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Old 27th March 2013, 06:11 PM   #41
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Thanks for the tip AVWERK. Finding a great transformer i can feel confident in is a challenge. I'll look into it. Ive heard ofnthem, but mostly passed them by at first notice as they seem obscure. Thats not a bad thing necessarily. I want to get the best out of the pearl i can first time through.

Any advise is great
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Old 27th March 2013, 06:57 PM   #42
6L6 is offline 6L6  United States
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Overkill, but in stock and the proper voltage -- Antek - AN-2222
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Old 28th March 2013, 08:12 AM   #43
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Thanks for the hand 6L6

*hoping i'm not in over my head here*

-Formosa
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Old 28th March 2013, 08:25 PM   #44
6L6 is offline 6L6  United States
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Quote:
Originally Posted by FormosaWest View Post
*hoping i'm not in over my head here*
Go slow, ask LOTS of questions. The only dumb question is the one not asked.

The general order of operations -

Build and test the PSU first.

Build the regulator portion of the RIAA, test.

Build the rest. Tweak and adjust.

Enjoy!
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Old 28th March 2013, 08:50 PM   #45
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For me, the tricky part were some of the options in the BOM. When to use a jumper, when to use a component, when to keep it open, etc. .

C15 - Leave out ( I put a jumper in by mistake)
R15 - Jumper
C22 - Leave Out, no jumper
R20 - Leave out, no jumper
C7 - Can cause issues. Wayne after the Pearl 2 article was published recommends leaving out.

Of course, double checking your component values before soldering - using the correct part. I got on a roll with all those 10R resistors and used them at R8 and R10 by mistake - they should be 10k! Also, good soldering, especially on the ground plane side of the caps, takes a little more to flow the solder well.

I learned a lot doing the Pearl 2.It took a lot longer than I planned - a couple months. Patience - number 1 skill.
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Old 29th March 2013, 02:32 AM   #46
Mr. dB is offline Mr. dB  United States
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Quote:
Originally Posted by bnorrish View Post
Also, good soldering, especially on the ground plane side of the caps, takes a little more to flow the solder well.
They just about sinked my Hakko tempco soldering station.
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Old 29th March 2013, 08:50 PM   #47
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You guys are great. Im glad i found this forum!

Regarding R19, 47.5k .. Im assuming thats the default value / resistor slot for the cartidge loading.

Then theres R20, which is left open and exist as an optional slot for alternative cart loading..

Quesion: say i wish to try loading my cartridge with a higher resistance cart to brighten it up. loading R20 with a given cartridge load-value resistor to achieve a target of 100k loading (higher than 47) vs loading to achieve a target of 35kohm (lower than 47) would be accomplihed best how?
It looks like a paralell (not series)organization so adding resistors to r20 would drop the cart loading (due to the inverse mathematics af resistance in paralell - if i recall correcty)..

What would you recommend to allow easy cart load swapping within the full range of say 13k to 150k? I was thinking of replacing R19 47.5k with a couple of gold plated TO pin sockets based on the assumption thAt if i wish to go above 47.5k i will need to be able to remove it. Which leads me to ask why r20 was put in at all and why r20 is the "user selectable loading slot". My understanding is limited so any thoughts regarding the setting of cart loading would be great.
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Old 29th March 2013, 09:15 PM   #48
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Continuing to learn about transformers.

Anyone know a source for a good 2x22 r-core ... Or is it not worth the trouble? Strange they are so rare. Ill be waiting for a transformer regardless i think (as plintron and antek are favorites at the moment) and im willing to be reasonably patient to ensure i get a good one. Antek has stock coming on torroids, and plintron may make one for me though they are pricey and would have to be worth the cost. The use of EI cores would likely be okay if a good one was found as it is encased in a separate enclosure, but finding one quiet enough amidst the multitude of cheap and questionable cores would be daunting and a little random chance.
There're Chinese r-cores on eBay but I'm hesitant as they look unbranded - not just because they are chinese. Found some in france but the web info is critically limited and they are likely all 230-240v primaries.
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Old 29th March 2013, 10:28 PM   #49
AVWERK is offline AVWERK  United States
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Ebay is where I got mine. Make sure the vendor states accurately the voltage. Mine were 4 volts over what they specd. Not even close... Maybe they used a 5$ china DVM before printing transformer labels?
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Old 30th March 2013, 03:02 AM   #50
Mr. dB is offline Mr. dB  United States
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Okay, I must be mentally deficient - which way round do the ZTX450s go? They confused me by putting the writing on the small side. These are the Diodes Inc. parts. The pinout on Digikey's site looks opposite to the photos of 6L6's boards. Thanks for any help.

Click the image to open in full size.

Last edited by Mr. dB; 30th March 2013 at 03:10 AM.
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