Modification that has proved to be transformative

in a manner well beyond swapping out gear, tweaks, wire and the like. Ok Agoners I have owned and gone through lots of great gear as evidenced by my feedback:-)

However, over the past year I have learned something I want to share. Some of you will know all about this and others will have heard about it, but with doubts. Three words....

Duelund CAST capacitors

Sure, I have cap rolled and part rolled for a few years now. Fun stuff to do and sometimes I liked the change and other times not so much. However these CAST capacitors are an entirely different animal. I placed them in my tube preamp, hybrid amp and speakers. In each component the improvement was dramatic and a game changer in many ways. Universally, each component was greatly improved by a percentage easily exceeding 25 -30%. I can't understand why gear retailing for $10,000 or much more would skimp on a crossover or coupling cap. My hybrid amp used $30-$50 caps that sounded good, but not great. Same thing in my speakers for the midrange crossover caps. The Duelund CAST caps made these high dollar pieces sound the best they are capable of.

I picked these up at Parts Connextion at a great sale price recently. They are very expensive caps, but made more affordable due to the recent sale.
I cannot overstate how superior these are to all other boutique type caps often talked about in audio threads. This, at least in my experience, has been the case in my cap rolling endeavors. I say confidently they will greatly improve any component they are used in. No need to debate about synergy and the builders tuning with parts these CAST caps are just going to make good and great sounding gear much greater!

So if you have gear utilizing coupling caps in key circuit positions this is an upgrade that will deliver far more then their high cost. Spend your thousands here before any wire change or buying and selling gear. If your gear is of very high quality and the key circuit caps are good, but not Duelund CAST, consider a cap upgrade.

I purchased two .47 uf caps for $398 and four .22 uf caps for $800. I used these in my tube pre and hybrid amp. This is easily the best $1200 I have spent in my 30 plus years in audio. As much as wire and certain tweaks do improve the sound, these caps did even more. Other highly touted caps did not garner quite this reaction from me in my system.

Now, these caps would have cost me double this if not on sale. However, they would still have qualified as a best buy in terms of their impact on my music.
Duelund Capacitors are indeed great - but expensive - if they were to be used within the regular retail chain they would add about $6000 to the price of the equipment they were installed in - in your $ 1200 cost scenario.

You should try the Jupiter Beeswax capacitors too - not quite as expensive as the Duelunds - but also very good.

As always, good listening

Your right in terms of retail Peter, at least in some cases. That is why I suggest the owner take their great gear to the next level on their own. Not hard to do with some soldering practice and internet training videos.

Folks spend thousands on gear and wire upgrades and this is one way to keep the gear you currently enjoy. Of coarse one will not recoup the cost if they sell it quickly. I did these upgrades in lieu of selling and buying again. I plan to keep this gear for many years.

I still feel putting a $30 cap in a key circuit position in a piece of gear retailing for ten to twenty thousand is a bit unsettling. It is done all the time. I can't tell you how many high dollar speakers use cheap caps and resistors. I am talking from experience as I have removed the crossovers and was floored. The same is true in amps etc...

Yes, the Duelund cost, but so do these high end pieces.
I appreciate your very interesting experince/insight with these capacitors. It does seem like money well spent. My amplifier and linestage use interstage transformers in place of coupling caps and resistors.But this has me curious in regard to my speaker crossovers(would I have the space for them?). I`ll have to do a bit of research to find out.It sounds like a worth while project.
Simply locate your crossover and see the brand and size caps employed. I don't know the type of crossover, or how complex, used in your Coincident speaker. The cap values are printed on the cap.

Duelund caps are larger as they are oil types. Not sure how much room or where they are placed in your speaker. I removed the crossover from the box of my speaker and built an external crossover box so cap size is not an issue. This improves the sound by removing all the parts from the massive amount of vibrations in the bass cab of the speaker. It also helps by eliminating any interaction with the driver magnets.

Sound improved with the same parts and I took it even further with the upgraded caps.

My previous pair of $10,000 speakers used $15 Chinese caps. Hard to believe really.

If the bass cap is a large value like 50 or 60 uf , I would leave it alone and stick with the mids and highs.

