Bottlehead Forum
Bottlehead Kits => Crack => Topic started by: adamct on January 15, 2013, 05:02:59 PM
-
So.....as with many others, I'm interested in upgrading the caps in the Crack. I understand that I'm looking for something rated at least 100uf / 250V. That's about the extent of my knowledge. I found the following that - to my ignorant eyes - look like the meet the requirements. Can anyone give me any advice as to which of these is likely to offer the best bang for the buck? Are the Obliggatos listed below the ones that several others have installed? Lastly, do I just need two of these? Or do I need more? Apologies, I've tried searching the threads, but I can't figure out exactly which caps people are talking about (or where I can, I can't find those caps available for sale anywhere).
MUNDORF-71346
(metalized polypropylene)
100uf / 250V
M-CAP
-
Adam,
I don't listen to headphones so I don't have a Crack. I can't give you advice on which of those are best for the output cap. But, the Obbligato caps I use are here:
http://www.partsconnexion.com/capacitor_film_obbligato_oil.html
They do not go big enough for the output cap. I think these are usually a great bang for the buck. The Crack requires a large value of capacitance.
-
Any of the caps listed would work. I'm using Auricap 100uf 200v in mine. Just depends on how much you want to spend. I haven't used the Mundorf EVO series caps in any projects so would be interested in how they sound. I have used the Jentzen Cross Caps from Parts Express which are $34.76 for 100uf 400v and Madisound has the Clarity SA for $51.50 and the ESA series 100uf 250v for $85.30. You could also use a cheap larger cap bypassed with a more expensive small teflon cap. Just depends on how you want to do it.
-
ERSE is a good brand for a big cap like that as well and competitive with Solen in price.
-
Thanks for the responses! Quick question: is there a difference between "metalized polypropylene" vs. the Mundorfs and Obbligatos that are listed as "film capacitors"? Is metalized polypropylene just a kind of film capacitor under a different name, or is it entirely different?
Apart from whatever I need to do to securely attach these, are any other changes necessary to the Crack, or can I just clip the leads on the existing caps and solder these in in their place?
Best,
Adam
-
Short intro to film caps:
1) The dielectric (he insulator) is a plastic film. The most common films are polyester (a.k.a. nylon; Mylar is a brand) and polypropylene. Some are more linear than others, which is thought to be an audible source of distortion. The actual measured evidence is pretty thin, so you have to use your ears too. Teflon is the most linear, followed by polystyrene, polypropylene, then polyester. An older technology is to use paper impregnated with various oils or waxes (which dominate the performance). You will see the term paper in oil, abbreviated PIO. Some plastic film caps are also bathed in oil, though the oil does not absorb into the plastic itself.
2) The conductive metal can be deposited in an ultra-thin layer on one side of the film (called metalized film) or it can be a separate foil (called film and foil). Aluminum is most common, though copper, silver, and tin are also used. Metalized film is self-repairing - a short between layers will vaporize the metal -. Foil is thicker and needs a thicker film since it can't repair itself, so they are much larger. The foil is thought to reduce internal vibration.
3) There are electrical forces between the layers of a capacitor, and the dielectric itself will respond mechanically to electric fields. This causes capacitors to vibrate in response to the signal voltages, which in turn modulates the signal - causing audible distortion. Some caps are more prone to thisthan others, and the importance of this effect like so many others is still debated.
Bottlehead mostly uses well-made but inexpensive metalized polypropylene when we have film caps. We think these are the most cost-effective choices.
-
Paul,
I think that post should be a sticky in tech topics.
-
Here's a link you might find interesting http://www.troelsgravesen.dk/super-caps.htm (http://www.troelsgravesen.dk/super-caps.htm)
-
Adam,
Also, don't overlookthe mundorf m-tube ps caps even thought their voltage rating is far higher than you need in this application (I believe the voltage rating of the stock caps is 160v.)
Paul, where does polycarbonate fall in this hierarchy? I've seen more and more audio caps made with polycarbonate (as dielectric) in the last couple of years but haven't tried them myself yet.
-- Jim
-
...Paul, where does polycarbonate fall in this hierarchy? I've seen more and more audio caps made with polycarbonate (as dielectric) in the last couple of years but haven't tried them myself yet....
