leok Posted June 13, 2004 Share Posted June 13, 2004 I took Dean up on the offer to participate in a special order of 2uF PIO caps from Jensen (2.2uF are stock, and many Kilpsch crossovers use 2.0uF). On Fri evening I installed the 4 caps I'd ordered into the tweeter circuits of my Chorus-IIs, replacing the Hovland 2uF "Musicaps" which have, to date, in my opinion, sounded best in that application. I did condition the caps at about 140VDC, each way, prior to installation. The caps are 250V caps. Just after installation and into Sat. AM the results were disappointing: sound was more harsh and imaging was completely destroyed. I use Aztec 2 Step's "Highway Song" as an imaging test. It is a simple, well recorded Elektra record. Instruments are far right and far left, but the 2 male vocals are just left and just right of center. Very consistant frequency response and lack of distortion is required to keep the vocals and associated sibilances, all in the correct location. With the Hovlands, the imaging had been good. With the Jensens, at first, it was completely impossible to locate either singer. Frequencies and sibilances were smeared everywhere. I took my own advice and left the system running all day Sat., with the FM tuned between statons. Upon returning home, after about 8 hours, I repeated the "Highway Song" test. 1 simple thing: Imaging was dead on. All frequencies, including sibilances were correctly focused at the source of each singer. The impact to overall sound is better than I had anticipated. With the Hovlands, the Chorus-IIs had a soft, warm, but not real coherent sound to them. With the Jensens, the sound is much crisper, but also cleaner. So, harmonics that used to be soft, and nice, but not very tightly connected with instruments, have now become much more "serious." (This IS the high frequency information that belongs with this instrument.) The high end presentation of the Chorus-IIs has lost its softness, and also sounds much less like sound coming from a speaker. The mid-tweeter combination is almost seamless (the mid circuits in my Chorus-II crossovers use Jensen PIOs also). The highs, although less soft, are not at all harsh, but are more detailed. Violin and small chamber ensemble music, up till now the domain of the RF-7s, is being reclaimed by the Chorus-IIs. The Chorus-IIs, and my listening enjoyment have benefited tremendously from this improvement. Thanks to DeaG for the opportunity, and his effort. Leo Quote Link to comment Share on other sites More sharing options...
pablum Posted June 13, 2004 Share Posted June 13, 2004 oils are rolled off, lousy, inferior, poor measuring, leaking devices that are unfit for high fidelity audio. Right? Surely. Again, we must go with the machine for it does not lie. Remember, test twice, listen once; two out of three isnt bad, right? presumptions loosely based on supposed science are MORE harmful to learning and progress than the other way around for it stops the open mind. Nice post showing a good combination. Quote Link to comment Share on other sites More sharing options...
Number 9 Posted June 13, 2004 Share Posted June 13, 2004 I'm now dubious wether the 140VDC conditioning did anything based on how the testing went. The xover point of the tweets is pretty high in the Chorus ...so I'm also surprised the PIOs made such a big difference. Hmmm...can you describe the metaphor a little better? What does the "highs being better connected" mean? Does this mean the RF7s will be up for sale? Are the changes that good? Quote Link to comment Share on other sites More sharing options...
jorjen Posted June 13, 2004 Share Posted June 13, 2004 Leo, Glad you are pleased with the results. Do you feel it would have just taken longer for these caps to settle in without conditioning? Or, in your opinion, did the conditioning procedure not help much if at all? I would certainly think that the voltage you used would be sufficient. How long did you let them cook each way? I would also like to increase the voltage on your cooker which I made. Runs anywhere from about 35v to 45v now. Would like to take it up into the neck of the woods you used on the Jensen caps. How would I accomplish this? Thanks Leo. Quote Link to comment Share on other sites More sharing options...
Deang Posted June 13, 2004 Share Posted June 13, 2004 Conditioning does work, and if anything, shows how break-in times can be greatly reduced with its use. Normally, at least in my experience -- break-in takes between 60 to a 100+ hours with most caps. However, this is presuming you actually run some voltage through them (at least 50 watts or more). Of course, the majority here rarely climb past 10 watts, and because of this -- it is possible that the caps NEVER get completely broken in. Leo, if you still have the original capacitors, I would like you to send them to Bob Crites for testing -- unless of course you are already in possession of something that can measure the ESR of the caps. Surprising result, considering my adherence to the idea that the high quality replacement capacitor should have an ESR close to the one being replaced. I had figured if some loss was in the original circuit to begin with, then the additional resistance would have played a sigificant factor or role in the voicing of the speaker. Based on this idea, PIOs in the Heritage networks made perfect sense -- which is why I chose to use them. With this logic (if you can call it that), I was certainly expecting to see your replacement of a film type with a PIO type to result in some attenuation of the high frequency response -- due to the addition of resistance into the circuit that wasn't there to begin with. At any rate, this is why I would like you to send those capacitors to BEC for testing. I want to know those ESRs. Positive reports are starting to trickle in on the new Heritage networks, which I half expected considering Bob's testing results of the old motor runs. I guess I need to shut up now, or Craig will ONCE AGAIN accuse me of blaming every system problem on old networks. Quote Link to comment Share on other sites More sharing options...
