I have a Preamp that has a couple of tubes which has some Vishray 1813 1.5uf coupling capacitors.

There is not much room in there for large capacitors, so I was wanting to try some bypass caps across them.

I see the Duelund Silver bypass 0.01uf caps get good recommendations but they are quite pricey. Unless someone thinks they are worth the extra in this situation.

 

The other one I saw mentioned and was thinking of trying was the Jupiter Copper Foil 0.01uF 600VDC.

http://www.partsconnexion.com/capacitor_film_jupiter_copper600.html

 

Anyone have a suggestion to try a certain brand as a bypass cap in this preamp?

 

Not expecting any big changes but if I get that extra 1% then I am all for it.

 

 

Edited May 13, 20178 yr by rocky500

28 minutes ago, rocky500 said:

I have a Preamp that has a couple of tubes which has some Vishray 1813 1.5uf coupling capacitors.

There is not much room in there for large capacitors, so I was wanting to try some bypass caps across them.

I see the Duelund Silver bypass 0.01uf caps get good recommendations but they are quite pricey. Unless someone thinks they are worth the extra in this situation.

 

The other one I saw mentioned and was thinking of trying was the Jupiter Copper Foil 0.01uF 600VDC.

http://www.partsconnexion.com/capacitor_film_jupiter_copper600.html

 

Anyone have a suggestion to try a certain brand as a bypass cap in this preamp?

 

Not expecting any big chances but if I get that extra 1% then I am all for it.

 

 

I bipass all my bigger caps with Jaycar high voltage (630V) 0.1uf brown polies. Cheap and effective. 

You could replace both caps with physically larger ones (but with the same values) by stacking one on top of the other and zip tying both together. But you have to make sure that the leads are long enough to do it this way.

 

I'd recommend using TRT Dynami-caps as affordable but high performance replacements or as by-pass caps. If you have the funds, Teflon V-caps (or any other brand of Teflon caps) would be a very good and noticeable upgrade (however, they take forever to break in)

 

If you are already using silver cables or interconnects in your system, I would hesitate in putting another silver component in the system. 

 

Edited May 13, 20178 yr by Sir Triode

A friend has some spare Mundorf Silver/Oil 1.5uF caps but when I place just one in there, the lid does not close properly and hits on it.

 

 

Actually just tried again and they just fit with the lid on in this position.

Would these Mundotf Silver/Oil caps be better than looking at a using a bypass cap on the existing ones?

They cover up the terminal block which is for connecting an optional phono board. I won't be looking to add anytime soon.

If the caps had long enough leads, you could place them on the empty space beside the PCB and hot glue them in place or use double sided tape.

 

I think it would be better to use Teflon bypass caps in this case. Easier to add on or remove with better performance. And they would look stock rather than a DIY job.

 

BTW, the originals are Vishay polyester capacitors which aren't the best. You want to use at a minimum a Polypropylene cap. Telfons being the top of the heap.  

 

Edited May 13, 20178 yr by Sir Triode

No point bypassing as they are not electrolytic capacitors, you may as well remove the Vishay's and replace it with something better. Bypassing the films with another film will be paralleling, i.e. increasing the capacitance. Those Vishay's do the job just fine. You'd get a bigger difference by tube rolling, from a glance you have ECC88 to roll.

 

You don't need to have everything in tightly, just use a hook up method to the solder pads.

 

Cheers,

Edited May 13, 20178 yr by willio747

They're fine; leave the poor things alone.  

What is the brand and model of tube preamp is that btw? It looks to have pretty decent quality components and PCBs.

2 hours ago, Sir Triode said:

What is the brand and model of tube preamp is that btw? It looks to have pretty decent quality components and PCBs.

Its a Octave Preamp. Have had the volume upgraded. Recently had a local SNAer cut a whole if the front panel to to add the 2 LED display for the volume. (Fantastic job he did on that one!) Thanks Doncentric!!!

My amp is back from an upgrade with new transformers with shielding, so was looking at these coupling capacitors as my last thing on the list. Currently waiting on some more tubes to do a bit of swapping and testing.

 

I am only guessing their coupling capacitors but it seems about where they would be looking at the components around there.

Edited May 13, 20178 yr by rocky500

Thanks guys for the info so far. Trying to google as much as I can as I would like to try bypassing or replacing these Capacitors, so any help here is much appreciated.

It already has been modified a bit so definitely not original anymore as in the pic below.

It is quite a slim profile which might make it tight for those bigger type capacitors. Those Mundorfs just squeeze in. They any good as I can get them at mates rates.

Don't mind spending more as it will be staying around for a while.

