JAM by Duelund

Has anyone tried these new reasonably priced tinned copper caps from Duelund in any positions?


I have not try the Jam caps yet but by their look it's either made by F&T or Jenson.  Not an in house like most of the Series they made.  I can say they are cutting cost and going to a more productive and cheaper way to produce their caps.  This is just my honest opinion!  
I just ordered the Jam caps after speaking with Frederik at Duelund
He said they are made just like the cast, except the cast use further resonance 
And high compression paper case which is much more labor intensive then the Aluminum  and better sounding still.which is made in house  ,most likely on a Jensen machine but to 
A much higher standard. The Tinned Copper is shared by only the Jam,and Cast.
He said it is noticsbly better then the older Alexander,and the paper in oil dielectric allows that deep rich Tone ,where the tin allows the top end to shimmer and Copper gives it depth of detail. My friend in the U.K has used them and he said 400 hours to fully develop but a true bargain. These are currently introductory 
Priced . P.s they have the .01 silver paper oil bypass caps which my brother put 4 in his preamp, for $100 each he said it was a bargain for gains in  resolution alone and very natural no silver brightness what So ever.
Sounds great Audioman, please come back and tell us how it goes : )

Enjoy the tunes

Any more feedback on JAM caps?

 You've recommended Arizona Cactus + Jupiter Copper combination which is potentially better than Duelund. Is the cactus + Jupiter combination better than JAM in your opinion?
I personally like Jupiter copper foils as much as Duelund CAST and more than the Duelund RS. The JAM is not as good as RS .... well they are under the RS in the Duelund Line. I would go with 100% Jupiter Copper foils.  This is especially true in electronics.  Not sure if these are for crossovers or elsewhere? 
I have to Agree with ZGranny.  The Jupiter foil is just a great cap it does take 
All of 400+ hours to fully develop. Thr Arizona cactus Blue say 20% of the value 
Of the Jupiter makes a great combo the Aluminum foil in oil for whatever  reason works.
 the Japanese team who developed the cactus caps had,tin as well as Copper 
With the specific Mineral oil Aluminum just works well. magical and he uses this in his amps in Japan. 
These caps add a bit of air and depth . Together a great team and much less $$ to the Duelund Cast. The toe jams are still very good But the Jupiter Copper ,
Blue Cactus combo is excellent. I have in my preamp as well as cap- s to my Voxativ driver  which will let you know if it is not natural to the ear.
@grannyring @audioman58 I ask your expert advise on caps choice regarding my speaker crossover. I'm using pure audio Project Horn1 (not the Leonidas crossover)

Crossover currently has 20uF cap installed. Jupiter copper or Arizona cactus doesn't have such high value available. Ideally I'd like to use 18uf reasonable prices cap + 2.2uF top quality ones. That's the right course of action without breaking the bank, right? What combination and values do you suggest?

FYI, I value smooth/musical yet detailed and transparent sound. And I'm ready to sacrifice little detail for smooth/organic/meaty sound if I have to make a choice.
To Radiohead99
Look for the New Clarity CSA, c for Copper ends a excellrnt cap for the money and clear  you have roughly 5% you can go over tolerance wiithout issue..
I have a 68uf cap in the Leonitis crossover this way my Voxativ driver just operates from 350hz on up.  Just factor in a 15uf clarity 250v which is more thrn enough volts, a 3.3Jupiter copper, and a 2.2Arizona Blue cactus  Jupiter condenser 
Sells both caps  that is s perfect match . The Jupiter is a 100v  for Loudspeaker
You are pulling less then 15 volts on average. Good luck and slliw a minimum of 300 hours runin 
Please note ,call Jupiter condenser ahead of time,
Chris doesnot all ways have the 3.3uf 100v Jupiter Copper foil made.
If not get a date and secure them,  that extra 1uf  makes a small additional difference Worth the wait ,if you can't wait just reverse to cactus Blue 3.3uf.
Please note put a drop of hot glue on all leads where  coming out of caps a little fragile
And any bending hold with one hand at least 1inch from where lead comes out for support No one wants to ruin s $200 cap ,or any for that matter.
For a large value cap like that I think the best sounding large  value cap is the Mundorf EVO Supreme Silver, Gold, Oil.  They are expensive, but the best large value cap I have heard. Watch the size of the Jupiter line when the value gets big as they are huge! A 15uf Jupiter VT cap is 5 inches long! 

I also like the Clarity CSA as Audioman68 mentions. Not as good sounding as the Mundorf above, but still good and very affordable. 