leok Posted June 13, 2004 Author Share Posted June 13, 2004 pablum, glad you found it of merit. I have always liked PIOs, but these results were not what I expected. I expected the highs to be even softer .. I thought the softness was part of the Chorus design. Number 9, the highs seem more a continuation of what is going on with the mid. horn, rather than simply some good sounding stuff with the right power spectral density. I wouldn't say the highs have the coherence I hear with the RF-7s. but they sound like they were made at the same time by the same instruments. Since this mid/tweeter coherence is my biggest problem with 3-way speakers, this improvement in the Chorus presentation is a very big deal for me. Instruments and vocals sound much more real, and less like they are comming from a speaker. I am no longer particularly aware of a mid/tweeter split. jorjen, I don't know about the conditioning. I have waited much longer for PIOs to even begin to sound right, so maybe the conditioning shortened the burn-in time required. To achieve the higher voltage (only good for higher voltage caps) I removed the resistor I have that in parallel to the cap (it forms a voltage divider with the input resistor). I "cook" them for 20 seconds / side. Leo Quote Link to comment Share on other sites More sharing options...
BEC Posted June 13, 2004 Share Posted June 13, 2004 Dean, I think you should also send me some of the Jensens for similar testing. Bob Quote Link to comment Share on other sites More sharing options...
Deang Posted June 13, 2004 Share Posted June 13, 2004 Forget that. I don't want you testing the parts I use -- that would be like suicide. I wish we knew decisively how these different dielectrics can cause things to sound so different. Looks like I'm going to have a few extra 13uF Jensens left, I'll send you one of those. What I might do is just build up a set of Type As to send, that way you can measure and listen. Quote Link to comment Share on other sites More sharing options...
BEC Posted June 13, 2004 Share Posted June 13, 2004 Dean, Sending the crossovers would be even better. I do listen to music also. Some probably think that I only want to see it on a scope. Bob Quote Link to comment Share on other sites More sharing options...
Deang Posted June 13, 2004 Share Posted June 13, 2004 "I do listen to music also. Some probably think that I only want to see it on a scope." I think everyone here knows better than that. Unlike me, you've actually heard your caps in your crossovers -- I'm at the mercy of my customers. God help me. I apologize to you for giving that impression. Quote Link to comment Share on other sites More sharing options...
BEC Posted June 13, 2004 Share Posted June 13, 2004 Dean, No need for an apology, I did not take what you said as being anything negative. Listening is always the "proof" in the quest for sound excellence. How it looks on test equipment is "assistance" toward that end. Bob Quote Link to comment Share on other sites More sharing options...
leok Posted June 13, 2004 Author Share Posted June 13, 2004 Dean, I can put one of them on a meter at work. I'll let you know what I learn. If it continues to not make sense then we can look further. Interesting results so far. Leo Quote Link to comment Share on other sites More sharing options...
NOSValves Posted June 13, 2004 Share Posted June 13, 2004 Leo, I hate to ask but to what SLP have you pushed the new caps too ? Craig Quote Link to comment Share on other sites More sharing options...
NOSValves Posted June 13, 2004 Share Posted June 13, 2004 ---------------- On 6/13/2004 4:07:29 PM BEC wrote: Dean, No need for an apology, I did not take what you said as being anything negative. Listening is always the "proof" in the quest for sound excellence. How it looks on test equipment is "assistance" toward that end. Bob ---------------- Very well said Bob !! Quote Link to comment Share on other sites More sharing options...
leok Posted June 14, 2004 Author Share Posted June 14, 2004 Craig, What's "SLP?" If it's amplitude, not much .. maybe 100dB at a meter, on a peak or two. Leo Quote Link to comment Share on other sites More sharing options...
Frzninvt Posted June 14, 2004 Share Posted June 14, 2004 Dean, if you have a couple of the 13uf Jensen PIO's left I am interested in purchasing them for my Khorn's updated AK-3 networks to replace the current 13uf Aerovox's that are in there. I wonder if they will work some magic for the K-55M's. Lemme know will ya. Quote Link to comment Share on other sites More sharing options...
NOSValves Posted June 14, 2004 Share Posted June 14, 2004 Leo, 100dB is a fair enough SLP. I just am curious as to what this caps act like once pushed I guess I will have to get some and see for myself. Craig Quote Link to comment Share on other sites More sharing options...
leok Posted June 14, 2004 Author Share Posted June 14, 2004 For the 2uF Hovland "Musicap" at 1000Hz and 250Hz, 1V and 50mV rms, no dc offset: measured: 2.05uF dissipation factor = .001 calculated: ESR = about .0014mOhm Whatever is going on, I don't know how to measure .. but it sure is going on. I put all my best equipment on the Chorus-IIs (Philips 963SA and the SET amps). Holy Smokes .. I guess people who have been using all oil caps all along have been hearing this. The detail and clarity is way beyond anything I've heard. Is Alnico next?? Leo Quote Link to comment Share on other sites More sharing options...
Deang Posted June 14, 2004 Share Posted June 14, 2004 Jensen 2.2uF, two random samples: ESR 44.20 mOhms, DF .6000 @ 1kHz. & 120Hz ESR 37.70 mOhms, DF .6200 @ 1kHz. & 120Hz Terrible, just plain terrible. Quote Link to comment Share on other sites More sharing options...
BEC Posted June 14, 2004 Share Posted June 14, 2004 Pretty good numbers. Bob Quote Link to comment Share on other sites More sharing options...
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