As Roxy54 noted, it seems that both paper-in-oil and mylar are available:
http://jeffsplace.me/wordpress/?p=3794 |
I have Mundorf S/G/O in my speakers but am going to replace them with Duelund VSF copper. I ordered the VSFs earlier this week. If I had room in my speakers I would have opted for the CAST copper capacitors.
Having lived with the S/G/O for the past five months, what has me wanting to move to the VSFs is that I want to go from "slight top-end emphasis" to "tonal balance near perfection" as Tony Gee wrote.
Compared to the Mundorf S/O or S/G/O, might I also be picking up a little more richness or liquidity in the midrange? |
I have one other question that I'd like to ask this group. In my speakers I am using Mundorf S/G/O and Mundorf M-Resist Supreme resistors. As I mentioned in my previous post I am planning to replace the S/G/O cap with VSF copper, but am also wondering about the resistor. If I keep the M-Resists then the VSF will be a simple drop in replacement. If I change to a Duelund resistor, I'll have to figure out a different topology.
I am wondering if changing out the Mundorf resistor for a Duelund resistor would make an audible difference? |
Volleyguy and Irish65:
I wanted to thank you both for your responses. I am going to place my order for a pair of the new CAST resistors today. Duelund is going to make them a little shorter and wider than the standard offering so that they'll fit better in my speakers.
And I must add to this thread that over the weekend I exchanged several emails with Frederik Caroe, owner and founder of Duelund Coherent Audio. He was a huge help! When discussing the dimensions of his CAST copper capacitors he offered to custom make them if necessary to make them fit in my speakers. I didn't follow up on that discussion because I suspected they would still be too big for my application (too bad!!!!) so that's why I opted for the VSFs.
But the point I want to make is that working with Duelund Coherent Audio has been great. I haven't even heard Frederik's products but I am already a big fan of his company and give my highest recommendation to anyone considering his products.
Also, regarding the potential for the VSFs to sound flatter compared to the Mundorf S/G/O, I asked Frederik about that and I trust that he won't mind me posting his reply to me on the subject:
"It's not a question of lack of depth, the VSF simply doesn't sound shut in like a metalized cap does. The shut in effect is often mistaken for depth."
That response has me very intrigued and anxious to experience the new sound that my system is going to provide. I'll update this thread accordingly, but it'll take a couple of months for everything to arrive and get broken in. |
Volleyguy,
Wow! Thank you for your responses. I had kept the original internal wiring and only changed the capacitor and resistor. I had been reluctant to change the inductor or internal wiring, but do you have some wire in mind?
Also, I hate to admit it, but I had not thought about the noise. Ive been so focused on tone. But no matter how much Id rather have the CAST capacitors, I dont have room in my Silverline SR17.5 speakers.
But I did order a pair of CAST resistors today. I think they are normally about 12.5cm long, but to fit into my limited space, Frederik is going to make them 10cm x 0.8cm.
PartsConnexion is having a 15% off sale, but still the total for the two caps and two resistors was around $400. I hope that's enough $$$ for caps that are not too noisy! I'm hoping too that my (although ballsy) monitor speakers won't vibrate the caps enough to make resonance become an issue. I sure know the S/G/O seems quiet to me and if the VSFs are that quiet, then I'll be a happy camper.
And thanks again for your help! |
Irish65 and Volleyguy,
Thank you for your comments about the external crossover. While I cannot pursue that option with my current project, I am working with a friend on an outboard crossover for his Silverline Bolero speakers. His project is moving along slowly at the moment but I am sure both of your council will be very helpful when things get going again.
The Duelund cast components my be a little too pricey, but since the crossover would be isolated from vibration by virtue of its being outboard, would the sonic gap between the VSF and CAST components be substantially narrowed?
Thanks for both of your help. |
Irish,
Thanks for your note. For my SR17.5 speakers I did get the CAST resistor. I received shipping notification on Thursday, so maybe by next weekend I'll be getting my first impression of the new crossover.
As for the Bolero, I don't know the values yet as my friend has not had a chance to measure them yet. It may take him a little while to get to it, but once he does I'll pass along the information.
Thanks again for your help. |
Volleyguy: Your friend is lucky to have your help.
Volleyguy and Iris65: I'm curious, what components do you have in your system? I have Rogue 99Magnum preamp and M180 monoblocks. I'm running NOS RCA tubes that I got from Andy.
My VSFs arrived the other day. These things are dense! They feel like they just have to sound good! I took them by the shop. I dug out a regular $3 cap (3.3micF just like the Duelund)... the two shop owners were in separate parts of the shop, so I did this separately...I had each close his eyes and hold out both hands. I put the $3 cap in one hand, then the Duelund in the other. Both times their eyes shot open! It was good for a few laughs. I can only imagine how heavy those cast caps must be!
