Starting my Wreck board and I have a question

[Blackburn]

Cool, Dave. Thanks for the info.

[lgehrig4]

Are you using original Mallory PVCs?

Yes

[lgehrig4]

For cap orientation, see here:
https://tubeamparchive.com/files/expres ... il_997.pdf

With respect to Miles' seemingly cheeky comment, I think there is true meaning there IMO:

If you want a copy of an Express that may or may not be truly brilliant, make a copy and nothing matters.

If you want an Express, pay attention to each detail, no matter how small, and everything matters.

People may scoff and say, p-shaw, it's just a modified Fender, but anyone who has built one and has really gotten it right, the difference is in those very minute details. It matters.

I'm all about the details! Thats the diagram I was referring to.

[lgehrig4]

The foil to ground matters less than the actual values of the resistors compared to their marked values, unless you are just looking at an open amp.

I've been measuring the resistors. All are close, but none were exact.

[Reeltarded]

Ehh.. i only measure resistors because it is easy to remember how to read a meter but I don't want to learn a language made of colored stripes. Even if you used identical everything, two amps would sound different and act different. They just do.

The only really special thing beyond the design of a TW is that Ken built it. They are folk art with electricty... or folklore. I haven't thought much about that part.

[randalp3000]

Don't be hatin' on me as I'm sure this is on the site somewhere.........

But how do you test a cap to determine outer foil orientation? scope or otherwise.

I have searched in the past.

thanks
rp

[Reeltarded]

For anyone finding this thread interesting:

http://www.aikenamps.com/OutsideFoil.htm

Put AC across the cap with a wire coil around the body of the cap. Try one way (ac polarity) then the other. The lowest ripple on the scope is the outer foil to ground.

Most mo.. some modern caps have a line on the outer end.

[randalp3000]

thanks much, I saw that a long time ago and could never find it again

[martin manning]

Most mo.. some modern caps have a line on the outer end.

But the line might not mean anything (the direction of the printing on the cap is random), so no conclusions about orientation can be drawn from photos unless there is an obvious hand-drawn line, and if this is important to you, you should test each cap yourself.

[Reeltarded]

Hear ya. Sozos tested correct everytime so I only tested one batch of like 70 caps. Uhhhg

[Colossal]

Most mo.. some modern caps have a line on the outer end.

But the line might not mean anything (the direction of the printing on the cap is random), so no conclusions about orientation can be drawn from photos unless there is an obvious hand-drawn line, and if this is important to you, you should test each cap yourself.

Martin this was my question about Mallory PVC regarding Redshark's observation that only two of the caps in the Express photoset match that of the cap orientation diagram we did. I have a pile of PVC for my builds but no longer have the sizable stash that I used to have. I'm wondering if the black bar printed on the PVC series was random or actually indicated the foil position.

[randalp3000]

For anyone finding this thread interesting:

http://www.aikenamps.com/OutsideFoil.htm

Put AC across the cap with a wire coil around the body of the cap. Try one way (ac polarity) then the other. The lowest ripple on the scope is the outer foil to ground.

Most mo.. some modern caps have a line on the outer end.

Figured it out after I finally got my scope set.

5 out of 5 Jupitor's had the line opposite the outer foil.
Mallory 150's are all over the place
Mojo Dijon's also all over the place

thanks again

[Reeltarded]

lol

Good deal, buddy.

[Blackburn]

Randal, now you need to acquire a good set of Mallory PVCs and do them.

I'm surprised about the Jupiters being labeled like that. Chris Young makes those caps out of his house and I always thought more care and attention to detail went into them, but that's pretty strange. I'll be sticking with Sozos.

[Blackburn]

Damnit. Double post.