Where to put some Vishay z-Foil resistors in a 5e3

[The Guy]

So, i'm ordering some top notch resistors to try in a tweed deluxe and i would like to know what's the best place to put those super silent Vishay z-foil and also what's the best place to instal carbon comp resistors.

I plan tu use Vishay Z-Foil and cc's in specific places and the rest with carbon film resistors.

For those of you that don't know the z-foil's they are the most silent resistors in existence, and they apparently "sound" sort of super detailed and transparent, if such a thing exists. That's some of their biggest advantages. But mainly they are dead silent.

Thanks!

Guy

 

[SacDAve]

I think you have opened the door to one of those never ending debates. I built with all metal-film and one with all carbon-comp and a few with whatever was around of them all the one with Metal-film is lacking something just to sterile. Next one is going to be all Carbon-film

 

[The Guy]

@SacDAve I know... Can of worms right?

I only want to experiment a little and see if I can learn a thing or two.

I just need to know what is the best place to put those resistors. They are expensive and I don't want to use them everywhere.

 

[bparnell57]

Input tube stages. Only place to use carbon comp is on the output and possible phase inverter plate resistors. They will add noise there though, but they'll also exhibit their minor linearity discrepancies.

Kind of an oxymoron to put silent resistors in an amp that also has some carbon comps. You won't gain anything from the silent ones.

 

[JD0x0]

Here's my personal general rules for a quiet amp, as far as components.

-Mark and properly orient outer foil on caps. 'right' way shields the cap. 'Wrong' way can cause the shielding to act as an antennae for noise.

-Metal film on all plates (unless you are going for CC resistor distortion, in which case the phase inverter is the only place I'd use the CC on the plates, but even then benefits are minimal) MF are pretty much good all around, except their inductive properties can sometimes cause issues as grid stoppers. Some people complain of a 'cold' or sterile tone, but I haven't had issues, with the rest of the amp voiced properly, I actually tend to think they can add potential clarity.

-Wire wound for the dropping resistors in the power/filter supply (Note: these are very quiet resistors, but if used on input grids will act like RF antenna)

-Pay attention to lead dress to the tubes. Solder grid resistors as close to the tube as possible.

-The power filtering network is also to be looked at carefully. Not enough choke resistance and/or capacitance will cause insufficient filtering in the power section. Sometimes a choke is better for having a quiet amp, but it adds more weight and expense and can change the response of the amp.

-As far as gain stages, the earliest stages are most sensitive to the introduction of noise, so the earliest stages are most important to keep noise down.


This is the first I'm hearing about 'Z-foil' resistors. What are they? Metal film with an outer foil layer, like some caps have? They'd probably be good on the input plates.

 

[The Guy]

Here's my personal general rules for a quiet amp, as far as components.

-Mark and properly orient outer foil on caps. 'right' way shields the cap. 'Wrong' way can cause the shielding to act as an antennae for noise.

-Metal film on all plates (unless you are going for CC resistor distortion, in which case the phase inverter is the only place I'd use the CC on the plates, but even then benefits are minimal) MF are pretty much good all around, except their inductive properties can sometimes cause issues as grid stoppers. Some people complain of a 'cold' or sterile tone, but I haven't had issues, with the rest of the amp voiced properly, I actually tend to think they can add potential clarity.

-Wire wound for the dropping resistors in the power/filter supply (Note: these are very quiet resistors, but if used on input grids will act like RF antenna)

-Pay attention to lead dress to the tubes. Solder grid resistors as close to the tube as possible.

-The power filtering network is also to be looked at carefully. Not enough choke resistance and/or capacitance will cause insufficient filtering in the power section. Sometimes a choke is better for having a quiet amp, but it adds more weight and expense and can change the response of the amp.

-As far as gain stages, the earliest stages are most sensitive to the introduction of noise, so the earliest stages are most important to keep noise down.


This is the first I'm hearing about 'Z-foil' resistors. What are they? Metal film with an outer foil layer, like some caps have? They'd probably be good on the input plates.

They are very beautiful resistors (i know, sounds weird) I just want to have them in there somewhere... They are called the VAR series Z-Foil Vishay resistors.

(link removed)

 

[clintj]

After reading the datasheet, I'd say the input grid stoppers. They're only rated to 200V, so I'd shy away from them as plate load resistors for tubes. They only list values up to 100k, so that rules out the input grid leaks (another big noise source). They really look to be a bit snake oil and designed to appeal to audiophiles. We, as guitarists, intentionally seek to add some amount of harmonic distortion to color the guitar sound to make it pleasing to the ear.

If you use 1W metal foils for the input stage grid and plate circuits, you should drop enough noise that tube noise becomes significant. Want quieter still? Drop the grid stoppers to 10k or less, and add a capacitor to ground to adjust the input bandwidth back to stock.

 

[robrob]

The theory on throwing in some carbon comp resistors for a little mojo says to use them for the plate load resistor in the last stage that's outside the NFB loop. Inside the loop the NFB will kill it's hiss mojo. If there is no NFB loop use them for the driver or phase inverter plate loads.

 

[Ricky D.]

I built my Mission kit 5E3 with the ordinary caps and resistors that Mission supplied. Nothing special. No carbon comp, no carbon film, no metal foil. The amp sounds great and is silent with the controls on 12 as long as my Tele is pointed in the right direction. Am I missing something here?

I have no idea why it turned out this way.