It may be a week or so before I can get them put into my speakers - I'm out of town at the end of next week and have to get ahead on a project at work before I leave. But I'll update you guys when I finally get them in. |
Michaelvv,
I had the Mundorf S/G/O in a pair of speakers but changed them out for the VSF copper. The S/G/O had too much emphasis on the high frequencies for me. The VSF, on the other hand, sounded faster and richer, with great detail. In my system and for my taste, I enjoyed the VSF much more than the S/G/O. |
Volleyguy,
It's been a while since I last posted on your thread and I have some updates to give, and a lot more questions to ask regarding a new crossover project.
When I last posted here I was had two things going: (1) I had ordered the Duelund VSF Copper caps for my Silverline SR17.5 speakers, and (2) I was helping one friend with the prospect of modifying the crossover in his Silverline Bolero speakers. Since my last post I installed the VSFs in the 17.5s, ended up selling them to a friend, and bought the Boleros from my other friend. The Bolero crossover project was never undertaken, but that is the project I'm considering.
I. The Silverline SR17.5 upgrade: Duelund 3.3micF VSF copper capacitors and cast resistors: The cast resistors are normally 5" long but that would have been a tight fit in the 17.5s. I exchanged a few emails with Frederik and he said they could make them any length I wanted. We agreed on 4" and he said to have the folks at PartsConnexion put that specification on the order form. However, the resistors I received were 5" long. I don't know if the person at PartsConnexion ignored my specific request to make it clear on the order form that I wanted a 4" resistor, or if Duelund made the mistake. I decided to try to make the longer resistor work - as I said, 5" would be a tight fit, but not impossible.
On the first speaker I got the VSF capacitor and resistor installed and the mounting board put back into the speaker cabinet. I was anxious to hear the VSF so I immediately went upstairs from the basement, connected it to one of my monoblocks and gave it a listen. The sound was clear, but a little bright and thin. A few moments later, literally as I was walking across the room, the volume coming out of the speaker suddenly dropped - the sound was then richer and more harmonically balanced - I instantly knew what Tony Gee was talking about. I guess the cap got its first good charging. At first I thought I wasn't hearing as much information through the VSF as the Mundorf S/G/O, but after listening for a little while longer I realized that everthing was there, it was clear as a bell, but it was more harmonically balanced and structured than the S/G/O, and this was after about 20-minutes listening, not the 200-hours break-in on which I was still planning before forming a definite opinion.
I went back down to the basement and installed the Duelund components for the second speaker. However, when I was putting the panel back in the speaker one of the leads from the CAST resistor got stressed and snapped where it enters the resistor. Like I said, 5" was a tight fit. I was a little annoyed and didn't feel like fooling with getting another one so I put my Mundorf resistors in the circuit. I took the speaker upstairs and listened to them both in the system, one with the Mundorf resistors and the other with the Duelund. I listened for only a few minutes but didn't hear a glaring difference so I took the CAST resistor out of the first speaker, replacing it with the Mundorfs so that the crossover components would be consistent between the speakers.
A few days later the guys that own the local stereo shop here came by for a listen. They'd heard the 17.5s with the stock and the S/G/O capacitors. Upon hearing the VSFs one of them quickly remarked that they were faster than the S/G/O caps. I hadn't thought of that, but I think he was right. Compared to the S/G/O, in summary, I found the VSF's sound to be more harmonically structured and balanced; richer; denser; faster. It had all of the detail of the S/G/O, maybe more, but it was all in balance. It certainly did not have the "slight emphasis" in the treble of the S/G/O.
My friend with the Silverline Boleros had to put his crossover project on hold for a while and in the meantime acquired a pair of Sound Lab electrostatic speakers and made me an offer on the Boleros that I couldn't refuse. So, to help fund that purchase, I sold the 17.5 speakers to my best friend back home for his home office. I had helped him put together his system, which was intended originally for a room larger than his home office. He had a Denon PMA 2000 Mark-IV integrated amp, Rega Saturn CD player, Canton Chronos floorstanding speakers, and some vintage Audio Magic Sorcerer silver speaker cables and interconnects. We swapped out the Chronos speakers for the 17.5s, the Chronos will end up in another system at some point.
Over the next several months I kept telling him that he didn't need the power of the PMA and that he would likely enjoy having a small tube amp in his office instead. He had never heard a tube amp before - I'm not even sure he'd ever seen one. In the shop here there was a mint condition Ayon Spirit-1 integrated amp for sale and I thought it would be a good amp for him. I took it with me when I went home for Christmas to see if he would be interested in buying it. We put the Spirit into the system and it wasn't long after the amp had warmed up that he looked at me and said, "I only thought I knew what texture in music sounded like." Although he is new to this level of audio, he has good ears and just nailed it with that and a subsequent comment about the tube/Duelund combination: textured and organic. And that, I think is the best assessment of the Duelund VSF, and from reading this thread, I am sure is even moreso with the components higher up in the product line.
