AudioNervosa
Self Medicating => General DIY => Topic started by: BobM on September 10, 2012, 12:23:21 PM
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I've got 2 left over V-Cap .1uF's and 2 Russian .1 UF Teflons that I want to use on my speakers tweeter crossover. I have Apogee's, so this crossover schematic might look a little strange to some of you. My question is, where shold I put the teflon bypasses?
I figured, put the best cap (V-Cap) at the earliest part in the circuit (C5) and the Russian Teflon at the next closest point (C1). Anyone disagree with me, or have a bettter suggestion (short of buying more V-Caps or replacing them all with $20K worth of Duelands :duh)?
Thanks
(http://www.audiocircle.com/image.php?id=67514)
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Similar question about the resistors. I plan on using Mills, but I am wondering if I can use the MRA5's (5 watt power handling with 25 watt peaks) or should I step up to the MRA 12's (12 watt power rating with 120 watt peaks)? I am using a high powered McCormack amp that could push 1000 watts into 2 ohms.
Are the MRA 12's overkill or necessary? In a normal speaker I would say 5 watts is plenty, but I'm not sure about these.
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I figured, put the best cap (V-Cap) at the earliest part in the circuit (C5) and the Russian Teflon at the next closest point (C1). Anyone disagree with me, or have a bettter suggestion (short of buying more V-Caps or replacing them all with $20K worth of Duelands :duh)?
Thanks
That's what I'd do... C1 and 3 could be replaced by film caps if they are currently electrolytics... C5 could too but it would be very large.
The resistors and inductors might be a good upgrade too depending on what's in there now...
edit... I like Mills resistors, they are very clean and neutral sounding to me. I'd go with the 12s if there's any doubt, they aren't that big or much more expensive.
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All the caps are films (old Spragues originally, but now a combo of Auricaps, Sonicaps, Multicaps and a few leftover Spragues). I've found that mixing and matching cap brands delivers better sound overall than sticking to just one brand, especially when the values are large (like 70uF) and you need multiple caps in parallel to get the value right.
I'll probably get a .1uF Sonical Gen II bypass for that last C3 position just to be a completest.
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I've never liked the sound of bypass caps in a speaker crossover. Either replace the large caps with caps of better quality or leave them alone.
Claritycap has all the values you need among their misc. lines.
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All the caps are films (old Spragues originally, but now a combo of Auricaps, Sonicaps, Multicaps and a few leftover Spragues). I've found that mixing and matching cap brands delivers better sound overall than sticking to just one brand, especially when the values are large (like 70uF) and you need multiple caps in parallel to get the value right.
I'll probably get a .1uF Sonical Gen II bypass for that last C3 position just to be a completest.
I'd guess bypassing or replacing caps is only going to make for a small difference and not really better unless you spend big $ on them... I also agree that bypassing might be worse, especially at .1 uF, the combination might not work out so well. Partsconnexion is having a big sale on Duelund :D
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My recommendation is to replace the 70uF cap with whatever you prefer and can afford. Try to use the best polypropylene cap(s) possible. This is the place where a decent bypass would be most effective. The problem is you will have to use a decent quality and larger value cap to notice a difference.
The second two caps are small enough that they can be replaced with good quality capacitors of your choice.
I would. Ertainly replace the resistors with Mills 12 watt units and if possible, replace the inductors since everything is in series.
Not sure how far your skills go but I would measure the DCR of the inductors and try to come close with the replacements. If the replacement inductors have a lower resistance, you always place a small value resistors in series with the inductor to equal that of the original.
These circuits are critical as they help control dips and peaks in the ribbon tweeter. If your values are off, it can really effect how the ribbon performs and sounds. Something to consider before taking the Inge into crossover tweaking with this type of speaker.
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For the inductors, partsconnexion will custom tailor their foil inductors to your specs for a very small charge, you just buy the next largest value and they will unwind it for you. They would also supply you with the new DCR spec so you can match the old ones.
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BTW - I started the same thread over at AC. An interesting reply over there states that due to the low effeciency of these speakers, a bypass of .1uF will have little effect and I should use larger values. Don;t know about that because I definitely hear a difference in my initial tests.
C5 is actually 7 x 10uF foil caps in parallel. This is where I am using 2 Sonicaps, 3 Auricaps, and 2 leftover Spragues. I have bypassed this with my .1uF V-Cap.
C1 is a 10uF Sprague. I have bypassed this with the .1uF Russian teflon.
C3 is a 5uF Sprague.
The initial result I heard last night was a definite increase in top end extension. Perhaps too much so, because it became a little hard (all these teflons have been used before and should be fully broken in, but I am not ruling out that more break-in could smooth this out a bit).
