Painful Reality Posted November 24, 2003 Share Posted November 24, 2003 ---------------- On 11/24/2003 5:01:03 PM NOSValves wrote: I'm pretty sure you have never checked !! Why would you I pretty sure all your amps are self biased. This was a absolute measured and proven accurance on 4 caps !! At or near idle no leakage and steady negative voltage to the grid as you turn the amp up the negative voltage would drop. Changing caps no more drop ! Craig Why is it your posts seem more and more meaningless anymore ?? ---------------- Two bad guesses in the first two sentences Craig! I used a lot of these copper and the tin caps from Jensen (I do prefer the tin foil over the copper but few distributors stock them now). I do build either fixed, adjustable bias or self bised amps for myself. I now have no personal preference. I did prefer fixed or adjustable biased amps over self bias before I started to use grid chokes. As for my posts being more and more meaningless well... It was only "sharing my experience" me too. Sorry if it doesn't match yours. On the other hand your posts seems more and more opinonated. I personally still have no favorite configuration, topology, etc. I only believe that a good design is a good design. Today was a good day for me Craig as I submitted my PhD thesis. I hope you had a good day too. Quote Link to comment Share on other sites More sharing options...
NOSValves Posted November 24, 2003 Share Posted November 24, 2003 There now that was a informative and meaningful post ! Now my day is complete thank you You have sent me many schematics and I have never seen one with any type of bias control built in so I assumed you didn't use them. I never stated it was a bad thing just figured you would never check for DC leakage ! You must not if you don't realize that they leak because they absolutely do this is not a mystery its a fact. Craig PS Congratulations on the PhD thesis !! Quote Link to comment Share on other sites More sharing options...
Parrot Posted November 24, 2003 Share Posted November 24, 2003 ---------------- On 11/24/2003 7:19:58 PM painful reality wrote: I submitted my PhD thesis. ---------------- Was its subject the Klipsch Forum? Quote Link to comment Share on other sites More sharing options...
Painful Reality Posted November 24, 2003 Share Posted November 24, 2003 ---------------- On 11/24/2003 7:32:07 PM paulparrot wrote: Was its subject the Klipsch Forum? ---------------- About the same as Neverland being raided... Edited Lord... Misread you again... No it wasn't but it could definitively be an interesting subject! Quote Link to comment Share on other sites More sharing options...
Parrot Posted November 24, 2003 Share Posted November 24, 2003 What was the subject, Mr. Painful. Quote Link to comment Share on other sites More sharing options...
Strabo Posted November 24, 2003 Share Posted November 24, 2003 ---------------- On 11/24/2003 5:52:42 PM Strabo wrote: I wonder how big a 4uf would be if they made it. The 1.5uf I just recieved for my Forte crossovers is about the size of a D cell battery, maybe even slightly larger. ---------------- LOL, I wasn't too far off. About the same length but slightly larger diameter than a D cell battery. Anyway, the point was that these are generally for crossovers. To quote James Woods in Jaws, "We're going to need a bigger boat!" I don't know anything about rebuilding amps and stuff, but I can imagine that a slew of these woundn't fit. P.S. Leok, Told you I wasn't in a hurry on this project. As you can see, they're still not installed. Quote Link to comment Share on other sites More sharing options...
Painful Reality Posted November 24, 2003 Share Posted November 24, 2003 ---------------- On 11/24/2003 7:35:45 PM paulparrot wrote: What was the subject, Mr. Painful. ---------------- Influence of ore pass design on gravity flow Starting again, I would choose to work on the ability of the internet forums to attract strange animals. Yourself Sir Parrot and Romy the Cat would have filled at least two chapters. Quote Link to comment Share on other sites More sharing options...
Parrot Posted November 24, 2003 Share Posted November 24, 2003 Are you going to be called Dr. Painful? That does not make one feel at ease. Quote Link to comment Share on other sites More sharing options...
Painful Reality Posted November 24, 2003 Share Posted November 24, 2003 No worries, I have small fingers! Quote Link to comment Share on other sites More sharing options...
NOSValves Posted November 24, 2003 Share Posted November 24, 2003 Hey I guess dangerous was a poor word choice your correct the leakage is not dangerous. But I guess your just a guilty telling everyone there Can caps are going to explode ion there face !! But it is more than you think especially when you monitor it while the amp is passing a signal ! In other words while in use playing music which is what matters here ! I find that the Russian caps FILM AND FOIL , Auricaps, Sonic caps, Orange drops even your Xicons do not do this if they do my meter can not react quick enough to catch it while its blatantly obvious with a oil cap. Its not a small matter to my ears ! It's not just that they leak I don't like the sound they produce its just my opinion that is all nothing more or nothing less. I think its 90% audiophile romance. Metalized Polypropolyne just doesn't sound as cool as "Paper in Oil" just like "Sprague Atom" just doesn't sound as cool as "Black Gate" or "Elna Cerfine" Craig PS I capitalized and bolded Film And Foil because the russian caps ARE NOT PAPER AND OIL. Quote Link to comment Share on other sites More sharing options...
