Siemens stacked film caps

[Panelhead]

While digging around the local surplus shops I picked up some rectagular stacked "film" caps. These have conductive metal end caps. There is a stiff lead on each end.
All three stores have these. They range from 0.1 ufd to 2 ufd. With voltage ratings up to 400v. Most are not branded, some are coated all over, and the 2 ufd 100v ones are coated on the conductive ends.
These were picked up to bypass decoupling caps, but the larger ones look interesting for use as a coupling cap.
Are these good quality parts for either decoupling or coupling in solid state gear?

George

[cocolino]

Hi George,

do You mean this ones?
If so, I wouldn`t recommend for coupling in audio applications.
IMO any cheap MKP type is better than those Siemens MKT`s.
The only advantage they have is that they are small in size compared to other types.

I cannot comment about decoupling.

[Panelhead]

Thanks Christoph!

What is the dielectric of these? I bought them for bypassing some elctrolytics used for chip decoupling.
The idea of using them for coupling was something I thought of after finding some 2 ufd ones. They look cheap, but I had hoped they might have good electrical properties.

George

[JOE DIRT®]

I think they would be fine for power supply decoupling...they look like a solid cap to me

[cocolino]

What is the dielectric of these?

It`s called (sit down now): Polyäthylenterephthalat
That`s what I found in the catalog from where I usually buy my parts. They are listed under MKT foil caps.

The idea of using them for coupling was something I thought of after finding some 2 ufd ones. They look cheap, but I had hoped they might have good electrical properties.

BTW: actually the bigger values are not sooo cheap anymore - for the price You can get a decent MKP already.

I have also some of this 2µF (to be exactly they are 2,2µF) but I don`t use them for coupling in audio.
Maybe the overly small size and the dielectric (other types of MKT`s of same voltage rating and value are much bigger usually, not to speak from MKP`s....) have something to do with it - I really don`t know.
I never measured one regarding dissipation factor.