[time-nuts] Thunderbolt - Hardware Versions -Performance& Differenences

[Connie Marshall]

Okay, so where do we stand on this item. Are we in a holding patteren for a
while. I have heard and seen enough to know I don't want to pay $250 at this
point..... Hmmmmmmmmmm

Connie
K5CM

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]On
Behalf Of TheInfamousFlavio at hotmail.com
Sent: Saturday, February 17, 2007 11:13 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Thunderbolt - Hardware Versions -Performance&
Differenences


**That's a big problem if there is no power conditioning board. ** The DC-DC
converter is very expensive itself and there is A LOT of filtering before it
AND that's all after a DC input!!!  I saw somebody suggested a cheap
switching power supply as a power source, but that will not be sufficient.

There is a reason for an expensive DC-DC converter and all that filtering...
"Garbage in, Garbage out".   The precision of the circuitry, antenna, 10Mhz
and cpu all require a very clean and stable power source for good
performance.  Anyone who knows switching power supplies will know that they
are sensitive and noisy.  They are cheap and small but not good  enough to
feed directly into the processor board.  The DC-DC stabilizes the input
signal, switching power supplies, especially the cheap ones, are extremely
sensitive the power anomalies on the input side and load variation on the
output side (like the OCXO oven turning on and off).

Take a look at the Z3801A's power conditioning board, that's after the dc
input! Take look at all the conditioning that the other Thunderbolt board on
ebay has on it (which is more than a regular Thunderbolt too).  There is a
reason for that...clean and stable power to all the components.

That's why the industrial versions of the Thunderbolts like the Z3801A clone
have more filtering and higher quality parts then your standard Thunderbolt.
.the cleaner the power, the better the performance i.e. "Garbage in,
garbage out".

I just feel sorry for that person  who has already bid on the one for $250.

After realizing the whole power conditioning board is gone, the price I'm
willing to pay has gone down to $50-$75 even with the splitter and pretty
cables.


----- Original Message -----
From: "Didier Juges" <didier at cox.net>
To: "Discussion of precise time and frequency measurement"
<time-nuts at febo.com>
Sent: Saturday, February 17, 2007 11:51
Subject: Re: [time-nuts] Thunderbolt - Hardware Versions - Performance&
Differenences


> TheInfamousFlavio at hotmail.com wrote:
>> I saw the vendor put up new pictures of the "Thunderbolt" that he has
>> hundreds of up in his auction .  The pictures aren't very clear but it
>> looks
>> as though HALF of the "Thunderbolt" is missing.   There doesn't seem to
>> be
>> any power conditioning board.  Am I wrong about this?
>>
>>
>>
>
> I believe you are correct. Someone stated there was no DC/DC converter
> board, so you need to provide +5 and +/-12.
>
> The Thunderbolt data sheet is very confusing about power consumption. It
> states the unit needs about 10W, but lists the current draw as 300mA on
> the +5V and 25mA on the +/-12V. Where  is the oven power coming from? My
> Thunderbolt with DC/DC converter draws about 400mA from +24V, so the 10W
> stabilized sounds about right.
>
> I wish the pictures were clearer, and that there were a picture of the
> front of the unit. It's hard to believe the seller has 100's of those
> units which he tries to sell for $250 or more, and can't even afford to
> make a couple of decent pictures of what he sells.
>
> I am not sure what is the device that looks like a coupler on the
> bottom, but it seems like you get a couple of cables with it.
>
> Didier KO4BB
>
>
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> time-nuts mailing list
> time-nuts at febo.com
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>


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