Capacitor log Mundorf Silver in Oil

Volleyguy,

It's a new entry level copper coupling cap.

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

Reynolds853,
I have a pair of North creek 8 gauge inductors left over from a project, yes an expensive left over! If your interested they are 1.5 mH, if these are too big you can have them sent for a small fee back to north creek and wound down to your needed size, but at least the copper is saved which is pricey in these. If interested make me an offer. Thanks

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.