hooman

nt2a circuit for repair
« on: July 26, 2019, 08:27:38 AM »
hi
 someone send me rode nt2a for repair ...... noise problem ::). rode used prefect  circuit in nt2a.


hooman

Re: nt2a circuit for repair
« Reply #1 on: July 26, 2019, 09:30:13 AM »
as we know nt2a is multi patterns.first transistor   is smd n channel j  fet . cod is 450 but no data in net .  best choice is j111 from on or sst111 from vishay .left leg is ...s...  if see 5 v  to 5.5 v in d of j fet ...meens this part of circuit is ok .most of time noise comes from caps .chang and clean  pcb after soldering . complementary feedback pair (CFP) by adding a PNP transistor in the drain circuit of jfet.rode make good sound for record by choice this  perfect circuit . some   n and p  transistor with jfet in frontend .feed back for reduce noise.

Re: nt2a circuit for repair
« Reply #2 on: July 26, 2019, 05:14:55 PM »
I'm not sure why you would call it "perfect circuit", however i do agree they make great microphones, way underrated.

Thanks for the schematic, but you could just try to contact them, they are often willing to replace the mics even years after warranty expiring.

hooman

Re: nt2a circuit for repair
« Reply #3 on: July 27, 2019, 10:29:41 AM »
 in tubes  circuits  ... one tube and  one transformer  this is all...quality   of output  sound depend to  tube and transformer quality.
but in fet circuit we can use  more active parts .some of them  control the dc and some   make feedback circuit  for reduce noise .

rode  nt2a   is  simple but  clever    design.they used  jfet in classic way and  control this jfet with  3 transistor for stable result and low noise  .very simple and good hpf switch   :D  nice class a amp in 22 v ..control for temperature  effect  in dc ....in output no transformer and simple xlr   .
rode company   in out of warranty should  repair   pcb by component level for customer.
or  replace  pcb.i don't know way they replace   mic  ? they need good technician :D

« Last Edit: July 27, 2019, 11:14:26 AM by hooman »

gyraf

Re: nt2a circuit for repair
« Reply #4 on: July 27, 2019, 11:10:29 AM »
..isn't this pretty much like the later neumann tlm-series mics, impedance-balanced and all...?

Jakob E.
..note to self: don't let Harman run your company..

hooman

Re: nt2a circuit for repair
« Reply #5 on: July 28, 2019, 09:39:25 AM »
yes same in output xlr but different in some items .

gyraf

Re: nt2a circuit for repair
« Reply #6 on: July 28, 2019, 11:41:46 AM »
Nice - thanks for sharing!

Jakob E.
..note to self: don't let Harman run your company..


 

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