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Old 17th January 2018, 06:24 PM   #2881
canute is offline canute  Denmark
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Quote:
Originally Posted by 6L6 View Post
Tin Whiskers -

An easy way to stop that? Leaded solder...
Are there any "best alloys" for our purpurse?
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Old 17th January 2018, 06:48 PM   #2882
6L6 is offline 6L6  United States
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Yes - leaded solder. The lead stops that from happening. 60/40 rosin core is fine. 63/37 also.

Lead-free solder sucks.

My favorite solders are

Kester "44" It has a TON of rosin flux. Makes really, really nice joints and flows better than anything I've used, due to the flux. Joints have a bit of a fluxy mess on them, but worth it.

Cardas Quad Eutectic - A 4-metal blend, mainly Tin and Lead, but with a couple percent of silver and copper as well. Low melting point, good flux, very easy to desolder. The silver is there not for any audiophile reasons but because silver plated contacts and wire will whisker and corrode in presence of non silver-bearing solder. The Cardas Quad is allegedly the same recipe that the Bell Telephone system used, where longevity and reliability was paramount.
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Old 17th January 2018, 08:17 PM   #2883
MASantos is offline MASantos  Portugal
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I bought a big roll of cardas solder a long time ago and it is great to work with. I have an 12 or 13 years old headphone amp with solder joints looking as good as new!

Quote:
Originally Posted by 6L6 View Post
Yes - leaded solder. The lead stops that from happening. 60/40 rosin core is fine. 63/37 also.

Lead-free solder sucks.

My favorite solders are

Kester "44" It has a TON of rosin flux. Makes really, really nice joints and flows better than anything I've used, due to the flux. Joints have a bit of a fluxy mess on them, but worth it.

Cardas Quad Eutectic - A 4-metal blend, mainly Tin and Lead, but with a couple percent of silver and copper as well. Low melting point, good flux, very easy to desolder. The silver is there not for any audiophile reasons but because silver plated contacts and wire will whisker and corrode in presence of non silver-bearing solder. The Cardas Quad is allegedly the same recipe that the Bell Telephone system used, where longevity and reliability was paramount.
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Old 18th January 2018, 12:16 PM   #2884
Eric is offline Eric  United States
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Quote:
Originally Posted by 6L6 View Post
Tin Whiskers -

Click the image to open in full size.

Whisker (metallurgy - Wikipedia)


An easy way to stop that? Leaded solder...
Sadly, this is something that I only recently learned when I visited the production line of an aerospace defense contractor. I guess they are used to people not asking too many questions because the president of the company did a double take on the shop floor when I asked him a specific question about the physical configuration of the regulated power supplies that were coming off the line
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My DIY Basement Theater, Aleph-X Amps, Avro Open Baffle Speakers, LDR based BA-3 pre, Pearl II, highly modded Technics SL-1200, F4, M2, a40, several ACAs, FHXL, Tang Band 1772 bass-reflex
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Old 21st February 2018, 04:24 AM   #2885
Lbcyclist is offline Lbcyclist  United States
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Hello All,

My first post on this thread. First, many thanks for the ongoing support and contribution to this thread, it makes a fascinating reading. Special mention to 6L6 for the build guide, patience and guidance, multiple others for the knowledge and expertise. And espcially to Wayne and Nelson for their support of DIYers.

I received my Pearl 2 boards and they are almost completely populated. One question I am debating is the resistive loading. I have currently an Ortofon with '10 Ohm or higher' recommended loading, but will have 2-3 more cartridges in the future, some mention 90 Ohm or higher.

I would like to avoid having to resolder resistors and therefore would like to use the solution mentioned in post 2717 of using a rotary switch in parallel to R19 [presumably using R20 holes?]. I have a 12 position MBB rotary switch I would like to use and thought I'd start at 7 Ohm and use a 1.4 factor to get to 320 Ohm at the last position [power of 2 series]. Does such a scheme make sense? Should I use different values? I know it's somewhat over the top, but isn't DIY all about pushing the envelope, or at least the wallet?
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Old 9th June 2018, 02:15 AM   #2886
KevinHeem is offline KevinHeem  United States
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Since it doesn’t come in kit form, I had to buy a preassembled XP-15...WOW! That’s all I’ll say about that.

However it gives me perspective on the Pearl II which is a great phono-pre in it’s own right. I’ve had a few really nice phono stages at home lately, and the Pearl II is playing in the same ballpark. The Pearl II has served me well and will go on to play beautiful music for someone else I’m sure. What a gift to the DIY community...thanks Wayne!
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Old 9th June 2018, 10:30 AM   #2887
Wellerman is offline Wellerman
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Quote:
Originally Posted by Lbcyclist View Post
I have a 12 position MBB rotary switch I would like to use and thought I'd start at 7 Ohm and use a 1.4 factor to get to 320 Ohm at the last position [power of 2 series]. Does such a scheme make sense? Should I use different values? I know it's somewhat over the top, but isn't DIY all about pushing the envelope, or at least the wallet?

I would start a little higher, I think there are not that many cartridges that need a 7 Ohm loading. Medium output mc's (that go well with the 55dB gain of the Pearl II) like a loading of aroud 400 Ohm - 1k or something like that. Starting at 33 Ohm will get you to around 1k3 (50 -> 2k). I would also consider leaving one position on the switch unoccupied which would get you 47k for high output mc's.


I've got a slight rebuild of my Pearl planned where I use dipswiches for gain, capacitance and resistance. The ability to parallell more resistors gives you lots of loading options.
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Old 22nd June 2018, 02:31 PM   #2888
naturallmystic is offline naturallmystic  United States
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Wellerman I, for one, would love to see your implementation of your ‘slight rebuild’. ��Preferably with lots of pictures and a schematic! ��
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Old 22nd June 2018, 10:51 PM   #2889
takitaj is offline takitaj  United States
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Join Date: Apr 2012
Location: Maine
I finally broke down and bought a decent MC cart, an Audio Technica AT33PTG/II. WOW what a difference!! I was using an Ortofon 2M Red that came with the turntable. It generally sounded pretty good but I struggled to get it to work with the Pearl2 for over 2 years before this. I could not get rid of the overload/distortion on voices and highs. I tried EVERYTHING. I could get it a little better but it was never right. It's 5mv output is just too much for the Pearl2. The new cartridge is only 0.3mv and is just wonderful. Well worth the upgrade to finally hear the Pearl2 sing as it was intended. Thank you Nelson!!
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Old 23rd June 2018, 12:27 PM   #2890
Wellerman is offline Wellerman
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Quote:
Originally Posted by naturallmystic View Post
Wellerman I, for one, would love to see your implementation of your ‘slight rebuild’. ��Preferably with lots of pictures and a schematic! ��

Well, nothing really special. Parallel the 47k input resistor with a dipswitch with 12 choices, another dipswitch with 4 choices for input capacitor and a dipswitch that lets you choose gain between 42.5 and 65 dB in 10 steps.


Then probably a few slight changes in values in the RIAA section as suggested by Jackinnj to make it more linear and a change in capacitor value to slightly decrease the low end roll-off.


The PSU will be changed to CRCRC, and I will experiment a bit with the onboard regulators to get it more quiet. Add in a few fancy Mundorf capacitors and that's about it.


But other projects await my attention, so it might be this winter ore even later before I get to it.
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