6655 Wedgwood Road North| Maple Grove|MN|55311
6 763.577.9700
[email protected]”
 

@wrxified 

"your post about Audio Research stating the KT150 was safe to run in the REF 110" - I didn’t state that. I asked a question whether or not it was OK to run the KT150.

I later posted an update which came from AR directly, stating that KT150’s are fine. 

If you have a beef with running KT150’s in the 110REF, take it up with Audio Research, not me. (i.e - don’t shoot the messenger)

This is the response I got from Audio Research

Dear [Name redacted]

Summary: There was never a proper "SE" update for the REF110. You can use KT150’s in that amp, that is not a problem. The dealer may have called it an SE but technically that is not correct. I had our sales manager call the dealer and ask. They said the would be happy to explain so I encourage you to call them about that.

As for the box, we do have those available. They are $230 plus shipping. If you want to purchase the box, I’ll need your address (billing and shipping) to enter the order and once I do that, you’ll receive a credit card payment link for processing.

If you have any questions please let me know.

Thank you,

Greg Christensen
Audio Research Customer Service
www.audioresearch.com

@rooze 

I’m certainly not trying to shoot the messenger here. I’m just relaying exactly what AR told me when I reached out. Ironically, the AR employee who responded to your email back in July 2020—Greg Christensen—is the same person who responded to my inquiry today.

My intent wasn’t to call you out or suggest that you provided bad information. If my earlier post came across that way, I apologize. What I was trying to convey is simply that the guidance AR is providing today appears to be different from the guidance they provided you six years ago.

I don’t have any issue with running KT150s, and it’s clearly a question many people have had over the years since it’s what prompted this thread in the first place. My search for answers actually started with your review. I noticed the note at the end mentioning the conflicting information regarding the amp’s ability to run KT150s in stock form and that you’d be reporting back in the future. I looked around for a follow-up but couldn’t find one, so I started digging elsewhere.

When I came across your post here showing AR’s response, I was excited because it suggested there might be additional options worth exploring. Before going down that road, though, I figured I’d go directly to the source and ask AR myself. As of today, their response is different from the one they provided you in 2020.

The only point I’m trying to make is that AR’s position appears to have changed over time. Whether that’s because of field experience, reliability concerns, warranty claims, or something else entirely, I honestly don’t know. I’m simply sharing the most current information I received directly from them so others researching the same question have another data point to consider.

@wrxified 

Yes, it certainly looks like they've updated their thinking on the Ref 110. You didn't date your email from Greg, so I'm not clear whether the rethink has been a recent one, or something older. 

For the sake of clarity, I've added a 2026 update to my review here: Audio Research Reference 110

@rooze 

Thanks again for your follow up.  My communication from them was from this week.  They really are awesome at responding very quickly to questions.  
 

I just received another email from Greg just now confirming what prompted them to pivot from their initial opinion that the KT150 was okay to run.  
 

“June 16th, 2026

Dear Andrew

Summary: Yes, there was a time when the engineers thought the KT150's would be ok but later changed their mind after we started to see some power transformers burn out. Our current official recommendation is to not use the KT150's in that amplifier.

Thank you,

Greg Christensen
Audio Research Customer Service
www.audioresearch.com”