Tube DIY Asylum

Re: How to design a passive single-network RIAA (two tubes)

208.29.72.73

[ Follow Ups ] [ Post Followup ] [ Thread: Display Email ] [ Tube DIY Asylum ] [ FAQ ]

(A)

In Reply to: Re: How to design a passive single-network RIAA (two tubes) posted by Chris O on March 25, 2002 at 06:38:45:

Hi Chris
my verion of SRPP z-out formula with both sections identical and top tube designated as having RK1:
Zout= 1/gm*(mu*(Rk+1/gm)/Rk1)) - hope that's correct - its easy to use dos version of ECAP to get Zout, gain etc for a tube circuit using FET model then placing plate resistance (rp) across it to emulate a triode (or pentode) - just draw a schematic then number nodes, and give values to resistors, etc
sometimes a bit more gain can be squeaked by having RIAA eq's ~1Meg grid resistor preceed caps but overload of 2nd stage might be an issue at times (?) - I'm outta practice with tubes - anyone here using lumped RIAA phono with grid resistor up front?
Freddy

Follow Ups:

Re: How to design a passive single-network RIAA (two tubes) - Kurt Strain 10:54:54 03/25/02 (1)
Zout= 1/gm*(mu*(Rk+1/gm)/Rk1))
Something's wrong with that. I get a 6922 tube to give Zout = 2.4 ohms with Rk = Rk1 = 1K. That's much too low.
Kurt
- Re: How to design a passive - botched equation - White CF? - freddyi 11:41:58 03/25/02 (0)
  my fault Kurt
  sure didn't get it writtren right :~( - even a White-cathode follower won't quite do that - ever hear a Tube-God NB-1? - had one of first - used 6DJ8 cascodes, passive RIAA with 6DJ8 White CF - actually sounded pretty good on Magnepans resolving massed voices
  Freddy

This post is made possible by the generous support of people like you and our sponsors:

Schiit Audio

You can not post to an archived thread.