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Has anyone tried replacing the CJ Polystyrene caps in their Conrad Johnson amp/preamp coupling caps?. Plan to replace them to Mundorf Silver in Oil , but the problem is CJ uses 0.15uf while Mundorf values have 0.1uf and 0.22uf. The VH Audio TFTF have very good feedback from other users. It has a 0.15uf value but a bit pricey as i'll be needing 4 pieces .Is it OK to replace 0.15uf CJ polystyrene replaced to a 0.1uf Mundorf SIO or should i go for the 0.22 Mundorf SIO .. any pros and cons ?
Follow Ups:
I stronly suggest to wait until you can afford the teflon v-caps. Why only get a small improvement if you can have a big one?2 weeks ago the replaced the 3,3 uF Mundorf Silver/Gold caps in my Omega Duos tweeter XO with the teflon v-caps and In can tell they make the Mundorfs sound broken
I've used both V-Cap TFTF and Mundorf Silver/Gold in much smaller values as coupling caps in amp, PS, LS. While the V-Caps are better, the Mundorf Silver/Gold hardly sound "broken" by comparison. Perhaps the gap between the two caps widens at larger values associated with speaker xovers. The Duos are somewhat untypical in requiring just medium-value caps, which represent the top of the range of V-Cap TFTF. You're lucky in that regard. But I wouldn't generalize much across all applications.
I can't comment how the v-cap compares to the silver/gold in other applications and smaller values like coupling caps but the difference in my tweeter XO is really large and all my audio buddies immediately notice that the speaker is a lot more transparent and clear sounding without any brightness or hardness. Even my buddy with his Kharma Mini Excuisites with Diamond tweeter mentioned how good the highs are!
My system is very resolving and shows the differences immediately. I can imagine in a less resolving system the differences between those caps might not be that large.
Yep, the more refined a system, the more small changes are perceived to make large differences. And V-Cap TFTF will make a greater improvement than ANY megabuck cable swap.
I've read that you can actually burn-in by playing pink noise without the power tubes. So this would burn-in the new caps without burning your power tube life and electricity bill. Is this applicable and safe to other tube amps like the CJ amps ?
Appreciate your suggestion ... i just hope the price of the V-caps drop so that i don't have to wait for too long.I am also a fan of Mundorf caps. I use the Silver in Oil in my Consonance Ref 2.2 tube CDP and the Supreme in my XO. They are really great caps but the V-cap TFTF kicks em as i've read on users here at AA.
Yes, I have replaced the cj coupling caps. I'm not a big fan of them. Mundorf supreme, Jensen pio, and Hovland all much better depending on what flavor you need to compliment your system.
Thanks for the info. Are you refering to a CJ amp or preamp ?
So far i've used Auricaps and Solens as coupling cap i another gear ( Consonance ref 2.2 Tube CDP ) and I've settled with the Mundorf SIO. Now i want to try it on my CJ amp to see if it will bring the sound quality to higher level.
As coupling caps in the D/A 2b tube converter. Forget Solen, their worse, and I personally dislike Auricaps. I actually have a bunch of Cj caps I got from somewhere and I have used them in my own Diy tube preamp for awhile I do like them better then the ones metioned above.
If you want an opinion of a person who compared lots of caps, look for the capacitor shootout in the Chinese audio magazine. Coupling caps can make an important difference in the sound. I suspect that the Mundorf caps would improve the sound over the stock caps.The capacitor value affects the bass. A smaller value will pass less bass than the larger value. Whether it will make a significant difference in the bass you hear is a function of the grid resistance it sees at the output tube.
Retsel
Is the cap shootout online? If so, could you please post a link?Thank-you,
Fred
Here it is ....
I've read the 21 caps shootout and known that the V-caps and the AN Teflon caps are the best sounding caps as per the reviewer. But the cost is the one hindering me to use them :). The Mundorf Silver in Oil is just right for my budget .I've upgraded the coupling caps of my Cayin A88T to Mundorf Silver in Oil and very happy with the results. Quite easy to accomplish since this amp uses point to point soldering. Not really sure if lowering the value from 0.15uf to 0.1uf will give significant audible effect.
If you have some 0.1 uF caps laying around (even crumby ones), you can put them in to test their effects on bass. If Ok, then you can purchase the better Mundorfs in confidence.Retsel
Here's a different view. I have a CJ PV8 preamp. When it was stock, compared it to a upgraded PAS, which ran circles around it. Upgraded the PV8 line level section to PV11 which did improve the head room. Started playing with coupling caps, sound difference was not small. Tried from very expensive caps to orange drops and many in-between. Sound changed each time. I did all of this after switching to an OTL amplifier which revealed everything.So, from my experience, experiment. Depends a lot on the rest of the system, and what you like. No right or wrong answers, just what you like.
