Just looked at your photo... This can be reversed engineered.
HELP AFTER MY MODS, My tweeters are subdued and weak-
So I have a pair of Mirage M1 speakers, I changed the caps in the crossovers to Jantzen Superior Z (for the tweeters) and standard z for the mids and bass.
I also changed the internal cabling to Supra Classic 2.5.
First Impressions- Not burned in yet
The highs are there but really recessed in the background. Theres a song I reference and it has a steel guitar solo, I can bearly hear it through the vocals because its seems recessed so far back.
SO HERES THE QUESTION- Is that a symptom of unburned in cables and or caps, or is that just what Supra cables give you?
When I changed the internal cabling a few years back on the same model speaker, I used DH LABS t14 Silver plated cable, This had the opposite effect, it was super bright and fast, but it smoothed out and the brightness relaxed, leaving a lot of detail but not so much your ears bled.
But here its the opposite, its dull on the top end and the vocals kind of take over and blur out the top end.
I also changed the internal cabling to Supra Classic 2.5.
First Impressions- Not burned in yet
The highs are there but really recessed in the background. Theres a song I reference and it has a steel guitar solo, I can bearly hear it through the vocals because its seems recessed so far back.
SO HERES THE QUESTION- Is that a symptom of unburned in cables and or caps, or is that just what Supra cables give you?
When I changed the internal cabling a few years back on the same model speaker, I used DH LABS t14 Silver plated cable, This had the opposite effect, it was super bright and fast, but it smoothed out and the brightness relaxed, leaving a lot of detail but not so much your ears bled.
But here its the opposite, its dull on the top end and the vocals kind of take over and blur out the top end.
Showing 16 responses by timlub
Hi Idahifi, The last time that I used the Jantzen Z caps as replacements, I had the exact same issue. It took about 40 hours before they came to life. If it is truly a problem of ESR differences in caps, that can be measured and compensated for with a resistor. Really the series resistance shouldn't be great enough unless there are alot of caps paralleled maybe, but if resistance is that far off, it could even effect the crossover point. Overall simple cap replacements in a crossover should not be a problem. |
Thanks for posting the schematic Sean.... I can see a lot more now.... OK, so this is a series crossover, parts burn in takes about twice as long to burn in rather than a paralleled layout.... Yes, I had a similar effect on my speakers and no, I would not change any resistors. My instincts are that your ears will take some time to adjust even after these break in. The Z is a tad more laid back than most, yet a very detailed pleasing cap. I suspect once they break in fully and you become accustomed to them, you won't want anything else. |
C1 is in the woofer circuit C3 & C4 are in the midrange R3 is in the midrange R4 is comp on the tweeter I'd put a signal on these and let them burn in for 100 hours or so, then listen again. If these are anything, but a nice improvement in smoothness and detail from before the mod, then there is a problem. I'd let this play for awhile, then sit down for a serious listen. |
Sean, if you want to keep up with the speaker building hobby, I would suggest something like this: https://www.amazon.com/Hiyadeal-Inductance-Capacitance-Resistance-Meter/dp/B008QKJOCQ/ref=sr_1_23?ie... This is really cheap, but I suspect it will give you fairly close measurements. |
By the way, I completely agree with georgehifi's recommendation of pulling these out from the wall also to start. Hopefully leave them out, but if your high end doesn't return as strongly as you like, as you move them back towards a way, the higher frequencies should be what you hear reflected first, reinforcing or enhancing the high end a bit.... good luck in your journey brother, sounds like fun. |
Hi Sean, Well since its your thread and you asked, I'll go a bit off subject and answer your question. There are some general rules about cables, that overall hold true... overall, but not entirely... Heavy gauge solid core transfers bass better, lighter stranded cables transfers high end better. Of course a lot of other things affect this.... wire coating (skin effect) purity and type of copper or coating on copper, is there a braid or only multiple individual strands...etc etc etc. Myself, My favorite cables were made of 38 gauge cotton coated litz.... Multiple stands were used in several different braids twist etc until we found the right mix.... final result was about a 9 guage cable... this was a very pleasing, yet detailed cable. In your woofers, I would probably use the heavy belden on the woofer, then make sure that you use one of the nice standed wires on your tweeter. As far as your speaker cables, I'm sorry, but I have no experience with the Tara Labs, that's why I gave a very basic elementary cable explanation, to help you discover what might make a difference in your system. Next, don't throw in the towel yet, your speakers will continue to go through minor changes for quite awhile. I hope this all helps, Tim |
