Author Topic: 10 MHz Everywhere!  (Read 6167 times)

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Online TheSteve

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Re: 10 MHz Everywhere!
« Reply #25 on: April 11, 2017, 05:38:49 pm »
I used a modified VDA previously and the output quality was crap. Obviously they vary in quality like everything else, the one I chose was clearly junk.
« Last Edit: April 12, 2017, 02:38:06 am by TheSteve »
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Offline Harb

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Re: 10 MHz Everywhere!
« Reply #26 on: April 12, 2017, 02:07:50 am »
I just use a big VDA....I think it has 100 or so outputs.....10 on each euro card.

One 'trap for young players' when you convert a 75 ohm Video Distribution Amp to 50 ohms is total load.  I use a VDA that uses an Analog Devices amplifier.  It can handle 8 75 ohm outputs but only 5 50 ohm outputs.  It's not a big problem because you can daisy chain multiple inputs together.  But it's something to keep in mind.

Ed

Yeah Mine had heaps and heaps of headroom so after the conversion it still drives all the outputs fine.......I don't use all of them though......I daisy chained all the cards together and just spread the load across all of them
 

Offline DaJMasta

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Re: 10 MHz Everywhere!
« Reply #27 on: April 12, 2017, 04:21:03 pm »
I've been considering a distribution amp for a bit now, but I stumbled on a ESE ES-247E for about $30 on ebay.  It's a 75 ohm 4x6 amp (4 banks of 6 outputs), but it's got the same form factor and look as their 50 ohm variant (which is several times the price on ebay).

Well I bought one and cracked it open - uses an OPA603 on each channel, with a 15 ohm series resistor to each of the 6 outputs, very simple design overall, and the input has two connectors, one for the signal and one for a terminator.  Waiting on a set of 4 50 ohm terminators and I'll see if the opamp can handle.... but the resistors are easy-access and the chips are even socketed if they're not up to the task.  Seems like a great little unit to try and convert over.
 


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