Tagboard insulation failure in Quad II amplifier

[Radio Fixer]

Well I think swapping an engine out of a classic car is stretching the comparison hugely to replacing old resistors in an Amp.  What do they do inside the engine?  New bearings, bore out, new pistons and so on. Looks the same when it goes back in.

A friend sold some EL34's to a Hi-Fi nut who said they had to be Mullard as they were the only ones ever made that were "sonically perfect".  Nuts to me   but each to there own.

Gary

[Valvebloke]

The debate's as old as the hills really, but here goes one more time ...

If all that matters is performance/reliability then we should strip out absolutely everything we possibly can and replace it with new. It will measure better and last longer. (But maybe we should really just buy a new one ?)

If the vintage nature counts for anything, anything at all, then we will have to draw a line somewhere. The debate now is just about where to draw the line - vintageness versus performance/reliability. For some folks it's OK if it looks the same from the outside (I've seen radiograms which contain not a single piece of the original electronics, or speakers, or record deck - lovely cabinet though). There are others who are happy to preserve the concept of the original piece, and maybe one or two components (the mains and output transformers in a power amp, say) but who will modernise any of the other components they can get to. The next bunch down (actually up, since I'm in here somewhere) will keep what they reasonably can, tweaking it if necessary and only replacing it completely if it's failed completely or if it's likely to fail and take something precious with it (yes, I mean you, Hunts Micamoulds !). Then there are the people who are primarily in this game for the vintageness. The thing is not going to have to earn its keep - it's going to sit on a shelf instead. It'll look wonderful, it may be worth proper money to like-minded collectors, it'll have been a joy to get 'just right' and it will give future generations a really accurate guide to how this stuff was once done. For them there's no need to change anything really, except to reverse anything at all that's been done since the kit was built, because all the more recent bits are not true to the original.

You pays your money and you takes your choice, as they say, and I don't really have a problem with that. If I ever do feel the urge to describe someone else's approach as 'nuts' though, well, I bite my lip and remember that I voluntarily spend my time out in a workshop fiddling with vintage audio gear. Mrs VB would remind me very pointedly about a bloke in a glass house not throwing too many stones .

VB

[Murphyv310]

Well I think swapping an engine out of a classic car is stretching the comparison hugely to replacing old resistors in an Amp.  What do they do inside the engine?  New bearings, bore out, new pistons and so on.  Looks the same when it goes back in.

A friend sold some EL34's to a Hi-Fi nut who said they had to be Mullard as they were the only ones ever made that were "sonically perfect".  Nuts to me   but each to there own.

Gary

Good post Gary.
The thing is who takes a Quad II out and shows their pals the old resistors? Same as in an engine or chassis of a car.
Call me what you like but I don't pander to these folk that know nothing and demand you do a job in a certain way....... they are shown the door along with a few choice words.
I know VB is a brilliant engineer and his work is 100% but I'm sorry I really feel that ones engineering should never be compromised by the demands of Audiofools that have their heads stuffed with cotton wool. Fit decent components and don't fudge the job, if they don't like it refuse to do the work.

[Radio Fixer]

Sorry! VB not trying to upset anyone. Calling someone a HI Fi nut I don't think is derogatory as folks call me an Old Radio nut; its almost a term of endearment.

Yes! true about the "stones and glass house": it makes no sense to many buying and spending far more on a radio that ends up, after countless hours, worth not much at all. But it gives me pleasure and passes the days.

If you have customers who want their Amps fixed the way you do then why not. Trevor does them his way and there's presumably enough for all so each to his own.

Its a bit like modern poly caps and re-stuffing: some see no point others wouldn't do it any other way.

Gary

[ppppenguin]

I'm firmly in the "good quality modern parts and no disguise" camp. Basically I'm lazy and a fairly conventional engineer. I don't denigrate the restuffers though you really need to leave a note in the set to say what you've done. just to stop some other poor fellow in the future who thinks they need replacing. I don't "get" the 'phools and their strange habits but if they want to spend their hard earned cash on woowoo then let it at least be safe woowoo.

VB is catering to a very specific market and does it very well. He should have many happy customers. I don't doubt there are plenty of bodgers out there who will claim authenticity but do a horrible and possibly dangerous job on your precious kit.

Likewise Trevor is catering to a specific but probably somewhat broader market. Again he does it right.

[Nick]

A couple of years ago I found a good condition but cheap Quad 405-2 and decided to have a go at it.

The amount of opprobrium that came my way was extraordinary - 160,000 of these amps were made - it's not like they're rare or exotic. What's more, it's mine, not the complainants' and I doubt that Peter Walker could care less.

If you're the owner, then do with it as you will... I you're doing the work at someone else's behest and don't like the mandate you've been given, walk away.

[ppppenguin]

Nick, you don't say why you were getting flak about your 405. I suspect it was because you were making sensible engineering mods rather than keeping it original. Things like uprating some resistors, different opamp and better connectors.

Rarity may catch up with the 405 one day. Think of the plentiful R1155 after WW2 and the many mods that hams did to them. All perfectly sensible at the time. Fast forward to today and unbutchered R1155s are very rare.

[Kalee20]

One wonders what would be the case if the situation was reversed - capacitors of yesteryear were polyester film types, lasting virtually forever but became unobtainable and outlawed for some reason - the modern replacements being waxed paper. For those who 'modernised' their amplifier by fitting present-day paper types in waxed overcoats, devalue their amplifiers? And would they be sounding muddy and lacking in the clarity of the original?

Bear in mind that polycarbonate types are already obsolete, and some people pay heavily for NOS Mullard C296 polyester types!

[Murphyv310]

Two things come to mind.
One was a good number of years ago, a Bush TV22 with height creep and line oscillator drift. The guy told me he wanted totally it original and the work done by another repairer was to be left as is.
What had been done was very neat and tidy, no complaints at all with the workmanship. The problem was the early 50's resistors had been padded with small 8th watt resistors to bring the wildly out of spec resistors back within tolerance. The problem was a number of the old resistors were failing which caused the issues. The caps had been restuffed with modern types.
I explained to the customer that the resistors needed replacement and padding was no use. It landed in stalemate and he took the set away. About a year later he came back and said it stopped working completely, the result of the conversation was that I got the go ahead to do the necessary. On completion and return to the customer I was thanked very much and a letter received a couple of months later was very nice and complementary saying the set was 100 times better than ever. So sometimes sticking to your guns pays off.

One thing I have said to the Phools who have say a classic car is this. Would you fit an over-sill to the existing sill? Surely you would cut out the old rusty mess first and fit a sill of the right spec and dimensions rather than an oversize one to cover the mess. Usually I find this approach works wonders.

[Valvebloke]

...  One thing I have said to the Phools who have say a classic car is this. Would you fit an over-sill to the existing sill? Surely you would cut out the old rusty mess first and fit a sill of the right spec and dimensions rather than an oversize one to cover the mess ...

Yes, things that are completely shot have to be replaced. I replace the Hunts caps. Things that have just drifted a bit don't have to be replaced. We can replace them if we want (more exactly, if the customer wants - it is, as Nick says, his kit when all's said and done). But for a vintage amp the 'right spec' was carbon comp resistors, like 'em or not. Fitting metal films would be upgrading. I have customers who bring kit to me for upgrades, and that's fine too if it's what they want.

VB