LonestarBlues Posted June 16, 2004 Share Posted June 16, 2004 Hello. I talked to Kara Chaffee- head designer at Dehavilland last week. I was asking about paper in oil capacitors for my Verve preamp. They use Russian mil spec K40Y9 paper in oil caps in their upgraded preamps. My Verve preamp has Auricap capacitors. Kara told me I could have a pair of Russian paper in oil K40Y9 mil spec caps soldered in parallel with the existing Auricap capicitors. They do this in their upgraded preamps. Can someone explain to me what soldering a pair of Russian pio in parallel with the Auricaps would be. I am going to ask the Repair Tech at Sound Vibes-local pro music store if he will do this for me. Willam has 25+ years experience & works on tube guitar amps. Kara told me a good tech would know what to do-solder Russian pio caps in parallel with existing Auricap caps. I told Kara I was a non technical tube Jethro. I will buy the Russian pio caps from Dehavilland if I can get William at Sound Vibes to solder the caps in for me. Thanks for the help. Regards, Mike Quote Link to comment Share on other sites More sharing options...
3dzapper Posted June 16, 2004 Share Posted June 16, 2004 Lonestar, Putting the caps in parallel should be no problem for anyone who can use a soldering pencil. It just means to put the caps in at the same connections, in the same direction. If you can't do it your local guy should have no problem. Rick Quote Link to comment Share on other sites More sharing options...
capacitive reactance Posted June 16, 2004 Share Posted June 16, 2004 The Russian K40Y9 series of hermetically sealed, metal jacket capacitors are not paper in oil. They are 1980's production capacitors that consist of a mylar film, aluminum plates, an insulating oil to compensate for temperature change, and a hermetically sealed metal body with glass ends. They were manufactured for use in communications equipment that still operated on tubes. The Russians were behind in technology in the 80's and used tubes for the sole purpose of EMP protection that would otherwise damage solid-state devices. Once the Russians figured out how to implement EMP proof semiconductors, the tube equipment became obsolete, thus the surplus of high voltage military capacitors. They make good general replacements for audio equipment, however, they are not "high-end" capacitors by any means. Just good reliable capacitors designed to take a beating. I don't know of any improvements to be gained by forming a "composite" capacitor, by bypassing the Auricaps. The Auricaps are metallized polypropylene, and have better high frequency characteristics than Mylar. You couldn't gain anything other than a change of capacitance, which would alter the frequency response. I would recommend using either type of capacitor, but not both types in parallel. Paralleling capacitors is not good practice, as ESR, circuit Q, and other variables would impact the circuit. There is no harm in trying it though. Simply tack the K40Y9 across the Auricap. It is simple to reverse if you don't like it. Quote Link to comment Share on other sites More sharing options...
Deang Posted June 16, 2004 Share Posted June 16, 2004 Good post. Really. Based on what little I know, bypassing does seem to cause more harm than good, though I've done it several times in the low frequency section of the RF-7 -- using a Theta with a Solen. My confusion comes from so many experienced people supporting and utilizing the practice. Northcreek Music strongly supports it, and that's where I originally learned of it. I have mixed feelings on paralleling, since I've done this several times as well -- and simply cannot hear a difference between using say, two 9uF's and a single 18uF. In my minds eye, I see splitting, and creating two signal paths as a generally bad idea, yet the ears say it's O.K. I can definitely say paralleling two great caps sounds better than using a single crappy one. I sometimes worry about the additional inductance from the additional leads, but I think it might be hair splitting for audio applications. At any rate, bypassing an Auricap with a Russian film and oil does seem like a bizarre recipe. Quote Link to comment Share on other sites More sharing options...
NOSValves Posted June 17, 2004 Share Posted June 17, 2004 Ryan, Yup the Russian Caps are not PIO in any way shape or form wonder where you learned that? I have cut them apart and they are a film & foil. Now how someone can say there Mylar and Aluminun without sending them to a lab I have no clue. Craig Quote Link to comment Share on other sites More sharing options...
neo33 Posted June 17, 2004 Share Posted June 17, 2004 I don't see a "Ryan" post in this thread. Quote Link to comment Share on other sites More sharing options...