Now to the Silverline Bolero speakers I acquired. They use Dynaudio drivers, including the Esotar tweeter. The stock crossover uses two each: Solen caps, cement resistors, and I assume in-house wound inductors. The speakers sound nice, but what I really hear when I'm listening to them is potential. The Esotar tweeter handles everything I throw at it without strain, but I have a strong feeling that it is capable of much more than what I'm currently hearing.
For this project I am going to go outboard with the crossover. My first choice would be to use VSF copper capacitors, and Duelund inductors and resistors, but using those components in the crossover I have in mind, I estimate would put the cost at around $5000. I can't justify that cost so am going to have to make some compromises. I know that the main contributors to this thread have long since settled in on the excellent Duelund CAST components, but I would like seek your advice based your experience with very good components with which you had prior experience.
Here's what I am considering:
1. Capacitors: Each speaker uses one 4.7micF and one 15micF capacitor.
a. Mundorf MK Supreme. This would be the most economical of my group and I'm sure an improvement over the stock caps. Of my group it may be the best choice sonically too. I would appreciate your feedback.
b. Mundorf S/O. I've read this thread pretty much entirely and am aware of you and Tempo Electric having heard an upward tilt toward the high frequencies, though some disagreed. My experience was with the S/G/O and I certainly didn't care for what Tony Gee described as its "slight" emphasis in the treble. I noted too, however, that Tony Gee did not mention an upward tilt associated with this cap. As one comment on this thread mentioned, perhaps Tony Gee has a preference for a bit of an upward tilt, so he didn't think to mention it in his review of this cap, whereas what he described as a "slight" upward tilt with the S/G/O was just too much for me.
However, the SR17.5 speakers used the Dynaudio Esotec tweeter rather than the Esotar, and they are definitely different to my ears. I think of the Esotec as a high-revving Honda and the Esotar as a big Harley - just cruising along, never strained. If the S/O has an upward tilt, but less than the S/G/O, I may be okay given the way the Esotar is used in the Bolero... I read a comment in a review of the Bolero that Alan Yun seemed to operate the Esotar in such a way as to let it sing rather than its trying too hard to make a case for itself when compared directly to the Merlin VSM. In fact, the friend from whom I bought the Boleros used to own a pair of VSMs and said that their implementation of the Esotar was indeed entirely different.
c. Clarity Cap MR. I am intrigued by Tony Gee's mention of its ability to seperate instruments, but am concerned about his mention of "slight focus on the lower treble" for the reasons related to the S/G/O above. But if anyone would please share his experience with the MR it would be a big help. This cap is also available in 15micF so would be easier to deal with.
d. V-cap (Oil Impregnated Metalized Polypropylene) Series. This one intrigues me and I am tempted to fly blind and give it a shot. Does anyone have any comments about it? Also, some of the capacitors in this series have a breakdown voltage of 150VDC, is this enough? The VSF is 200VDC. Therefore, not knowing any better, if I were to go with these I'd use the ones with the 250VDC in parallel to achieve the required 15micF.
2. Resistors. I'm going to go with the Duelund CAST as I figure that I can install them in an outboard crossover without breaking the leads. I hope!
3. Inductors. Here's where I'm flying totally blind. In an email exchange with Alan Yun a while back about the inductors in the SR17.5, he mentioned that the internal resistance, inductance and capacitance were optimised and designed for the best synergy. He mentioned that a heavier gauge on the inductor would result in unwanted larger capacitance.
On this project, however, I'm going to go ahead and replace the inductors too. Instinctively I was thinking that I'd go with Alpha Core 12awg but PartsConnexion is carrying ERSE which they claim is a better and lower cost alternative. I guess I'd like to ask for comments related to:
- Alpha Core or ERSE, North Creek, or Mundorf Inductors
- And what are the benefits/penalties of increasing the awg of the inductors? I noted that the Duelund inductors are 12awg, so that again instinctively seems like maybe a good place for me to be as opposed to the NC 10awg or 8awg, but I would appreciate any advice.
Volleyguy, I also want to take this opportunity to commend you on an absolutely great thread. I spent several hours yesterday reading it from the very beginning. I learned a lot and really appreciate what you and all the others on this thread have shared.
Much thanks,
John |
Undertow,
Thank you for your reply and for the offer of your North Creek inductors. I have not measured the values of the inductors in the crossover yet, but I will certainly keep yours in mind if it looks like they will work.