The Wikipedia article on film caps is worth looking at, though it is quite exhaustive (i.e. often boring!) There, it is said that polycarbonate film (PC) production ceased some time ago, though one cap manufacturer claims to be producing their own. In a quick search, I could find no data on dissipation factor (ESR) or dielectric absorption (distortion) except that dissipation is "low".
It still appears that teflon is the only dielectric superior to polypropylene in these measures. PPS (Polyphenylene sulfide) has potential, closer to PP (polypropylene) than PET (polyethylene terephthalate aka mylar) with good temperature tolerance - it's showing up more because of surface mount solder temperatures.
Among ceramics, NPO is nearly as good as PET but the others with high capacitance per volume are terrible.
These are just comments on the properties of the film; remember that construction is also important. And there are almost certainly other parameters we don't know about yet which are also audible in the right circumstances.
-
Paul,
Thanks for another great lesson/resource. I'm definitely going to wade through the wikipedia article.
-- Jim
-
Help! I'm about to place my cap order, but then remembered that there were two sets of caps in the Crack, with different values. Can anyone fill me in on what values I need for the other caps, and tell me whether upgrading them is worthwhile (and what caps are recommended for that purpose)? Unfortunately, I'm at work and don't have access to the Crack parts list or manual.
Thanks!
Adam
-
Adam,
The most critical caps are the 100uF output caps. They need to be rated equal to or great than 160 volts.
The other caps are in the power supply. These are 220uF 250volts.
You could also consider using bypass caps in both positions. There has been discussion on the forum about what values to use and best position in the power supply, so a quick search should yield a lot of good information.
-
Brad,
Do the power supply caps have much of an audible impact? I'm not looking to upgrade for the sake of upgrading, only if it will actually make a noticeable difference.
Thanks for your advice,
Adam
-
Adam,
I did not change the caps in the PS, but I did bypass the last electrolytic cap with a 2.0uF claritycap I had from my S.E.X. amp. I though it made an improvement.
The Crack power supply is well designed and you can get improved performance, but they will only be subtle. The best improvement would be from the Speedball, if you do not have it installed already.
Brad
-
It has been said previously, that the last power supply cap may improve the performance if upgraded.
-
Thanks, Brad. I do have the Speedball installed. When you say you bypassed the last cap, are you referring to bypassing one of the caps in the power supply?
Best regards,
Adam
-
The last cap in the power supply has the audio signal returning through it. So it does have an effect on the sound. This is the cap that is on the left side of the transformer, closest to the front of the chassis.
-
Thanks, Grainger. And that one is 220uF 250volts, correct?
Best regards,
Adam
-
Yes, it is 220uF@250V.
-
Where exactly should the bypass cap be added for the last cap in the power supply(what terminals). Is 2.2uf 250 a good choice?
-
Bypassing is simply paralleling a better, smaller value cap with the existing cap. Since film caps are not polarized you pick one lead for the plus the other is the minus lead. Getting them on the terminal strip will be not so much fun. Maybe wrap the leads around the bare legs of the existing power supply cap?
-
Would a mundorf 2.2uf 250V mkp be a good choice to bypass the last cap in the power supply?
-
That value will work. I connected one leg of the bypass cap on 11U and the other to B5 on the octal socket. The size of the cap I was using made it too difficult to try and connect to the other leg if the cap.
-
I like Mundorfs as bypass caps.
-
Sigh. My caps arrived today. The damn things are huge. And the leads are short. At a minimum, I'm going to have to raise the case height. In the mean time, I have three other concerns/questions:
1. I assume I will have to install "fly leads", which I also assume are just bits of wire that run between the leads on the caps, and the terminals they are supposed to be soldered to. Basically just extension cables for the caps, is that right? Can i just use a bit of the hookup wire i have left over from the Crack kit? Does having leads that long raise any concerns (e.g., risk of picking up interference, etc.)?
2. My caps are ClarityCaps from the ESA series. The outside looks like it is aluminum foil. I assume it would be a bad thing if the cap were to touch other things in the Crack? The one on the left would be at risk of touching terminal 11, the resistor between terminals 12 and 13, and probably a couple of the terminals on the octal socket. That can't be bad, right? ::) The one on the right would be at risk of touching terminals 17 and 18, whatever octal terminals the left cap isn't touching, and...um...the left side cap itself.
3. I assume I should just give up and send these caps back, correct? :'(
So frustrating...
-
In case you are in need of a good laugh, here are a few pics to show the caps. I took pictures of the caps in both orientations to show that they don't really fit either way...