I don’t like mixing brands ands materials of caps in speaker crossovers. I would stick with one brand/type. You can combine the same value to get your end value. Best to split evenly such as two 10 uf.  10uf and 5uf is also fine. Be sure to get them matched within 1%.  Sonic Craft will do that.  
Thank you both for the excellent suggestions!

@grannyring I've heard that as good as mundorf silver, gold, oil is - it is little on the leaner side. That gives me pause. I've some Jantzen silver zcap 22uf. Last night I put them in and the sound became detailed but lost some musicality. But this same cap sounds superb with Voxativ. Not so much with horn. Hence making sure to go with less detailed (no silver), musical, smooth and organic sounding cap.

@audioman58 Great tops about hot glue. Btw, I don't think there's enough space to fit all three caps on the crossover board. If I've to pick two caps, Clarity CSA + Blue or Clarity CSA + Jupiter?

What do you mean no room ? Is this on s munforf screw down board ? 
If space needed I put the 2 bigger ones together between dome hot glue 
,and sit the smaller one ,cactus in between. No 3. If Jupiter's available 
I was told . Go with the 3.3 Arizona Cactus Blue, and a 2.2 Jupiter Copper,
15uf Clarity Csa,250v  there will be enough room .  
Myself took 2 1ft ,1inch thick Birch and mounted Xover to it .
Had Verastarr make me s longer wire harness by a foot longer progressive per driver . If you don't have the Verastarr cables ,for sure get them .
Bigger difference thrn the cap upgrade the stock wire it comes with ok,
But not in the same League .  Greg  Weaver- Stereo times gave me the hint 
He did all power cords ,then expanded. The owner Mike Powell,
Totally stands behind his gear. $$ back if not happy Period.
Yes, I'm using the mundorf board. I believe the legs of the caps needs to be long in order to fit them on that board.

Interesting that you mention Verestarr cable upgrade will be bigger than caps upgrade. I use duelund hookup wire (also western electric) inside the PAP. Both are excellent. Not sure how much of upgrade it'd be going to Verestarr from Duelund/WE

You are referring to a different Mundorf cap ... Supreme Oil, Silver, Gold. I am referring to the Newer EVO Supreme Oil, Silver, Gold. They are very nice. If you want smooth over detail, then the Jupiter VT cap line is the perfect choice. They get big fast, but you could combine with Clarity CSA.

Be sure to give any cap you put in at least 200 hours before making any initial judgements. Many take up to 500 hours to sound as intended. They can change substantially and often do. I find they get better up to 50 hours and many then go south and sound pretty rough until you cross 100 hours. This is real and I have tested and heard it over and over.

Another good cap cap for the money is the Obbligato Gold. Very smooth.
The new Mundorf Evo Supreme best,Gold Silver oil,
Vs the older Supreme Silver,Gold Oil. The new ones seem to be a bit more extended but a bit too tipped up on upper treble. Personally capacitors made with natural paper mixed somewhere as a dielectric, and or in oil sound more natural, or even harmonics to the ear . A team study of Japanese designers stated  this too In their findings. Having to do with even harmonics  more do when there were distortions in the signal path ,similar to a Vacuum tubes harmonics vs Solid State. .
Correct @audioman58    However when large value caps are needed and space is tight these are oftentimes one of the best options.  Another good option is Sonic Craft Gen 1.  
Just couple of notes, the Clarity CSA has copper in the connection matrix, not the foil. I find the larger values are improved upon with a true copper bypass cap.


