ARC Ref 75 vs. Ref 75 SE

Lostbears ... I may have overstated the arcing frequency. It really doesn't occur all that often.

Yeah ... I'll check the tube bias about once a month, especially with new tubes for the reason you said. Sometimes if I'm bugged about something, I'll check the bias just to take my mind off other stuff.

As far as tube replacement goes, I follow ARC's recommended guidelines. In the case of 6550s and KT-120s, ARC said 2000 hours. Maybe I'll went out to 2200 hours, but I started to get nervous that a tube might arc.

Kal told me that the KT-150s should run longer, maybe 3000+ hours. I need to recheck KT-150 tube life again with Kal. Frankly, I forgot.

Oh ... one practical point about biasing tubes, which I'm sure you already know. Tube bias readings can vary based on AC line voltage, which in turn can vary by region of the country and the time of day.

So after all these years of owning tube gear, I don't obsess about bias adjustments. I try to get the set tube adjusted to 65 mV, but I'll take 64+ mV as long as the slave tube is within spec (57 to 73 mV). If the amp sounds differently because of small bias voltage differences, I can't detect it.

Last point about repairs. I would be very circumspect about sending any of my gear back to ARC unless there was a compelling reason, e.g., a massive component failure or an important factory upgrade such as the SE upgrade. For small stuff like burned bias resisters, I call an ARC authorized service tech who makes house calls. The gear is simply too heavy to schlepp around.

If and when my tech retires, I would not be overly troubled to call another qualified tech who knows how to use a soldering iron. Bias resisters are not a high tech fix.

Other stuff, dunno. I'd call Kal and ask his advice. After reading about UPS and FedEx shipping horror stories, I'd really prefer to avoid the hassles.

Best,

BIF

There's nothing mysterious about Tom. He's been the tech at Brooks Berdan Ltd. for ages. He's in the shop on Wednesdays and Saturdays. The rest of the week he's employed at one of the TV studios in L.A.---yes, he's a professional engineer. Does he design and manufacture Class A electronics? Why---is that a requirement to point out what he feels are poor engineering choices? Of course, in his profession, reliability is taken very seriously. In consumer-grade electronics, he is very complimentary to Jadis and Music Reference, to name just a couple of companies.

Where should power tubes be mounted? On the chassis, as they are in those Jadis and MR amps, as well as Atma-Sphere's and others. Heck, even budget amps from the 60's had that! If you haven't seen burn marks around the tube sockets in ARC amps, perhaps it's because ARC owners seem to be constantly "upgrading" to new, improved models before the boards get singed from the heat---ARC tends to run their tubes relatively hard. The one's I looked at in the shop clearly had burned circuit boards. Which is bad enough, but what of the parts thereupon mounted? Heat can shorten their lifespan drastically.

The car tire/suspension was an analogy, not to be taken literally. Still, it's not that much of a stretch, IMO!

Yes, I've heard modern ARC products (and owned a couple until a few months ago. I still have the LS-1 I bought from Randy at Optimal Enchantment almost twenty-five years ago!). And yes, they sound great, but that's not the issue. There are many great sounding amps and pre-amps now, no need to settle for failure-prone ones. Are ARC power amps more likely to fail than other tube amps? Seems like it to me, just anecdotally. And though you may feel the bias resistor design in ARC power amps is acceptable, I consider it a ridiculous way to build an amplifier, I don't care how good it sounds. No, I don't design and manufacture Class A electronics.

But it's the constant, frequent, expensive, never-ending "improved" versions of each and every ARC model that disgusts me. ARC pulls the same stunt on every new model, leaving out the improvements that could have been incorporated into the original version (always increasing the power supply capacity, right? How many times can ARC "rediscover" that concept?), so as to generate new revenue from the same customer of the same model a year or two or three down the road (oops, another car analogy ;-), without having to sell him a new piece of gear. I'll bet THAT has played a significant role in keeping ARC in business for forty years. But ARC is doing fine without me---they have a loyal customer base, one whose members don't seem to mind being manipulated. Do I need to design and manufacture Class A electronics to have that opinion?

Sheesh, I didn't intend to ARC bash (though when pushed I obviously have no problem doing so), just to offer the tip above about a great alternative tube power amp, one that I prefer to own over any ARC. No, I haven't heard most of them (remember, it's not their sound I question), and couldn't afford them anyway. The Music Reference RM200 is available, by the way, with transformers (the heart of every tube power amp) hand-wound personally by Roger Modjeski, something I don't believe anyone at ARC is capable of doing. They don't offer that option, at any rate, no matter how much you pay for one of their amps. The sacrificial bias resistors, however, are mandatory, though free of charge. Until, that is, they need to be replaced.

I just now remembered another tactic ARC has employed that I find most objectionable---last one, I promise!

When the LS-2Mk.2 was being discontinued, ARC shipped their remaining inventory to select dealers at a discount, who then also sold them discounted. The ARC dealer in Orange County, California advertised the pre-amp and it's price, and included in the ad the fact that the remaining available LS-2MK.2's were ARC reconditioned pieces. Fine, all above reproach. The original price of the pre-amp had been $2995 (I've always loved the blank blank ninety-five pricing structure of ARC---very classy!), the close-out price $1995.

However, once all the reconditioned LS-2MK.2's were sold through, what did ARC then do? Why, they offered their remaining stock of non-reconditioned LS-2 MK2's at the same $1995 price! I don't know how you would feel, but I felt violated!! If they were honorable, ARC would have offered the remaining stock of both reconditioned and non-reconditioned LS-2Mk.2's at different price points (say, $1495 and $1995, respectively). Don't you agree? I vowed then to never again buy a "new" ARC piece, which I haven't. Who needs to?---there are so many used one's around!

ARC debuts gear implementing Tung-sol's new audio tube KT150. Customers clamor for retrofitting tube to previous generation but still current gear, ARC complies. Customers are happy with SE versions audio improvement...sounds reasonable. I can't comment about their past policies re upgrade path.

Model updates to facilitate use with a new tube is, of course, an entirely different matter, and most welcome.