I read your posts on this thread and found them very helpful, especially with regard to the Clarity MR caps. I may just go with all Clarity MR. However, I also read your comments about the combination of caps and was wondering if you would please give me your take on the below options. I haven't confirmed the crossover topology yet, but I am assuming the 15micF is associated with the midrange and the 4.7micF with the tweeter. The ratio of capacitor values were based on what was available on PartsConnexion:
1. midrange: 15micF Clarity MR
tweeter 4.7micF Clarity MR
2. midrange: 12micF Clarity MR + 3micF Duelund VSF
tweeter 4.7micF Duelund VSF
3. midrange: 12micF Clarity MR + 2 x 1.5micF Mundorf S/O
tweeter 4.7micF Clarity MR
Also, with regard to the inductors, if I do use an 8awg on the woofer, would it be advisable to use an 8awg for the midrange for consistency, or back off to 12awg, etc?
And finally, does the increase in gauge of the inductor increase the intensity, say of the bass, or does it just speed things up?
Thanks again for your help,
John |
Undertow,
Since posting my response last night I went out to the North Creek website and in their write-up they mentioned the 8&10awg inductors being associated with both the mid- and low-frequency drivers. Whichever I do, 8awg or 10awg, I think I'll use the same gauge with both drivers for consistency; and for this project I believe the North Creek is the right choice.
Also, the crossover in the Bolero is 1st order:
tweeter: RC
midrange: RLC
woofer: L
Of the following three options:
1:
midrange: 15micF Clarity MR
tweeter: 4.7micF Clarity MR
2:
midrange: 12micF Clarity MR + 3micF Duelund VSF
tweeter: 4.7micF Duelund VSF
3:
midrange: 12micF Clarity MR + 2 x 1.5micF Mundorf S/O
tweeter: 4.7micF Clarity MR
I think option No. 1 seems pretty straightforward, but I sure would appreciate your comments on Nos. 2 & 3.
Thanks again for your help. |
Undertow,
Thank you for your reply, and I apologize for the confusion - I sure wasn't clear what I was talking about in my previous post. The current project involves my pair of Silverline Bolero speakers which still has the 100% stock crossover in it.
The VSF capacitor I mentioned in the previous post went into an earlier set of speakers, a pair of Silverline SR17.5 (2-way) monitor speakers that I ended up selling to a friend to help fund my acquisition of the Boleros. I was trying to relate, albeit poorly, that on the earlier SR17.5 project I had kept the original inductor on the mid/bass driver. The original inductor used a small gauge wire. While the tweeter ended up with a very fast and organic sound thanks to the Duelund capacitor, it always seemed to me that the mid/bass driver couldn't keep up with the Duelund's speed - that it needed a bigger engine behind it.
The Silverline Bolero speaker's stock inductors use a similarly small gauge wire, so on this project I want to make sure that I give the woofer and midrange drivers a more potent engine. That's why I am focused on the larger gauge inductors.
I have not made my final decision on the inductors, but your experience with the 8awg North Creeks compared to the 12awg film inductors was exactly the information I needed to help me make my decision.
I still need to measure the values of the inductors currently in the speakers. If I can match those values using large gauge inductors (10awg) that will fit in the outboard crossover enclosure I have in mind, then the crossover I have envisioned is:
Capacitors: 100% Clarity MR
Resistors: 100% Duelund CAST
Inductors: 100% 10awg Mundorf film
I recognize that with this crossover I am not going to achieve the same results as going 100% Duelund, especially CAST, but I am confident it will be a big improvement over the crossover that's in the speakers now while at the same time fitting within my budget for this project.
I want to thank you again for your time and help, and I apologize for the confusion caused by my previous post.
Best regards,
John |
Undertow and Face,
Thank you both very much for your replies, they were very helpful. Based on your experience, for this project I'm going to go 100% Clarity MR.
As for the inductors, I was planning to match the manufacturer's values but experiment with a heavier gauge. But Face your comments are well received and appreciated. I figure that if I don't go too exotic then I can always backtrack without much loss. I don't know what the gauge of the wire used in the stock inductors in the Boleros is, but it looks pretty dinky. And Undertow, thanks for the warning about the size of the 8awg inductors. Once I had the required inductance values I was going to figure up the layout requirements, but something the size of a car battery is likely bigger than I would can use due to space constraints.
I was just looking at the U.K. site, hificollective, and the Mundorf 10&12awg foil inductors look interesting, particularly the 12awg as they are not too expensive should my foray outside the 5% DCR value Face recommended prove disastrous... and from looking at the stock inductors I'm assuming I'll end up outside that 5% boundary. The same would hold true for the more moderate gauge North Creek inductors too I think. I'm just going to have to get the inductance values I need and have a look at the dimensions of these options to see what's feasible for me.
Well, I think capacitors and resistors are settled: Clarity MR and Duelund CAST, respectively. I'll just have to decide between the North Creek wire and Mundorf foil coils.
I also want to say that, Undertow and Face, I have read all of your posts on this thread and they were exactly what I needed. For this project I needed to make the best compromise I could for cost/performance and I am very confident that the MR is the way to go. Thank you again for your help and for sharing your experience.
