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

VAC and others have built and sold monster tube amps with vertical designs but power is useless without reliability and user-serviceability.

Even the biggest VACs still use only 8 output tubes per side, compared to 16 in each Ref 750! At that point IMO you really need smart audio-bias circuitry to continually monitor & regulate the bias of each tube and shut down problem tubes (hopefully) before they spiral into a smoke show. VAC went that way starting with their "iQ" series. I have 200iQ and Master 300iQ now, and trust them implicitly. I believe ARC also started using their own version in Ref 160 series. But the Ref 750...yeah that’s gonna be a tough one to keep running. The fuses in my Rogue Apollos did NOTHING to prevent the KT90 arc/short problem.

I have also heard warnings about KT150 tubes. I would definitely move into KT120 or KT88. You need extremely reliable output tubes if you’re running 32 of them.

@mulveling You are one of the most knowledgeable regulars on this Board. When you post, particularly in the analogue section, I read what you have to say. I appreciate your input here. 

Just catching up on my Agon reading. 😀

@tattooedtrackman I’m sorry to hear about your experience! That had to have been a shock! I’m not writing about the amp situation however. 

You said you have a pair of B&W Matrix 800s. As rare as they are I’d love to talk with you about them. My pop’s (RIP) are in storage pending our next home.

Good luck with the Ref 750s!

Happy listening.