The resistors and inductors used also greatly impact the sound, but the caps, in my experience with Duelund, offer the biggest improvement. Duelund makes great sounding resistors as does Mundorf for very reasonable money.
I just read Coincident uses metal oxide resistors and they may be Mundorfs and that is good. The inductors also seem to be of good quality based on current builds. The Auric caps are good, but the Duelunds are in a completely different class to be honest.
Thanks for the additional information.I sent Israel Blume an email today and he replied the caps won`t fit the space available.He is`nt impressed with the Dueland caps(I realize it`s just his opinion).In my prior preamp(Quicksilver) I installed(by a tech) Sonicaps and some V-caps and the improvement was significant.
Best Regards,
Meant Duelund not Dueland.
I got another email from Israel for clarification. The crossover only uses 'one' capaacitor and that`s for the tweeter and that`s it. So it`s a very minimal/simple first order design.So it may not be a case of him being unimpressed but that he feels it is`nt worth the effort for that 'single' tweeter capacitor.
I just read Coincident uses metal oxide resistors and they may be Mundorfs and that is good. The inductors also seem to be of good quality based on current builds. The Auric caps are good, but the Duelunds are in a completely different class to be honest.
A Duelund on the tweeter is the most important place with the mids to place a CAST cap. It would do wonders Charles. For the builder to say he does not like the CAST is, I have to say it, strange and I am being most kind. Read any and all other reviews and they always are rated #1 by a wide margin. In audio, nothing is absolute exempt CAST always being a nice improvement :-)

I figured he would say that, but the CASTs are simply without equal and on your tweeter would be heaven. No way his comment is based on using the latest CAST cap in that position. Oh well, I wish builders were not so closed minded and defensive. Of coarse some are, but many are not.

Tell him I will eat the cap if it does not indeed sound better. Well I suppose it depends how big it is!
Charles, I have Coincident Super Eclipse III speakers and upgraded the (horrible) Solen cap used in the midrange part of the crossover to a Dueland VSF (not CAST). Night and day...the improvement is major and took me by surprise. I can't figure out Israel's comments as it is clearly a significant improvement. One note of caution, the caps are glued to the speaker sidewalls and with the internal construction the parts swap is a major pain....clearly the speaker is not designed with upgrade/repairs in mind. Being a 1st order speaker there are not too many parts in the crossover so relatively cost effective to upgrade. I highly recommend Dueland...including their resistors. All IMHO and experience.
I`ve never read a negative comment about Duelund caps(only high praise). Actually I`m pleasantly surprised at how simple and bare bones the crossover is(a single cap,hard wired and no circuit board). If there were room for the Duelund I`d give it a try just out of pure curiosity, but I won`t go to the extent of external crossovers.I suspect Israel feels that with such a minimalist design perhaps a single cap won`t matter much(just me speculating of course).

Grannyring I don`t doubt for a moment the improvement you`ve found with your speakers. My 8 watt Frankenstein drives this speaker so effortlessly and with such sucess I`ll leave well enough alone.
Grannyring,I am amazed that a 10,000.00 pair of speakers came with 15.00 Chinese caps.You would think at that price point better parts would be a given.Im guessing that a certain amount of talent went into putting 10m speakers together,cabinet,drivers,finish,crossover parts,that would convince someone to pay 10m.You would think!Thanks for bringing this up.
Charles, I think the CAST cap would fit depending on the value. No doubt it would improve the sound, but understand it would cost and it can be hard to break away and go to someplace new. I have done it so often now that I no longer mind or fear the whole process. I have learned a great deal.

My crossovers are also hard wired and many are.

Raytheprinter, I would say the vast majority of speakers selling for $7500 and above use decent sounding and performing crossover parts that can be purchased very cheaply. $30 caps are a norm.

They are usually housed in a speaker cab full of vibrations that hurt the sound. Many have tested this and plotted the improvements. Actually pretty simple to mod a speaker with an external crossover. I purchased custom made wood cabs that match my speakers, upgraded the caps, speaker wire and damped the crossover cab fully with proper deadening material.

The fact is we owners can greatly improve the sound of our existing, highly touted and reviewed gear, with parts like Duelund CAST caps etc... The builder may or may not agree, but no worries as they don't often know as they have either not tried or decided they they cannot afford it. Some don't believe in these boutique caps etc... So they scoff. This scoffing is also prevalent.

I owned Soundlab speakers that came with $30 caps etc...and the owner actually helped me mod the speaker to great effect. I did a host of modifications to the active crossover based on a schematic he made for me. Great guy!

