2N5485/2N5088/2N5089

[zpyder]

Interchangeable?

[Phorhas]

The first one is a FET, isn't it?

it won't be a dead-on replacment. although with some modifications you could stick a FET into a BJT's place - it'll have less output...

As far as the 88/89 - these are pretty much interchangeable

[markm]

2N5089 is a higher gain version of the 5088.

[theman]

yes, the 2n5089 is a higher gain version, but also lower noise. the collector emitter max voltage is 25V rather than 30V for the 2n5088. you can get all this info on the datasheet at faircild.com:

http://www.fairchildsemi.com/pf/2N/2N5088.html

[zpyder]

So a lower collector-emitter max voltage means lower noise?  Could you explain?  Is my guitar signal ever going to even approach 25 or 30 V???  How many questions can I ask?  Also, I noticed that the operating tempature range is -55 to +150 deg. Celsius.  I'll put a pot of water on the stove...........

[theman]

lower collector-emitter breakdown voltage doesn't necessarily mean lower noise, though they might be related depending on the doping profiles used for the n-p-n regions. your pure guitar signal will never be 25V. for bipolars, the signals are applied at the base of the npn, and usually taken off the collector for voltage gain, or off the emitter for unity gain (typical for buffering like in the ts808).  what it means is that you probably can't use too high of a supply voltage, but for most pedals, using a supply of 9V, 12V, 18V will probably be okay.