(https://www.head-fi.org/image/id/3884568/width/900/height/900/flags/LL)
(https://www.head-fi.org/image/id/3884569/width/900/height/900/flags/LL)
(https://www.head-fi.org/image/id/3884571/width/900/height/900/flags/LL)
Grrrrrrrrrrrrrrr!
Adam
-
Ha!!! ;D
You should check out the Gallery section of the forum; plenty of very big caps there. You'll find plenty of company in the big cap zone....
http://www.bottlehead.com/smf/index.php/topic,3370.0.html is my Crack amp.
-
I know others have done it, but give that the outside of mine seems to be tin foil, I can't help but feel it will be dangerous if I install them. I can't tell if there is a plastic film covering them...
-
If you want to use film caps you'll have to deal with the space problem.
You can use an Ohm meter to see if the outside is conductive.
I added about 3 inches in height to the base of mine along with a cross brace at the bottom and tie wraps to hold the Auricaps I'm using.
I started off just adding some wire to the leads and setting the caps outside of the orignal base.
Didn't look too good but worked fine.
The ESA's should sound good I've used them in several speaker projects.
-
Who needs those little girly electrolytic caps, when you can have a real mans cap like these.
Well I was able to fit the 100uF motor run caps in and I still have the Russian Teflon caps as well. The Teflon caps help to keep those big caps from toughing anything. It is making music, but have not had a chance to do any real listening. I had to increase the depth of the base to fit them in as you can see in the picture.
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fi597.photobucket.com%2Falbums%2Ftt55%2Fpnalitt%2FIMAG0189.jpg&hash=c21c55f9b5eb8cd26003aa9f1ce0664a36be109e)
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fi597.photobucket.com%2Falbums%2Ftt55%2Fpnalitt%2FIMAG0192.jpg&hash=305772294a5ed89be4ed35bd11f3c7b64d029652)
I used big caps and bypassed them with big Russian 0.22uF Teflon caps. I have since removed those caps a d replaced them with Mundorf caps.
-
Dont send them back! They are much too beautiful to send back! As others have said, we build our homes AROUND our caps. You can extend the leads. I would use Teflon coated pure silver, or a good solid core copper. If it seems the outside is conductive you can wrap them with electrical tape (banish the thought). Big honkin caps are a thing of pride. Ask Granger if you dont believe me!
-
Adam,
Yup! Film caps of higher values are BIG ! ! Consider the size of a 1uF film cap. You bought 100uF. But they sound very, very good!
I'm a confessed capacitor junkie. I have a pair of big oilers, see the post 2 above me, in my FP 2 Pseudo Dual Mono Power Supply set up. Those are bypassed with KK (Kommie Kap) PIO and KK Teflon caps. Ok, I'm a strange man but my wife loves me.
You could attach the caps to the sides of the base and use stranded wire to attach them to the circuit. Stranded is much more flexible and will withstand repeated flexing without breaking.
-
I have since removed those caps and replaced them with Mundorf caps.
[/quote]
Hey Brad - curious what Mundorfs you used and how you found them to sound? - thanks - Eric
-
caps attached to side of base.
-
Those metal straps attached to the side of the case are exactly what I need...I'll have to make a trip to the hardware store...
Thanks for the words of encouragement, everyone! I was really bummed last night. Feeling better now...
-
Also note the felt glued inside the the copper strap. Protects the caps case, and snugs up the fit some.
-
If my ohm meter reads zero, then the outside of the cap is NOT conductive, right?
-
You are right. However, first touch the leads together so you have a feeling for the exact zero on your meter.
-
Hmmmm....not sure i understand. I have an auto ranging meter. If I touch the leads together, the readings keep fluctuating. If I separate them, I get a dead zero rating. If I touch them to the outside of my cap, it's the same thing: dead zero. I assume that means I'm OK?
-
I am the one who was confused. You are looking for infinite resistance not a short. So you should read something in the mega ohm range. If it is zero, like touching the leads together then the outer layer is conductive.
What I am confused about is that you say you get zero (ohms?) with the leads not touching. It should be a high resistance. But this is different for every meter maker.
-
OK. When the leads are NOT touching, then the meter shows the mega ohm symbol, but then the display reads 0.L I don't know what the "L" is for, but that is what it says. The same thing appears when I touch the leads to the caps. I think I'm OK.