My next thought is to replace the (C3) 5uF Sprague with a 1uF Russian K40Y paper and oil + a 4uF Sonicap. I'm thinking this will give me some additional midrange warmth and bloom.
I might also remove the .1uF Russian teflon from C1 and replace it with a .1uF Sonicap Gen II, depending on how the K40Y changes the sound. Or perhaps just replace it completely with a 10uF Sonicap.
Thanks
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Bob would it feasible to leave the internal crossover build an outboard crossover and disconnect the internal to directly compare to internal ?
This way you could do direct comparisons. The beauty of the Apogee crossover is it warmish character. The Maggie antithesis.
Actually what areas are you looking to improve or change. Topend, bottom, mids, all of the above.
BTW V-caps when sitting for a while will require break in again. I would recco the copper versions over the tin version. More detailed without the Teflon sound. If you could swing Dueland for the top alone I would do so. Even if just the Cast resistors. I would not bypass, especially the top. Look at Northcreek inductors if Dueland is out of reach. The Northcreeks will tighten up any bass.
Have fun trying.
charles
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I've actually removed the crossover from the speaker and put them in outboard boxes. This makes changing components far easier than otherwise.
Yes, I think I've lost that warmish character with too many bypasses to open things up on the top end and better caps to tighten them up on the bottom. Maybe re-break-in will resolve this, and one of the reasons I'm contemplating including a Russian K40Y PIO in there somewhere.
Another good idea from the other forum - Connect the bypass cap at one end only and play some white/pink noise , then touch the loose end of the bypass cap and see if I can hear the effect/difference and whether I like it or not.
Duelands of any kind are out. So are any additional V-Cap purchases. The original house wound inductors have all been potted and seem to be doing a decent job (tight tuneful bass with the cap changes), so I am not inclined to replace them.
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Claritycap ESA have a warmish character and will improve spacial info(imaging/soundstage). As for resistors, Mills have a warmish character too.
http://www.partsconnexion.com/capacitor_film_claritycap_esa.html (http://www.partsconnexion.com/capacitor_film_claritycap_esa.html)
http://www.madisoundspeakerstore.com/esa-cap-630vdc/ (http://www.madisoundspeakerstore.com/esa-cap-630vdc/)
IMO, a single cap always sounded better to me than multiples. But if you must split a value, always split evenly.
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Well I tried lifting the .1 Russian teflon bypass on C1 while playing pink noise. No discernable difference that I could detect with my ear right next to the tweeter ribbon. So I'm going to pull that off and replace the old Spragues in C1 and C3 as follows. In fact, here are the components of the reworked crossover in their entirety (once they arrive):
C5 (70uF) =
~ 1 x 20uF Sonicap
~ 2 x 10uF Sprague (original caps)
~ 3 x 10uF Auricaps
~ 1 x .1 uF V-Cap Teflon (bypass)
C1 (10uF) =
~ 1 x 1.0uF K40Y (Russian PIO)
~ 1 x 4.0uF Sonicap
~ 1 x 5.0uF Sprague (or maybe a Multicap I have lying around unused)
C3 (5uF) =
~ 1 x 1.0uF K40Y (Russian PIO)
~ 1 x 4.0 Sonicap
I'm hoping to get some additional bloom and midrange PIO warmth by using the Russian K40Y PIO's, but if they don't work out I have either 1.0 Sonicaps, Multicaps or Obbligato Coppers I could use instead.
All resistors are being replaced with Mills MRA12's. The inductors I am leaving alone (for now).
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Hey Bob
SoniCaps are the last capacitor to have in a crossover if warmth is what you are looking for. In my opinion, the best choice for this would be the largest value Mundorf Silver/Oil you could afford to put in. The down side is that you will not experience the warmth and smoothness of this cap for many hours (200 or so).
An exceptional capacitor for smoothing out a tweeter or even an aggressive analog circuit.
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Bill,
I've heard a lot of good, and bad, about the Mundorfs. I can't say that I've tried them myself. Basically, people seem to like them initially, and then don't after a while once they are fully broken in. They seem to have a bi-polar reputation.
The Apogees are still very smooth and not aggressive in the least. I'm trying to improve the openness and bloom while still retaining their overall tonally even character. I think I might have gone a bit far one way and want to see if I can bring it back a notch with the PIO's as I move into the "second half" of the crossover.
The Auricaps were recommended to me by several Apogee owners who have upgraded their crossovers, so I used them in my original mod of the Calipers. They are clean and open and transparent and fast, but I also tend to find them a bit dry with maybe a bit of a loss of harmonic richness and a bit of plastic sheen. Anyway, I've got them and I used them. They may be the real culprit in what I am hearing now.