One of my favorite all time speakers are the Silverline Bolero's. They came with $20 crossover caps and the sound was greatly improved with Duelund caps. The builder did not believe in these caps! Ha!

I own another set of speakers that sounded great, but once I opened up the speaker I noticed the tweeters were wired incorrectly. They always sounded good, but a bit dull in the highs. I reversed the wires to the tweeter and bingo - huge improvement. HUGE. I will not mention the company, but they are well known.

My Aesthetix Atlas amp is amazing and a great sounding amp. I noticed the rather mid grade caps employed in key positions and replaced them with with the Duelund CAST caps and the amp now sings so much better in every single way important to the fidelity of the music we love.

One has to be willing to learn, try and perhaps make mistakes along the way. Yes, even Sphile Class A gear can be greatly improved! No, builders don't always think their gear can be improved.
As stated earlier I`ve changed caps in a preamp with good results.The cost of the Duelund would not deter me. Israel says the cap does`nt fit(he should know). Otherwise I`d be willing to give it a try to hear for myself.
Yes, the VSF are flat style and may also fit. They are also very good indeed.

Charles, you would need to know the size of the space and cap involved to know for sure regarding fit. Perhaps you can find out the value of the cap needed and look up the physical size and determine if it will fit? Duelund has changed the look of the CAST over the last 5 years so perhaps the builder does not know today? The VSF would also be a big improvement.

Perhaps they won't fit, but I would check it out to be certain. You could also put it in a different spot also with some effort may require some creativity which can be fun.
Thanks for your feedback it`s inspiring.Your speaker apparently uses different caps from the Total Eclipse.The TE is very natural and disappears with most of my recordings.The possibility that it could further improve is tempting. Perhaps from excellent to truly sublime(like the amp and linestage are).This will take more investigation.Thanks again for your insight.
My current speaker project involves nine caps per speaker! Yikes! I wish I only had one. These speakers actually came with some very good parts mixed in with mid grade $30 caps. The crossover is hard wired to boards resting in the woofer chamber. All those caps were rocking with the bass line and that is not ideal.

I replaced 4 caps in each speaker to Mundorf silver, gold and oil caps. The other 4 caps were already Mundorf SGO's. I replaced some Clarity SA caps with the SGO's.

I am intrigued with a speaker that only uses one cap? Interesting indeed. Mine is a three way Nola speaker. Not sure if the Coincident is a two or three way? I assume a three way? My speakers are about 89bd efficient so I bet my crossover is to blame for that. They are wonderful sounding speakers (Viper Reference 1ax's) and only two sets were ever made. The builder has been most helpful in this instance and is sending me some of his special internal speaker wire plus helped me with several questions.

The upgrade is almost done and they are sounding like speakers 10 times the price they cost me.
Charles, I just finished reading several reviews of your fine speaker. I now remember they are three way with 5 drivers! Amazing how efficient they are with all those drivers? Funny thing is I have always wanted to own a Coincident speaker. My audio buddy has a set of the Total Victory V's. I have listened to them on several occasions and liked them.

I actually make an offer last month on a set of TV 4's , but the offer was declined. So instead, I have decided to make my speakers be all they can be. The results are amazing thus far.

The fact that your speaker has such a simple crossover makes upgrading them very simple indeed. I would be in there looking at the internal wire, cap and resistor. That is a speaker you can keep for many, many years indeed.
Your comments are on the money. Since Israel confirmed there`s only one capacitor per speaker it seems to me that an improvement there should be quite obvious and effective. The speaker wire is the same ultra quality wire he uses for his cables and for wiring his amplifiers and preamps(6N copper,I won`t mess with that. My thought is to consider the Duelund caps(Cast or VSF and their best resistors). I have a friend who`s capable of doing the work and can tell me if it`a go or not.

Grannyring thanks for this thread, it really has me thinking.

fizzletop, do you get to the crossover via the bottom of the speaker?
I can understand your interest in other speakers even when you`re happy with what you have,there`re very good choices available(and you can`t own them all).In my case the Horning speakers and also the PHY driver Ocellia and Tonian Labs interest me. They `re all high efficiency,easy load and all have very simple crossovers.

