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Hi, just got my new Stereophile, September 2023. On review was the Audio Research I/50 reviewed by John Atkinson.I got a question or two.Why did Audio Research go with a printed circuit board in a vacuum tube power amp with 4 6550 tubes relatively close to each other.If any of the paths from the various circuit components lifted off the circuit board wouldn't you have to replace the whole board vs.just the component in point to point wiring such as in the Primaluna amps? Also, I see air holes on the base of the amp and a cage over the transformers.I understand they must be for cooling on the base,but why is the cage only covering the transformers?Wouldn't the cage be more important over the tubes for safety or is there cooling matter with the amp that over rides the safety factor? Thanks for any answers, sincerely Mark Korda
Follow Ups:
They used circuit boards from the beginning in their amps. Built quality of ARC amps is exemplary and pretty much unmatched in the industry. Usually there is an access to the bottom of the boards by either removing a side or bottom cover. In newer amps you lift the whole board. Since the solder points on the circuit board are plated through you can pretty much tackle the repair without removing the board. People want to see glowing tubes nicely arranged on the top of the chassis .
Hi,
This isn't to be argumentative, but I'm wondering why you say this in particular: "Built quality of ARC amps is exemplary and pretty much unmatched in the industry."
I've been to Audio Research a few times -- but I've also been to more factories than I believe any hi-fi writers has ever been to. So, I've seen a lot of manufacturing.
There's certainly nothing wrong with the way Audio Research builds amp from what I've seen, but "unmatched" I don't think is accurate. I've seen numerous companies as good or better. Why do you believe they're unmatched?
Doug Schneider
SoundStage!
I referred to their tube equipment because that's their forte.
Which tube brand you feel is on equal footing with ARC regarding construction techniques, parts quality, fit and finish ? Mind you I don't talk of sound since it's a subjective opinion. I'm not a fan but working on some of tube equipment I simply haven't seen better built gear. The latest stuff from ARC looks more mainstream and disposable but parts quality still good . Yeah , I saw Lamm stuff, also pretty nice with parts costing 1/5 th of what's on ARC boards and triple price. VTL ? sorry mess , not bad sound. European brands hit and miss but mostly cramped, cheap components and lousy built , often surpringly good sound but questionable reliability.
I guess it's much easier to CAD perfect looking colorful interior with parts costing close to zero than taxing tube amp which will last decades.
Hi,
In your post, you did say "in the industry." If you're narrowing it down to the tube industry then, there are a few companies that come quickly to mind -- the USA's Rogue Audio, Germany's T+A, and Japan's Luxman all make outstanding tube gear.
Doug Schneider
Considering that tube equipment is far more challenging than solid state I wasn't far off. Can you tell resistor from capacitor? If not, there is no point.
The companies you mentioned do make solid products but construction and parts quality wise not on level of ARC. Esthetics and sound quality not considered. I have Lux CL38 pre and had ARC reference preamps. I prefer Lux but there is no denying material and construction wise ARC is far ahead. Rouge is different league all together
Well, we can agree to disagree because "far ahead" it's certainly not. I know because I've been and also had quite a bit of the stuff here. It's good -- which is what you'd expect for the price. No more, no less.
Doug
It's true that the latest series became more " flimsy" and are cheaper made and more in line with what other manufacturers do while prices went considerably up. So, maybe you have the point.
I personally think ARC has a lot of work to do to get back to where it once was. We'll see.
Doug
Howdy, Doug:
What's your impression of Quicksilver tube amps? Years ago, I recall Sam Tellig marveling at the build quality and reliability of Mike Sanders' products. Point to point wiring and all that jazz. Apparently Sam had given a Quicksilver amp to his daughter, who had enjoyed years of trouble-free use from the unit.
Those I have no idea about. I'd seen them at shows, but that's about it. Never examined them closely. Some people get worked up about seeing point-to-point wiring, BTW, but it's sometimes more impressive to see than it really is. But in this case, I don't really know. Sorry.
Doug
Hi Wojciech, what do you mean by (plated) when you were talking about the circuit board? What I was wondering about was the foil,or the lines/ wires going from component to component.If my Heathkit AA-32 needs a new cap I can solder one in. If the foil lifted on the Audio Research's circuit board wouldn't you have to replace the whole board. Four 6550 tubes close together could heat my house. I once saw a picture of an audio nut's wife warming her feet by a Dynaco Mark 3 side by side. That was 4 6550's going. Thanks for the info....Mark
What I meant is a circuit board which has copper foil traces on both sides and the holes to mount components are copper plated inside so both side of the copper trace are connected even if no component leg is mounted in the hole. If component fails ideally you want to heat up a solder point from underneath to form a new connection but in many cases you can heat up failed component leg from the top and the solder will melt so you can remove the component from the top without necessity to remove the board to get an access to the underneath of PCB. You clean the hole insert new component and solder from the top. The solder will melt through the hole and form connection. If you blow the trace off the board like it sometimes happens in ARC amps when screen resistor fails you can either try to repair the trace with a kit where you glue a part of trace and solder the ends of damaged trace. I simply use a piece of wire to form a new trace. Copper is copper and it will conduct. It's not going to look super pretty but if you use a bare wire and solder it neatly it will look OK.
4 6560 tubes is nothing. I once had a pair VTL750 amps with 12 6550 tubes in one channel so 24 6550 plus signal tubes heating living room.
Don't you use F150 to drive to office? I think it's the main purpose of this truck in US:)
Hi Wojciech, thanks.That was a good lesson for me that I don't think you would find in any book.Thanks for taking the time to type that out....sincerely..Mark Korda
This picture, you mean? (link below)
BINGO! Shovel!.....thanks Mark K.
There's no load connected to the output, and the bottom vents are completely blocked while sitting on a rug. The amps wouldn't last long if they were actually powered up, but it does make for a nice picture.
Which shows how that amp is built.
View YouTube Video
Estat, thanks for sending the video. I haven't watched it all the way yet.It was up against Wagon Train. You are always a fountain of info and help...thanks Mark Korda
,
I've been a fan of ARC since I was a teen.
So ARC is down to one tech and struggling to find another. A microcosm of the high-end industry as a whole.
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