Joining turret lugs

[Jarvini]

Begs the question why would it be made ? If there was absolutely no difference or benefit then no one would buy it? as for jewellery never worn it never will and if I did it wouldn't be 10ft of 18awg plate

[eschertron]

Begs the question why would it be made ? If there was absolutely no difference or benefit then no one would buy it? as for jewellery never worn it never will and if I did it wouldn't be 10ft of 18awg plate

Back in the 70s handmade jewelry was all the rage amongst my friends. Beads on silver plated wired would be the norm for the hypo-allergenic crowd.

I'm not sure if the wire you purchased was advertised for its electrical properties, but there's another crowd (besides jewelry aficionados) that will eat up any hint of mojo for things even remotely related to the audio world. And unscrupulous resellers that'll buy those remotely-related things and market them to any phool who'll buy.

[eschertron]

I thought maybe I could get a clue about the wire's intended use by the package in the picture. Unfortunately, the "Daubert Cromwell" bag the wire came in is merely a protective package, made by a third party, there's no link to the OEM of the wire.

edit: D'oh! Now I see the Weico reference. And the tinned copper is less than a third of the price. Not sure how that shakes out for small quantities, with shipping.

[Leo_Gnardo]

I'm not sure if the wire you purchased was advertised for its electrical properties, but there's another crowd (besides jewelry aficionados) that will eat up any hint of mojo for things even remotely related to the audio world. And unscrupulous resellers that'll buy those remotely-related things and market them to any phool who'll buy.

A serious dyed-in-the-wool audiophool would hold out for five-nines pure silver wire, "plated" would be frowned on as being declasse'. After all silver is the metal with the best conductive properties. And of course the Manhattan Project used miles of silver wire to create the electromagnets they used to separate fissile uranium from plain old ordinary everyday uranium. It's the stuff of legend! That's what you want in your amp!

[eschertron]

A serious dyed-in-the-wool audiophool would hold out for five-nines pure silver wire, "plated" would be frowned on as being declasse'. After all silver is the metal with the best conductive properties. And of course the Manhattan Project used miles of silver wire to create the electromagnets they used to separate fissile uranium from plain old ordinary everyday uranium. It's the stuff of legend! That's what you want in your amp!

I remember reading about the requisition process for that silver. Engineers ask for XX tons of silver, the mint reps respond with "how many troy ounces is that?"

[Leo_Gnardo]

I remember reading about the requisition process for that silver. Engineers ask for XX tons of silver, the mint reps respond with "how many troy ounces is that?"

Just the kind of question engineers love to answer. Break out the slide rule! Train cars loaded with silver bars, imagine that. They got all they needed too. And the mint got it all back when they were done. Good ol' fashioned accountability. Couldn't do that these days, I don't think the gummint stores much silver for coinage anymore.

[Chuck H]

I don't think the gummint stores much silver for coinage anymore.

With copper increasing in value they don't make pennies out of that anymore either. They're copper plated.

No one's come right out and said it (though some got close) but the silver plated copper wire is probably made almost exclusively for the audio amplifier industry. Someone that knows how much pseudo tech is bandied around in the genre decided (probably correctly) that since it's easy to plate copper with silver there might be a $h!t ton of profit on such a product.

There's nothing wrong with it. There's just no special property for any purpose that wire has as a result of it's plating other than marketability.

[Enzo]

Begs the question why would it be made ? If there was absolutely no difference or benefit then no one would buy it?

Jarvini, we already answered that. I never said there was NO difference or benefit. What I did say was the difference you proposed - reduced conductivity of the wire - was not the reason for it.

Others have suggested that silver plating offers no benefit IN GUITAR AMPS. That it might be used in jewelry is one benefit of the stuff, lots of people still do wear jewelry. And in the hifi audio world all sorts of silly things are used.

Synthesizer keyboards these days use carbonized rubber contacts on copper pads for the key contacts, but some years back, silver plated wires (And also gold plated wires) were commonly used as key contacts in electronic pianos and synths. The silver oxidation is still conductive and so extends the contact life.

