nt2a circuit for repair
- Thread starter hooman
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Help Support GroupDIY Audio Forum:
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.
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.
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.
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
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
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
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
..isn't this pretty much like the later neumann tlm-series mics, impedance-balanced and all...?
Jakob E.
Jakob E.
Nice - thanks for sharing!
Jakob E.
Jakob E.
charlygrand2013
Member
Hi !!!, my name is charles, sorry to revive this tread, sorry about my english, i got a rode NT2a i found 4 bad capacitors y i need to find out the correct values of them, some one can help to me ? , i ve attached a pic of the board marking with a circle in red and green the caps that i want to replace, and i like to know the values y what tipe of smd cap are them. Tanks in advance.
Attachments
charlygrand2013
Member
Sorry, the problem of the mic is some cracling noise. y remove the caps market in green and red and cracling disapears, but now the is a constant wind noise, perhaps cos missing of theses caps ? tanks
charlygrand2013
Member
Thank you very much !!! fast response !!! a question what kind of cap did you use ? ceramic ? thanks in advance !!!
RuudNL
Well-known member
In the NT1 it is always the (SMD) capacitor for the polarisation voltage that fails.
Yes, ceramic - it's only filtering the tiniest of currents, with large-value resistors upstream of it, so there was no point in going with (physically much larger) film caps. And it's also kinda tight in there...
I still find it so odd that, ironically (?) enough, it's the FILM capacitor that fails, not the ceramic that's in parallel with it. Also odd that they parallelled the two kinds after the last series resistors...
zaraki1337
New member
Do i have to use smd component of similar physical appearance or can i use through hole?Yes, ceramic - it's only filtering the tiniest of currents, with large-value resistors upstream of it, so there was no point in going with (physically much larger) film caps. And it's also kinda tight in there...
I still find it so odd that, ironically (?) enough, it's the FILM capacitor that fails, not the ceramic that's in parallel with it. Also odd that they parallelled the two kinds after the last series resistors...
can i use this cap instead of those 4 smd capacitor?
btw i have windnoise problem
Attachments
You'll want a voltage rating of at least 100V. If you decide to use through-hole capacitors there, it might not be a bad idea to also glue them down somehow, so the solder joints (or rather, the glue between the copper and fiberglass of the circuit board) are not the only things mechanically supporting them.
zaraki1337
New member
should i change all or one by one?
zaraki1337
New member
yes
there is less noise in -10db
but there is still noise
there is less noise in -10db
but there is still noise
Then it's quite likely at least the film cap on the positive bias rail (that's always connected to the front diaphragm) is to blame. That's the one nearest to the yellow capsule wire.
And as i mentioned in one of my earlier posts here, i replaced that film cap with a ceramic one (there's another ceramic one there from the factory anyway), and that made all my noise issues go away.
And as i mentioned in one of my earlier posts here, i replaced that film cap with a ceramic one (there's another ceramic one there from the factory anyway), and that made all my noise issues go away.