Deang Posted June 17, 2004 Share Posted June 17, 2004 "...they are a film & foil. Now, how someone can say they're Mylar and Aluminum... Mylar (polyester) film/aluminum foil I can't tell by looking at the insides, but I can sure tell by looking at the outsides. Mylars are much smaller than polypropylenes for the same voltage rating. Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted June 17, 2004 Share Posted June 17, 2004 Hey, Mike: Combining capacitors in parallel will increase the value of the original capacitor. Do you know what the values are of both? This may simply be a bypass of a much lower value cap to try to smooth the response a little -- which an oil cap might do to a film and foil or metallized capacitor. Paralleling capcitors increases the value by the value of the caps used, whereas paralleling resistors does the opposite. Depending on the quote you get for the work -- send me an email, ok? This work would take literally 5 or 10 minutes. How far is the drive from Houston? I could use a little road trip! Erik edit: an idea: Listen to the component with the existing capacitors and get used to the sound. Then we can add the other capacitors and see what the difference is. Listen over some time, and decide which you like best. I think someone mentioned this above, and it's really good advice. I'll help ya either way. I'm off for the summer for teaching, and so have the time to do this. I'll show you how to solder, and you can even do the work yourself. There's no magic or special skill required. If you can jab at a big steak with a knife and fork, you can solder. It's easy! Quote Link to comment Share on other sites More sharing options...
Deang Posted June 17, 2004 Share Posted June 17, 2004 "...a bypass of a much lower value cap to try to smooth the response a little -- which an oil cap might do to a film and foil or metallized capacitor." How? Quote Link to comment Share on other sites More sharing options...
capacitive reactance Posted June 17, 2004 Share Posted June 17, 2004 ---------------- On 6/17/2004 12:27:25 PM AK-4 wrote: "...they are a film & foil. Now, how someone can say they're Mylar and Aluminum... Mylar (polyester) film/aluminum foil I can't tell by looking at the insides, but I can sure tell by looking at the outsides. Mylars are much smaller than polypropylenes for the same voltage rating. ---------------- Not exactly, Dean. I think you're referring to METALLIZED Mylar capacitors, those are very small compared to either metallized poly or poly film/foil. True Mylar film/foil capacitors, like Black Cats or Good-All's are monsters, they're huge. They are about 25% larger than Poly caps because more Mylar film is needed to make the same capacitance value. Mylar film is obsolete, so you won't find many new types. Back in the 50's and 60's, these were very popular. These were replaced with metallized types, and, like you mentioned, they are much smaller. It wouldn't make much sense to make a small transistor radio with 1 inch diameter mylar film caps. Judging from size only, those Russian caps could only be one three dielectrics; (1) Paper, (2) Polypropylene, or (3) Mylar. I know they ain't paper, because I cut one open and the dielectric wasn't a brown color. That leaves only 2 or 3, and based solely on Russian technology of the 80's, my guess is Mylar. Craig, it would be interesting to send the film to a lab to verify what they really are, but you're talking a minimum of $500. They are Mylar, take my word for it. Xc Quote Link to comment Share on other sites More sharing options...