 

 

Edited May 13, 20178 yr by rocky500

Hi Rob , Jantzen Superior Z caps are worth a try as they have a less etched quality than the Mundorf Silver oil while otherwise being neutral and detailed and are transparent to musicality if it is in the recording. Available from Speakerbug in Australia at very reasonable prices :

https://speakerbug.com.au/index.php?route=product/product&path=25_31&product_id=404

Bypassing those stock Vishays IMO is lipstick on the pig! 

 

Jupiter Copper Foil is what I use - but they look to be as large as the Mundorfs.  (JCF 1uF is 55mm long x 34mm diam.)

 

Andy

 

I would bypass every cap. But generally with just a brown ploy of 0.1uf. 

58 minutes ago, rocky500 said:

 Those Mundorfs just squeeze in. They any good as I can get them at mates rates. 

 

 

Yes they are extremely good, one of best caps available.

If you can fit them in get rid of the vishrays and go with the Mundorfs !! 

These Mundorfs 1.5uf are 36mm in diameter. The Lid will close.

 

Superior Z-cap is 23mm (fit well) in diameter and at a great price.

Aydyn Cap true copper max seems to be a bit big at 50mm diameter. Would have to move them off board.

VCaps are over 500 pounds. Wow, I did not know Caps could cost this much!.

Jupiter copper foil are 42mm in diameter (not sure how they would squeeze in) and within budget too.

http://www.soniccraft.com/product_info.php/jupiter-copper-foil-15uf-600vdc-p-4628

 

TRT Dynami-caps  do not make a 1.5uF it seems.

Edited May 15, 20178 yr by rocky500

Well my mate said lets just try the Mundorfs.

So he put them in. He snipped off the old ones and joined the new ones to the bit sticking up left behind for now. No removing any boards.

 

Just powered it up and it does sound different. Will see how they go in the next few days.

 

8 hours ago, rocky500 said:

These Mundorfs 1.5uf are 36mm in diameter. The Lid will close.

 

Jupiter copper foil are 42mm in diameter (not sure how they would squeeze in) and within budget too.

http://www.soniccraft.com/product_info.php/jupiter-copper-foil-15uf-600vdc-p-4628

 

 

Aah, yes, sorry - obviously 1.5uFs will be bigger than mine! 

 

5 hours ago, rocky500 said:

Well my mate said lets just try the Mundorfs.

So he put them in. He snipped off the old ones and joined the new ones to the bit sticking up left behind for now. No removing any boards.

 

Just powered it up and it does sound different. Will see how they go in the next few days.

 

 

Should sound great - you might have to wait 200 hours for their 'final' sound, though! 

 

Andy

 

Edited May 13, 20178 yr by andyr

You'll love it once settled in. Mundorf ZN caps were the single largest improvement in my Yaqin MC10T amp, followed by tubes and volume pot.

Sent from my Redmi Pro using Tapatalk

8 hours ago, rocky500 said:

Well my mate said lets just try the Mundorfs.

So he put them in. He snipped off the old ones and joined the new ones to the bit sticking up left behind for now. No removing any boards.

 

Just powered it up and it does sound different. Will see how they go in the next few days.

 

 

Smart man your friend !!

Looks like he did a nice job of it too !! 

You must be pretty happy to have the pre back in your system


Sent from my iPhone using Tapatalk

1 hour ago, A J said:

You must be pretty happy to have the pre back in your system


Sent from my iPhone using Tapatalk

Yes it is great to have it back and finished. Can see the volume setting now from across the room is a big plus. Don did a super job and it looks original.

 

Edited May 14, 20178 yr by rocky500

15 hours ago, Ozcall said:

Hi Rob , Jantzen Superior Z caps are worth a try as they have a less etched quality than the Mundorf Silver oil while otherwise being neutral and detailed and are transparent to musicality if it is in the recording. Available from Speakerbug in Australia at very reasonable prices :

https://speakerbug.com.au/index.php?route=product/product&path=25_31&product_id=404

So far it sounding so much better today. I like what these Capacitors are doing to the sound.

It could just be that they are just better than what was in there already, but I really like it.

This preamp has always sounded more like a solid state preamp with not much tube goodness but today it is sounding very relaxed and great to listen too. Last night was just awesome after 1am but I had been drinking a bit, so does not really count.

Could just be replacing the caps with anything a bit better was going to help it.

Edited May 14, 20178 yr by rocky500

15 hours ago, rocky500 said:

 

It already has been modified a bit so definitely not original anymore as in the pic below.

 

 

What is that very shmik-looking stepped attenuator, Rob?

 

Andy

 

6 minutes ago, andyr said:

 

What is that very shmik-looking stepped attenuator, Rob?

 

Andy

 

That is one I got from this guy below. 64 Step with relays inside. Included a 2 LED dimming display and remote. Great to deal with too as I had problems with the first model. He sent me out a new section and even new remote and boards. Works super great now. Was all silver to start with.

http://www.hattor.com/

 

Edited May 14, 20178 yr by rocky500