I've found Sonicaps to be one of the most balanced caps around for a crossover, with a very even character - not overly warm and not shrill in any way. Yes, they are open and fast too, but they retain that harmonic stuff that makes the magic. They work very well on the bass too, being extended and tight. They are my "go-to" cap when I want to keep things on an even keel, and allow me to tune things with the other outlying caps.
I know I will get where I want eventually, but it is fun to learn new things as I play a bit. :mrgreen: After all, I'm not in any rush and have all winter to experiment (that's typically my audio play time).
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I like the Mundorf SIO, but I think I'm going with copper foil caps in the future, got a pair of RelCap PCUs in the preamp that are fantastic.
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IMO, Mundorf caps in general aren't bad, but aren't worth their asking price.
Huge fan of Claritycaps. For warmth and on a budget, I use ESA caps. For transparency, dynamics, and when price or space isn't a concern, I use MR caps.
I'm a fan of Duelund too, but am not a fan of the regular VSF in speaker applications. Except for large values, I would only use VSF Black or CAST series in speakers.
Claritycap and Duelund are really onto something with their encapsulated/resonance free capacitors. The competition really needs to catch up.
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I'm with you 100% face. I was just thinking he wanted more warmth. The Clarity are a great capacitor and the ESA is a great value. The MR is one of the best capacitors on the market IMHO and why we use it in our upper end preamps. Still not an inexpensive cap at almost $200 for a 22uF.
If the wallet can handle it, the Duelund Cast cannot be beat. They bring to the table more than any other capacitor out there but at a premium price. (you don't want to know what our 10uF with .5uF built in silver bypass cost us that we use in our Ultra GT).
I don't have a problem with the Mundorf S/O but they sound like a completely different capacitor after full break in. One needs to be. Ery patient when using these as not to make premature evaluations of their true characteristics. I do prefer the S/G over the S/O.
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Got my delivery from Sonicraft. I can't put the caps in yet because I'm still waiting for my Russian PIO's. But I did swap out the old resistors for Mills.
Surprising what a good resistor brings to the table. That bit of bright harshness I heard before is gone now. Smooth and extended with a bit more spaciality, believe it or not. And this is with no break in yet.
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Got my delivery from Sonicraft. I can't put the caps in yet because I'm still waiting for my Russian PIO's. But I did swap out the old resistors for Mills.
Surprising what a good resistor brings to the table. That bit of bright harshness I heard before is gone now. Smooth and extended with a bit more spaciality, believe it or not. And this is with no break in yet.
Mills have a warmish tone to them, that's no surprise.
I wouldn't be surprised if the Russian PIO's have a negative effect on overall SQ.
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Maybe, but I've got other 1uF caps that I can substitute for them if they wind up muddying things up instead of giving things the glow that I hope for.
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I replaced Kiwame resistor in my SET amp's plate and cathode positions with Mills and the improvement was dramatic. They are more neutral and less warm and colored compared to Kiwame, with an increase in clarity and detail.
I hope your cap replacement brings further improvements!
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I just ordered some of this yesterday to pot the home-made-looking wire air core inductors that all factory Apogees have inside. It is Red Insulating Varnish. Once applied it needs to bake for about 1/2 hour or so to fully harden. Hope it doesn't stink out the oven or the house.
http://www.mgchemicals.com/products/protective-coatings/insulating/red-insulating-varnish-4228/ (http://www.mgchemicals.com/products/protective-coatings/insulating/red-insulating-varnish-4228/)
Why do this? Inductors can hum as the currents heat up the coils due to:
a) loose windings in coils, or coils that are not firmly secured in place, or
b) magnetostriction in magnetic material, or loose laminations in iron, or not fully compressed gap in pot cores. These can be exascerbated by mechanical resonances near the operating frequency.
If they are loosely wound there is an obvious noise source as the wires bounce off each other. Varnishing them is effectively "potting" them so the vibrations are hugely diminshed. (and it is far cheaper and very effective than buying Air Coil's or Erse replacements and still having to deal with different resistance from those new inductors).
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Have you measured the DCR of your coils? Except for the woofer of a three way, I would avoid cored inductors whenever possible.
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Got my Russian PIO caps today and put them into the crossover as spec'ed above with the new Sonicaps.
They need time to break in obviously. At first I heard a spaciousness enhancement but also a closed in sound without extension.
Now 3 hours of playback later I hear it opening up while still presenting that sense of space that I had hoped the PIO's would bring to the table. So ... so far so good. I will let it continue to play overnight and tomorrow and hopefully give another listen sometimne tomorrow. I think it may take 100 hours all told to really get a grasp on this though. So time ...