NOSValves Posted November 24, 2003 Share Posted November 24, 2003 Ryan, No your mistaken what I was measuring was the Negative voltage at the grid with all things being up to snuff the Bias Ma will fluctuate with music playing . But the actual Negative bias voltage should hold dead stable at the grid with Jenson caps this was not the case changed the caps and it was dead stable again ! They were leaking DC along with the AC it was measurable !! Oh and I have a top notch Cap leak tester !! I pay more attention to what a cap does when it is IN THE CIRCUIT where it counts. You know I bet money I could dig up a old post of yours on the Scott list server or forum saying Jenson caps were over priced piece of garbage ! Craig Quote Link to comment Share on other sites More sharing options...
ben. Posted November 24, 2003 Share Posted November 24, 2003 I can get motor run caps cheap through a distrubitor at work. Are they any good for crossover use? I think Guy Landau's are motor run caps, aren't they? Also, can 12.5uF be subbed for a 13uF without a real problem? Seems to me that would be within tolerance any way. Quote Link to comment Share on other sites More sharing options...
Painful Reality Posted November 24, 2003 Share Posted November 24, 2003 These motor caps have their adepts and detractors too. I can't say I am crazy about these in amplifiers but these are dirt cheap so the loss is minimal if you end up in the disliking camp. Quote Link to comment Share on other sites More sharing options...
Painful Reality Posted November 24, 2003 Share Posted November 24, 2003 See what I meant... Quote Link to comment Share on other sites More sharing options...
ben. Posted November 24, 2003 Share Posted November 24, 2003 For the $25 in caps to build a Type A network, I think it's worth a try. At their rated voltage, seems to me they'd be good at passing 60 Hz and that's about it, but we're talking low voltages in a crossover. Quote Link to comment Share on other sites More sharing options...
NOSValves Posted November 24, 2003 Share Posted November 24, 2003 Ryan, Why is when cornered you always get nasty ?? You didn't just say they were over priced pal ! The words were Over priced Pieces of Sh!t. Once again you did not read my post yes the current flow changes with the music BUT THE ACTUAL NEGATINE BIAS VOLTAGE APPLIED TO THE GRID SHOULD HOLD DEAD STABLE !!!! if it doesn't it is a absolute sign of excessive leakage of the coupling cap or a faulty bias circuit !! This is simple tube electronics trouble shooting at work here dude. I can't believe you don't get it ! Craig Quote Link to comment Share on other sites More sharing options...
mike stehr Posted November 24, 2003 Share Posted November 24, 2003 "About the K40Y9 capacitors: The 630V and below versions in colored body (red or green) are MYLAR FILM capacitors. The 1000V+ version is PAPER IN OIL, found in the silver body." Hell, I guess I'm glad I bought 1000 volt ones. Quote Link to comment Share on other sites More sharing options...
Chris Robinson Posted November 24, 2003 Share Posted November 24, 2003 ---------------- On 11/24/2003 7:19:58 PM painful reality wrote: ---------------- On 11/24/2003 5:01:03 PM NOSValves wrote: Today was a good day for me Craig as I submitted my PhD thesis. I hope you had a good day too. ---------------- Jeff, mucho congrats on finishing the Long Haul !! Hope there are champagne corks popping up in QC! Damn, that must feel FINE !!! Quote Link to comment Share on other sites More sharing options...
Deang Posted November 24, 2003 Share Posted November 24, 2003 I've got my own thoughts about caps, does anyone care to hear them? I just want to know how Leo put together the 5uF value. Best I could do with these things is 4.8. Leo, have you yanked the polyester monster out of the notch circuit yet? Still using the stock air cores in the HF section? Quote Link to comment Share on other sites More sharing options...
3dzapper Posted November 24, 2003 Share Posted November 24, 2003 Several thoughts: Painful, Congradulations on your paper. I wish my wife would finish hers. She's been ABD for about eight years she's afraid to finish. Good to see that you had the courage and perseverance to complete your quest. Ryan, I built an EL-84 PP amp recently and used highly esteemed( and expensive) hermetically sealed PIOs in the coupling circuit from the 12AU7 to the outputs. I set the initial bias at 35mA and when I went to reset it again in a couple of hours it was up to 60+ and the tube was glowing. I tested everything no problems could be found. I swapped tubes bias resistors and pots and each time I could set initial bias but when hot no go. Finally I started taking voltage readings when cold everything was fine then gredually the voltage on the grid of the problem output would climb to over 10V. Another to 3V+. Itook out the PIOs and put in some Sprague Orange Drops end of story. PIOs can be bad. 50% of the sample in that amp were. I used the same PIOs in my EICO to replace the 4 red caps, no problem. In the higher voltage circuit though I used poly film and foil. bclarke421, Klipsch used motor caps for many years in their crossovers with good results. Some here like them better than film and foil. I prefer the F&Fs myself seethe posts in the Odds and Mods forum. Of course those caps were close to thirty years old and I don't know their history. Newer stuff is built to tighter tolerance than in the past. I'm sure your 12.5mF is a lot closer to 13mF than the caps used in the sixties and seventies. They were probably -20/+50 in tolerance range. Rick Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.