BadAssBluesDude Posted December 29, 2008 Share Posted December 29, 2008 I have insomnia and an addiction to this %$#@! hobby so I was re-reading old posts. I hate to aim a public question at anyone, but in an earlier post Gil said I learned a good lesson from that and now use a cheep green 0.68uF/100v metal film caps in parallel with the cathode bypass caps C3, C4, and C5. It opens up the top end, and can help smooth the typically harsh top end of an el84 or the spikey high end of an Orange Drop coupling cap for example. First off, if I try that I want to make sure I'm doing it right. Would it be like this? I have 5uf on C3 and 1uf & 5uf on a switch on C4, so I'm assuming I'd want to run an 0.68 cap in parallel with each? Next question...when I'm spending to big bucks (actually just a few) on Sozo caps and whatnot, why use cheap caps in this application? Thanks, TC Link to comment Share on other sites More sharing options...
Eracer_Team Posted December 29, 2008 Share Posted December 29, 2008 I don't think you'll hear much difference from 5uf and 5.68uf but if you might hear the difference from .68 and 1.68uf. c3 & c4 are stock 22uf which has been stated pretty much full bass by-pass, by making those smaller the bass rolls off since most find the bass in these amp's mushy. You still have quite a bit of bass at 5uf that's why some lift the c3 cap. other's have reduced their caps depending on which pickups they mostly use (humbuck vs single). Here are two calculator's I think will help you. http://www.electronics2000.co.uk/calc/calccsp.php http://www.electronics2000.co.uk/calc/calcrsp.php Link to comment Share on other sites More sharing options...
BadAssBluesDude Posted December 29, 2008 Author Share Posted December 29, 2008 Is my diagram correct? Is that "parallel"? Series is placed end to end, correct? Thanks for the link to the calculators....they are great. Thanks, TC Link to comment Share on other sites More sharing options...
m-theory Posted December 29, 2008 Share Posted December 29, 2008 Is my diagram correct? Is that "parallel"? Series is placed end to end, correct? Yes, and yes. Link to comment Share on other sites More sharing options...
BadAssBluesDude Posted December 29, 2008 Author Share Posted December 29, 2008 I think I need to give you Gil's full quote. But electrolytic caps don't filter high frequencies as well as non-polar metal film caps like Sozo, Mallory, and OD, etc. This is one of the reasons for having that big .1uF C11 in parallel with C8. On the pcb, C11 was also due to noise picked up from jumper Jp3. I learned a good lesson from that and now use a cheep green 0.68uF/100v metal film caps in parallel with the cathode bypass caps C3, C4, and C5. It opens up the top end, and can help smooth the typically harsh top end of an el84 or the spikey high end of an Orange Drop coupling cap for example. That might help make more sense of my original question and the logic behind the original statement. TC Link to comment Share on other sites More sharing options...
layboomo Posted December 29, 2008 Share Posted December 29, 2008 Just FYI....in those applications anything 10uf and up is considered "fullrange"......below 10uf you are attenuating certain frequencies. Link to comment Share on other sites More sharing options...
cGil Posted December 29, 2008 Share Posted December 29, 2008 Who? Me? I'm just the mouse on the shoulders of giants and other mod junkies on SEwatt and 18watt.com. Good thing, too. My species of meeces is just smart enough to deny everything and thereby avoid terminal lab-rat duty. ;) I was even peeking over shoulders when I came across this link. http://www.parts-express.com/pe/showdetl.cfm?Partnumber=020-1848 Gil... Link to comment Share on other sites More sharing options...
Eracer_Team Posted December 29, 2008 Share Posted December 29, 2008 if Gil is the mouse on the shoulders of the EE's at 18watt then I must be the dust mite in the cuff of Gil's shoe laces... Link to comment Share on other sites More sharing options...