John |
Undertow and Face,
I don't think this is necessarily a good question as you probably don't have enough information about my system to provide the quality of answer you would prefer, but I'll ask anyway: Do you guys have a preference between wire versus foil inductors? It doesn't escape me that the Duelund is a foil inductor, so maybe the Mundorf foil might be a good compromise for me. But I also note that Undertow has used North Creek wire inductors before and that Face mentioned the Goertz Copper Foil inductor in one post.
Between the two types of inductors, what would you say are the trade offs?
Thanks again for your help,
John |
Face, Ait, Irish65 and Undertow,
I wanted to thank you all for your replies, each was very helpful. While I would love to use Duelund CAST in part or all of this project, unfortunately my budget priorities preclude it. I believe, however, that with the advice I am getting here I can arrive at a very musically satisfying crossover that I will enjoy for years, and I may indeed upgrade it again to include some CAST components.
I haven't measured the values of the inductors yet but was planning to send them off to have that done more accurately than what I think we could do in the shop here in town. As Undertow suggested I did a bit more digging and basically found that there doesn't seem to be a clear cut answer as to which is better it seems application driven but the film inductor being a little more organic really hits home with me. I may try the 10awg Mundorf film just to do it, but I'm sure the 12awg would indeed already be overkill. I recently put some Telefunken ribbed plates in my monoblocks and feel that I have some system dynamics to spare, so moving more in the organic direction of the film inductor rather than more punchy should be the right move.
I'm sure that either of the inductors I am considering will be better than what's currently in there. I figure too that making such a radical change in the inductor, particularly in terms of DCR, will have a big effect on the speakers. I had avoided doing this on the 17.5s, staying instead with the stock inductors. But as organic as those speakers sounded, it just didn't seem that the midrange/woofer driver had an engine behind it that would let it keep up with the speed that the Duelund VSF brought to the tweeter. It's somewhat of a shot in the dark, but that's what I want to see with my first pass at the inductors on this project will the large gauge film inductors take the system in a faster and more organic direction.
Again, thanks so much to each of you, you have been a HUGE help.
John |
Irish and Ait,
Thank you both for your replies and for your suggestions about the inductors. My primary motivation for this project is not actually the improvements brought by the inductors per se but rather the improvements that I know an upgrade in capacitors and resistors will make.
On the earlier SR17.5 speaker project, that speaker was a 2-way monitor with a 1st order crossover. There was a single capacitor and resistor going to the tweeter, and a single inductor on the mid/bass driver. I heard the benefit from the capacitor/resistor change, but decided that if I ever did anything like this again that I was going to replace the inductors as well, it is only a question of which type to use.
The experience you and others have shared on this thread has been tremendously helpful and appreciated. I know that I am not going to get the improvements I would if I were to use Duelund (I'm a big fan of that company and its products) but I am confident that I am on a path that will yield very good crossover nonetheless.
Again, thank you for sharing your experience and for taking the time to post your response.
John |
Ait and Irish,
Thank you for your suggestions regarding the potting compound idea, and I apologize for not acknowledging your suggestions before now. I didn't immediately comprehend your suggestion, but I got it now. For this project I am not going to use the stock inductors, but constructing my own improvised CAST-like inductor with whatever new inductors I get is an intriguing idea. I may not pursue it, but I'd like to understand your idea a bit more. Since we're talking about loosely wound wires, here's my loosely wound notes and questions!:
- Is the potting compound you have in mind 3M DP270?
- I wanted to confirm, by ABS, do you mean acrylonitrile butadiene styrene, and where does one find such containers?
- I noted on the North Creek website that their inductors are varnish sealed in a vacuum chamber so that the varnish penetrates into the inner coils.
- In a previous post on this thread regarding his CAST components, Frederick mentioned, The CAST is special in the sense that we can harden it after the vacuum impregnation. If Duelund's CAST material is similar to the DP270, then I could well imagine it being a more robust compound than varnish penetrating into the inner coils, but I believe I understand why you were thinking of the potting compound as an additional step taking the inductor in the direction of the CAST system.
- I am intrigued with the idea of doing this with a North Creek inductor. Once I get my inductors measured and the dimensions of the equivalent 10awg and 12awg inductors, I'll calculate the volume of potting compound required. Perhaps an ABS tube down the center of the inductor would be okay to take up some volume, thus reducing the amount of potting compound required to cover the inductor?
- If I go with Mundorf coils it doesn't look like there's any chance of the potting compound penetrating to the inner coils, but the North Creek website mentions possible oxidation issues with foil inductors so the potting compound would certainly eliminate that issue.
This is a really neat suggestion, and as always I thank you for your time and help.
John |
I want to thank each of you again for the help you have given me and for sharing your thoughts and experiences. You have all been very thoughtful with your responses, and very generous with your time that it took to write them, and I again wanted to express my appreciation. Given the philosophical nature of some of the recent responses, I wanted to explain the reasoning behind the course I have decided to take so as to avoid giving the impression with any future questions that I had not appreciated or recognized the wisdom of your suggestions.