And if my ever dimming memory serves me, old Maestro units and Farfisa organs used silvered wire contacts for patch switches.

[Jarvini]

Overpriced shiny pointless wire aside I have one last thing to buy for the amp the power transformer in the book it recommends a power transformer with the following specs:-
240v primary
310-0-310 To 330-0-330 secondary (centre tapped)
Rated for at least 70mA -80mA
6.3v AC centre tapped filament supply @4A
5.0v AC rectifier filament supply @ 3.0A
After some searching I just want to know if the attached would be correct ? It was noted on an earlier thread that the filament amperage was too high and I could get away with less !!
Also they make a 100mA version which according to the data will run cooler ??

[Jarvini]

So basically I've fallen for the hype and spent more than I needed to but no harm in using it now I've got it I suppose?

[eschertron]

... I have one last thing to buy for the amp the power transformer in the book it recommends a power transformer with the following specs:-
240v primary
310-0-310 To 330-0-330 secondary (centre tapped)
Rated for at least 70mA -80mA
6.3v AC centre tapped filament supply @4A
5.0v AC rectifier filament supply @ 3.0A
After some searching I just want to know if the attached would be correct ? It was noted on an earlier thread that the filament amperage was too high and I could get away with less !!
Also they make a 100mA version which according to the data will run cooler ??

Add up the heater current requirements for the tube complement you will use. For example, I know that a dual triode 12A_7 will consume 300mA (0.3A) at 6.3 Volts. The power tube current reqs I haven't memorized yet I don't see mention of what amp you are building, so simply list out the tubes, note which are 6.3V heaters, add up the current demands. Note if there's a rectifier tube that may need 5V; I suspect so. Use the numbers that you derive to spec the PT. The one you suggest may well be fine for the job.

edit: IIRC, Classictone targets specific amp designs with their trannys. If your build is a clone of an existing design - that matches the suggested use by Classictone for the PT - then you are OK with their recommendation. If your build is not an exact replica, you may need to do the math in order to be sure.

[Jarvini]

It's the dave hunter two stroke (the single power tube version) you can use either a 6l6 a 6v6 or an el34
6l6 = 900mA
6v6 = 450mA
El34 = 1.5A

So if I'm right the highest would be the el34 and 12ax7 together meaning a max total of 1.8 Amps so the 2.25A that the transformer supplies should be plenty ? The amp is basically a hot rodded princeton I think and the classictone transformer is a for a princeton
Thanks for your help I appreciate it

[eschertron]

Only one 12AX7? Even two preamp tubes would be under the spec. I think you're OK. Did the recommendation for 4A @ 6.3VAC come from the designer? Seems excessive.

[Jarvini]

It uses a 5y3 rectifier one of the 3 power tubes (6l6 6v6 el34) and a single 12ax7 it also says that you can swap the 12ax7 for 12ay7 and after looking back at the text it also says a kt66 or a 6k6gt can be used
And yes the 4A 6.3 was the designers spec from the book
Not sure how much current the pilot lamp draws but I shouldn't imagine it would be 450mA !!

[Chuck H]

Maybe it's different for some, but most magnetics manufacturers rate secondary voltages at current. So, if you want exactly 6.3V on your tube filaments the secondary should be rated for the exact current the tubes will draw. Not critical however. You can drag it down a little or over rate a little and it's honestly ok. But drag it down a lot and you can get excessive heat and below spec filaments. Over rate too much and you get above spec filaments. Anything out of spec is a detriment to tube life and higher is a little worse than lower IIRC. A filament secondary rated at 2.25A seems fine for your project.

The mistake I made early on was that over rated is "better" by default. But WRT transformer secondaries that's not exactly the case. Sure, we want the amp to run cool and have leeway in the part specifications. But we also want (very much) to be within voltage specs for the tube filaments. Several of my amps are now loading the filament winding with low value resistance to drag the filament voltage into spec. Energy wasted as heat in an added pair of resistors. So, just to reiterate, the filament winding current spec is NOT typically what the max current through the winding can be, but the current at which the specified voltage is present.

HTH