Home SET Asylum

Single Ended Triodes (SETs), the ultimate tube lovers dream.

RE: Determining the size of inter-stage coupling cap

A little more,

the "AC impedance" (known as reactance) of the choke falls with frequency. A 1000Hy choke has a reactance of 6.3 meg ohms at 1000Hz but only 125k ohms at 20Hz.

The other issue is this, when you have a cap feeding a choke you have a 'tank circuit' and that LC tank circuit will have a low frequency resonance.

Depending on the DC resistance of the choke, to keep the resonance frequency below the audio band (and low in amplitude) it takes a rather large coupling cap (3uf to 10uf just as a ballpark number).

The BCP-16 GC has 3850 ohms of resistance and that's not enough to allow a "normal" sized coupling cap (.1uf to 1uf just as a ballpark number).

When the coupling cap is too small you can get an audible increase in the level of the low frequencies. Some use this to "tune" a system.

Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"


This post is made possible by the generous support of people like you and our sponsors:
  Signature Sound   [ Signature Sound Lounge ]


Follow Ups Full Thread
Follow Ups

FAQ

Post a Message!

Forgot Password?
Moniker (Username):
Password (Optional):
  Remember my Moniker & Password  (What's this?)    Eat Me
E-Mail (Optional):
Subject:
Message:   (Posts are subject to Content Rules)
Optional Link URL:
Optional Link Title:
Optional Image URL:
Upload Image:
E-mail Replies:  Automagically notify you when someone responds.