Author Topic: Psu caps  (Read 8065 times)

Offline ozcal

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Psu caps
« on: December 01, 2011, 03:22:51 PM »
Well ! as part of my Christmas present to myself I bought a couple of Obbligatto film in oil psu caps to replace the single remaining electrolytic on the ht side of the Supratek . The Obbligattos replaced a Jensen 100 uf electrolytic.
So far nice improvement in solidity/ body to the sound , wider and deeper soundstage for about the same price as the Jensen.
Definetly worth a try guys.
Listening with my ears :)

Offline springcreek

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Re: Psu caps
« Reply #1 on: December 01, 2011, 09:34:32 PM »
Hi Ozcal

Thats a nice looking cap! Looking for some new power supply caps for the Fisher, was thinking of using motor run oil caps, though the Obbligatto's look very nice.

Cheers, Andy

Offline zenelectro

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Re: Psu caps
« Reply #2 on: December 02, 2011, 08:24:09 AM »
Hi Ozcal

Thats a nice looking cap! Looking for some new power supply caps for the Fisher, was thinking of using motor run oil caps, though the Obbligatto's look very nice.

Cheers, Andy

The Obbligatos are essentially motor run caps, same construction I believe.

T

Offline ozcal

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Re: Psu caps
« Reply #3 on: December 02, 2011, 05:32:23 PM »
Hi Ozcal

Thats a nice looking cap! Looking for some new power supply caps for the Fisher, was thinking of using motor run oil caps, though the Obbligatto's look very nice.

Cheers, Andy

The Obbligatos are essentially motor run caps, same construction I believe.

T
Is that a good or bad thing T?
 Edit :Just spent a fun hour reading about motor run caps , the consensus seems to be that they are an excellent replacement for electrolytics in valve psu s
« Last Edit: December 02, 2011, 06:44:17 PM by ozcal »
Listening with my ears :)

Offline springcreek

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Re: Psu caps
« Reply #4 on: December 06, 2011, 11:22:09 AM »
Thanks Terry

I was hoping to replace the power supply caps in the Fisher valve amp with motor run style oil caps...I was hoping to increase capacitance to reduce PS ripple, are there any issues with using too many caps for filtering??? I can make a bigger sub-chasis to fit them if it will work.

Cheers, Andy

Offline vitavoxdude

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Re: Psu caps
« Reply #5 on: December 06, 2011, 02:54:17 PM »
Motor run caps are good. ;)
You will need to look at the rectifier, is it valve or solid state?
Valve reg's have definate maximums for capacitance which can not be increased, the use of chokes between the caps increase performance (sonics) further too.  Don't forget to fit bleed resistors across the terminals and check the secure mountings.  Due to size, it is probable that a larger chassis may be required. 20uf is about the largest I have seen so lots needed for a power amp.
Enjoy and send in some pictures of the finished power supply. ;D
V :D
We all like different things so lets all agree to disagree and if any common ground is found then worship it.  Mine is the KD hence being present on this forum.

Offline ozcal

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Re: Psu caps
« Reply #6 on: December 06, 2011, 05:54:27 PM »
Hi V , 5ar4 valve rectifier, kept the capacitance the same ie 100uf in series with 2uf.There is also a choke in the psu  not sure what value.
Will take some pics the next time I have the psu upside down :)
Listening with my ears :)

Offline Jehuty

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Re: Psu caps
« Reply #7 on: December 06, 2011, 07:04:04 PM »
Hi V , 5ar4 valve rectifier, kept the capacitance the same ie 100uf in series with 2uf.There is also a choke in the psu  not sure what value.
Will take some pics the next time I have the psu upside down :)

If possible, you might want to try U52 rectifier ozcal...

Cheers,
William
Not all that matters can be measured, not all that can be measured matters.

