Repairing an u87

[LevinGuitar]

If you don't trust Texas Instruments TI 2N3819 fets on sale (there are still old stock aviable and I believe they shouldn't be fakes), you could try a Motorola made ones, surely there aren't fakes and they all work pretty good in my experience.

 

[Ricardus]

If you don't trust Texas Instruments TI 2N3819 fets on sale (there are still old stock aviable and I believe they shouldn't be fakes), you could try a Motorola made ones, surely there aren't fakes and they all work pretty good in my experience.

I found some NOS motorola and they ALL test really close to one another, and a mic maker of some note told me that Neumann used Motorola in the 70s. No idea if it's true though.

 

[Ricardus]

^RE my last post, I've made a pair of KM84 clones and several FET847s with my NOS motorolas and they all work and sound amazing. I'm going to do two more of Dany's U87's with them next.

 

[Gus]

It wasn't a voltage or capsule problem. I had fake 2N3819s.. The microphone seems to work with a BF245 now.. BF245 is probably not a very good choice though..

Since I shouldn't comment on its frequency response, noise level etc., I am giving the microphone back to its owner.. We can later try other FETs. The capsule might also need cleaning or reskinning..

The BF245 is good it is the same as a 2n3819 look up the specs

 

[ZHOUJUN]

Please go ahead and check all electrolytic covers, where there are leaks, and resistors, I have repaired many U87s like this.