Hello  please let me regress ,every speaker or driver has different characteristics
no one capacitor is good for everything . 
I was just mentioning the cactus cap and Jupiter to be 90%+of theDuelund cast
at 50% less.  The Rike Q caps are a great new cap very well balanced
as well as their S-2  caps which are very well priced.
i am putting the jams on the speaker outputs, and as a large output fill with Mundorf Supreme 23uf-3.3uf combo  this week
the Duelund Jam are one of the top 4-5 caps in production very detailed
warm,and the tinned Copper ,paper in oil is warm and better then any Jensen copper rip off upcharge because of the paper casing ,total scam
slightly better 35% higher cost use your brain a few % points at most .
duelund great if you have money to forget about  and your system better be
well refined first in every phase ,to hear all the micro macro acoustics it does better. If not you will not hear everything Duelund  has to offer.  Your cables included. I know through over 35 years and a the cost of a nice home in Audio
think things out first. I will update you on these Jam caps in 10 days ,
Happy listening😎 
Hello Grannyring as far as mixing Clarity and Mundorf do very good 
go to Humblehomemadehifi cap test  Tony Gee ,whom helped me many times in the past when living in the UK is pretty accurate 
sometimes because of workload he does not allow full breakin 
especially on oil,foil type caps can vary . Even the new Clarity
Copper, CSA- caps with copper lattic3 end caps I think at least a 9.5 to 10 very well balanced and Clearly better then last years Silver Color ESA caps. These blend excellent with Mundorf.
the new Mundorf Supreme Evo caps are a bittipped up then 
the Black Supreme Silver Gold oil caps  I found the out when they first came out and in the Humble cap tests comments on this 
 jantzen superior, and their new Black aluminum foil cap excellent 
caps . All depending what to do . Several Japanese designers 
stated and I agree  the poly caps are not quite as natural as a cap 
having at least a bit of oil, and or Paper even harmonics smoother 
to the ear. Just a guide line.
I just installed the 3.3 uf jame , with Mundorf Supreme 
pit it should be a big jump , these will take at least 100 hours to start opening up  400 hours + to fully runin .
these are very similar to the cast except cast use a paper tube
heavy resin isolation and apes tube takes much longer to make then the Aluminum can ,1/2 the cost. Maybe 95% of the greatness.  
To Radiohead 99 I used the Duelund Wire for several weeks this summer 
plenty nice but warm and not as extended by any means as well as the Verastarr.
 I have upgraded from Copper interconnnct which is Very good to their Silver Gold Alloy interconnects, which are one of the best I have ever heard. That being said if your system amp is light sounding the Duelund Wire will be a plus  .cable 
harness without question the Copper Verastarr is very special after 100 hours ,

 The Verastarr Starr are in another class of upgrade cables ,  Duelund capacitors
are top of the heap in their Cast caps . 
Duelund wire, copper stranded, cost $9 meter for 16ga. 🙂 Great wire for speaker internals or outboard crossover if you need 15-60 meters of wire! That’s what my last two upgrades needed. I can only imagine what the total bill would have been for 60 meters of said Verastar. I bet it is good indeed. Like to use it if were affordable.
The Duelund RS in my set up the New Duel7nd Jam caps are not full6 broken in my still very similar in build to the Cast same tinned Copper, paper in oil , but cast has there labor intensive resin paper housing  vs the Aluminum  it has a more dense deep presentation 
but not bevy that much . The RS does Not have the Tinned Copper 
which all cast caps now have it opens up the top end a bit without 
having to go to Silver which is better still. The Adams Are the Best Buy of the Duelund line . Give them at least 150 hours to start opening up and just get better several guys in the UK told me 400 hours is not out of line. Currently intro priced at 40% off .parts connecxion got a big buy at over 60% off. A great bargain  and 600
volts inside amp or speakers . 
Another less expensive Excellent speaker only cap I just mixed with Jupitercopper caps the New Jantzen AlumenZ  foil caps ,100 v 
super thin dielectric  very fast detailed and smooth.
hifi collective is the only place to buy I know of UK  get 3 day Fedex shipping around $30.  Jantzen best cap a pr of 3.3uf caps under $100. Very easy to get along with I have Jams caps in preamp.
i took the Arizona Cactus Blue caps nice cap for $$ and put in my external linear power supply for Lumin player ,nice filtering,using thesealso in 
Brick wall line conditioner . Can’t go wrong  in PS .
Granny ring The Duelund Wire is a Very good Buy ,especially if need loner runs.
myself just needed  about 40 ft total for both speakers for all 6 drivers.
actually a great deal $700 for the Verastarr Copper Wire harness.
Radiohead99 99  you didn't mention total cap value .unless 20uf is the total for the horn  the new Jantze n Alumen z  are very good   they are smooth and detailed 
The Jupiter Copper are dense and smooth , the duelund Jam  or still running in 
But starting to smooth out excellrnt top end extension if you like natural cymbal 
And piano  for example.  Compared to the New Duelund RE,  these Duelund Jam 
Are a bit more open having Exactly the same New Tinned Copper as the new Cast
Caps  ,and paper in oil.  The New cast just coming out is top dog but Huge and $$
Expensive,  I have the JAMS IN MY PREAMP , and very impressed my brother has the jams 3.3 if and 2- Jsntzen 10uf Alumen Z caps for highs and mids  Excellent 
Combination slightly warm but Superior top end ,even better then the Jupiter Copper 3.3 they were in there , the Jupiter are excellent but if you need or want 
The extra extention as in the New Duelund Cast but at a much lower cost 
These caps are Great buys at 40% off retail ,Only while they have them ,parts connexion bought a bunch at 60% off ,as a prokotion from Duelund.
There is no such best cap for everything,  size,and price come into play. 
The New Jantze n, Alumen Z  sound great and blend well with others 
Smooth and detailed ,run just with these and say Duelund Silver oil bypass caps 
A great cost effective setup. For your horn $600 for Both speakers 20uf.
Just a thought.its your $$ 
One thing guys for big values over 10 w the Munforf Supreme Resistors are very good. For tweeter- midrange  the most musical I have found Path Audio, ,and most certainly the most accurate out of of 12 ,not 1  even came to 1% variance and have a nice natural balance and depth far better then then even Duelund which mask s bit of detail even their cast very up to 10%,5%+, 5%-. And are $$ . Don't over look them 
I had the mundorf on the Voxativ driver, when the Path came in replaced  even without breakin  better everything especially depth,kidbass,low bass.
The engineer said 150 hours to fully runin, and they have a ground wire to ground 
For added quiet if needed.  For roughly $28 each  well worth the small investment.
Agreed on a Path Audio as they are quiet and even handed throughout the frequency spectrum.  . Best resistors I have used. I like the Mills MRA12 better than Mundorf, but both are good. Mills are nice and extended, but never bright.  
@audioman58  Extremely helpful feedback. My PAP Horn1 crossover came with 20.2 uf cap installed per channel. Here are the options you suggested so far:

