rbaker

7602 input transformer change, cap value across secondary?
« on: February 20, 2008, 12:58:48 PM »
I'm changing out the chameleon 7602 transformers with carnhills.  I've read that I should put a 150-200pf polystyrene across the input transformer's secondary.

When I took out the chinese version from the 7602, it has a 1000pf.

Any idea why the change or what different it would make?


rascalseven

7602 input transformer change, cap value across secondary?
« Reply #1 on: February 20, 2008, 03:21:57 PM »
When using a Carnhill mic input use a 180pF polystyrene across the secondary.  If you're also swapping line input trafos, the Carnhill line input should have a 1500pF (1n5) polystyrene across the secondary.

I wouldn't concern yourself with what they're using with the stock iron.  Stick to the above values for Carnhill (or St.Ives or Marinair) components.

That should be a nice little box when you're done!

:thumb:

JC
"If you dig the gig, do it. -But listen to the signal, not the person talking."  -Keef

rbaker

7602 input transformer change, cap value across secondary?
« Reply #2 on: February 20, 2008, 07:06:14 PM »
Thanks Joel...

I actually changed the 2n3055's a long time ago (they use ST micro)

I bought some ON Semi's and some nos motorolas and spent a good amount of time listening to them.

They were close but I think I was able to pick the motorolas over the ON semis 80% of the time.  Both were definitely better than the ST in there.

I also just changed some of the electrolytics to tants

I believe the bc184c's they use are motorola.  Do you think it's still worth it to change them out?

Next I think I'm going to make a new front panel.  :)


 

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