Sean, I've been reading trying to find why your Tara Labs might be sounding so differently... Still not sure that I ran across it, but I would rather send you down that path before going through a speaker tear down. Your cables are solid core, so they naturally will have a roll off on top. From what I've read, they decoupled the cable and added some sort of coupling cap inside of that box...Wire capacitance is well known for how it affects the high end (treble). As you turn up the wire, It changes the capacitance to increase the treble within your cable.... These cables appear to be around 25 years old. What if a connection was broken poor inside of your cable box or if a part was going bad? Not sure that you can open this thing, but I'd take a look there... Right now, You've got a lot of cooks in the kitchen, you know how to get ahold of me, so I'm going to bow out for now, Tim |
well that is partially what I said... I said that the electrolytics that you replaced are all in the midrange and that your tweeters should be functioning correctly. Either the issue is in the midrange or you have a bad tweeter diaphragm from overheating during soldering. Next I believe that if a cap is most likely not bad, but when you had the Jantzens in that you could have had a bad solder joint.... next, I said that the only 2 caps that could have much if any ESR stray is the 2 - 2200 mic electrolytics, you said that you replaced those with the exact same value. Even those, the difference should be minimum. and no, this is not an ESR problem ... unless for some reason a cap was overheated at some point in its history any you have a bad ESR cap... of course ESR is an AC measurement and the cap ESR is far above the crossover frequency.... |
Sean, also as I mentioned in email, the 2200 mic caps are big enough to make a difference and they are polarized, so to reiterate my email... could it be that you had polarization backwards on 1 or both caps? Again, these 2 caps have enough resistance that they could matter and they are polarized... Also being 35V electrolytic, I would much prefer to see you replace those with a higher voltage polarized electrolytic. And to ask the same questions that I asked in my emails to you.... being these are all in the mid circuit, are you sure that it is the tweeter that is the problem? I haven't seen an answer to that. |
Ok, I have avoided trying to come off as a know it all. I don't want to be that way, nor known to be that way, but I'm going into teaching mode....We are combining some difficult theories with some very elementary basics. I'm going to speak only as thought this is a tweeter. You have a 6 ohm tweeter and it is too sensitive to match your mid range or 2 way woofer, The way that most designers handle this is to add an Lpad to match sensitivities, then properly build a crossover for your 6 ohm tweeter to the woofer or mid. Another way to do it if conditions are right is to add a 2 ohm resistor... The resistor adds a pad to the tweeter, effectively turning it down and also add resistance so that you can now use an 8 ohm crossover. So 2 birds are killed with one stone. In this scenario, extra resistances reduced the tweeter output and raised its impedance. So now, ESR. l When I build a crossover, I do compensate for ESR, but it is more for exact matching crossover points than the bit of gain difference, even so, I try to match gain correctly also. So, when Sean replaced the Electrolytics or any of his current caps, the replacement caps had lower ESR resistance... The argument being made is that the reason his output is diminished is that the resistance is so far off that it is reducing the output of the tweeter. Ok, to start with, the resistance on his new caps are much lower, what that means is that there is less of a pad, adding resistance will be helping to reduce the output back to the level of the original caps.... Next, we discussed the crossover point being changed, if that happened with the exact same value of caps, his crossover point would be effectively lowered meaning... So, lower crossover point means more perceived output, less resistance means more output. Significantly lowering ESR in theory would make his tweeters louder. I hope this all makes sense. Tim |
@imhififan ... well, again, ESR should've had the opposite effect. The old caps matter, plus his Tara Labs are solid core. Typically solid core are not as extended on top, plus those Tara labs have some sort of circuit in them... But overall, you are correct, the Tara Labs should not have made such a big difference, unless there were other problems involved. Solder joint or one of the big caps out of phase or a combination is my best guess. |
Sean, I see that you are going to purchase a meter... The one that I posted is more of a general speaker builders tool. It doesn't offer esr ratings, but it will measure capacitors, resistors and Inductors all 3. If you aren't worried about speaker design then you can purchase a simple cap meter. Tim |