Rothwellaudio wrote:They're British, therefore inherently unreliable? That's simply predudice. Quad amps are known for their reliability.
Personally, I would just switch them on. Electrolytic caps can age, but they age much quicker when in use, not in storage. Everything else won't mind a 10 year rest. Measure the total current drain and output valve current drain (if you can) to check that everything is fine before going ahead with long term use.
RANT WARNING RANT WARNING RANT WARNING RANT WARNING
a) Electrolytic capacitors, if kept in constant/regular use will usually last indefinitely. I have some 1920s vintage radios that I purchased from the original owners who used them 'since-new' very nearly every day - and their capacitors test well and are just fine in use.
b) Yet, I have some NIB Display-only electrolytics from as recently as the 1960s from good names such as Cornell-Dublier, Sprague, Frake and similar that look brand new - but are dead-shorted or 100% open - mostly short. I would no sooner use a 40-year old NIB electrolytic capacitor than I would use a pull from the junkyard.
c) Low-value paper, wax or "Black Beauty"/"Black Cat" capacitors are accidents waiting to happen - and potted output transformers such as what appears to be in those Quads ain't nohow cheap.
d) A marginal electrolytic capacitor can allow a piece of equipment to appear to be working correctly - especially if one has no instrumentation to show otherwise. And give no indication of failure until the tar comes bubbling out from the power-transformer can.
e) How this happens: Say... a unit should draw 100 watts (for round figures) if all is well. So, the main filter array is slightly off - now it is drawing 115 watts. Probably not enough to make an absolutely certain naked-eye difference on a dim-bulb tester, nor blow most factory-fuses or circuit breakers. Those, really, are designed to protect real-estate not equipment (and I will spare all here my fuse-rant unless requested). But, that 15 watts will be expressed as *HEAT* somewhere within the system - typically in the power-transformer. Which, eventually, will fail under those conditions, especially if potted where heat is trapped more efficiently.
At the very best, your [wretched] advice is simply wrong. At worst your advice will lead to the development of a very expensive bit of slagged iron.
Further to Quad's 'reliability', from my direct and indirect experience with them - and from the literature available on the web, they have an excellent reputation for their iron and the sound they can produce. But several sites suggest that 100% of the resistors (in that model) be changed as they tend to drift, and that 100% of the capacitors be changed as they tend to short. Cutting the the chase "Just Plug It In" doesn't wash.
Now, I may be prejudiced against British equipment, but that is based on direct experience with the species. At the same time, I keep a decent array of test instruments including a ESR meter and a full-voltage capacitor tester. But I have learned over the 40 years or so I have played around with this hobby to test even brand-new, recent manufacture caps before installing them. With electrolytics, the off-tolerance/failure rate is about 2%. With film caps, the failure rate is vanishingly small - but the out-of-tolerance (especially for China-origin material) is also about 2%.
Humorous aside: Comparing Quad to Dynaco is a wee-bit unfair. David Hafler, the creator of Dynaco, was renowned for purchasing all his parts from the lowest bidder, at auction and at surplus sales. He did command quality for his transformers, and he contracted with first-line tube houses (Mullard, Telefunken, Sylvania & GE) but he would never use a cheap control when a cheaper one could be found. And it was quite common to find the "same part" from three or four different sources in one of his kits. He had no factory and no warehouse. He did not even package his kits. His "Headquarters" in Powelton Village (West Philadephia) was a three-bay former garage with a small office attached. Been there. His "Factory" was Drexel students on piecework - Look at some "Factory Assembled" products next to a kit - like-as-not the "Factory" unit had wire all of the same color, even looms and ribbon wire - but no two were alike.
He used packing services to receive components and parts from many sources, assemble them into kits, and then ship them as-ordered. His boxes had two different outer flaps, one saying "Factory Assembled" and one saying "Dynakit". How it was folded over was the only difference. So, he would never see anything going through his shop. That was all handled 'by others'. Much as his speakers were made, packed and shipped from elsewhere with just the name being on them. 100% horizontally integrated, to use his business model.
The Hafler "Factory" in Pennsauken, NJ (directly across the river from Philadelphia) was even smaller - a 2-bay garage with a very small office attached. Been there, too.
Quad, on the other hand was a first-line, always expensive name in the industry - more akin to McIntosh and Marantz than Dynaco.
Vintage equipment can be made to be as safe and reliable (often more so) than any modern item out there. Hobbyists have no accountability for costs and are not required to make a profit - and so may use parts and techniques of a higher quality or superior to OEM parts and techniques necessarily limited by the bean-counters. But, and for the record, in my experience, there is no reliable and direct correlation between initial cost and quality. Some manufacturers simply made good products at a reasonable cost. Some made cheap products at a low cost, some made very questionable products at exotic prices. And some made superior products at superior prices. But in very nearly every case, better parts and pieces than OEM are available - and should be used if needed.
As to variacs and such - I keep one of these ( http://www.oaktreevintage.com/web_photo ... _small.jpg
) please excuse the small picture. It is an isolation transformer and variable autotranfomer in one box with very good meters for voltage and amperage. Two scales on the ammeter 0 - 1A and 0 - 3A, each separately fused. Heath did make a 240V version - basically a different scale on the volt meter. I cannot convey how many times this device has save equipment and time during the diagnostic process.
Melrose Park, PA