What are these capacitors?

[Smoothfingers]

Friends I am refurbishing a 1969 Drip edge Princeton. There are these Brownish/Orange caps (picture attached). Are they Spragues? Mallories? Are they sought after? Thanks

[martin manning]

Not sure there is any consensus as to who manufactured those. They appeared with the silver face cosmetics. Nothing wrong with them, in spite of the derogatory name by which they have become known.

[Smoothfingers]

Thanks, Yea odd. I am replacing the can cap (it exploded) and the white Mallories. Ive seen the Dark blue odd shaped ones that are nicknamed (Turds) I think. And of course the nice Blue Mallories everyone wants. But I have not seen Orangish Brown. I was wondering if they are vintage Orange drops that have just discoloured through the years. thanks for the reply.

[nuke]

Ditto what Martin said, not sure who made those, they're common in the silver face era along with the blue Paktron. They are nearly always fine. I don't recall ever needing to replace them. Some call 'em kitty-turds. But as capacitors, they're generally fine.

[Smitty]

I have several Twin Reverbs. Because I had two 1968s assembled just months apart--one with blue Molded Mallory and one with ITW Paktron brown--I fussed with them until they were exact except for those capacitors. One plate resistor had drifted out of spec and was replaced. Tube test and measurement took the longest (four hours), but I was able to control for everything and experiment with only the signal caps. What I found is that the two amps sounded just very slightly different with the controls set exactly the same. After tweaking the Treble and Mid ever so slightly I could detect no difference between the amps. I used a Weber amp switcher on the output and a mechanical A/B pedal on the input to ensure proper testing.

After the experiment I couldn't get those old white Mallory cathode bypass caps out the amps fast enough. They're all terrible.
After replacing them with NOS Sprague 30D caps I could detect no difference between the two amps with the controls set almost identically and they now sounded clear as a bell.

I've measured these brown caps with inductance and capacitance meters and found them to be very similar to Sprague 6PS series caps in terms of quality.

There is some internet chatter that the brown coating is not as impervious to moisture over time as other types of capacitors. I have not encountered this. Once the polyester dielectric absorbs enough moisture it can pass enough DC to shift the bias point. Measure the grid pins on the tube sockets with the amp on and the tubes out to find leaky coupling caps.

Hope this helps.

[Smoothfingers]

I googled ITW Paktron Brown, you are absolutely correct!. Waiting for the new caps to replace the white Mallories then I am looking firward to hearing what the sound like. I wanted to make sure they dont have a bad reputation like the white mallories.

Thanks yiou for your advice!!
Chris

[R.G.]

[...] I am replacing the can cap (it exploded) [...]

You're probably all over this, but an exploded can cap could be a result of or the cause of damage to rectifiers, choke, or outputs - the other stuff in the power path.

[Smoothfingers]

Thanks I did go through it from input to output. I put the Hayseed Can Cap in it, supposed to be much higher quality then the CS. I have left the Mallories & Paktrons in for now. It sounds great very quiet. I included a before (purchased a year ago) and after refurbishment.
Thanks Chris

[martin manning]

Very nice work, looks almost new!

[Smitty]

Nice work. Great job cleaning up the drip edge.

[SoulFetish]

Thanks, Yea odd. I am replacing the can cap (it exploded) and the white Mallories. Ive seen the Dark blue odd shaped ones that are nicknamed (Turds) I think. And of course the nice Blue Mallories everyone wants. But I have not seen Orangish Brown. I was wondering if they are vintage Orange drops that have just discoloured through the years. thanks for the reply.

The "nice blue Mallories" aren't Mallories. They are Ajax capacitors, if you are talking about the molded blue tubular ones