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Posted
unsure.png Does anyone know if Lil Knight were active last week? I was buying a set of KGSSHV boards and the communication was great. My payment went through on July 5th, and I have not heard back from Tran since that. I know that Tran is no scammer whatsoever and I have no problem waiting, but It's quite frustrating to be left in the dark.
Posted

correct, and you will need 2 of them and they have to be 1kv rated reed relays.

Anything else sparks pretty nasty.

Any chance you could suggest one? Thank you.

Posted

stax definitely did not use reed relays. since i don't have one open at the moment i

can't pick the exact part they used. But they also used lower voltages too, so

if you were to use the stax relay at 450 vac, it might not behave so nice.

I use those sealed reed relays at work up to and including about 15kv.

(well different models, but the same thing) switching AC and switching DC.

work great.

Posted

The Stax amps use just a standard relay but the AC voltages are far lower. I'll check out the part number when I do final checks on this SRM-007tII I have here.

  • 1 month later...
Posted

I’m going to do some experimenting with the bias current. My 400mm 3U Modushop heatsinks are running cold with the A1968’s . I assume the only change out is the 1.2k resistors for the current source? I don’t want to go too nuts, just enough for some get some heat happening. How to do I go about working this out?

Posted

Please do report your results, John. I'll be very interested in seeing if how high you can crank her and if you can hear a difference.

Posted

Please do report your results, John. I'll be very interested in seeing if how high you can crank her and if you can hear a difference.

I shall, I don’t want to push her sky high, just enough to justify these big sinks.

I’m going to do some experimenting with the bias current. My 400mm 3U Modushop heatsinks are running cold with the A1968’s . I assume the only change out is the 1.2k resistors for the current source? I don’t want to go too nuts, just enough for some get some heat happening. How to do I go about working this out?

Well for starters I’m not using 1.2k resistors, I’m using 500R for the A1968 current source, I really should pay attention.

In regards to increasing current I assume the 500R’s are to be replaced? Just after a little knowledge on how to derive mA values.

Posted

Thanks Kevin and Birgir, I really appreciate your help with this.

I've been digging around here and in the Headwize forums.

I can't find a formula for the final output in the fourth stage.

If a 2.1V LED yields ~ 4 x 5.5ma for 20 watts. How do I for example equate a 3.8V LED?

I just don't want to crap shoot this...

John

Posted

2.1v - vbe junction (.7) /180 ohms == 7ma.

But the led's actually are more like 1.7 volts due to

the drive current.

So its about 5.5ma.

You can change to a higher voltage led, but the red led's thermally

match the output transistors.

So you want to cut the 180 ohm resistors to something like 150 or 120 ohms.

Posted (edited)

So,

150 Ohms should give 6.60mA, and,

120 Ohms should give 8.25mA. Hopefully.

100 Ohms = 6.9mA

82 Ohms = 12.07mA

68 Ohms = 14.56mA

56 Ohms = 17.68mA

47 Ohms = 21.06mA

Edited by wink
Posted (edited)

Do a search in the T2 thread for "Dalbani". Buyer beware!

If they honor their 14 day return policy, one could dust off the trusty transistor tester and check for Vbr.

VCEO should test at 900V minimum if they are the real deal. If not, return them FAST!

Edited by livewire

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