Offline zenelectro

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Re: Psu caps
« Reply #8 on: December 07, 2011, 09:30:18 AM »
Thanks Terry

I was hoping to replace the power supply caps in the Fisher valve amp with motor run style oil caps...I was hoping to increase capacitance to reduce PS ripple, are there any issues with using too many caps for filtering??? I can make a bigger sub-chasis to fit them if it will work.

Cheers, Andy

Andy,

The only real restriction is if you have a valve rectifier feeding straight into a cap (as opposed to an L).
There will usually be a max cap size in the rectifier data sheet. For example Amperex 5AR4 specs 60uF.
http://www.wooaudio.com/docs/tube_data/5AR4.pdf

If the amp has a standby switch between rectifier tube and first cap (often disconnecting ground leg), this will put much more stress 
on the rectifier tube when the standby is turned on by virtue of the fact that there will be a huge 1 off current surge at that time
charging the cap up. Later model Vox AC30 gtr amps are a good example, commonly blow up rectifier tubes.

Do you have schematic for the amp?

cheers

T

Offline vitavoxdude

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Re: Psu caps
« Reply #9 on: December 07, 2011, 11:44:06 AM »
Sound advice Terry.  ;D
Plenty of inductance combined with multiple motor run caps should be just the ticket if you can stand the voltage drop across the choke. :o

One chap I know in WA runs 3 chokes to reduce pS ripple down to very low levels. :P :P
V ;)
We all like different things so lets all agree to disagree and if any common ground is found then worship it.  Mine is the KD hence being present on this forum.

Offline zenelectro

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Re: Psu caps
« Reply #10 on: December 07, 2011, 07:11:49 PM »
Sound advice Terry.  ;D
Plenty of inductance combined with multiple motor run caps should be just the ticket if you can stand the voltage drop across the choke. :o

One chap I know in WA runs 3 chokes to reduce pS ripple down to very low levels. :P :P
V ;)

I usually run the psu config through a simulator and it spits out everything, so you know exactly
how much ripple / OP voltage you will get for a given load and transformer voltage. It takes a lot of
guesswork out. 


Offline ozcal

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Re: Psu caps
« Reply #11 on: December 08, 2011, 04:53:13 PM »
Hi V , 5ar4 valve rectifier, kept the capacitance the same ie 100uf in series with 2uf.There is also a choke in the psu  not sure what value.
Will take some pics the next time I have the psu upside down :)

If possible, you might want to try U52 rectifier ozcal...

Cheers,
William
Thanks William , will investigate .
Listening with my ears :)

Offline vitavoxdude

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Re: Psu caps
« Reply #12 on: January 19, 2012, 12:31:45 PM »
Hi V , 5ar4 valve rectifier, kept the capacitance the same ie 100uf in series with 2uf.There is also a choke in the psu  not sure what value.
Will take some pics the next time I have the psu upside down :)
So come on then Grodon, 8) we are still waiting for the pictures you mentioned. :'(  Additionaly to what Terry said re cap sizes the big cap will too much if driven direct from the rectifier but it's more than likely on the other downstream side of the choke and smaller 2uF cap is hooked up to the valve as this is the only way the circuit makes sense. :-X  I would also try replacing the 2Uf with a nice Dubullier PIO up to 8uF if space permits as this should bring a tad more colour / body/realness and may obviate some of the wiryness metioned earlier, love that word, got a few scratching their heads here (All IMV).
V ;D
We all like different things so lets all agree to disagree and if any common ground is found then worship it.  Mine is the KD hence being present on this forum.

Offline Erik van Voorst

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Re: Psu caps
« Reply #13 on: February 21, 2012, 07:53:14 AM »
Hi guys,

I am testing a homemade tube rectification circuit.
At the moment I have 2 items bought as a winner being a Parmeko Choke 5H and a U52 Mullard tube (bloody expensive)

As a first cap..I have on a test the Obbligato, ASC, General Electric 10 uF.
My sec cap is a 100 uF Blackgate.

now my question...has anybody ever tried film as a first cap.....I am thinking of a claritycap MR
a bit expensive for a tryout..but it is tempting....