Fred
Thanks for sharing your experience in tweaking your CJ preamp. I agree with you, the sound will change and it all depends if you like the outcome. After all you own the system and you are the one enjoying it.:)
I use Mundorf SIO's in 2 different pieces of gear (a DAC and a E-FP III preamp) . Make sure before you start the project that you have enough room for the Mundorf's . They are enormous !!!! They sound very good ;~))Joe
Polystyrene caps (once common, now rare) are the best available for audio after Teflon. CJs are very high quality too.
Oil caps are fasionable and trendy but grossly overrated.
I think you will ruin the sonics CJ tried so hard to perfect.
And your resale value will go down the drain, unless you do not disclose the sin.
What are you trying to achieve? Just curious.doggy
Yes, the CJ polystyrene caps are Conrad Johnson's propriety caps and considered high quality, but i think the newer technology caps are equal or may be better that these caps. I've read that the polystyrenes poor heat resistance and they can be damaged by soldering ( http://my.execpc.com/~endlr/film.html ).. hmmm inside the amp is quite hot.:)As for the resale ... i think the Premier 11a is a keeper and don't intend to replace ( as fo now ). Further more, the mod is reversible so if i plan to sell it in the future, i can just solder back the original styrene caps.
" Polystyrene:
Polystyrene (PS), (the Europeans often call it "styroflex" or "styrol") has long been the material of choice for critical analog circuits. Low leakage, low dielectric absorption and a shallow, flat temperature curve makes these capacitors suitable for timing circuits, filters, integrators, and sample-and-hold circuits. Moisture absorption is very low. Size, cost, availability, and temperature range limitations make polystyrene unsuitable for most other applications. Heat resistance is limited to about 85C, so forget surface mount. They can be damaged by soldering and by chlorinated board cleaning solvents. I don´t believe I have seen them in metallized film, only in film-foil.Because of the poor heat resistance, polystyrene has largely been replaced by polypropylene and C0G ceramics, and the capacitor-grade film is no longer being made. There is several year´s supply still available, and they are still being sold, but be careful using them in new applications. Some manufacturers have noted that polystyrene caps are "not for new designs". One company, ITW Paktron, makes polypropylene capacitors with a guaranteed temperature drift similar to (if not quite as good as) polystyrene. PS's other electrical properties are mostly very similar to PP.
Whether polystyrene capacitors will really go away any time soon is not certain. I have been warned of polystyrene´s demise "in a few years" for over a decade now, and yet it is still available. There almost seems to be vast supplys of the film stashed away in manufacturers back rooms. It may also be that declining usage will extend available stocks for many years to come. I imagine that many of polystyrene´s traditional applications are fading away as newer technologies take over. "
Polystyrene production came to a screeching halt because it's production had hazardous wastes, including dioxin. This brought most EU production to a halt. Recently, however, I have heard rumors of a factory in China gearing up for polystyrene production.Polystyrene is supposed to have the shortest 'memory' of any dielectric, IIRC. Even better than teflon, which was the original reason CJ elected to build their custom caps from 'styrene. I do recall there were many problems when polystyrene product halted and CJ was forced to used alternate purveyors for their caps. Not all were as good as the original vendor (Southern/F-Dyne, IIRC).
Stu
Hi.Obviously swapping caps seems to be the easiest way to change the sound of an amp, for better or worse (who knows). But please don't make it a habit.
Those costly exotic cap vendors should chime in here to thank for interest-free financing from those frequent cap buyers.
I have done tons of sonic build/upgrades, from phonostages to power amps, & loudspeaker systems, changing caps to me is a minor & very passive way of sound upgrade, if any at all.
c-J
But it would be a good way to "mush-out" the sound if you want it to sound slow and syrupy.
.
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Tin-eared audiofool and obsessed landscape fotografer.
http://community.webshots.com/user/jeffreybehr
Yes, CJ uses 0.15uf Styrene caps as bypass caps in the power supply . I am actually referring to the 0.15uf Styrene coupling cap from 6FQ7 to 6550 tube in the Premier 11a amp.
...I'd use either SoniCap Platinums or, if I wanted a somewhat warmer sound, a combination of Jensen PIO/CFs and SCPs, about 2/3rds and 1/3.I added the 4 0.15µF 'styrenes to the output of the main PS, 2-each immediately AFTER the high-Voltage fuses.
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Tin-eared audiofool and obsessed landscape fotografer.
http://community.webshots.com/user/jeffreybehr
High voltage fuse? Hmmm are you refering to the BBS-1 connected to the output transfomer?Just curious, how did you install the caps . Did you disassemble the PCB or just cut the existing styrenes and solder the NEW caps?
...cutting old leads and soldering new parts to those leads...but I suppose that would be necessary in some cases.Here's a pic of the new couplers...
This was the later of the 2 Elevens I owned....and here are the old 'styrenes added to the PS fuse.