I have speakers that I intend to own for a long time and I could live with them as-is very happily. I would not have bought them otherwise. I believe that Duelund CAST would be the best way to extract their full potential, but as I have mentioned previously my goal with this project is to extract as much from them as I can on a smaller budget.
When I decided to undertake this project the caps that immediately came to mind were Mundorf Supreme, Mundorf S/O, Mundorf S/G/O, Clarity MR, and Deulund VSF. I arrived at the decision to try the Clarity MR was based on the following:
- As I read this thread, and I have read it in its entirety, the MR was for one of you the last cap standing, so-to-speak, before the full transition into Duelund, so I figured that was a good place to start.
- My experience with the Mundorf S/G/O was with a Dynaudio Esotec tweeter. This project involves a Dynaudio Esotar tweeter. The fact that I am already making such a big change from my previous speaker makes me willing to establish a new baseline with the MR, Tony Gee's comments about its sonic nature notwithstanding.
- Neither the S/O and S/G/O are available in a 15mF value and I'd rather just try a single MR.
- While the MR is certainly a compromise compared to the Duelund, several of its attributes described on this thread are appealing.
- I do not foresee to changing my preamp, amp or cablin. I have access to quite a lot of tubes that I can use to make further refinements as long as the MR gets me close to where I want to be.
- Duelund CAST resistors are a no-brainer.
- From my prior project I know I want to try larger inductors, but which ones, that is the question. That's where the most recent responses have been so helpful. I haven't decided which way to go yet. A potted North Creek is attractive because I could just send the stock inductors to North Creek, have them measure their values, and then build the new ones. On the other hand, there's a chart on the Mundorf website showing how quiet the 10awg foil inductor is already, and maybe I could pot one of those. I'd just get my stock inductors measured elsewhwere. I'm still digging around trying to figure this one out, but the fact that you guys told me about doing this is really great and I am truly thankful to you.
John |
Irish,
Thank you for your reply. I did not take your suggestions as your trying to pound across your point. I am keenly aware that you and the other members are genuinely trying to help. Your sincerity has never been lost on me, and the time you have taken to help me has always been appreciated.
I was feeling bad that you and several others were spending more of your time trying to provide guidance when in fact I had reached a comfortable launching point for the project based not only on your advice but for reasons I had not communicated based on the merits of the MR cap as well as through a process of elimination of other options that I just didn't want to try. I wanted to acknowledge your replies - I certainly did not want to come across as ignoring your suggestions or as being unappreciative. The only considerate thing I could think to do was to explain my thoughts more completely. I am glad that you received my explanation in the friendly spirit in which it was intended.
Undertow and Irish,
I finished writing the above note and just found your comments about the Jupiter HT cap. There's certainly no problem with throwing a monkey in the wrench! I'm going to dig around a little and come back with a few questions if you both don't mind. As always, I appreciate your help! |
Gentlemen,
Would a steel or aluminum enclosure be a bad idea for the crossover?
Also, I think I'll be able to keep the crossover about a foot away from my monoblocks. Inside the crossover I'll certainly orient the inductors so that they don't interfere with each other, so while I'm at it I suppose it would be a good idea to orient them so that their magnetic field isn't pointed at the amplifiers too.
As always, I appreciate your thoughts,
John |
Regarding my last questions, nevermind. I found the answer regarding the enclosure - definitely not a good idea! And I think I'll be okay with the placement relative to my amplifiers. |
Tom,
Thanks for your reply. Below are a couple of the comments I found on another forum that had me thinking that I should stick with a wooden enclosure:
"...I think you are right about the enclosure. It is a Faraday box. Any magnetic fields inside that box tends to get squashed if they are not static."
"An aluminium box will lower the inductance of the coils quite a lot, as would a brass box. A steel box would increase the inductance a lot. Either way you could also be having a faraday effect, or at least a compression of field lines, or even a coupling of 2 coils via the box."
I don't know if the above statements are correct or not, but they raised my concern. If a steel chassis is in fact benign related to the inductor's magnetic fields, then that would be one option I might explore.
Thanks again for your help,
John |
Tom,
Wow! That is a generous offer, and thank you. However, I would hate to see you or your friend go to any trouble since I have not decided upon a metal enclosure but rather saw some when looking on the internet and was curious, although instinctively skeptical, about using them for the crossover chassis. I know some guys around town who are woodworkers and was thinking of having them make me a couple of enclosures out of black walnut. I would have them made out of solid wood and mount the crossover components on the base in the manner you suggested. I will use some spikes to couple the enclosures to the floor through the carpet also as you suggested.
Thanks again for your help,
John |
Gentlemen,
For my crossover one of the required capacitor values is 15micF, which is an available value in a single Clarity MR.
