Audio Research Reference 150 severe distortion


My Reference 150 is emitting severe distortion in both channels. I checked the bias of the K120 tubes and one tube in both channels is reading as low as 20, rather the the standard 65 range.

Does anyone know of a possible fix that will not involve me shipping the amp back to Audio Research?

Both bad tubes are less than 3 months old.

I gotta play my Liberace Christmas music!
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Shaq ...could be bad tubes; could be blown bias resisters. Switch "good" tubes into the sockets that read 20 mV. If the bias stays at 20 mV, that's a good sign there's a blown bias resister. If the bias can be adjusted to 65 mV and the problem moves with the tube, it's the tube.

I find it odd that both channels present the same problem. Try the diagnostic technique I suggested and report back. Do you have any spare KT-120s. If so, you might need them.

Hopefully, the problem is just a bad tube or blown bias resister. If a blown bias resister, I would ask Kal (ARC service rep) if there's an authorized repair center near you. I would avoid shipping the amp for a simple bias resister repair if at all possible.

Rather than me whining on, try what I suggested and report back.
It looks like AudioReseach Ref series are similar to Ferrari that have great performance but for the price of poor reliability.

...which is the reason why I will never own a Ferrari!
"It looks like AudioReseach Ref series are similar to Ferrari that have great performance but for the price of poor reliability."

I don't know much about Ferraris, although I think many of them look sharp. But I can  tell you that ARC products are very, very reliable. Yes, they require periodic tube replacement. But the gear is very reliable and very serviceable.
"It looks like AudioReseach Ref series are similar to Ferrari that have great performance but for the price of poor reliability.


Czarivey ... strongly disagree.  I am waiting for Sha to respond to my post.

Cleeds, I just follow frequent facts about Ref series.
It doesn't look like tube(s) problem. It looks like functionality problem.
bifwynne, you've mentioned bad bias resistor which may go with bad tube didn't you?
OP mentioned that tubes are less than three months old... What does it tell?
Just count facts and science becomes simple math.
Go with more facts throughout Audiogon posts about Ref series reliability: frequent premature tube blowing, bias resistor, bias DC cap etc... All these combined dictate sending unit to repair facility and back to get ripped off just like Ferrari owners do.

"... I just follow frequent facts about Ref series.
It doesn't look like tube(s) problem. It looks like functionality problem ...
Just count facts and science becomes simple math.
Go with more facts throughout Audiogon posts about Ref series reliability: frequent premature tube blowing, bias resistor, bias DC cap etc... All these combined dictate sending unit to repair facility and back to get ripped off just like Ferrari owners do."

ARC has a tremendous reputation for long-term reliability, so I'm not sure why you feel that you have access to special "facts" just because you read A-gon. I base my opinion about ARC reliability on years of personal ownership and ownership by personal friends, rather than on hearsay posted to an online forum.

Your personal ownership is probably from at least 7...8 years ago. Now I feel that it's different. I haven't seen word dropped about Ref series reliability till recent and mostly on current models not ones built back than.
Tube amp designs have lots in common between each other and frequent blowing tube is functional or design problem. 
"Your personal ownership is probably from at least 7...8 years ago. Now I feel that it's different. I haven't seen word dropped about Ref series reliability till recent and mostly on current models not ones built back than."

No, my experience is both long-term and recent with current ARC Reference components. ARC has an enviable reputation for reliability.

I have a Vt-100 Mklll since 2001 and the only thing I have ever done is change tubes. I currently need my tubes changed so I asked my technician is there any thing else I should do because my unit is 14 years old. He said if it still works fine there is nothing I need to do but change tubes and have them biased.

i had a brother in law that had several Ferrari's that I used to have serviced for him. The amount of money he spent servicing those cars you could own any new ARC amp you wanted plus a pair of high line speakers and still have money left over. Trying to compare the maintenance of a ARC amp to a Ferrari is ridiculous.

shaq,

The fact that both channels exhibit the same symptom, at least that is what I understand from your message, points to a power supply issue.  It may not be so serious as it seems.  I would suggest looking for an experienced servicer in driving distance if at all possible.  

