Audio Research REF 750 pre July 4 FIRE WORKS. TUBE ARC.

Well I just had time to finally hook up my new Audio Ref 6 se for the first time as I got it back from AR last week. So I waited patiently for my night off from work last night and was also very excited to finally hear that for the first my Audio Research REF 750s. that came with the KT 150s with 660 hrs on them. I was really enjoying the beautiful sound of these phenomenal amps for a few hours and called my wife up to hear how amazing Barbra Streisand sounded playing The way we were. I had all the lights off in my listening room and we were lost in the sound quality as my B&W matrix 800 speakers disappeared and melted also to the beautiful sound of her voice and when all of a sudden there was an explosion as I had first thought. The middle of the top KT150s there was a loud SIZZLE a FIREBALL and a loud POP !!!! And WHITE SMOKE and then cut off. We immediately jumped up and my heart sank as I yelled OMG. I jumped up and ran to my L amp and I pulled the plug while the R amp and speaker was still playing. I said WTF happened?? My heart sank in my stomach as the first thing I thought was now after all the anticipation of that night to finally arrive I was now devastated as I had no idea WTF just happened. I was numb. I finally calmed down some looked over the amp on top. Didn’t see no damage and texted my guy that I bought them from and he told me it sounds like a tube arc. He then told me to take all the top tubes out but u can leave the 2 inside ones in. He then said to carefully take off the top cover as I did. I turned the cover over and saw black underneath as I then turned it over I saw it was V10. He said now look at the resistors by V10 socket. Sure enough the wire leads were gone. He said your V10 tube is shot and u will need to replace the resistors by V10 socket. I said does it have to be sent to ARC ? As I just got delivered the REF 6SE that had been upgraded and just got it back from ARC on Tuesday. I couldn’t think now about packing up the Left Ch REF 750 and shipping it back to ARC. He said nope no need to. Just have the Resistors replaced and get a new V10 tube with the same number on it from ARC. And call your ARC dealer here in NJ to see if his technician can come to my home and replace and solder the new resistors back on. Put the new KT 150 in and you will be back in business. So now I am waiting for my ARC dealer to open this morning and hopefully he will tell me some good news. Just don’t understand how or why this happened? Has anyone else had a similar experience? Wow I will tell ya that it was a very scary thing.BTW I never owned a tube amp except for my REF6 SE pre so this is still very new to me.

128x128Ag insider logo xs@2xtattooedtrackman

I've had ARC amps for 30 years and this happens.  I have some of the resistors around someplace, hopefully.

It is the reason I would never leave home with the amps on though and usually want to be in the room with them.  your tube cost is going to be $3-4/hour, so don't leave them on if you are not listening.

This is not uncommon. I had a pair of ARC Ref600s, predecessor to the Ref750, and this happened every once in a while. The fireballs can be quite harrowing, but getting the amp fixed was always pretty easy: just replace the resistor and the tube. 

So, my take on this might deviate slightly from what has been contributed so far. I have owned many Audio Research amplifiers over the years. On two occasions, with two separate amplifiers (D70MKII and VS110); the same pyrotechnics you experienced took place. Both occasions sacrificed components (resistors) in circuit and required a trip to Audio Research for repair.

On both occasions I was living in a costal community, in a home without air conditioning and it was summer. Neither one of these amplifiers could possibly put out the heat of your Ref750 amplifiers. One key takeaway for me; if you’re using an Audio Research vacuum tube amplifier(s), make darn sure the listening room is plenty cool.

Currently enjoying a VSI75 in an air-conditioned environment…

@tubegb  Wow yes u are so right the fist thing I noticed was like how much heat these 750s put out. It was like having 2 big heaters on high with them. I heard they would be putting out some heat but they really blow some high heat. Lol. I thought my Krell FPB 600 put out some heat lol. Also yes I definitely have AC in my listening room. I would definitely would not be able to stay in there without one especially with the REF 750s. In the winter it will be nice as I don’t get the best heat upstairs in my listening room. 

Thank you all who responded. My ARC dealer in NJ contacted me this morning. John Rutan from Audio Connection in Verona NJ. Even before I had the chance for his store to open and call him first. He read my post and called me as soon as he read what happened. He also explained how and why this could happen. And said to call ARC and order the V10 K150 and some extra resistors also to have on hand. As soon as I get them delivered from ARC to call him and he will have his Service tech come to my home and repair what has to be with the REF 750. And basically said it’s not a big deal that this does happen ever so often with a bad tube. Hopefully it wouldn’t ever happen again but I am grateful that I don’t have to send it back to ARC for repair. I have known John Rutan since I bought my first amp and preamp from him in 1991. It was a Counterpoint SA 220 amp and an SA 2000 pre. He is such an awesome guy and SO very knowledgeable. He really left me feeling so happy and positive about what happened last night. Thank you so very much John !!!!