1. Clarity Cap CSA (15 uf) + Cactus Blue (2.2 uf) + Jupiter Copper (3.3)
2. Jantzen Alumen Z cap ( 10 uf + 8.2 uf) + Dueland Jam (2.2 uf)
3. Jantzen Alumen Z cap (10 uf + 10 uf) + Dueland Silver Foil by pass cap

Option 1) is the most expensive. Option 2 and 3 is very close in price. Not sure what will sound better. What do you think about the following:

4. Jantzen Alumen Z cap (10 uf + 8.2 uf) + Cactus Blue (2.2 uf)

Option 4) is cheapest (only by a tiny bit).

btw, I ordered Path resistors to replace my Mundorf supremes in the crossover. However the Path resistors are 10W and going to replace Mundors 20W in PAP. Is that ok?
A 2.2 Jupiter Copper  and 18uf Jantze n is also a very good combo.
The bypass caps can all ways be added ,you have a Copper, or silver option 
Depending what you need more of . Silver for more top end, copper for more meat
On the bones.
 The path Audio are 10 watt . For horn Only . For woofers not as sensitive 
To critical midrange.  Write yo Chris , parts connexion tech support 
The munforf 20W  supreme is there for the big woofers If you want to improve them cut off rivets holding wire , get 18awg Neotech solid core wire 2- 4inches pieces solder where you cut . Much better. Stock are Nicole plated copper.
Just order two Path Audio and put in parallel. They will now handle 20 watts. Two in parallel always sound better than one! If you need a 4ohm resistor, example only, put two 8 ohm in parallel for your 4 ohm spec. 
My Duelund Jam 3.3 caps put in my preamp are finally settling in nicely 
about 200 hours still another 100 hours to go it sounding excellent 
remember these have the same Tinned Copper as the new cast, and paper in oil.
but in a less expensive Aluminum can vsthe resin paper that the cast has which 
gives it a deeper sound stage and image depth .these are as good and better then the RSmodel on the top end having the Tinned Copper ,the RS don’t have ,
but has better imaging . For the money especially the introductory price a true bargain.  Very nice cap ,one of the best out there .
for Speakers New cap Jantzen AlumenZ foil caps Very well balanced and decent price.
Finally run in the New Duelund Jam caps are Excellent, great detail, depth 
And with this latest technologies, The Tinned Copper gives thst extra sparkle and air vs just Copper  these being too paper in oil. They do not have the paper case which is better still .
But Duelund just came out with a Bypass cap with Paper case ,
And s silver foil if your system iscslready rich ,and even better detail,
But not as much body .you will have to decide which us better. 
Both are under $100  each at Parts connecxion.
Hi Audioman58,

Do Jam caps sound lean or full body like Duelund Cast Copper?
Can you compare sound of Jam to Jupiter Copper caps?
I use Audio Note Copper in my phonostage.
But I want to upgrade them to something more open and transparent but with the same lush, honey sweet midrange.


Did anybody compare  Duelund  JAM to CAST-PIO Copper or CAST-PIO Tinned Copper?
I have compared Jupiter copper foil to the RS and CAST. I just prefer the Jupiter by a wide margin over the RS. The RS sounds dark compared to the Jupiter. The Jupiter is more open, airy and better micro details. It does this always with a natural richness and smooth presentation. The CAST as very good and I find the Jupiter a little better in the micro details and airy top end while the CAST is a tad more organic and midrange resolving.

