Lightspeed Attenuator a new passive preamp

[georgehifi]

Yes, see what you mean, looks very misleading, as the Electro Optical Characteristics say that with the max led current of 40ma you should get an on resistance of 1.5ohm and then the off resistance is 10megohm.
Then the chart shows it different the lowest being again 40ma led current but the resistance is only at best 60ohm.
Can't trust anything from Asia. It's all double Dutch to me.
Stick with Silonex.
ActuallyPerkin Elmer HQ is American , can't trust those Yanks either.

Cheers George

[EUVL]

There are a few errors on the datasheet for the VTL5C3.
The 1.5 ohm should be 1.5k instead.

Pity, I would have wanted to use the 5C3 as well because it is of material type 3.

So the next best thing as far as I can tell is VTL5C2, material type 0.

George, I thought Silonex was also Yanks ?

: )


Patrick

[georgehifi]

Nuh, Silonex is Canadian, and yes the next best in Perkin would be the VTL5C2 but that 200Ohm min is a worry for having a quite min volume.
Wouldn't it be nice if the VTL5C3/2 (a dual in one package with one led, wow!!) had a min of around 50ohm instead of 700ohm, NO BLOODY MATCHING, but you could use it as your not worried about min volume from previous a post.

Cheers George

[EUVL]

I need for each channel a single LDR with 200ohm min., so either VTL5C2 or Silonex.

Sorry, of course Silonex is Canadian.
Allied is American, but I know you don't trust them either.

: )


Patrick

[serengetiplains]

PE's optoelectronics office is in Canada, so their devices might be Canadian made, cough.

I did notice that my test results match the data given on the resistance/current graph.

[Badge]

I have a commercial account with Allied and would be willing to purchase a quantity and ship them to Europe. Here are the limits. I would only do one bulk purchase and one shipment. Those wanting the units would be responsible for coordinating the amount, payment and distribution once they get to the designee. I just have to many irons in the fire at this time to coordinate and do the distribution myself.

[Lostcause]

OK...so another Lurker jumps in to join the group buy....how do you do one of those voting threads to determine the numbers?
Thanks for the offer Badge.

Cheers

Lee

[Panelhead]

George,
Did you try other options for suppling the power? I have an unused battery pack with +13 volts to power it with if this really is an improvement. Will need to add a switch and not run 24/7 like the wallwart.
I am shut down for right now, my inlaws are here for a while. Hope to start building again after first of the year. Got some nice projects yet to finish and others to start.
This project was one of the big surprises this year. Low expectations, high return on time and money spent to build.
I agree on the LDR's. sorted versus sorted. If the unsorted are spec'ed with a letter like the sorted, these will end up being the same as sorted. The range on mine was very large and these were sorted all with the same letter for current. But it allowed for several circuits to be built, just closer matching was used for the series and shunt elements so that channel tracking was maintained. I was less concerned about resistance matching of series vs shunt tapers. This made it easier, just needing to match two pairs exactly and not a quad for a stereo SE attenuator.
I matched up quads for my balanced version, but never installed in my differential input line stage. Another one for next year.

George

[serengetiplains]

I heard back from Perkins Elmer who admitted the 1.5 ohms specification on the VTL-5C3 was a typo .... should be 1.5K ohms.

[pinkmouse]

If this is a serious attempt at a group buy, I'll set up a wiki, as I might well be interested in a few.