No sound of discontinuity or disjointedness from the mozxed caps. Yet.
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About 30 or so hours of break in by Sun afternoon, so most of the heavy lifting should be done, so I sat down to listen and ... began smiling broadly. Nice spaciousness, no shrill or edgy or plasticy sound, open and extended and tight, good imaging. Perhaps one instance where a piano sounded a little nasely on a passage. More break in time will likely fix that.
Next - the insulating laquor should be arriving this week and I will "pot" the inductors sometime in the near future. All in all, it seems to be coming together nicely.
On another topic - there's a thread over at Audiogon about how caps vibrate when a signal is running through them. I'm sure it is very small and only seeable/hearable with a stethoscope or some other sensitive measuring device. But in any case it speaks to the need to make sure caps are hot glued down, or somehow not left dangling in space and securely fastened to their circuit board. I know I have heard improved results doing this in power supplies - using Moretite to fasten the caps down to the board and dampen them. If you look inside many commercial devices it is a bit unsettling how often you will see caps sticking up above the board on their thin little legs, not even securely pressed down before soldered.
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Securing them to the board isn't enough. That's why Claritycap and Duelund have their ESA, MR, and CAST series capacitors.
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Yes, but it is probably the best a DIYer can do, short of spending a large fortune on those products. And certainly better than doing nothing at all.
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So I "potted" my big assed inductors (and the small ones too) last night. I used the MG Red Insulating Varnish from the link above, applied to the bottom first (and let it ooze into the cracks) then the sides and top. Ordered 3 x 2oz bottles of it and glad I did. 2 would not have been enough.
I'm pretty certain I got all the way through the coils of wire because there was plenty that leaked out the other side and left a puddle in the bottom of the external crossover box as it was drying. Looks like a blood puddle, but it did a good job of gluing the coil down too. I finished up by re-tightening the zip locks around the coils to get them as good and tight as possible as they were drying. Messy stuff, for sure, so use gloves.
It dried well overnight and this morning before work I siliconed down whatever else was loose. Letting that dry all day to be sure and will give a listen tonight to see if I can hear any difference in the sound quality.
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Does the varnish dry by evaporating a solvent? Do you think it is fully dry down deep inside the windings? Does it have a strong smell? Tx
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Yes, it smells just like varnish :-)
I've been told that this varnish dries fairly quickly and should not pose a problem with undries mush in the center of the windings like other "potting" products have without baking. The exterior seemd to dry pretty quickly (1-2 hours).
I suppose that it would make sense to leave the cover off the external crossover box for a while and let the system play. That way if the coils heat up things can off-gas appropriately.
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That way if the coils heat up things can off-gas appropriately.
Or explode... that would be cool, heh heh... :D
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Well, all that I can do has been done. I've given it all 2 days burn in so most everything should be somewhat where it will end up (at least 95% anyway). The potting of the inductors resulted in exactly what you would expect, a tighter sound overall but still deep and tuneful. At first I thought it sounded leaner, ands turned up the sub. But then I played a different CD and had to turn the sub back down.
The very tinkly top end seemed a bit reticent, so I put a .1uF teflon bypass back on the last set of caps (10uF) and those tinkly things came back. So I guess it does make a difference to the better, to my ears anyway. Perhaps more break in time will lead me to remove it in time. We'll see. That's the beauty of an outbound crossover with easy access to parts and a soldering iron that heats up quickly :thumb:
Now I can finally sit back and just enjoy things for a while. It's taken a bit of time to get to this point, but it was fun taking it slow and hearing what each change did to the sound overall.
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Progress - what a wonderful concept. Yes, my Duetta Sig's are singing wonderfully now. The reticence I heard was really due to a bit of a setup issue. Now that the crossover has been externally housed and parts replaced and such the speakers needed to be slightly repositioned.
If you have Apogees then you know that literally 1/4" can make a huge difference in soundstaging and presentation. This fro the view of distance to the listening seat, distance to the front wall, toe in, cant of the speaker. What a pain to get right, but when you do it all comes together nicely.
I think I have it together now, just in time for the cold winter months when I can sit and listen without having to worry about cutting the lawn, or playing golf, or doing the gardening, etc.
What I am hearing, in terms of improvement (from memory, obviously):
- tighter bass overall
- tighter character everywhere
- more even presentation across the spectrum
- less "in your face-ness", more behind the plane of the speaker presentation, just as deep
- no etch
- still top notch imaging and soundstaging
- less of an initial "surprise" at how nice these are and more of a natural sounding presentation. No ear popping standout surprises.
- Just as dynamic