Cap upgrades (bear with me)

[Grainger49]

It sounds like the outer surface is not conductive. 

[adamct]

Tons of thanks to everyone! I got the caps installed. I took pictures and will upload them later. 

[adamct]

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...

[adamct]

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...

[dwilli852]

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.

[adamct]

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....

[adamct]

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?

[adamct]

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?

[adamct]

Please help before I go mad...

Look forward to your collective advice tomorrow. Thanks in advance!

Best,
Adam

[Grainger49]

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.

[adamct]

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?

[earwaxxer]

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.

[adamct]

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.

[Grainger49]

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.

[adamct]

Oops! Glad I asked. I will stick with the kit wire for now, and buy some proper wire later. Thanks!