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Old 21st June 2012, 09:16 PM   #41
VT67 is offline VT67  Belgium
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Yes, fast shipping indeed.
About the kit, everything looks okay. Nice PCB by the way.
I'm not sure if I will use the two supplied Silmic's, maybe I will go for Nichicon FG in that spot. Also I'm thinking about to put some Caddock's in the direct signal pat instead of the supplied resistors, although there are some Dale's in the kit.

@bcmbob
Some nice soldering there.

Regards
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Old 22nd June 2012, 09:22 AM   #42
bcmbob is offline bcmbob  United States
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Thanks for the complement VT. A good clean up helps me see any mistakes. My process:

1. A toothbrush and denatured alcohol. Flux sticks to bristles, so avoid build-up.
2. Modified toothbrush handle as scraper. Fingernail when needed
3. Dow bathroom cleaner (Scrubbing Bubbles - certified for use in Nuke plants) and a soft back brush.
4. I use a wet-dry vac to remove cleaner as most fabrics and paper towels leave a lot of lint.
5. Repeat 3 and 4 as necessary.
6. Polish with a clean - dry shoe brush.
7. Convince yourself that your soldering skills are so good you actually didn't do steps 1-6.

Component side clean up is pretty much limited to wet and dry Q-Tips.
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Old 24th June 2012, 04:26 PM   #43
squalor is offline squalor  United States
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Wow, I didn't do any of that on my FE. I wonder if that's why I'm having problems ?
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Old 24th June 2012, 05:02 PM   #44
bcmbob is offline bcmbob  United States
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It's not a fix in itself, but things like a cold solder joint or a short/bridge can hide under a very small flux build-up. Just make sure everything is completely dry before reapplying power. The shop vac helps that also.
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Last edited by bcmbob; 24th June 2012 at 05:19 PM.
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Old 29th June 2012, 05:33 PM   #45
bcmbob is offline bcmbob  United States
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For what it’s worth –

I have been doing some comparisons of volume control options over the past few days.

1. Alps 27 bare pot (included incorrect link in previous post) – My first Alps unit was very impressive at first listening. The detail was outstanding and the smoothness of the mechanics was impressive. The entire audio spectrum was presented fully with dynamics intact. The clarity and sparkle in the upper registers brought forth some excitement not heard before. I was so impressed I suggested to Dario that some of the cap/resistor mods may need to be adjusted to dial in on what the Alps offered.

2. eBay SDM bare pot – I had to rewire this one as it was controlling the JC-2. Once that was done, a clear difference could be heard between the two. This one sounded as though more of the mid frequencies were getting through, e.g. warmer. The 21 step adjustments are defined and physically perceived when opposed to the smoothness of the Alps. This only means a few minute increments can’t be obtained, but I don’t think that is significant in real world listening situations. The SDM pot allowed a fuller stage than the Alps. The width was about the same but the instruments/voices sounded like they were more spread across the image with this one. I can’t call a winner because again, so much depends on the associated equipment and cap/resistor choices. It will take some time to determine if the SDM pot is actually filtering out some elements of the signal. Either would be a top choice for FE builders who have no need for any gain in driving their speakers to enjoyable listening levels. Some experimentation is advised.

3. The Lighter Note - still shines for simple purity and balance, to my ears. What I said in post #18 is as accurate a description as I can offer so I won’t repeat it here. I also encourage builders to take a serious look at the simpler Lightspeed and similar LDR designs as a less expensive solution for those who prefer a non-mechanical device.

4. JC-2 Pre – I’m impressed as ever with this kit. Yesterday I played some full symphony stuff that sounded distorted (intermodulation) at the top of very loud violin section crescendos. I couldn’t tell if I was pushing the FEs too far with the gain settings or if the noise was coming from the preamp. Lower volume took care of most of it. I realized I was playing through the CD drive on the Music Server, so this morning I ripped it to an uncompressed file with Exact Audio Copy to eliminate that link. It sounds great. The JC-2 has been able to handle all the dynamics, be they crescendos or bursts of percussion or brass. To me, it really sounds like that “straight wire with gain” description mentioned earlier. I have held off buying the Caddocs till Dario and VT67 offer up their reviews after some hands-on time, but I’m hoping they get the same impressions as I have reported. I’m looking forward to tweaking an already excellent addition to the FE builds.
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Last edited by bcmbob; 29th June 2012 at 05:41 PM.
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Old 29th June 2012, 06:38 PM   #46
bcmbob is offline bcmbob  United States
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New RCAs just arrived in the mail. I had salvaged some old tin pieces from the stash. We'll see if gold makes everything shine and sparkle.
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Old 29th June 2012, 08:48 PM   #47
SoIL4x4 is offline SoIL4x4  United States
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I received my JC-2 kit this week and my lighter note kit last week so I am excited to get to work on both of these. I am on vacation this week so hopefully I will have time to populate both of the boards. I have a good start on an enclosure for the lighter note and all of the small parts needed to finish it, so it will be done first.

It will be interesting to compare these two when they are done. I am debating on whether or not to replace some of the components on the JC-2 right away or wait and install some sockets at the critical points and do some swapping.

I am hoping to have at least one of the pres completely finished by the time the fe boards arrive. We will see though.
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Old 29th June 2012, 09:20 PM   #48
bcmbob is offline bcmbob  United States
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That's encouraging. Very happy to hear the LNs are moving again. Both of those are top of the line. Reminds me I haven't tried using them in combination with the FEs.

Good luck with your builds.

Be sure to follow Uriah's instructions on limiting the amount of heat on the LDRs. Use either good liquid or paste flux when you solder them. Put the solder on the tip of the iron and let it flow to the lead/pad. They will tolerate that but not much more. Cat-6 cable is great for connecting the pots. Post or PM me if I can be of any help.
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Old 29th June 2012, 09:38 PM   #49
SoIL4x4 is offline SoIL4x4  United States
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I forget who mentioned using a regi-reg setup to power an LDR , but it seems like it could be a great alternative to a conventional pot for volume control with the JC-2.
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Old 29th June 2012, 09:43 PM   #50
bcmbob is offline bcmbob  United States
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Made a reference earlier in the thread, but if this - and the next post is what you are proposing - they work very well together.
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Last edited by bcmbob; 29th June 2012 at 09:46 PM.
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