'Upgrading' resistors in eFP

[mikeyh]

Hi All,

Mixed feelings to the historic occasion for the wonderful FPIII. Oh well, we gotta move on .

Just a thought, has anyone 'upgrade' the resistors [or some of the values] on the C4S and Shunt boards? Like to Caddocks or Tantalums...
I understand the 22.1K metal films were in the signal path on the original FPIII, and it is taken out when installing the two C4S boards on the eFP.

Would it make any difference to the sound if replacing the resistors on the three boards, if any?

Just wondering...

Thanks.

Cheers,

Dean

[Grainger49]

Dean,

I don't know the values for E FP III but the R1 position on the C⁴S board is the place for an upgrade.  I was suggested using a THICK film metal film resistor.  IIRC Tantalums were discussed as well.  This was in relation to the Eros, but the same thing has to be applicable to the E FP III. 

Now to expose my ignorance.  I know the FP III circuit well but am not too familiar with the Extended circuit.  I have an old FP 2 and have put in both the VA plate load C⁴S and the CF cathode load C⁴S.  So I am extrapolating from this knowledge.

It is my supposition that if upgrading in the Eros, at the very low signal voltage there, is good it will also be good for the E FP III.

[mikeyh]

Hi Grainger49,

The R1 value in question is 237R 1/4W, and very difficult to get a value like that in the 'audiophile' parts. Any suggestions?

Thank you for the reply, really appreciate it.

Dean

[Grainger49]

There is a SHINKOH Tantalum  1/2 Watt 240 ohm available at Parts ConneXion:

http://www.partsconnexion.com/resistors_shinkoh_half_watt.html

I don't know if this is a thick film as recommended to me.  The three ohms difference will  probably not make a big difference.

Maybe Paul PB Birkeland will chime in?

[Paul Joppa]

+/-5% is fine for the C4S R1. What's most important is that it be a low noise resistor, and bulk metal or wirewound is best. Metal film is next, and the thicker the better. "thick film" often means metal oxise which is NOT GOOD for this application. Really good carbon film can be OK though not the most reliable, but stay away from carbon composition.