The Jupiter’s are far more affordable than the CAST however. My all time favorite is combining a Jupiter copper foil with a Duelund Silver foil bypass cap. Pure heaven and better than the CAST for less money still. All my opinion😁.

The JAM are not at the same level as the Jupiter copper foil just by where they are in the Duelund Line and how Jupiter compares to the CAST higher up in the line.
Hi grannyring,

Thank you for reply!

Now I’m using Audio Note Copper capacitor in EAR834 phonostage between first and second tube. This capacitor works in the circuit without feedback. So the quality of this capacitor should make a big difference.
The problem is AN Copper are very lush and sweet in a mid-range like Duelund Custom-CU, or even more!
And I like the tonal balance of my phonostage. I just want to make it more transparent.
I afraid that Jupiter Comer can make vocal sound a little bit thin.

Jupiter is far from thin sounding as an FYI. It is lush, sweet, and has full bodied tone. Still my favorite! Better bass than Duelund in electronics also. That has been my experience. 
How much time does take burn-in of Jupiter?
Do they sound bad during burn-in like Duelund RS do?
Yes these well damped, large and dense caps all take a good 300-500 hours to fully burn in. They will sound good after 100 or so and just continue to open up a get better. The larger the cap value the longer....closer to 500 hours. Many don’t wait long enough and change things far too early. They will sound good right away and up to 50 hours. At 50 hours or so things go worse unexpectedly. Yes, frustrating but true. However at 100 hours or so they start sounding good again and just keep getting better with time. This has been my experience and trust me when I say I have been through this cycle many, many times and know from experience.

I wish this were were not true as some think. However, it is the case and real on these caps.
I did burn in speed up for 4uF Duelund RS using Frybaby2 cable burner.
It helps. But in any case, it needs some number of hours of natural burn-in after a harsh Frybaby2 burn-in.
I received Jupiter capacitors and start running them in Frybaby2.
I think 3 days of a fast burn-in will be enough.
 I burned Jupiter Copper 3 days in Frybaby2.
I soldered capacitors into my phono-stage and listened. After that I connected Frybaby2 to phono-stage and run it about one hours. This extra hour didn’t do any difference.
The tonal balance after installing new capacitors was even. It looks like capacitors path about 90% of break-in.
Compared to Audio Note Copper capacitors that where before in phono-stage, Jupiter capacitors have more high frequency extension and bigger base. They have much more resolution in all frequencies spectrum included lower midrange. All violins, saxophones, trumpets have more body and midrange tones. Soundstage became more 3d and further.
Arensky trio with Heifetz- Piatigorsky sound more energetic and emotional. Most of jazz music sound more real. But on rock music Jupiter capacitors show more records flaws too.
I can compare Jupiter Coper to Duelund Custom Cu capacitors directly. But I changed Audio Note to Duelund Custom Cu in my integrated amplifier, so I can compare Jupiter Copper to Duelund Custom Cu capacitors indirectly. This comparison is based on my memory and not too accurate.
Duelund Custom Cu capacitors have bigger, deeper and slower base. Jupiter Copper capacitors sound faster and very energetic. Duelund Custom Cu capacitors have lusher, richer low midrange on vocals. Duelund Custom Cu maybe a little better in term of tone.
They do need more time to break in with music.  500 hours with music. Pretty sure your cooker time fell short of that. These do take all of 500 hours to sound their best. Not sure what the cooker equivalent of 500 hours is? Not sure if it even gives the same result? 
Yes, I'm agreed. Cooker works different compared to break in with music.
Very long  break in with music always makes sound better and long break in with cooker sometimes makes sound too dull or bright.
But in this case with Jupiter capacitors, cooker helped me to pass quickly the most annoying first stage of the break in.
I ordered a pair of 1uF Jupiter Cu capacitors for my phono-stage (build based on EAR834 schematics) output stage.
The thing that impressed me most in Jupiter Cu is exceptional micro-dynamic that makes classical music sound very emotional.
Yes that is a wonderful thing to get most of the burn in behind you once a part is put in place. I do wish a had such a device.
Hi Grannyring,

How does change sound of Jupiter Copper after 100 hours?
Is it become quieter, warmer, smoother, more open, more dynamic?

What kind changes of sound does make Duelund silver bypass?

Did you try Duelund Cu-Sn bypass?

Jupiter goes south in sound quality right around 50 hours. Music sounds thin and just not right. They sound much better from 0-50 hours. Strange, but true. At around 100 hours thry just start getting more open, natural, relaxed and bloom. This all gets slowly better past 300 hours and at 400-500 they are set.

The Duelund bypass gives them more of the Duelund CAST realism and organic mids and highs. The combo is very special. More of a inner glow.