Most of the stuff I can borrow if I use clamps but my audioshopfriend does not do clarity......
« Last Edit: February 21, 2012, 07:57:58 AM by Erik van Voorst »

Offline zenelectro

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Re: Psu caps
« Reply #14 on: February 21, 2012, 08:52:13 AM »
Hi guys,

I am testing a homemade tube rectification circuit.
At the moment I have 2 items bought as a winner being a Parmeko Choke 5H and a U52 Mullard tube (bloody expensive)

As a first cap..I have on a test the Obbligato, ASC, General Electric 10 uF.
My sec cap is a 100 uF Blackgate.

now my question...has anybody ever tried film as a first cap.....I am thinking of a claritycap MR
a bit expensive for a tryout..but it is tempting....


Hi Eric,

Obbligato and ASC are actually film caps, being metalized polypropylene but oil filled.

You can really use any config you want to, as an example this Scott Thompson DAC, owned by S Meyerkort came in for
repair and went out with a tube rectifier stage added.

The config is rectifier  > C > L > C > L(Rch) + L(Lch) > C(R ch) + C(L ch).

So that is in effect a CLC filter then split in to individual R/L channel LC's.

The first 2 C's are motor start caps but the last cap was a high uF value electrolytic.

The 1st cap will have a strong effect on the voltage OP, so if this cap is small value the filter
starts to look more like a choke input filter and the OP voltage will start dropping.

Of equal importance to what type of caps you are using is how you actually wire the thing
WRT grounding  etc.

T

Offline Erik van Voorst

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Re: Psu caps
« Reply #15 on: February 21, 2012, 06:44:16 PM »
Thanks, yes I mistake them in speech, quite often I call them even elco's sorry for the confusion.

At the moment I am testing ASC in the config...takes a bit of time to burn in... :D

Offline zenelectro

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Re: Psu caps
« Reply #16 on: February 22, 2012, 10:10:35 AM »
OK found this in my web travels and thought of you guys  :D :D

http://www.dhtrob.com/keesolaf/elco.php




Offline Jehuty

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Re: Psu caps
« Reply #17 on: March 06, 2013, 08:55:58 PM »
Apologies for resurrecting an old thread.

I was looking for some cheap MKP power supply caps for my preamp and came across this review of supposedly top of the line Focal speakers (the Utopia line). Surprise surprise there were electrolytic and Solen/Axon MKP caps used for the beryllium tweeter and mid range driver in the crossover  >:( This probably explained my experience listening to the Focal speakers in the last two Australian hifi shows, harsh and edgy, lack of body and weight, poor timbre and tone, and simply unmusical  :(

The review: http://forum.audiogon.com/cgi-bin/frr.pl?rspkr&1283799651&&&/JM-Labs-Diva-Utopia-Be-Speaker
Not all that matters can be measured, not all that can be measured matters.

Offline ozcal

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Re: Psu caps
« Reply #18 on: March 07, 2013, 07:39:25 PM »
Hi J ,never heard Focal speakers but was just reading yesterday on the Jantzen website that Focal now use their caps in the Utopia range : see bottom of page : http://www.jantzen-audio.com/html/caps-superior-z-cap.html.
The Jantzen superior z caps are easily and relatively cheaply available in oz from Speakerbug and according to Humble homemade hi-fi cap test are quite musical.
Listening with my ears :)

Offline Jehuty

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Re: Psu caps
« Reply #19 on: March 07, 2013, 08:11:35 PM »
Hi ozcal, thanks for the info. I had the cheaper Jantzen in my pre and I didn't like it, replaced with Obbligato gold and things improved by a wide margin. I never like silver as well and for $269k pair of speakers (see: http://www.lenwallisaudio.com/blog/new-systems/grand-utopia-em-are-they-value-at-269000-a-pair/) I would expect Duelund caps. Oh well at least they get rid of the cheapo electrolytic.
Not all that matters can be measured, not all that can be measured matters.