babadono

I found this in the "Duke" thread linked to in this thread and found it semi amusing: "Dean--- The level controls as configured need 8" of shielded cable, and they use socket connectors to plug into the board. Shielded cable + series resistance is always to be avoided." As a statement of fact as if every one knows level controls and shielded cables are bad. What utter non sense. Oh my gosh 8" of wire might add 0.001 ohms to the 47k input impedance, whatever will we do.

People back then just stood on their heads Glad to be of service.

We've got Lasik for the eyeballs, how come something can't be done about losing one's high frequency hearing?

Thinking about it they're probably grooves so it's not too slippery when wet?

Are some of those hexagonal on the backing upside down. i mean what's with the stripes on a few of them? Or is it just my monitor playing tricks on me?

Of course how silly of me An englishman publishing in an American Radio Magazine

Right in the middle of PWK's article there's a tube amp by Joseph Marshall. Is that the Marshall of Marshall Guitar amps?

Things were cleaned /tidy'd up before pictures were taken

You can see some of the travertine flooring here:

I was fortunate when I built I was introduced to Mustafa. He was/is the direct importer of travertine and marble from Turkey. His family back home owns some of the quarries. One of the subs we used always told us, you can have something man made or something God made. When we saw the travertine, we said to each other yea that's what we've been looking for.

The boards(amps) I'm working on are circa 1990, they are D75s, yours is perhaps a D75/45 A ? Looks like they have fixed the pin 1 grounding scheme (maybe). A picture will take a least until tomorrow IF I can remember to bring my camera. BTW I still see something labeled "1" going all over the place including to another point labeled "S" and then to a main trace that I'm guessing is signal ground. Here is the schematic I am working from. These older units have hardwired (by hand) connectors not soldered to the board directly. D75_J0116-4_original.pdf

Yea winter time is when I have time to do this kind of stuff.

Thanks John, I will try to duplicate your tests. The way I was/am currently doing it is just feeding a pulse generator set to 1Khz but with 100 nanosecond rise and fall times. This gets changed to a differential signal by an "OUTSMARTS" demo board from That Corp. I then feed this into the balanced inputs. I make the measurement at 20Vpp and do the math. I then increase to 40Vpp and making sure it tracks. Of course with an 8 ohm load on the outputs. @John Warren Edit: I test with the differential to single ended converter included because it adds 1 more op amp to the input circuit and because that is how I am going to use the amps.

How many do you use at one time?

All the travertine and marble tile in my house was about $18k, the labor about $24k. Round figures from memory.

bingo

Or get some black tape Are those fixtures really black or rubbed bronze? Tile to the ceiling?, heck tile the ceiling too.

Yes, replied to it directly.

@Marvel do you have something that shows all the mods he did?

Yea sorry about that. I posted before I thought about it. I guess perhaps I thought maybe you heard them side by side. At least that might be different than say the Duke one day and then an unmodified one two months later.

Also I forgot to mention on these D75s I am fixing the ridiculous grounding scheme of the XLR input pin 1. The as built by Crown connects pin 1(the shield ) directly to the signal ground. Classic and classically wrong. I wonder if the newer versions of this amp are sill the same?

Why do you say this? If the boosters can be re used it's a step forward.

Well they both had the same velocity upon separation and both returned to the same gravitational body so it would be hard for them not to be pretty damn close.

Mistakes? See my signature.

Yea but can you get to the Cornscala page for instance? I can't get there with Firefox or IE.