Coupling caps for tube preamp

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21-01-2020, 11:25
Opti-cal

Coupling caps for tube preamp

Looking for some recommendations for coupling caps for my Musical Paradise MP-701 tube preamp.

2 X 0.33uf (0.22-0.33 are acceptable) + 2 X 2.2uf (1-4.7uf are acceptable). Voltage needs to be 450v or up.

I'm assuming towards the higher end of the values it just allows a few more low end frequencies in? Could be wrong though.

Would be nice to keep it under £100 the lot but its a very nice pre-amp so super-caps are not out of the question.

I've tried Obligato Gold premium which were very nice as well as Ansar Supersound Audio which again were surprisingly good to my ears. The Ob's being a little richer and fuller and the Ansar's more detailed and accurate.

Cheers.
21-01-2020, 11:41
Ali Tait

Lots of choice on Hi-Fi Collective.

Shootout here with lots of info-

http://www.humblehomemadehifi.com/Cap.html
21-01-2020, 11:44
Ali Tait

Found these good at (relatively) non-foo prices-

https://www.hificollective.co.uk/com...itycap_mr.html
21-01-2020, 11:58
Opti-cal

Cheers Ali,

indeed been reading all around those cap shoot-outs recently so interested to hear some "real" users opinions and what might work best in my particular preamp. As you know one man's "best ever" in his system, is another man's "don't touch with barge pole" in another.

Its got a lot of potential though this preamp so deserves some R&D on my behalf.

Nice one.
21-01-2020, 12:02
Ali Tait

No worries, yes you need to try yourself, as you say everyone's ears and equipment are different.
21-01-2020, 13:16
Firebottle

At pocket money prices I have always had good results with the Mundorf Mcap EVO.
If you want to push the boat out a little you could try the Mundorf Mcap EVO Silver/Gold, all at Hi-fi Collective.
21-01-2020, 13:36
Opti-cal

1 Attachment(s)

Quote:

Originally Posted by Firebottle

At pocket money prices I have always had good results with the Mundorf Mcap EVO.
If you want to push the boat out a little you could try the Mundorf Mcap EVO Silver/Gold, all at Hi-fi Collective.

Thanks Alan, yes they have popped up on the radar.

As for something a little left field (if not in the upper regions of my budget) these look interesting. Supposed to sound very good and something a bit vintage western electricy about them.

Not that you see them in the preamp but I like the tweed/cork look all the same. Subliminally organic, implying simple "get job done" attitude.

Also really like the twisted copper wires, very cool.

https://www.hificollective.co.uk/com...apacitors.html

Attachment 27256
21-01-2020, 14:04
Ali Tait

I have some of those in my speakers' tweeter crossover.
21-01-2020, 14:13
Opti-cal

Quote:

Originally Posted by Ali Tait

I have some of those in my speakers' tweeter crossover.

Did you go for the KPAL or KPCU Ali? (Aluminum or Copper).

If they're good I also plan to use them in a speaker crossover (actually to add a tweeter to a full range driver).

The 3.3uF has a diameter of 8cm . . . . much cap for your ££!
21-01-2020, 14:37
Ali Tait

KPCU. I've three caps in parallel though, so can't really say how they sound on their own. Very happy with the speakers though.

Also use these which are good-

https://www.hificollective.co.uk/com...il_in_wax.html
21-01-2020, 15:51
Opti-cal

Silly question (probably) but are caps directional? I would imagine only if they have polarity stipulated?

Logic would dictate not really, but once used in a certain direction for a time, best not to reverse it?
21-01-2020, 17:21
Firebottle

Film caps are reversible.
Some film caps have the outer foil lead marked, so that you connect the outer foil end to the lowest impedance to give a degree of shielding to the cap.

Every day is a skool day.
21-01-2020, 18:27
Opti-cal

Quote:

Originally Posted by Firebottle

Every day is a skool day.

Indeed sir.

Certainly learn more on here than in say, humanities.... Make that any subject for me to be fair!
23-01-2020, 14:58
Opti-cal

So, after realising my previously desired caps simply would not fit in my preamp I've decided to go with some Mundorf Supreme Silver/Gold/Oil cap for the higher power (4.3uF) duties. Along with an Audyn True Copper Max cap for the lower (0.33uF) duties. I'm hoping their virtues will complement each other having not really delved into the world of caps much before.

https://i.ibb.co/tBH8jk4/audyn-true-...-max-180-1.jpg

https://i.ibb.co/VMwsrT1/s-l300.jpg
23-01-2020, 16:20
Ali Tait

Can't go wrong with the Mundorfs I don't think. Haven't tried the Audyns.
24-01-2020, 07:51
Opti-cal

Quote:

Originally Posted by Ali Tait

Can't go wrong with the Mundorfs I don't think. Haven't tried the Audyns.

I'm hoping so Ali, also anything Mr Firebottle recommends can't be all bad . . . .

The Audyn's will hopefully add a touch of copper "richness" to proceedings too. People are going quite loopy about them. Quite expensive yes but quality costs!
07-02-2020, 10:40
fatmarley

Did you try the Audyn true copper max? Only asking because I have some 0.33uf for sale.
07-02-2020, 12:52
Opti-cal

Quote:

Originally Posted by fatmarley

Did you try the Audyn true copper max? Only asking because I have some 0.33uf for sale.

Tried them, love them. They certainly add something to my pre-amp (which has other issues unfortunately). When it was working it sounded excellent. I'm actually just looking in my other pre-amp to check the value of the caps as I'd be looking to put them in there too.

Will get back to you, cheers Matt.
07-02-2020, 14:14
fatmarley

Quote:

Originally Posted by Opti-cal

Tried them, love them. They certainly add something to my pre-amp (which has other issues unfortunately). When it was working it sounded excellent. I'm actually just looking in my other pre-amp to check the value of the caps as I'd be looking to put them in there too.

Will get back to you, cheers Matt.

Very natural sounding with no glare I thought. But not dull either.

Had them in my Quad 306 for quite a while but I started to get one channel acting weird, so I tried all sorts of things, but ended up with hum in both speakers that got worse depending on where these massive coupling caps were positioned (or even if I touched them). In the end I replaced them with some much smaller Mundorf Mcap evo oil and now there is silence. If I could put them back in without the hum I would :(

I wonder if it's the 5" long wires I have to use to attach them to the circuit board? Tempted to try something like screened cable before selling...
07-02-2020, 14:25
Opti-cal

Quote:

Originally Posted by fatmarley

I wonder if it's the 5" long wires I have to use to attach them to the circuit board? Tempted to try something like screened cable before selling...

Could try (gently) heat-shrinking them up to where they meet the board/cap. Might help if the hum is related to electrical noise. They are large, I was using them in conjunction with Mundorf Supreme Silver/Gold/Oil and the combination is something I won't forget in a hurry. Unfortunately the memory is all I have at the moment as like I say my pre-amp is playing up.

Never seem to have it all working together well for longer then 5 minutes!!
07-02-2020, 15:29
fatmarley

Quote:

Originally Posted by Opti-cal

Never seem to have it all working together well for longer then 5 minutes!!

That's part of the reason why I'm reluctant to try them again. It's working fine now and I don't want to risk breaking it because I've got a speaker build starting very soon...