Question For Those In The Know About Audio Research Power Amps

Yep, that is the case for KT150 tubes.  I imagine that one could use KT88, KT90, KT120 tubes instead if you desire and they fit the sockets.  You would have to know the new bias points.  But, a simple call to Audio Research would confirm this. 

Audio Research equipment was modified to accept KT150 tubes, this meant upgraded transformers to hand to power handling/draw capabilities of the KT150 tubes.  If they can handle KT150 tubes, they can definitely handle tubes that came before with lower draw characteristics.

But as I mentioned earlier, since most manufacturers can't possibly know what new technology or tubes will be produced in the far future, it is impossible to design for them that far in advance.  You design for what you know now.

If you can find an alternate tube supplier that will supply matched tubes within Audio Research's specifications for that amp, for a lower price, well,, go for it. 

I can tube roll to my hearts content with my REF 250 amps and my REF6 pre-amp and REF 2SE phono stage, up to the current level of tubes that they can handle.  'For my REF250 amps, I just can't go above KT120 level.  not big deal.

its like with supercars or Mercedes or high end cars.  The maintenance costs is very high. People find themselves in hot water when they purchase something without investigating the maintenance costs first. 

That is a serious shock when the bill comes.  not a big deal with pre-amps or tubed phono stages, but for large powerful tubed power amps,  This could be a down payment for a new car replacing the tubes.  

thinks the REF 150 tube replacement is bad?  or my REF 250?  Look into tube replacement for a REF 610 or 750 amp.  or other manufacturers that make large tubed power amps.  Tube replacement costs is no joke.

not for the faint of heart.

enjoy

Re: tube replacement costs. Apologies for the digression.

when I bought a Mesa Baron c. 1996, they offered half-off the cost of new, matched tubes (I understand their tube-matching is second to none) to original owners. Not a trivial expense, with 12 power tubes and 4 12ax7a’s.  They still honor that promise, 24 years later, long after withdrawing from the audiophile market.  Now THAT is customer service!  AR seems to take the opposite approach.
I enjoyed an AR linestage and and still have an upgraded ph3SE phono stage, but their power amps were always said to be difficult to bias and burn through tubes quickly.  I just couldn’t take it.

Not to beat a dead thread, but I have my (original owner) Mesa Baron being refreshed at Mesa right now (12/2021), and they are honoring the half price tube offer. Though the subtext was that they might not in the future, now that Gibson has bought Mesa.

I'm glad they're honoring the tube deal. When companies take over another's assets, they also assume the preexisting contracts and obligations. Or should.

I'm looking forward to getting the Baron back, and hearing it with new caps and tubes.

Cheers.

@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