Tantalum Capacitors in Signal Path

[schnullimaus]

Hi,

there is a lot of dicsussion on capacitors
anyway, but i've a special question:

Despite their bad reputation i've found tantalums
in the audio signal path of comercial products
from time to time.

My examples are :

Thorens PPA 990 :MC pre-pre-amp: tantalum as coupling
capacitor between discrete transistor stages

Marantz 2325 : Tantalum as input coupling capacitor in Phono
MM preamp

DENON POA800 : Tantalum in the inverter for bridge mode

You might have more examples. I admit, at least the Thorens
and the Marantz are somewhat vintage...not shure about the age
of the DENON design.

So if there are designers designing devices with say 50 +
electrolyts, and deciding to throw in a tanatlum at only one
out of 50 positions, i assume they have good reasons to do so !?
Most likely it is not the costs.

So are there any situations where a tantalum beats a standard
aluminium (or whatever) electrolyt?

My examples 1 and 2 could lead to the assumption, that a
tantalum is better, when there are yery low signal levels
together with relative high DC to block? Can someone
confirm ? Other Ideas?

Probably, nowaday's electolyts are better than those from
30 Years ago, so a tantalum would have been a valid choice
then but not today?

What would you recommend? Leave them in place, replace
against a new tantalum, replace against a regular low-ESR
electrolyt ? (Pleas no not suggest replace against foil etc,
I know, these are better then electolyts, but those foils
won't always fit)

Thanks a lot in advance for your valued comments,

regards,

Stephan

[AndrewT]

Hi,
I have never put a tantalum in the signal path because everyone else told me not to.
I did have a power amp that had a tant in the feedback path. I took it out and replaced it with back to back electro //foil. this sounded better but I had extra capacitance as well so it was apples and pears.

[jcx]

tantalum electros have more measureable distortion than Al electros, they don't dry out though so replacing them isn't functionally necessary if they're not blown

lower audio distortion is found in bipolar Al electros with a full thickness oxide layer on both foils - higher voltage ratings are better as well

but even mylar should be a step up from any electro and you might be able to fit them in some cases

[renes3]

It depends on how you use the tantalum capacitors. My idea is not to put them in the signal path, but if they are there and not blown, you could leave them were they are. My cd player is modified with only tantalum as decoupling capacitor troughout the whole pcb, and it is sounds darn good.

René

[jcx]

modern solid polymer electrolyte Al are better than older tantalums in decoupling apps too

African tantalum mining has bad ecological and humanitarian consequences, I won't design tantalum capacitors into any new product

TaN resistors use so little Ta that I will consider them, at least a case can be made for their audio superiority unlike capacitors where Ta is worse than the alternatives

[renes3]

African tantalum mining has bad ecological and humanitarian consequences

I often wondered what voting for Bush did to the environment, and what the long term effects are on nature after 12 years of Bush.

René

[EchoWars]

African tantalum mining has bad ecological and humanitarian consequences

Is that right? I knew there was something I didn't like about them.

[schnullimaus]

Thanks for the replies so far.

Very intersting aspects, especially those regarding bad ecological and humanitarian consequences in Africa. Never thought about
that.

Anyway I have still some strong believe that the designers
knew what they were doing and that there were reasons
to use tantalums here and there in the signal path.

Probably the tantalums were placed into the circuit
JUST BECAUSE OF THEIR DISTORTIONS ?? Sounding ...
What kind of distortions do they generate.
Whow does it sound?

Two of my examples list tantalus in the input section of
Phono amplifiers. ´Can tantalums "compensate" some
distortions typically found when playing back vinyl?


Thanks,
Stephan

[richwalters]

Hi there........tants are way better than electrolytics in signal paths esp in tube amps......cathode bypass is a typical place. Nearly all the low signal path tube circuits I've come across over the past 40 yrs sounded better with Tants in lieu of electrolytics......although there are many good quality low leakage electrolytics on the market. For those wanting to make an improvement on existing designs and not wanting to use tants -> go for electrolytic caps spec for use in switch mode power supplies.....i.e have low ESR. Price is swallable.

richj

[brady]

I tried Tantalum cap in coupling of a McIntosh MC7100. Sounded better than the original electrolytic. And then I shifted to BG-N. Sounded much better. 10uf/50v