-
I just remembered I've got another meter. On that one, if I set it to the highest ohm setting, it just shows a "1" on the display. Same thing when I touch it to the caps.
-
They are the Mundorf MKP's
-
OL means Over Limit.
-
It sounds like the outer surface is not conductive.
-
Tons of thanks to everyone! I got the caps installed. I took pictures and will upload them later. ;D
-
So, without further ado, I present the Clarity Caps!
(https://www.head-fi.org/image/id/3889187/width/900/height/900/flags/LL)
Big thanks to STURMJ for the tip on the straps. I managed to find some non-conductive straps made of very tough plastic capable of supporting 125lbs. Thanks also to STURMJ for pointing out the felt. I didn't line the entire strap with felt, but I did put a bit over the heads of the screws attaching the straps to the inside of the frame, in order to protect the caps.
(https://www.head-fi.org/image/id/3889191/width/900/height/900/flags/LL)
(https://www.head-fi.org/image/id/3889190/width/900/height/900/flags/LL)
I don't know if it is evident from the photos below, but there is good clearance from the other components, so no risk of touching anything. And thanks to the tips on checking conductivity, I confirmed that the caps themselves aren't conductive anyway.
(https://www.head-fi.org/image/id/3889188/width/900/height/900/flags/LL)
(https://www.head-fi.org/image/id/3889192/width/900/height/900/flags/LL)
Of course, I had to raise the frame in order to give the caps some clearance. I installed some threaded sleeves, then screwed in some bolts to create feet of adjustable height (have to leave room for future upgrades, amiright?). Then glued some rubber stoppers onto the heads of the bolts to protect the glass surface the amp will sit on.
(https://www.head-fi.org/image/id/3889189/width/900/height/900/flags/LL)
(https://www.head-fi.org/image/id/3889193/width/900/height/900/flags/LL)
Not the prettiest thing I've ever seen, but it will do for the time being...
-
There is only one problem with this setup....the caps are attached to the frame, so I need to unsolder them from the chassis whenever I want to remove the chassis in the future. I tried to solder the leads in in a way that would make that relatively painless in the future.
On the upside, the fact that the Crack is now suspended about an inch and a half above the black glass shelf it sits on in my rack means that I can see the reflection of the LEDs now (at least with the lights low), which is kind of cool.
I have to confess to one moment of panic and frustration. I set up the Crack for my first listen, turned it on, started the music, and only had sound out of one side. Concerned, I turned off the Crack and cursed like a sailor. I decided to wait until the tubes cooled down to try and diagnose the problem. While I waited, I mentally ran through all of my solder points to figure out where the problem might be. I was mystified. Then I thought maybe it was where I had jumpered the headphone jack to reduce startup voltage, a mod I had done at the same time. But as I mentally stepped through those joints as well, I was sure they were OK. I had gone slowly and checked each solder point multiple times before I finished. So I went back and turned on the Crack again. This time sound from both sides! Big relief...no idea what happened...
-
Well, how do the ESA's sound? Does sound quaility improvement justify the cost? I think most people that have done it will say yes.
-
Well, these were pretty expensive ($170 for the pair, shipped), so it's a bit tough to say. So far, I don't feel like they make a night and day difference. It does seem to me that the amp has gotten much quieter, but I don't know if that is just my imagination. Wen I first built the Crack (and even after I added the Speedball), I was a bit bothered by the fact that when I turned on the amp wearing headphones, I could hear some background hiss after turning the amp on that didn't go away, even after letting the amp warm up. It wasn't obtrusive, and wasn't noticeable even with the quietest that I listen to music, but it was there. It was reduced when I installed a 5998 instead of the stock 6AS7G I received, but it was still there. Now I feel like it is completely gone, dead silent. In fact, I tried listening to some non-contemporary jazz, and I felt that the background hiss in the recording leapt out at me. I also felt that on one or two tracks, the bass seemed clearer to me than before. I won't say tighter, because it never felt loose, but it felt as though clarity was improved in the bass a bit. Mids seem completely unaffected. Not sure about the highs. I'm also not sure whether any of this is even plausibly related to the caps. Finally, I note that I've only had them in with music playing for about an hour. We'll see how things develop....
