CJ Upgrades
chargerman426
Posts: 419
Hey guys I'm think about doing some upgrades this year on my CJ PV-11 tube pre amp. I want to upgrade the tube sockets,RCA jacks, Caps, possibly the resisters, and adding an AC socket. I have been reading all of the threads about caps and I'm just a little confused on what caps to replace. Do I replace all of the caps or is there few that I should replace? Should I change them all but buy nicer ones in a sertent spot as they will make a bigger difference? I also have the same questions about resistors. Any help would be greatly appreciated. I have attached a pic of the inside of the pre for reference.
If life had more tubes it would be a lot smoother.
Post edited by chargerman426 on
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IIRC, the output coupling caps are the ones that will give you the better bang/buck upgrade.JC approves....he told me so. (F-1 nut)
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I wanted to spend let then 500 for the caps so I was thinking that I could go with sonicap gen1 for everything to keep cost down and maybe getting some of the sonicaps platinum for the one that would make a difference.If life had more tubes it would be a lot smoother.
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george what does IIRC mean and how can I tell which caps are the output coupling ones?If life had more tubes it would be a lot smoother.
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If I Remember Correctly--can you take a couple more pics of the insides,,looking down?JC approves....he told me so. (F-1 nut)
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A schematic might help-- and let Fred look at the pic or schematic and you'll know in a sec.
I think your output coupling caps are 2.0 uf,,JC approves....he told me so. (F-1 nut) -
I'm guessing(need a schem to be sure) the black SCR's and or white film caps near the center rear directly behind the tubes are the output coupling caps.The film cap count is very high,I only see one electrolytic so CJ obviously doesn't like to use them even for power supply filtering duties.
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CJ said they use polystyrene or polypropylene (I can't remember) though the entire pre.If life had more tubes it would be a lot smoother.
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schematic is belowIf life had more tubes it would be a lot smoother.
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C26 and C27 in parallel are the ouput coupling caps so likely the two I mentioned in the previous post.
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Maybe a bit of both,the SCR's are likely Polyprops they are the guys that manufacture Solen's fast cap for them.chargerman426 wrote: »CJ said they use polystyrene or polypropylene (I can't remember) though the entire pre. -
^^^^^^^^^^^^^^^^told ya ^^^^^^^^^^^^^^^^^^^^^
Fred,, how long have you been doing this?
JC approves....he told me so. (F-1 nut) -
So would it be an upgrade if I go with the Sonicap Gen1 or the sonicap platinums?If life had more tubes it would be a lot smoother.
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Also the C26 caps are .15uf/220V (white caps) and the C27 or 2.0uf/250V (black caps). C22 and C23 are the same as C26 and C27, so does that mean C26+27 is for the right and C22+23 is for the left?If life had more tubes it would be a lot smoother.
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Started in around November.:biggrin:george daniel wrote: »^^^^^^^^^^^^^^^^told ya ^^^^^^^^^^^^^^^^^^^^^
Fred,, how long have you been doing this?
Only one channel(right) is shown in the schematic.C22 and C23 are the output coupling caps for the phono section.I would omit the .15uf bypass caps when installing a premium 2.0uf film.I believe George has tried a number of good caps in his own tube equipment so can recommend a suitable upgrade.chargerman426 wrote: »Also the C26 caps are .15uf/220V (white caps) and the C27 or 2.0uf/250V (black caps). C22 and C23 are the same as C26 and C27, so does that mean C26+27 is for the right and C22+23 is for the left? -
Ok I only posted the schematic part. I got the parts list to so I just assumed C26+27 were for the left. Should I replace the other caps or any resistors?If life had more tubes it would be a lot smoother.
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I would replace the caps that Fred mentioned with a flavor that you like/prefer,, as for the others,if they are good,,I'd leave em alone.I think that you are gonna get the biggest bang/buck with the output coupling caps,,and leave the bypass caps out,,how much money you wanna spend on caps?JC approves....he told me so. (F-1 nut)
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I was looking at less then 500 but that is what I was thinking for the whole pre. So if I'm only doing 2 caps less then 100 or so.If life had more tubes it would be a lot smoother.
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I have seen some nicer caps that come in 2.2uf but not 2.0uf is this a problem of I take out the .15 bypass cap?If life had more tubes it would be a lot smoother.
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Yes you can increase the value,but decreasing it will affect the bass response how much depends on the input impedance of the amp it's driving.
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Thank you guys for all your help. I think I'm going to go with the below cap in 2.2uf. Let me know what you think.
http://www.soniccraft.com/mundorf_silver_oil.htmIf life had more tubes it would be a lot smoother. -
Bump. Any input on that cap?If life had more tubes it would be a lot smoother.
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Sorry I have no experience with Mundorf so can't comment on it's SQ but it's value would be suitable.
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Cool, thanks for all of your help man. If anyone has any suggestions about a good cap that would be under 100 bucks for a pair that would be helpful. Also, would it help to upgrade the tube sockets over the stock ones?If life had more tubes it would be a lot smoother.
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Ok I think I have picked out all the caps I want to use. I was rolling some tubes and noticed the left side was microphonic out of the left channel. I switched tubes and the problem did not move. I think its the tube sockets as they are 20+ years old. Any suggestions on a good socket. I wanted to use a Teflon socket but I cant find it in a PC size.If life had more tubes it would be a lot smoother.
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chargerman426 wrote: »Thank you guys for all your help. I think I'm going to go with the below cap in 2.2uf. Let me know what you think.
http://www.soniccraft.com/mundorf_silver_oil.htm
I just sold a pair of Mundorf SIO 2.2 uf's.JC approves....he told me so. (F-1 nut) -
Do you have anything else in a 2.0 or bigger?If life had more tubes it would be a lot smoother.
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Hey I just did installed the new caps and I have a problem. I can barely hear anything out of my speakers. If I turn the volume up 3/4 of the way up it just sounds like they are just whispering in my speakers. Any help?If life had more tubes it would be a lot smoother.
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did you check your solder connections?JC approves....he told me so. (F-1 nut)
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Yeah I checked before I put the bottom back on. I checked for resistance with an ohm meter.If life had more tubes it would be a lot smoother.
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Hey guys I fixed it. I had two bad solder joints in the output caps. Goes to show what sleeping on it will do for your soldering skills If life had more tubes it would be a lot smoother.