However, I came across a website (reference and excerpt below) in which the author said that for values above 10micF it is better to use several smaller value capacitors rather than a single large value capacitor.
I was wondering if you would please comment on this?
As always, thanks for your help,
John
Reference: http://audio.calsci.com/X-Overs2b.html
10th & 11th paragraphs:
"Whenever you need a capacitor over about 10µF, it's best to build up the capacitor from several smaller capacitors...
"The reason for adding up many small capacitors is that the capacitors have inductance and lead resistance, which make the capacitor less useful. When you place resistors and inductors in parallel, their effect shrinks, but the capacitor's effects add. So, building up large capacitors by placing several small capacitors in parallel makes our capacitors act more like perfect capacitors. This is a good thing." |
Gentlemen,
Subsequent to my earlier post, I noted that Clarity MR is available in 7.5micF, so my question would come down to whether it is better to use two of those or a single 15micF?
Thanks,
John |
Tom, thanks for your response, that certainly makes the crossover more straightforward. |
K2,
Thanks for your response and your experience is certainly something that I will keep in mind if I don't like the results of my first iteration.
John |
Regarding my last post, I figured out the answer so would ask that no one waste their time writing a reply.
Jburidan,
There is a "Black" capacitor described on the Duelund website:
"The new VSF Black series, designed to fit between our VSF and CAST series. The black finish is the result of a light (or dark...) CASTing, resulting in a more resonance damped VSF cap, pushing the audio performance closer to the CAST."
The website says that it's ready to be ordered. |
Gentlemen,
Is PVC an acceptable material for a potting container?
Thanks,
John |
For my speakers I want to maintain as precisely as possible the original 1800Hz and 3500Hz crossover points. For the capacitors and inductors I will certainly maintain their original values, but I am wondering if I should be thinking too of the overall resistance of the original crossover should I maintain that as well?
The speaker has a 1st order crossover:
Tweeter: capacitor and resistor
Mid-range: capacitor, resistor ,inductor
Woofer: inductor
Let's say the tweeter circuit has a stock capacitor with a resistance of 2ohms and the resistor has a resistance of 2ohms giving a total of 4ohms. If the new capacitor I install has a resistance of 3ohms, should I decrease the resistor to 1ohm to maintain the 4ohm total for the circuit? The same question would apply to the capacitor associated with the mid-range driver.
For the inductors, I plan to use larger gauge coils than those that are in the speaker now, hence introducing lower resistance components. Should I add a resistor in series with each inductor to maintain the total resistance of those circuit branches?
Since I plan to use Duelund CAST resistors, I'm sure I would be able to request resistors with values permitting me to maintain the original total resistance of each component, but I am wondering if I am correct in thinking about it this way?
The alternative I think would be to just install RLC components that maintain the original values and let the overall resistance of each circuit drift a little from its original value.
I appreciate your recommendations, and as always, thanks for your help,
John |
Michaelvv,
The s/g/o caps were indeed used in the Silverline SR17.5 speakers.
John |
The manufacturing process is described this site and appears to relate conversations with Frederik.
The Duelund Coherent Audio CAST Capacitor: The World's Finest ...
jeffsplace.me/wordpress/?p=370 |
Parts Connexion has them listed. |
Bill,
You mentioned seeing some pictures of a sectioned Duelund CAST capacitor, are those pictures posted online? I wonder if it was one of the Mylar types but perhaps without the label visible. I also wonder if the resin matrix material could appear as the plastic type substance you mentioned. Regardless, I sincerely believe Frederik's products are as he represents them to be.
Cheers,
John |
Bill,
Frederik responded here to my email quicker than I expected, but I should have known he would as I have always found him to be very helpful. And please ignore my previous post!
Cheers,
John |
I have a question for the group.
Background: A friend just acquired a pair of Silverline SR17 Supreme monitors. The crossover is first order and uses a Dynaudio T330D Esotar tweeter. The plan is to take the crossover outboard, replacing the tweeter capacitor with a Duelund CAST-Cu. When I looked in the speaker I was surprised to find on the tweeter circuit a 3.3uF Solen with a 0.22uF WIMA bypass cap, the parallel arrangement giving an equivalent capacitance of 3.52uF. I've never encountered this arrangement in a Silverline before. I also found a picture on the internet (supposedly) of a stock SR17 Supreme crossover and it only had a single capacitor on the tweeter circuit, which is what I would have expected. I could not read the value of the capacitor in that picture but I suspect it was a standard 3.3uF cap as the 3.52uF value is nonstandard. So, with that background, here's where I could use this group's learned council on a few questions:
1. In terms of the crossover frequency, is the difference between the 3.3uF and a 3.52uF capacitance values even audible?
2. I can install a standard 3.3uF CAST capacitor or ask Frederik to make a 3.52uF capacitor. What would the group advise?
