Amp input selector

This works until there is no more plating left.

REALLY good switches used to be (solid) silver buttons that wiped across each other.

Cheap is gold plated brass. No oxidation until the gold wears off..

Really cheap is just bronze :-)

Reply to
The Natural Philosopher
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Been there, done that, got the noises to prove it didn't work.

Hmmm. Good idea. I shall try that as the next step after the Deoxit.

Except ... what's Silvo?

Reply to
Huge

Replace it? Even an upgrade?

Secondhand market for tasty hi-fi kit is in freefall. Forget eBay, try and hunt down an event like audio jumble which happens twice a year.

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'll find hardly used decent and audiophile kit at silly prices with plenty of life and spec left.

And there is a similar event on April 17th in Reading, the Thames Valley Audiofayre.

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And there should be similar events up and down the country, these events have taken the place of radio rally interest for some.

Reply to
Adrian C

It's like Brasso, but for silver.

Owain

Reply to
Owain

I don't recall ever needing to perform this trick on the same set twice and, despite the wear such contacts get over time, the Silvo never succeeded in removing the silver plating.

Of course, if somebody decides to use Brasso instead, all bets are off!

Incidentally, the sets we had the worst problems with were Bush. All other manufacturers used 13 channel turrets and variants thereof and it was usually possible to get to all the contacts, both fixed and moving, with a little dismantling.

Bush used an incremental tuning system with a band switch to select Band I and Band III. These had standard wafer switch contacts in the form of two fixed fingers, which gripped a sliding contact that performed the switching action. Therefore, all the contact surfaces were hidden on the underside and only the top surface of the sliding contact was partially accessible.

Reply to
Terry Casey

This:

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it doesn't seem so easy to find in liquid form these days and wadding is obviously of no use at all.

This:

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similar and may be easier to find - just take a look on the supermarket shelves.

On the other hand, one can of Silvo would probably last you a couple of hundred years so instead, why not ask around and see if anybody's got a can languishing away in a cupboard somewhere that you could borrow - you won't need much!

Reply to
Terry Casey

my fruitless search for Arcam spares...

Hmmmmm.

Reply to
Huge

audio jumble. (An Arcam Alpha 10 sells for well over £300 on eBay. That's a lot of money, in my book.) The only issue is, what to buy? Perhaps the Quad lineup I fancied in my youth?

Reply to
Huge

...for the younger generation who are incapable of getting out of their armchairs ;)

Reply to
Lobster

Precisely. :o)

Reply to
Huge

Quad 303 is relative crap, also 405..tested both.

Quad lost it when they moved away from valves,.. its built well, but the actual sound is nowhere near as good.

You probably want to go for a specialist brand in the post 1980 period: MOST of the issues of slow transistors and high crossover distortion were solved by then.

Technics and Sony are both surprisingly good, and Yamaha.

But my money would be on a specialist small UK firm..

Reply to
The Natural Philosopher

Oh. Expensive, too.

Mine also.

As long as they keep a reasonable stock of spare parts.

Reply to
Huge

I've no complaints about my Mission Cyrus. Built like a brick outhouse, still sounds good 21 years after I bought it. If I were buying a new amp I'd buy a Cyrus Cyrus 6[1]. If I had the thick end of a grand to spend on one that is.

If you want something to fill a gap and not crackle a s/h Cyrus One would cost about £25.

[1] A bit confusing now the company has changed its name to Cyrus. Is it a Cyrus 6 or a Cyrus Cyrus 6?
Reply to
Steve Firth

Would you be able to identify a good to spec one, 303 say, in a blind listening test?...

The 33 wasn't up to much..

Audiolab were and still are good...

Reply to
tony sayer

Theres a switch cleaner called "Servisol" we us in our workshop. I've never known it Not to work, tried that once?..

Just a thought .. you haven't somewhere perhaps got excessive DC leakage somewhere that can cause very noisy pots and sometimes switches?..

Reply to
tony sayer

Reply to
Huge

Might be difficult to know exactly without a manual, but it can and does happen. However I expect that the makers would be aware of that if it were a problem in that amp..

Does seem odd the way you describe it as a normal input switch isn't that complex in that its normally multiway from the input sockets to the input of the amp there shouldn't be anything during switching to develop a current that could cause noise if you see what I mean, unless your switching amp stages in and out so if you or anyone does have a manual be interesting to see..

Reply to
tony sayer

Of course he wouldn't. But more easy to tell it against a valve amp with their poor damping factor...

It's disc pre-amp was marginal on the high gain setting. Fine with higher output cartridges. Sadly most wanted the Shure V15 in those days.

Reply to
Dave Plowman (News)

303 had poor x-over distortion. Back then I COULD tell it apart from a good amp. There's a light edginess you can hear with X-over. Or a certain silkiness if its absent. What you need is low level complex harmonies..choirs or strings are good. If you can pick out each voice or instrument seperately, its a good amp for X-over.

Dunno if the lugholes are up to it these days.

valves better on X-over but worse on freq response, overall high power distortion and as you say, damping. However the ears are more tolerant of that.

What I designed in the 70s was better than both, but never went into production. That format of circuit was used widely in Jap amps in the 80s.

I don't know what went on inside the UK independents, but by then it was possible to get some really good power devices that made the job a lot simpler of getting almost undetectable (with instruments) X-over distortion and general harmonic distortion right down into the noise floor.

I was quite proud of mine, Got within about 3dB of ultimate thermal noise limits.

What I am saying is that by the time I left audio design in 1981, it was possible to make an amp better than ears could tell them apart, if you bothered to do it right. And it wasn't actually that hard to do it. For me there was no money and no challenge left, so I went software instead.

I think that's when the complete and utter bullshit of audio took over, there being no other way to differentiate between upper level kit. Whiter than white etc.

But 70's kit was a compromise. Either valves with their issues, or inadequate transistors with theirs.

Reply to
The Natural Philosopher

I think you'll find there was a "sort of" MK1 303 and a MK2 all to do with the biasing. In the earlier unit they used an arrangement of Four diodes of which they had a wide spread of values and could not set the bias as consistently as it ought. Later versions had a transistor and pot adjuster and that was better. I had the wife's 303 in here a while ago to change the caps etc and the bias was quite critical in its setting Distortion was very low with no visible residual on the scope all in the noise..

Yes time .. canna do much about that;!..

Reply to
tony sayer

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