BadAssBluesDude Posted December 29, 2008 Author Share Posted December 29, 2008 Holy crap, then what does that make me? I'm still confused. Is this something that I want to do? My newbie take on Gil's original quote was that rather than just adding 0.68uf of extra capacitor value to whatever you might already have in C3,4,or 5, because they are film capacitors they are filtering the highs in a more desirable way than the electrolytic caps by themselves. I believe in another post Gil stated that it added a bit of definition. Always learning....... TC Link to comment Share on other sites More sharing options...
cGil Posted December 29, 2008 Share Posted December 29, 2008 Seems to work that way. Ya probably gotta get your ears really tuned in to hear it though. Very subtle, like the hints of grapefruit (?) in the aftertaste of a different Sam Adams beer??? But I admit, I'm hooked on 'em, cuz I've found even the teeny tiniest of subtle improvements really do add up. Hey, if it works for beer... :- Meanwhile, I think I'll go throw up now. Heights just make me dizzy. Gil... Link to comment Share on other sites More sharing options...
BadAssBluesDude Posted December 29, 2008 Author Share Posted December 29, 2008 Heights don't bother me, it's widths......try the veal. I'll give it a try. Like I've said, I'm REALLY happy with my sound thus far, but when you mention something about more high end definition, I'm always interested. I have tinnitus, (constant ringing in my ears) so I don't know if I have a sensitive enough audio palette to tell the difference. As always everyone, thanks for all your help. I'm sure by the end of the night I'll have a new post started. TC Link to comment Share on other sites More sharing options...
Eracer_Team Posted December 30, 2008 Share Posted December 30, 2008 As long as you remember a few things you'll be fine... 1- this is a $100 +/- amp not a $2200 amp 2- you can always buy another $100 amp 3- you will spend $500~$1,000+ on parts. 4- pcb boards (black or green) can be destroyed, be gentle and use a sucker to remove the old solder; don’t just heat the part up and pull. 5-Heat kills the trace and heat kills the part. 6- There is no reason to switch to point-to-point or a turret board as long as you’re good with the board; switch when building from scratch or a board failure. 7- the first amp you build will have a billion holes in the chassis and a billion more switches to fill the holes. 8- amp’s 2,3,4,5,6,7,8~ ~ ~ ~ will have less and less holes and less and less switches. 9-You bought the amp to learn. It’s a simple amp with a volume control and not a lot in-between the input and the output; the simpler the circuit you do the better the sound (unless you like to make your life he## trying to fix the problem's you've added) Lastly 10- read, read and re-read all the posts before hitting the soldering iron; here and at sewatt.com and even the very old http://vj.minuteboard.com/m/b/go.html board contains info that spans over 3yrs. Link to comment Share on other sites More sharing options...
layboomo Posted December 30, 2008 Share Posted December 30, 2008 Guys like Phil over on 18watt are the true Obie-wan's of the amp galaxy.......the rest of us are just Jedi's in training! Link to comment Share on other sites More sharing options...
Eracer_Team Posted December 30, 2008 Share Posted December 30, 2008 sort of like this? http://www.ichibankarateschool.com/images/graphics/img4667edited1.jpg Link to comment Share on other sites More sharing options...
cGil Posted December 30, 2008 Share Posted December 30, 2008 Yep. Those are the guys who obviously stayed awake during Jedi class! Gil... Link to comment Share on other sites More sharing options...
BadAssBluesDude Posted December 30, 2008 Author Share Posted December 30, 2008 Yes, this is absolutely a learning "Swiss Cheese" amp. I got lucky. I got a great deal on a VJ stack on Ebay, and before it even arrived I got an even better deal on a head that had the turretboards.com Vox board, the Heyboer OT, and new tubes. I got that for considerably less than the parts alone would have cost. I then sold the stock head for about what the stack cost in the first place so I've got a great amp having not spent a lot at all. I read everything 2,3,4 times before I do anything. I kinda have OCD that way. Especially now that I've done a few mods, I'm learning what information to look for before doing another mod, where to find the info, and what questions to ask if needed. Thanks to everyone here. This hobby has been a lot of fun and I couldn't have done it without you. Thanks, TC Link to comment Share on other sites More sharing options...
BadAssBluesDude Posted December 30, 2008 Author Share Posted December 30, 2008 Also....................I go by Radio Shack every day. Would they have this and if so is there any reason I wouldn't want to buy it from them? TC Link to comment Share on other sites More sharing options...
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