capacitive reactance Posted June 17, 2004 Share Posted June 17, 2004 ---------------- On 6/17/2004 12:54:19 PM AK-4 wrote: "...a bypass of a much lower value cap to try to smooth the response a little -- which an oil cap might do to a film and foil or metallized capacitor." How? ---------------- That's pure crap Dean, no scientific proof what so ever. Think about it, putting a high loss PIO cap in parallel with an efficient plastic dielectric with better ESR, Q, and HF response. The only thing this would yield is a poor circuit with high leakage. You won't be smoothing out the response, you'll be chopping it up! You'll chop those highs right off. Xc Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted June 17, 2004 Share Posted June 17, 2004 I don't know how Dean but I've seen it done before. Whether there is an improvement is something I can't say. Bypassing electrolytics with a smaller value film and foil capacitor is fairly common, and I'm trying to figure out what the point of installing an oil capacitor in parallel. It was conjecture -- or 'pure crap' as was so eloquently stated. So, is the upgrade an oil capacitor or not? Paralleling a coupling capacitor (if that's what this is) on the output of a preamp will increase the net value of the two combined caps. This might have been done to help drive lower impedance loads, long runs of interconnect, that type of thing. It was never stated what the supposed effect of the upgrade is, but I have heard and read where capacitors of different type or construction are combined in order to ameliorate certain undesirable characteristics of either one by themselves. My description of "smoothing out the response" normally implies increased linearity, however in this case I was speculating that the inclusion of an oil cap(if that's what it is)combined with a F/F may have been found to take some of the sharpness or edginess off the original coupling capacitor. I never stated that this was THE reason for the modification, and was trying to figure out the idea behind it. An example: My AE-1 uses has a 100uf electrolytic capacitor across the output of the power supply. In parallel with it is a .22 film and foil capacitor. Bypassing electrolytics with a high quality F/F cap is common. I've seen it done very often. I have also built crossover that required uncommon values of capacitance that could only be obtained by combining different values in parallel. I thinks it's probably best to use capacitors of the same type, but we can only speculate what 'upgrade' would result from combining the two. Evidently, the Russion capacitor is not an oil capacitor at all... The values of each of the two capacitors might help point to the purpose behind the combination. Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted June 17, 2004 Share Posted June 17, 2004 "Paralleling capacitors is not good practice." It's done all the time -- in crossovers, to obtain odd values of desired capacitance, etc. My father has done it since before either of us were born, I have numerous texts that discuss it. As long as the capacitor being added in parallel has similar working voltage rating and ESR characteristics, there may in fact be positive apects of such a practice. It's important that a lower voltage rating NOT be used, unless the lower voltage is what's required by the circuit. If you take a 100uf filter cap rated for 450VDC and parallel it with 100uf rated for 50VDC -- what's going to be the overall working voltage of the two paralleled capacitors? Quote Link to comment Share on other sites More sharing options...
Deang Posted June 17, 2004 Share Posted June 17, 2004 50vdc Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted June 17, 2004 Share Posted June 17, 2004 LOL! That was rhetorical, but I appreciate your humor and direct response on this, Dean. I have some thoughts on the SET/PP equation I want to share if the forum isn't completely evacuated in a couple of days.... YOu once said something about using the right tool for the job, and, although SET has some very important characteristics for much of the music we listen to..............I'll report more on this when I have a chance to listen some more. I am trying to get Dee's SE OTL finished, packed up and shipped to him, and that is on my mind right now. While I was waiting for a couple of new tubes (one bad one was sent and I couldn't test the amp until I got replacements), I had the chance to do some significant work on a pair of 1950s vintage 6V6 PP amps, 12AX7 front end, tube rectified with a 5Y3. I rewired a couple of sections I did some years ago, replaced filter capacitors, took out a ceramic bypass cap in the signal path (made things Waaaaay too bright), and then sat and listened. And listened some more, and was amazed at the way music, when it needed to, stopped seemingly instantly with no overhang whatsoever... The two integrated monoblocks were purchased months apart; are a very simple circuit; they're almost dead-quiet with klipschorns; they have startlingly clear and articulate high frequency response; have an iron fist grip on the k-horn woofer; are only 7 watts more powerful than the max output on my own amplifiers; and they sound truly outstanding to both of us. They are push-pull amplifiers. We listened to Dee's SE OTL last night with Pat Metheny CD "One Quiet Night," and that amp was also just amazing, as was Wolfram's when it was here. "The right tool for the job..." Those were your words, which I think I may have responded to in a slightly defensive way. I'm sorry about that. You see I haven't forgotten what you said, though! There in fact may be some real wisdom in those words, Dean. As one friend said to me today in regard to this, "You're on your way :)" And another friend said "Another can of worms :)" Both are correct, I think, and both were meant positively. I know for a fact that I will have both types of amps -- SET and PP -- as key components in our system, and both will be used probably equally. I can make a switching device to go from one to the other, depending on music selection, mood, etc. All of that comes into play, I think. Maybe there doesn't HAVE to be only one way.... ...and maybe, hopefully, the anger can lessen. Quote Link to comment Share on other sites More sharing options...
sheltie dave Posted June 17, 2004 Share Posted June 17, 2004 Capman, mylar foil is being widely used to this day in some industries. I just ordered $10,000 worth of 8 microg/sq. cm density thickness mylar today for some radiation detectors. As far as caps go, it may have become obsolete due to its whimsical desire to work(or play) after years on the shelf for NOS material. Look before ya leap in traffic... Quote Link to comment Share on other sites More sharing options...
