Members nerol1st Posted June 2, 2007 Members Share Posted June 2, 2007 Hi I am a newb . Ok so here is my questions: What is the difference between a 47uF 25w Electrolytic cap and a 47uF 25w silver mica cap? Instructions called for the latter of the 2 but I could only find the first. Difference between adudio taper and linear taper pots (also same values)? Link to comment Share on other sites More sharing options...
Members cloudscapes Posted June 2, 2007 Members Share Posted June 2, 2007 electrolyte caps have polarity, meaning ground and v+ works one way but not the other, like a one-way street. silver mica cap (and any othersort of cap that isn't electrolyte) are bipolar, meaning it doesn't matter which of the two ends you put wherever. they also act differently. you'll need to find the latter. does the instructions/schematic specifically call for a silver mica? cause my guess is you can use any 47uf 25w non-electrolyte. linear pot means the resistance change as you turn it is linear/constant. audio pot starts slow (resistance-wise) and then the resistance changes faster as you keep turning at the same speed http://sound.westhost.com/pots-f4.giflog = audio Link to comment Share on other sites More sharing options...
Members Sir H C Posted June 3, 2007 Members Share Posted June 3, 2007 You are never going to find a 47uF silver-mica cap. Maybe 47pF, but never the latter. What is the schematic you are trying to do? Link to comment Share on other sites More sharing options...
Members nerol1st Posted June 3, 2007 Author Members Share Posted June 3, 2007 Actually I am stupid It calls for a 47pF 25 VOLT silver mica cap. I was wondering why the cap was so huge in comparison lol. I didn't install it I am thankfully not that dumb. Link to comment Share on other sites More sharing options...
Members nerol1st Posted June 3, 2007 Author Members Share Posted June 3, 2007 It's a valve Jr. mod. here is what I am doing (can't find the schematic at the moment) 1. Replace the stock 1M volume pot with a CTS 500K audio taper pot.2. Solder a 47pF silver mica cap across the right and middle lugs of the new volume pot.3. Replace C1 and C2 with 0.022uF Sprague 715 Orange Drop caps. 4. Change R8 and R9 to 1.5k carbon film resistors.5. Change R1 to a 1M metal film resistor.6. Jumper R2. - Actually I added a bypass switch instead it acts as a bright switch.7. Change C5 to a 470uF/25-volt electrolytic cap. 8. Change R4 to a 100k carbon comp resistor. I have done mods 4,5,6, and 8 but have to order the parts for the other mods as Radio Shack didn't have them. So far I like what it is doing. I have the schematic but it's on another hard drive that is not with me at the moment. Feel free to comment on this mod if you have this amp. I also have already put in a standby switch and gain switch (gain switch is bypass switch on R6 I think, amp is not with me either). Link to comment Share on other sites More sharing options...
Members nerol1st Posted June 3, 2007 Author Members Share Posted June 3, 2007 Found it: http://www.premierguitar.com/issue/webexclusive/200703_web_ragstoriches.asp Ok I found the right cap (mica) however the mod instructions doesn't say what voltage I need my options are 100v,300v,500v or 1KV. Link to comment Share on other sites More sharing options...
Members nerol1st Posted June 3, 2007 Author Members Share Posted June 3, 2007 Never mind guys I am all set . Link to comment Share on other sites More sharing options...
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