NOS Capacitors

[jestaudio]

I would like other peolples opinions on this but after a major amount of mods to my 36 watt build i ended up trying out some NOS mullard mustard caps in the preamp section plus a few tropicals on the cathode bypass of v1b and v2a, all i can say is what a diference, its took the fizzy edge out of the amps drive channel, maybe its just me but what the hell ,i pleased with the result

[selloutrr]

Materials used make a huge difference. Those brands makes of capacitors are not sought after for sucking. The biggest problem with vintage capacitors is leaking. If the caps test good they are great!

[Reeltarded]

Those are certainly at home in that circuit.

I don't have experience with much else, but sometimes I am not sure I shouldn't try a bunch of others for a change, just not sure what. I always miss those threads.

[rp]

What selloutrr said - if you can find reliable ones. My feeling is the old caps don't have any magic just less transparent and that was simply a part of the voicing of those old circuits. Modern caps seem to have a clarity that shouldn't be there in a vinatge circuit and unfortunately brings along the fizzy and the hard brightness. Before we start beating a dead horse, I can't hear one cap but shotgun a whole amp and I sure do. Those tropical fish are poop but even there they may be masking things in a positive way.

NOS mustards seem as reliable as modern caps and have held up well. The old Amercian plastic molded ones are seriously hit or miss. You can waste a lot of money on them.

[selloutrr]

For the most part when you use components that were intended/ OEM parts in restoration or a build it makes for a very pleasing finished product.
Keep in mind the circuits were designed a tweaked using those same components. It's only natural for it to sound right.

[jestaudio]

What selloutrr said - if you can find reliable ones. My feeling is the old caps don't have any magic just less transparent and that was simply a part of the voicing of those old circuits. Modern caps seem to have a clarity that shouldn't be there in a vinatge circuit and unfortunately brings along the fizzy and the hard brightness. Before we start beating a dead horse, I can't hear one cap but shotgun a whole amp and I sure do. Those tropical fish are poop but even there they may be masking things in a positive way.

NOS mustards seem as reliable as modern caps and have held up well. The old Amercian plastic molded ones are seriously hit or miss. You can waste a lot of money on them.

Got to say the tropicals seem to allow a bit more gain without the hoorible top end than the electrolytics i was using originally

[Aurora]

NOS film capacitors, - polyester, polypropylene etc - in practice orange drops, fish, etc should be OK even after decades. One rarely sees these fail in vintage stuff. It's the NOS PIOs, electrolytics and stuff like that that's usually the problem. I don't do much guitar amps, more vintage radios, transmitters etc, where the problems are really the same.
Mustards, fish and drops are usually polyester, and some polyprop's, so these are usually OK, albeit sometimes with a slight change in value. Remember these are mostly 10-20% tolerance.

[rp]

Got to say the tropicals seem to allow a bit more gain without the hoorible top end than the electrolytics i was using originally

As cathode bypass then? They might be off or on spec relative to the electrolytics you had and that would account for the gain. Likely the electrolytic is off and the film on. As a coupling cap the old mylar chicklet types are pretty blah I found.

I've opened old Blues, Black Spragues and Red Tiny Chiefs, CDE Blacks and Greenies and they are film and foil, vacuum molded, I've never been able to unwind them, just to chip and hack at them. They look a lot like modern caps and seem durable as hell but they actually drift and leak a lot when tested. I've never found paper inside the molded ones, just the nasty really old waxed ones.

I assume the little mustards are metalized film? If they're film and foil too why are they so much smaller than the equivalent American molded of the same era?

[diagrammatiks]

the mustards and sprague 196p's are difilm.

it was an intermediary step between paper, polyester and widespread polypropylene use.

the film is a paper/polyester blend.

Each of the different companies had their own unique recipe that they produced.

[rp]

As we are praising old caps, here's some really pretty ones :

image saved off ebay

[diagrammatiks]

I got some of those...those dry out pretty badly.

[jestaudio]

Got to say the tropicals seem to allow a bit more gain without the hoorible top end than the electrolytics i was using originally

As cathode bypass then? They might be off or on spec relative to the electrolytics you had and that would account for the gain. Likely the electrolytic is off and the film on. As a coupling cap the old mylar chicklet types are pretty blah I found.

I've opened old Blues, Black Spragues and Red Tiny Chiefs, CDE Blacks and Greenies and they are film and foil, vacuum molded, I've never been able to unwind them, just to chip and hack at them. They look a lot like modern caps and seem durable as hell but they actually drift and leak a lot when tested. I've never found paper inside the molded ones, just the nasty really old waxed ones.

I assume the little mustards are metalized film? If they're film and foil too why are they so much smaller than the equivalent American molded of the same era?

Suprisingly the tropicals are bang on the values which considering they were pulled from a knackered simms amp is pretty good, the elctrlytics were modern offerings and within 10 % but sound different

[Reeltarded]

As we are praising old caps, here's some really pretty ones :

image saved off ebay

Fuses on both ends? We can only have sparklers here.. legally.

[tubeswell]

I use the mustards quite often. I like 'em.

[rdjones]

A small amount of leakage could probably be tolerated at the cathode bypass position.
For tone caps and particularly couplers leakage would be unacceptable.

rd