Deang Posted June 17, 2004 Share Posted June 17, 2004 Heck no there doesn't just have to be one way -- that was ALWAYS the point we were trying to make with you guys. No self respecting Head Banger or someone who enjoys full blown Symphonic works at live levels has any business goofing around with "sublimity", and "see through quality". Those things just aren't pertinent with our music. With us, it's about control and unrestricted transients at live levels -- for those are things that make OUR music sound "real". I just don't seem to get that without some power and little bit of feedback (actually with the QUADs, it's A LOT of feedback). I have to be completely honest though, I don't think the Wrights I have over here right now have anything on the QUADs in any of the categories commonly attributed to SET -- I just don't hear it. I have to admit though, if I had the money, I would sure love to try the 845 Dehavillands. I just believe with all my heart that at some point -- power becomes a qualitve value instead of a quantitive one. Quote Link to comment Share on other sites More sharing options...
NOSValves Posted June 17, 2004 Share Posted June 17, 2004 ---------------- On 6/17/2004 4:12:25 PM capacitive reactance wrote: ---------------- On 6/17/2004 12:27:25 PM AK-4 wrote: "...they are a film & foil. Now, how someone can say they're Mylar and Aluminum... Mylar (polyester) film/aluminum foil I can't tell by looking at the insides, but I can sure tell by looking at the outsides. Mylars are much smaller than polypropylenes for the same voltage rating. ---------------- Not exactly, Dean. I think you're referring to METALLIZED Mylar capacitors, those are very small compared to either metallized poly or poly film/foil. True Mylar film/foil capacitors, like Black Cats or Good-All's are monsters, they're huge. They are about 25% larger than Poly caps because more Mylar film is needed to make the same capacitance value. Mylar film is obsolete, so you won't find many new types. Back in the 50's and 60's, these were very popular. These were replaced with metallized types, and, like you mentioned, they are much smaller. It wouldn't make much sense to make a small transistor radio with 1 inch diameter mylar film caps. Judging from size only, those Russian caps could only be one three dielectrics; (1) Paper, (2) Polypropylene, or (3) Mylar. I know they ain't paper, because I cut one open and the dielectric wasn't a brown color. That leaves only 2 or 3, and based solely on Russian technology of the 80's, my guess is Mylar. Craig, it would be interesting to send the film to a lab to verify what they really are, but you're talking a minimum of $500. They are Mylar, take my word for it. Xc ---------------- Well your theory isn't working because the Russian caps value for value are much smaller that Black Beauties and the like! In fact almost half the size .1uF to .1uF Craig Quote Link to comment Share on other sites More sharing options...
capacitive reactance Posted June 17, 2004 Share Posted June 17, 2004 ---------------- On 6/17/2004 10:17:49 PM NOSValves wrote: Well your theory isn't working because the Russian caps value for value are much smaller that Black Beauties and the like! In fact almost half the size .1uF to .1uF Craig ---------------- Hell, I almost forgot who I was posting to. Since you're such an expert in the electronics field, I was wondering if you could give me the answer to the problem below? I have a full-wave tube rectified power supply. The tube is a 5AR4, output voltage at cathode is 350 VDC. Off of the cathode is a series resistor with a value of 1,000 Ohms feeding a 60 uF 500 VDC electrolytic capacitor. What would the total impedance of this circuit be? There is no load connected after the filter. What is your answer in Ohms? A true electronics expert could give the answer. Quote Link to comment Share on other sites More sharing options...
Parrot Posted June 17, 2004 Share Posted June 17, 2004 Weren't you banned, Lyan? Quote Link to comment Share on other sites More sharing options...
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