I`ve own the Total Eclipse for 4 years and just love them.If a single capacitor and resistor swap can potentially improve an already very good speaker then why not give it a try? Worse case scenario, if I don`t like the change then it`s back to the original parts.My willingness to attempt this is increasing.The sound is already very open, transparent,emotionally involving and organic, if it gets better,wow!
Charles, I think the Duelund upgrade took the Coincident SE III speakers from being "very good" to "great" status. I did the mods a couple of years ago and IIRC there are cap/s, inductor and resistors also for the bass drivers. As these aren't such a critical position I didn't upgrade anything for the bass drivers except swapping in Duelund resistors. To get to the treble/mid crossover on the SE III I took out the top side firing bass driver and used this as the access point. It was really a difficult process as the crossover is actually placed up high in the speaker behind internal bracing. I have next to no technical knowledge and not blessed with an abundance of patience...if I can do it, anyone can! In my view, like don't really have anything to lose by giving it a go. Despite all this, I'm back to RMAF this year on a quest for my next speaker....based on auditions so far the contenders include Vandersteen 7, Nola Baby Grand or Verity can see that in my opinion you need to spend quite a lot more to improve on the upgraded Coincidents. I have heard that the Vandy 7's use Duelund in their crossovers....that's a plus! Cheers, Fizz
I think the larger and more exspensive Total Eclipse is a better speaker than the Super Eclipse(as it should be i.e. higher up in their speaker line). I heard the Vandersteen 5 extensively 2 weeks ago(in someone`s home system) but would much prefer the Total Eclipse.I`ve only heard the larger Vandersteen 7 briefly at both CES and RMAF so I really don`t have an opinion.I wish you the best sucess with your new speaker search.
Just discovered tonight that the Total Eclipse speaker does`nt use a resistor at all! All I`ll have to do is replace the one capacitor and I`m done.
Wow! Buy the best then - get a Duelund CAST! Parts Connection can get the value you need with a big savings. Call/email Chris for a quote. He is running a big sale right now. That's if it fits. These are flat style so I can't imagine why in the top section of the cab one cap would not fit.

So your speakers must use inductors for the most part. Goodness that is most intersting. I will learn more about this approach to speaker design and crossovers.
Usually speakers that use only one capacitor or resistor in their crossover design is using a series crossover. Fried uses a series crossover as well. A series crossover is a lot harder to implement and not many designers use them.

I bet they would be! It was also more costly for me to upgrade the caps in my 9 cap crossover!
The capacitor size is 5.6 mfd per Israel Blume. I`ll call the Parts Connection and see if Duelund has this size cap and if so how large.Israel suggested the
Mundorf Silver-Gold as a good alternative.The speaker does use a large inductor by the way,is this relevant?
I just purchased the Mundorf SGO caps for my speaker project and have also used them in preamps. They are simply not near as good as the CAST in every respect. The CAST are far more natural and organic sounding. The SGO caps are good, but sound Hifi compared to the CAST's.

I had to buy 8 caps for my current speaker project so the CAST caps were simply too costly. But only 2, then go for the best!

The CAST copper caps are just amazing and sound good right away without break in. With break in they get even better.

The SGO's are good and surely a nice upgrade, but the CAST, well they are a revelation.
if you include replacing a stock tube with a nos tube, than i have heard significant alterations in sound by selecting an appropriate tube and removing the tube supplied with the component.

Chris at Parts Connection can order that size for you and will get pricing
from Frederick at Duelund. I forgot to mention that be sure to order the
CAST copper caps for crossover use, not the high voltage 630 v ones
meant for electronics.
Thanks for your comparision/impressions of the Mundorf and Duelund capacitors. The key word you mentioned is "natural", that is of the highest importance and is how I tried construct my current system based on that principle. I`m allergic to the"Hifi" sound and approach, the sound must be holistic and organic = realism.

If the Duelund Cast copper caps will fit I`ll buy them. If they don`t then perhaps the VSF version caps will fit the available crossover space.

Grannyring I love the current sound of my system and don`t want to lose that.Your enthusiasm and description of the Duelund Cast seems it will push me further in the direction I prefer, natural music reproduction.
Despite 3 phone calls and an unanswered email I can`t get anyone at the Parts Connecxion to give me the dimensions of the Duelund CAST Cu capacitor 5.6 mfd. I do have a price(20% discount) and was able to get the size of the VSF Black Cu capacitor(it will fit the space) and price from the web site. what`s the difficulty in getting the CAST cap size is beyond me.
Chris has always gotten back to me when I emailed? Use the email
address on his site and in the subject line mention " attention
Chris". You could also call PC to place an order and ask the person
who answers to get you the size. Lastly, I would also email Frederick
directly at the Duelund site as he is the owner and can also help you. he
also responds promptly based on my experience.

