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Old 30th March 2013, 02:17 AM   #51
6L6 is offline 6L6  United States
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The flat side of the ZTX aligns with the flat side of the printed bit on the silkscreen stuffing guide. They all don't face the same way -- look at the silk.
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Old 30th March 2013, 02:21 AM   #52
Mr. dB is offline Mr. dB  United States
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Thanks.

Seems like the British do everything on the wrong side, including the labeling of semiconductors.

Last edited by Mr. dB; 30th March 2013 at 02:31 AM.
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Old 30th March 2013, 02:29 AM   #53
Mr. dB is offline Mr. dB  United States
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BTW, with my presbyopic eyes, I am immensely grateful for modern circuit boards with solder mask. Without that, my assembly would be a horrid mess of solder bridges.
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Old 30th March 2013, 02:53 AM   #54
Mr. dB is offline Mr. dB  United States
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And voila, I've just completed stuffing the Pearl Two boards. Earlier this week I finished the DCB1 board, so now all I have to do is the chassis and power supplies. Still waiting on a few parts for those.
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Old 1st April 2013, 02:05 PM   #55
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Default 3%.....?

Hi Folks,


I have just had a call from a tech .... I knew the P2 sounded off . He has measured 3 % distortion . My build ,although not a professional job is more than passable .

Surely this can't be right ? Has anyone any ideas please ?

Richard
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Old 2nd April 2013, 03:58 AM   #56
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Anyone ever house each channel of the Pearl in small separate enclosures? advantages? drawbacks?

Thanks AV werk. I ordered a 24volt model. Fingers crossed its not over voltage like yours was. If it is should I add regulator chips (redundant) to ensure stable exiting voltage, or use series resistors? Is there another way to shed voltage that might be useful? like a light or screen on something? LEDs?
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Old 2nd April 2013, 04:56 AM   #57
6L6 is offline 6L6  United States
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Quote:
Originally Posted by FormosaWest View Post
Anyone ever house each channel of the Pearl in small separate enclosures? advantages? drawbacks?
Yes, there was at least one 3-chassis build. It looked very nice.

Quote:
If it is should I add regulator chips (redundant) to ensure stable exiting voltage, or use series resistors? Is there another way to shed voltage that might be useful? like a light or screen on something? LEDs?
Let me repeat myself - It's not necessary, the external PSU is a CR filter with lots of capacitance, and the Pearl 2 PCB has an additional CR filter and regulator for each rail. What you are asking about is already designed into the project!

Also I will add that the original specified 7824/7924 can take in input voltage of 40v. So unless your transformer is wildly out of spec, there is nothing to worry about.
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Old 2nd April 2013, 05:44 AM   #58
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Cool. Didn't mean to make you repeat yourself 6L6. Thanks. My concern relates to the scenario you found yourself in, which I too may have to address. As you pointed out for us, The psu output needs to be 29-40v, though I don't want to input at max voltage, and would prefer to see around 30-35 to give some breathing room for variable power conditions.

I recall that you needed to add resistors between your caps in your build to get the PSU down a few volts because you used that nice plintron 30V. I just ordered a 24v P-Core from Hong Kong and Im hoping its not out of spec as AVWERK found with a similar P-core. If mine turns out to be, i was wanting to be prepared to handle the situation as well as you have. I dont have excess parts to play with and am preparing to place an order for a few tidbits and might throw in a few basic components now to cut down on shipping.

As you found you went over voltage with your 30V transformer, I too could if my 25v is as 'out of spec' as others have been noted to be. .. at 25v Im looking at max 35, but if it's out by 4 volts like others have been, ill need to be careful.

Its nice that the reg is on the board and in the design. Ive seen some discuss by-passing it and putting the reg in the power supply itself though im not contemplating it at this time, however would if my final voltage is too high. or if a sonic benefit might be had.

Is there an higher performance alternative to 7824/924 that might be okay to say 45V? this would be another idea.

just fishin'

.. re the PSU. any other foreseeable DC quality improvements to be made? ive picked out some 11.5ns Schottky diodes with soft switching already hoping to keep switching noise as low as possible
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Old 2nd April 2013, 01:10 PM   #59
6L6 is offline 6L6  United States
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Get all the parts for the PSU and build it. Test it and see if there are any issues --- there likely will be none.
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Old 2nd April 2013, 11:18 PM   #60
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What jfets did you use. Pass wants alot for theirs... Having issues orderng the boards... Te wenstore has yet again made a confusing change to the way it is listed... I ordered 2 with fets but they havent shipped and if i can get boards only cheaper i might do that asnthey want to refnd my orders because they failed to,charge shipping and asked me to re-order...
Arg... No longer listimg boards for 50$ each
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