I note that the difference between the two values in question is 6.7% This may be within any relevant capacitor or other design tolerances which may make the choice inconsequential, I just don't have enough experience to know.
I would write the manufacturer for his council but having found him to be reluctant to answer such questions in the past I don't think that is an option.
Thanks for your help,
John |
Salectric,
Thank you so much for your prompt and helpful reply. Your reply was spot-on for the help I needed. I'll indeed go with the single 3.3uf arrangement in the new crossover.
I didn't ask the gentleman from whom we obtained the speakers if he was the original owner. He didn't seem like the sort who would modify the crossover, but one never knows. I suspect though that you are correct that someone other than Alan Yun (Silverline designer) added that bypass cap.
There's another little oddity about the speaker: the internal wiring was been doubled, that is, two conductors have been twisted together on all of the connections. From having modified the crossover in a pair of Silverline SR17.5 monitors (I used Duelund VSF-Cu) and my Silverline Bolero speakers (Duelund CAST-Cu) I recognize the wire as what Alan used in those two speakers, but he only used single conductors for the connections. The picture of the stock crossover I found on the internet also used only single conductors. One more thing, whoever mounted the resistor, or re-mounted it as the case may be, must have lost control of the hot glue gun - what a big glob! I've never seen Alan be so sloppy before.
Thanks again for your help,
Cheers,
John |
Tom,
Thank you too for your reply. I posted my reply to Salectric before your note posted. Your suggestion is interesting but would it be needed with the CAST cap mounted in an outboard enclosure?
Thanks again,
John |
Johnk,
I would like to add to the present conversation by saying that I have learned a lot from this thread and it is by far the one on Audiogon for which I am the most thankful. I consider this thread and those who contribute to it a tremendous asset.
As a research engineer I understand performing design of experiments to gain an understanding of the contributions and/or interactions among system components, but here I think it comes down to how one defines success. If I were a speaker designer I might be inclined to define success by achieving a cost/performance target. In that case I would follow a process such as you describe to make sure the performance of each part within the system was worth any added product cost.
As a hobbyist, however, I define success simply by the pleasure derived from my system. Like Charles and some others here with their systems, the changes I have made resulted in profound improvements that met my definition of success and I too would consider going back to the original crossover a waste of my time. I simply have no motivation to do that, whereas for you it would to make perfect sense. To me the main thing to remember is that there are many people on this forum with many different priorities and interests.
Best wishes,
John |
Salectric,
Your points are well taken, and your advice always appreciated I might add. Like Charles I too originally changed from Solen capacitors. In one set of speakers the path was Solen -> Mundorf Silver/Gold/Oil -> Duelund VSF Copper. In my present speakers the path was Solen -> Clarity MR -> Duelund CAST Copper.
My decision to go to Duelund CAST was based on my experience with those earlier caps, from reading selected posts on this thread from those who expressed similar opinions of those caps, and from their subsequent opinions of the Duelund CAST. My goal was to combine the attributes of the Duelund VSF (tone, richness, harmonic structure, naturalness) with that of the Clarity MR (speed, very low noise floor, spacial retrieval). In my system I achieved those goals to my satisfaction with the Duelund CAST capacitors and am quite happy, and as I mentioned in my previous post, am therefore not inclined experiment further. I'm just enjoying listening to my system.
Thanks again for your reply to my earlier post about the capacitor values for my current crossover project. I was able to determine that the 3.3uF with 0.22uF bypass capacitor was indeed the original configuration. Just to be safe, I'm going to order the new caps in a 3.52uF value. As you mentioned the difference between the 3.3uF and 3.52uF values would likely be inconsequential in the speaker's first order crossover, I'm more comfortable staying with the designer's original values and since the CAST caps are made to order it's just as easy to order a 3.52 as it would be to order a 3.3.
Best wishes,
John |
Bill,
What were some of the effects the North Creek inductors made in your system? Also, did they permit you to send your original inductors and then match the original values?
In my last crossover I used Goertz 12awg ribbon inductors but am curious about the North Creek inductors and would appreciate your and Sal's thoughts.
Cheers,
John |
I have an all tube based system and am very pleased with the performance of the CAST-Cu capacitors in the speaker crossover. |
Pc123v,
On a couple of speaker projects I moved from Mundorf S/G/O to Duelund VSF Copper and eventually CAST Copper for the same reasons you expressed. I was very pleased with the results. I do not have any experience with the Alexander, however. If the Alexander is constructed with pure copper film as are the VSF and CAST copper, I would think it would have the sonic character for which you are looking.
John |
Volley,
I want to second what you and Charles already said. I've had my system in states before where I connected with the music intellectually but not emotionally (my way of saying the same thing you and Charles are saying) and the system configuration that permits me to connect with the music emotionally is so much better!
Cheers,
John |