The green wire is circuit common/neutral/return/ground.I state again that I'm no GEA, so I can't tell you how (or even 'that') these 2 changes improved the sound. I'm more of a longer-term-changes guy, but I sold both Elevens soon after this.
I do recall having some problem getting a couple of the the new caps' leads soldered effectively, but I was using 5%-silver solder then and didn't want to overheat the board. I now use Cardas Quad Eutectic; it flows MUCH easier.
Also, you might change slightly the value of the caps depending on how you're using the amp. For instance, if I were biamping and the Eleven was driving the upper 8 or 7 octaves, I might choose a 0.1µF cap. If I were using it fullrange, I might choose 0.22µFs.
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Tin-eared audiofool and obsessed landscape fotografer.
http://community.webshots.com/user/jeffreybehr
Cool pictures !! That's excatly what i am thinking as some problem might occur after dismantling the PCB and desoldering other connections. I think i'll settle on the 0.1uf Mundorf Silver/Oil since it's where my budget can reach and maybe upgrade to V-Caps TFTF in the future : )
the tube ones at least, the top plates comeoff as well as the bottom plates. Replacing parts is considerably easier compared to older designs, as you then have easy access to both sides of the board.
Stu
unclestu52,Thanks for the tip !! I unscrewed the six 4mm screws and was able to access the other side of the PCB. Time to clean the flux again !! Atleast i can just desolder the coupling caps i plan to replace.
By the way, have you done any tweaks/upgrades on CJ amps ? Care to share your experience .
Cheers,
Jason
and void your warranty?.....One cheap tweak: on the ground leg of your bias pots, install a small electrolytic cap (or film if you can find the space) to ground. Usually the ground leg has a resistor to true ground. A 5 to 10uF cap is sufficient at say 50 volts to be really safe will buffer the bias to the tube tremendously, and give your amp a significantly greater control of the bass. Remember the positive leg goes to ground for the bias supply.
Stu
Fortunately my Prem 11 warranty had looong been expired so i don't need to worry abouy voiding the warranty. I just want to tweak or update/upgrade some parts . After removing the top cover, i've noticed that the tube sockets are also quite dirty ( oxidized a bit ) and also some tubes are a bit loose. Maybe due to the aged tube sockets. Any recommendation of good tube sockets? ( ceramic or teflon types )Anyway , i tried to lay-out your suggested capacitor tweak. Is the schematic below correct ? There is a 18.2K connected on the ground leg of the bias pot which is connected to ground. So i just put the electrolytic cap in PARALLEL to the 18.2K resistor. Am i correct ?
I don't have the schematic in front of me but yes parallel the cap (4 of them) with the resister, remember the correct orientation, positive to ground!I wouldn't change the sockets. Those fancy ceramic gold plated pins stuff made in China, look good, but have terrible metal work, and lose tension quite rapidly. You can get those dental brushed for bridge users and clean the sockets quite nicely. Use a bit of alcohol.
What I don't like about many ceramic sockets is that they have an uncoated bottom surface. Cleaning solutions seem to penetrate the porous surface and they seem to get stained permanently.Stu
While you're at it, I like to reheat the tube sockets for the 9 pin sockets with a junk tube inserted to align the pins. Had some problems with Mullard made tubes cracking from uneven socket tension. If you want more pristine highs and very fine detail you can use a solder sucker and replace the leaded solder with unleaded stuff. Try the output sockets first before doing the rest of the joints, as it is quite a tedious job.
Thanks for confirming the capacitor tweak. Will get some BGs to try.Have seen some ceramic tube sockets at tubestore and also some pricey teflon tube sockets at partsconnexion. I also noticed some of the socket tension are uneven ., but i did not experience cracking sounds though. This is the reason i plan to change them. I think your suggestion of cleaning and replacing the solders with WBT silver solder is a better route... thanks mate !!
CJ does not remove the flux?
I think the flux become more noticeable as the amp ages. I called CJ service to ask any advise . They told me " If not broke .. don't fix !! ", but i still went ahead and use IPA to clean them. I didn't hear any sonic difference :)
about the flux getting more moticeable as the amp ages. The flux being organic in nature, tends to carbonize with heat. The pins certainly get quite hot on the tube sockets. I notice that with age the flux deposits get considerably darker. I always clean off the flux deposits as you do with alcohol, and I just feel safer with less of a possibility of arcing.
I know with burnt resisters which can also burn the circuit boards, it is imperative to cut all the carbonized sections off or else the traces will most definitely arc again in the future. You know what they say: an ounce of prevention....Stu
Nope, at least not at that point. I have an MV75 and a PV5 that have just as "dirty" boards.
I guess I'm spoiled because ARC boards are super clean. Also I occasionaly used the flux removal system at work to clean my boards.
Some solvents will attack the film caps, but there are safe alternatives.
CJ probably did not want to deal with it.
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