And no question, Audio Research has produced some of the most significant benchmarks in tube amplifiers for more than 40 years.  I have owned and worked on more than a few, and they definitely among my favorites.  


is VT100 recent ref series?
My imagination about Ferrari service compares to shipping 100lb or heavier unit back-fourth. Recent posts about problems shouldn't even be on the first place on $10k+ equipment makes me believe so. I believe that for the money spent on Ferrari all future services and repairs should be FREE for lifetime. Same with AudioResearch ref series.

I recently purchased a McIntosh MC275 Mark VI tube amplifier from my favorite shop in NYC. Not exactly their equipment pinnacle in terms of power,  but easily one of their hallmark/benchmark products which greatly contributes and perpetuates their quality reputation.  
2-3 weeks into ownership - whammo!  A blown tube.  Not McIntosh's fault by any means and I never considered it so.  I've owned other tube equipment before this,  other McIntosh equipment before this,  experiencing no problems of any sort. 
My experience with their customer service was woefully inadequate considering that I had only weeks before purchased the new MAC6700 Receiver from the same shop.  
But not only for that reason,  for any reason for someone who purchases equipment of such highly regarded reputations. 
In brief their communication was terse when they replied,  then non existent.  They still have not replied to 2 emails regarding the situation. I don't expect them to, either. 
Were it not for the owner of the shop stepping in between us, the problem,  a very simple problem,  would still be unresolved.  
I've spoken directly with people at Audio Research, Rogue Audio,  Pass Labs,  Thiel,  and Magnepan about products I bought on the pre-owned market and they treated me like I helped build the stuff.  Perhaps the customer service people at MC Labs were having a bad day the same day I was having mine. 
Should we experience issues with equipment costing $10k or better in the first couple of years?  I think not.  And I think the shipping back and forth ought to be borne 100% by the manufacturer if the issue was production oriented and not user-induced.  


Obigny,

That is why I will only deal with manufacturers that have local service centers. If the equipment can't be serviced locally I don't want it. Luckily I live in Southern California which has a lot of authorized service centers. If I lived in the middle of nowhere I would not own this type of equipment. 
Czarivey,

If Ferrari gave a lifetime of service and repair for free they would be out of business. They say the expensive thing about owning a Ferrari is keeping it running. Plus the fact they don't make many cars per year. Most of the money generated at the Ferrari dealer is from the service department. 


Taters,
My Subaru XV has lifetime warranty on drive train. Subaru isn't out of business.

You are comparing apples to oranges. Subaru is a mass produced car for the average person. Ferrari is a limited production car for the super rich. A Ferrari dealer would not exist without a service department. They just don't sell enough cars to make the dealership a profit. They might cover the overhead but that's about it. There service department is where they make their money. 
Wow I wish I can build some stuff that will require constant and future service for life! Nice business strategy indeed, but would still prefer to purchase products with no need of service or shipping 100lb components back-fourth. Even doing it locally within the state is burden. Driving to service location also requires time. To my personal happiness, I've never shipped any component to repair and never used any dealer to repair or service my automobiles. Pure DIYer on most of repairs and services if not all.

czarivey"Wow I wish I can build some stuff that will require constant and future service for life! Nice business strategy indeed ..."

If you like what you mistakenly imagine ARC's strategy to be, what's stopping you from pursuing it?
Taters
Ah, a luxury we NY'ers don't have.  I envy you in that respect!
My experience with McIntosh and the store that I purchased it from will benefit the store in the future, not McIntosh.  
Folks - free service for life?  Really.  Impractical, impossible. 
Free oil changes for the first 3 years...if you believe that the cost of offering such benefits is not built into the price beforehand you're kidding yourselves. 

Free drive train service... why not. Bryston has 20 years of warranty to begin with.


I wish audiogon  had a block user function.
dchang198118 posts12-03-2015 4:44pmI wish audiogon  had a block user function.

There are Report-it flags should be next to each answer or discussion but found only on few out of many for some reason.
The development crew of Audiogon is not savvy enough to properly test and develop applications. If you ask Justin(the developer manager) for this function, his crew may screw up whole site.
All you can do is ask admin to block and maybe perhaps probably possibly your dream will come true.