-
Well, somebody please help me...I'm having an odd problem. I mentioned above that when I first tried out the amp with the new caps, I initially only had sound in one ear. After turning off the amp and then coming back to it a bit later, it was working again with sound in both ears. Now I'm having the opposite problem: I turn on the Crack and all sounds good. Then, after 10-15 minutes, sound will cut out of the left channel and won't come back. I re-checked my solder joints - they all look good. I checked my interconnect connections, also good. I tried swapping tubes individually, but the same behavior persists: OK at startup, and for about 10-15 minutes thereafter, but then sound will cut out of one channel and not return. What could cause this?
-
This has now happened 5 times. I rechecked my solder joints yet again. Re-soldered two just to be extra sure. Swapped both tubes. Makes no difference. Both sides start out fine. Then after 10-20 minutes, the left channel just disappears. No static, it just fades out and is gone. WTF?
-
Please help before I go mad...
Look forward to your collective advice tomorrow. Thanks in advance!
Best,
Adam
-
An intermittent channel can be the headphone jack. This is why I suggested long stranded wire connecting the caps to the amp. That would allow troubleshooting and further modifications without hampering you.
Caps break in. The better the cap the longer it takes Teflons seem to take 4 weeks. So you will see improvements for quite a while.
-
Thanks, Grainger. Now I understand about the wire!
What do you suggest I do about the headphone jack? Should I just remove the jumpers I installed? What should I look for in terms of diagnosing the problem? Do you think I somehow fried something yesterday and will need to replace the jack?
-
I think Granger is right about the jack... When the channel goes out try touching and moving wires etc to figure out what causes the loss of circuit. Your observations about the boutique cap sound about right. 'Quieter, darker background, more defined', etc. The best advice is, dont panic! You will eventually figure it out, and learn from it. Tube amps are great - relatively simple and easy to trouble shoot and surprisingly reliable.
-
Question on wire...I had to go to Home Depot. The only flexible wire I could find was 16 gauge stranded wire, but it is marked as being for low voltage applications only...suitable or not? I would have thought yes, since the kit wire is 20 gauge, but wanted to be sure that there isn't a potential problem with the insulation, for example.
-
Well, crap! No, the caps see a high voltage. But if you can get a foot of 16/3 SO cord. That is the black lamp cord, three conductor, that is used for extension cords. Also, if they have SJO cord that is just a better outer insulator.
You should just strip away the outer covering and use the white, black and green inner conductors.
-
Oops! Glad I asked. I will stick with the kit wire for now, and buy some proper wire later. Thanks!
-
In my Crack I glued PVC plugs to the chassis and used wire ties to hold the caps in place. This way the caps cleared the electronics and I could still remove the chassis from the base.
From your description of your problem with the left channel going out it sounds like a bad solder joint. I would suggest looking at all the solder joints in the left channel and reheat them.
-
I agree about the bad solder joint, but the odd thing is that my Crack was working perfectly before this, and I only had 4 solder joints to install the caps. I've redone them each about 3 times now, and they never looked like there was anything even resembling a problem there in the first place. If I didn't know how to solder, it would be plausible, but it seems strange that I would suddenly become incapable of making a clean joint, even after re-trying it 3 times, when before I built the whole Crack without a single problem. I also find it odd that each time, the amp works fine for 15-20 mins, and then the left channel fades out, even though I haven't touched or imparted any vibration to the Crack. Anyway, I'll try again...it must be a bad joint somewhere... Caps can't be defective, can they?
-
I admit 'fading out' sounds strange. What happens if you crank it up for awhile. Wondering if that would 'heal' it, ex. if it was a cap. I guess a cap could be bad, others would have to chime in on that.
-
Adam,
Measure the voltages after the channel cuts out, then report back.
-PB
-
I've tried that, although only for about 10 minutes and not that loud. I'll try that if it still isn't working (I re-glued the "feet" and am waiting for them to set).
-
Will do. Thanks.
-
The epoxy on the feet had set, so I just fired up the Crack. Back to both channels working. We will see if it holds. In any case, it sounds great.
-
Well, that didn't take long. Back to one channel.
Time for dinner, so I will measure voltages later. So frustrating...
-
If it is one of the tubes, any idea which tube is the more likely culprit?
-
If it fades out slowly (several seconds) I would suspect the solder joint at pin 4 or 5 of the driver (12AU7). Each triode of the driver has its own heater, one goes from 4 to 9, the other from 5 to 9. You should be able to test this by observing the tube carefully - can you see both heaters glow when both channels work, and can you see them both when one cuts out?
