[time-nuts] Distribution amp - Use a video amp unit ?

Bruce Griffiths bruce.griffiths at xtra.co.nz
Mon Mar 26 06:05:15 UTC 2012


cfo wrote:
> On Mon, 26 Mar 2012 08:11:16 +1300, Bruce Griffiths wrote:
>
>    
>> Bruce Griffiths wrote:
>>      
>    
>> A circuit schematic for a current feedback triple with reasonably low
>> noise and distortion is attached.
>>
>> Bruce
>>      
> Thanx Bruce
>
> I'm an analog noob , so i have some questions.
>
> If i multiply that schematic by 8 , could i then just add the Tbolt input
> at all V1's ?
>
>    
The input capacitance may be a little high, however one could 
approximately compensate for it in a narrow band application.
> Should R15 + C11 + C12 also be multiplied ?
>
>    
One RC decoupling circuit like this for each amplifier is advisable to 
reduce crosstalk.

> Is V2 a 12v supply (i suppose so) ?
>    
Yes the schematic was taken from an LTSpice simulation.
> Could i replace the 2N3904 with BC850LT1 (smd) , and the 2N3906 with
> BC856ALT1 (smd) , else i have some BC337/BC327 - TO92 (non smd)
>
>    
No, the input and output capacitances of those transistors are probably 
a little too high.

> Would one chan work on a perf-board with wires (proof of concept) , or
> would it be to "RF sensitive" ?
>
>    
Its usually better to construct it over a ground plane "rats nest" style.
A piece of unetched PCB works well.
> regards
> CFO
>
>
>    
Bruce





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