I also suggest you ask if he is offering the same discount on your caps as
offered on the other sizes on his sight. I am pretty sure you will get an
additional discount beyond the 20 percent .

Good luck.
I was able to get CAST capacitor dimensions from Duelund site via email(finally!).26mm x 163mm round shape.I thought they changed to a rectangle chassis last year. Are yours round or a rectangle? Seems the rectangle would be a better fit in my crossover if available.What type of adhesive do you use to hold them in place?
I just learned that the new rectangle chassis is only for special order 'smaller' value capacitors. For me it looks like I`ll have to use the moonpie(round) chassis instead.
163mm diameter = 6.5" fairly large, height is 26mm.
Charles1dad, how do you access the crossover on your TE? I have the same speakers and this has thread has inspired me to contemplate changing out the caps in my speakers.
Hi Brf,
You just remove the lower 10" woofer. There`s actually a fair amount of space at the crossover site.Certainly enough to place the Duelund VSF caps and possibly even the larger and round CAST copper caps also.

All these years and I did`nt know the crossosver was so very simple with minimal parts,single cap and an inductor. I know what you mean Bfr. If this speaker sounds this good with the Auricap(considered a good cap) then in theory(anyway) it should improve if the Duelund is as superior as many claim it is.Grannyring really got my attention on this one.
Round is what I am used to. In terms of mounting I have used these with quality zip ties. You could put five or six of them down in an + pattern and secure with zip ties North/south and East/West.

You can also hot glue right to the speaker. I like the first method the most if you can get your hands in there.

You can also use the first method above and attach to a thin plank of wood first. The 1/4 inch plank could then be glued to the inside of the speaker.
My friend and I determined today that the CAST version will fit. I`m likely going to use Duelund`s hook up silver foil(is foil ok?) wire with the silk cover. What gauge hook up wire did you use/suggest for your crossover and what type of solder? Finally are these caps directional?
Charles, not sure why you need any hook up wire? Simply place where the other cap is and use the leads on the cap? This is best. If you need wire as an extension because the cap is going in a different spot, I would use the same wire in your speaker. Get some from the builder.

Your builder uses good quality copper and I would stick with that.

These style caps are not directional.
Due to the different site to accomadate the 'much larger' Duelund cap I`ll need an extended wire to connect the cap leads to the inductor. What type and diameter of solder is best for this project. I want to do things right the first time(rookie).See what your thread started? LOL.
I use Mundorf silver, gold lead free solder. 100 grams of it at PC for some $60. Any solder with 4% silver from WBT and Mundorf is fine. I like the Mundorf with silver and gold.
Well I placed my order for the Duelund CAST Cu capcitors today and should have them in 4 to 6 weeks. I`m quite curious to hear what they do to the sound of my 300b SET based system.Upgrading the one and only capacitor in the speaker 'should' in theory matter a lot. I`m rather optimistic. When I changed my 300b tube from the Shuguang Black Treasure(very good) to the japanese Takatsuki-TA the change was unexpectedly hugh(sublime now). If I can get even 1/3 of that level of improvement with the capacitor switch I`ll be very satisfied.
Congrats and I hope you got a good price. You will be most pleased I am confident. Give it some 100 hours for decent break in. That is a big cap and it will take a little time to hear all that is coming.
Thanks for the thread and bringing the Duelund CAST cap to my attention.
The CAST caps in my tube preamp and hybrid amp have now fully broken in and my music is so beautiful and natural. I was listening today and I could not turn the volume up too high no matter how many clicks I went up on the knob. I don't listen to loud music often, but it was pure enjoyment with peaks of 97-100 db. Smooth, natural, huge and effortless.

I usually listen with peaks in the mid eighties. Words cannot describe the utter beauty and scale of my music after this cap upgrade.

My CD player is next. I will need to learn which caps are most important in my player and that may take some time. All I see are Panasonic caps everywhere and I simply want to upgrade those most important to the signal.
Can you tell me which components were for the Atlas amplifier only since I am considering getting this?
Was the change in the Amp great enough as in the Pre-Amp?
Did it improve on the low end body as well as the resolution?
Sorry for all these questions.