-
OK, checking all the voltages will mean I'll have to de-solder the caps, then resolder them using new fly leads after I've removed the chassis from the case. I have an absolute ton of work to do tonight, and simply don't have the time for all of this. I just reheated the cap solder joints, including the joints on the leads I installed, all to no avail. Only sound from the right earcup. I'm frustrated beyond words, but so be it. I'll have to tackle this later in the week when I have less work. Frustrating, because I was hoping to listen to the Crack while I worked. Frustrating, because I have no idea how this can happen. The thing was working fine before this, I only changed four solder points, and those joints are all good. And I don't understand how the sound can repeatedly fade out in one ear cup, then come back again for no apparent reason, then go away again. All without any noise or static or pops or whatever. It just doesn't work. Maybe it is the driver heater as Paul suggested, but I can't figure out how/why that would suddenly go bad. Anyway, I'll investigate later. Grrrrrrr....
-
Grainger,
Any advice on what wire specifications I should look for? Maximum voltage rating, AWG, insulation material (Eric suggested Teflon, but any other suggestions)?
Even better, do you have specific wire you recommend?
Best regards,
Adam
-
I would suggest putting the stock caps back in if you still have them and then rechecking all of your voltages. At the very least it'll give you room to work and you can rule out the new caps if the problem continues.
Other things to consider: Hopefully you're removing the tubes from the sockets before resoldering connections. I recommend using a desoldering bulb for sucking out the old solder before adding fresh solder. I know the leads on the esa caps are stiff. Be sure they're not bumping up against the nearby pins. Check all connections in the power supply.
For wire I recommend homegrownaudio 22awg copper w/ teflon insulation. Very easy to work with and sounds great.
-
Thanks for the tips, Rob.
-
Grainger,
Any advice on what wire specifications I should look for? Maximum voltage rating, AWG, insulation material (Eric suggested Teflon, but any other suggestions)?
Even better, do you have specific wire you recommend?
Best regards,
Adam
The voltage rating should be 600V on SO or SJO. However if you are not in the states you are not looking at AWG (American Wire Gauge) and NEC (National Electric Code) rated insulation.
Well, crap! No, the caps see a high voltage. But if you can get a foot of 16/3 SO cord. That is the black lamp cord, three conductor, that is used for extension cords. Also, if they have SJO cord that is just a better outer insulator.
You should just strip away the outer covering and use the white, black and green inner conductors.
-
Thanks, Grainger. FYI, I am in the U.S. And I apologize for misunderstanding your wire suggestion yesterday, I thought you were suggesting that as a make-do option in a pinch, rather than a long-term solution. I'm sure I can find that in a nearby hardware store.
-
No problem.
I'm going to put IEC connectors on the back of my Paramour bases. I have a stack of toroid ferrites in the hot leg that will be secured to the base also.
Then I will run this same kind of wire to my power inlet terminal strip. I got it at Home Depot. The Paramour, ones, did not have an IEC connector.
This wire is very flexible. We used it in the mills I worked in for all kinds of things. Think of a commercial drill, black flexible cord. This is SO.
-
I thought about posting this on the main board, but then figured I would give first shot to those who have been helping me in this thread....is anyone interested in joining me to buy a GEC Straight Brown Base 6AS7G A1834 CV2523 at a very good price?
;D
Adam
-
Grainger,
I got some 16/3 SJO cable today, thanks. I also picked up some 14 AWG stranded THHN (Thermoplastic High Heat-resistant Nylon coated) copper wire rated for 600V. This would be a little easier to use. Any reason not to use it? I note the following from a web search "THHN uses a thinner PVC insulation which is a key factor in terms of its electrical properties. This thinner insulation can often lead to a current leakage and even a breakdown during chemical or environmental exposure. The PVC insulation in THHN also creates a toxic smoke when burned therefore making it undesireable in certain applications." Obviously I should try to avoid burning it and huffing the fumes, but is it otherwise OK?
Best regards,
Adam
-
I also picked up some 14 AWG stranded THHN (Thermoplastic High Heat-resistant Nylon coated) copper wire [...] This would be a little easier to use. Any reason not to use it?
Stranded wire is very difficult to use during construction. Try shoving four stripped ends of that wire through a terminal strip hole, the strands will fan out and touch other terminals and go places you don't want them to.
-
Hey Adam - These guys are a good place to buy wire IMO. I have used their silver wire for everything. Their prices are reasonable (I guess thats relative).
http://www.homegrownaudio.com/
-
So.......there is good news, and there is bad news.
The good news is that I am almost certain that I know what the problem is. :D
The other piece of good news is that it wasn't due to me having any bad solder joints. ;D
The bad news is....I think one of my very expensive caps is broken. :'(
When I desoldered the caps to allow me to remove the chassis from the frame, I noticed that one of the leads to one of the caps was, for lack of a better word, limp. The ClarityCaps have fairly stiff solid core copper leads, but one of them was limp. I think the solid core of the lead broke within the insulation sleeving, very, very, VERY close to the cap itself (although the insulation is still intact). This is a real problem. If it were further from the cap, I would just cut the lead where broken and solder a new fly lead to the remaining piece of good lead on the cap. But the break in the lead on the cap is so close to the cap, that I suspect there is hardly anything left for me to solder a new lead onto, and I'm worried that the heat from the solder iron would damage the cap even if I tried.
That basically means I have no option but to try and return the cap, but I have doubts that they will accept a return where the tips of the leads show evidence of having been soldered. That probably means I spent $90 for a paperweight.
Since the lead is still in the insulation, which itself is intact, I think that when I turned the Crack over, the broken lead moved a bit within the insulation. Just enough to make contact. But when I turned it over and started playing music, after 10-20 minutes, the lead or cap would settle just enough to lose contact again. The cap would slowly discharge, which would explain why the sound would gradually fade out, rather than being a sharp break. Every time I turned the Crack over to try and diagnose the problem, the lead and/or cap would shift again, just enough to make contact. Then the cycle would start again: I turn on the amp, listen to music in both channels, but then the lead/cap settles in and contact is lost again. Etc., etc.
Grrrrrrrr.....I really hope Madisound stands behind their goods and sends me a replacement....
-
You can't know that the cap is bad till you have it in the circuit. You might have a chance with a return.
THHN, IIRC, has thicker strands than SJO. The smaller the strand the more flexible the wire. At Alcoa and K-C we ran multi-conductor cables of THHN. So it pulls well and terminates easily in an industrial situation. As Paul points out larger stranded wire is a booger to get into a small terminal strip hole.
-
I broke off a lead like that on one of my big caps. I guess I bent the wire too many times. I think the copper leads are very fragile that way. That explains your symptoms. Bummer!
-
BIG props to Madisound! I just called them and they agreed to send me a new cap without any hassle whatsoever. Nice to get good service like that. The guy I spoke to (also named Adam) was very friendly.
I think the lead must have been damaged/weakened in transit. It was EXTREMELY cold last week, and I suspect that the leads became brittle, then got jostled enough in transit to create a problem.
Anyway, I can't wait to get the new cap and finally be able to enjoy the Crack again. I took the opportunity to also order a 2.2uf ESA ClarityCap, so I can bypass the last transformer cap, too.
Thanks to everyone who has been patiently helping me diagnose this problem!
Best,
Adam
-
Adam,
Yes, I've never had anything but first rate service from Madisound. Also, congrats on nailing down the problem -- that was some nice detective work there!
-- Jim
-
2+ for Madisound!
-
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fi1278.photobucket.com%2Falbums%2Fy504%2FBNAL%2Fcrackcap2_zps52e6d5b7.jpg&hash=9699edad68fe11bbb3854b49d701d738c07436b8)
This is how I mounted my caps the top plate. I used a glued a PVC end cap to a wire tie holder. As you can see from the picture I drilled a hole in the PVC end cap so that I could use a wire to secure the cap. In the past a I had a big motor run cap with a Russian Teflon bypass cap on this holder.
This way the caps clear everything and I can still get under the hood.
-
Just a quick update: I installed the new ClarityCap ESA 100 uf output cap I got from Madisound. I took the opportunity to also order an ESA 2.2 uf cap to bypass the last cap on the power supply. Installing that one was...um...not fun (its getting #%^
-
When I OD on my stereo it usually means passing out only to be jerked awake at 4:00AM by a particularly dynamic passage.
-
I know the feeling! Its always a bit mind boggling to me how other male creatures of my generation do not at all get this addiction. My 'seestum' and I are in a zone right now. We are in a discovery mode. No desire to 'upgrade'. A very nice zen if you will.
-
Don't worry........it will pass! ::)