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Old 9th February 2019, 04:54 PM   #91
JeffYoung is offline JeffYoung  Ireland
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An update on the board designs. Main amp changes are to shorten paths in CFP and to join +/- outputs before feedback take-off point.

Regulators (both Naim and inverted-Naim) also get shorter paths in CFP, along with more compact compensation networks.

Compensation schemes are traditional Naim: Miller + triple lag compensation for amp and Miller/dominant pole hybrid for regulators.
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File Type: jpg YoungNAP_layout.jpg (445.7 KB, 400 views)
File Type: jpeg YoungREG_layout.jpeg (383.6 KB, 398 views)
File Type: jpeg YoungREGMOD_layout.jpeg (409.0 KB, 392 views)
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Old 9th February 2019, 06:09 PM   #92
traderbam is offline traderbam  Canada
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I've given your NAP board a look. Pretty good. You may want to check the pin-outs of your drivers and power transistors.
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Old 9th February 2019, 07:43 PM   #93
JeffYoung is offline JeffYoung  Ireland
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Quote:
Originally Posted by traderbam View Post
.... You may want to check the pin-outs of your drivers and power transistors.
Well, rats. I thought that worked out a little too well....
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Old 28th February 2019, 11:13 PM   #94
JeffYoung is offline JeffYoung  Ireland
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Next iteration:
- fixes the issues regarding TO-3 & TO-126 pinouts @traderbam noticed
- rotates the top TO-3 180 as I got some heatsinks from Les and my guess that the two output devices were in the same orientation turned out to be wrong
- larger I/O holes as I found some swank pin connectors (https://www.mouser.ie/datasheet/2/57...IL-1013710.pdf) to use
Attached Images
File Type: jpg YoungNAP_layout.jpg (430.3 KB, 303 views)
File Type: jpeg YoungREG_layout.jpeg (397.6 KB, 291 views)
File Type: jpeg YoungREGMOD_layout.jpeg (411.7 KB, 42 views)
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Old 7th March 2019, 05:19 PM   #95
JeffYoung is offline JeffYoung  Ireland
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Default BC239C avalanche testing

I bought some BC239Cs and ZTX108s from Langrex.

I just avalanche tested the BC239Cs. +V through 33K resistor to collector; emitter to ground.

With bases tied to ground, all of them made it to +86V.

With bases floating, about 1/3 avalanched just above 50V, 1/3 between 50V and 60V, and 1/3 made it past 60V (I didn't run them all the way up to 86V).

This would suggest Naim didn't have to do a whole lot of rejecting -- or I just got lucky.
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Old 22nd July 2019, 06:09 AM   #96
thimios is offline thimios  Greece
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Quote:
Originally Posted by JeffYoung View Post
Next iteration:
- fixes the issues regarding TO-3 & TO-126 pinouts @traderbam noticed
- rotates the top TO-3 180 as I got some heatsinks from Les and my guess that the two output devices were in the same orientation turned out to be wrong
- larger I/O holes as I found some swank pin connectors (https://www.mouser.ie/datasheet/2/57...IL-1013710.pdf) to use
Please can you share the pdf for home etching?
Thanks.
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Old 22nd July 2019, 07:51 PM   #97
JeffYoung is offline JeffYoung  Ireland
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@thimios,

I haven't built the boards yet, so I'm hesitant to share a design that might not work. There's one build still in the queue in front of it (a DIY Pass HPA-1), and then I'll be getting stuck in to it.

Once it's built and works, I'll definitely post Kicad files, Gerbers, PDFs, or whatever else folks need.

Cheers,
Jeff.
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Old 22nd July 2019, 08:17 PM   #98
thimios is offline thimios  Greece
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Originally Posted by JeffYoung View Post
@thimios,

I haven't built the boards yet, so I'm hesitant to share a design that might not work. There's one build still in the queue in front of it (a DIY Pass HPA-1), and then I'll be getting stuck in to it.

Once it's built and works, I'll definitely post Kicad files, Gerbers, PDFs, or whatever else folks need.

Cheers,
Jeff.
Thanks Jeff!
I will wait to see what you will find.
Too many projects on the way, that's mine problem too.
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Old 20th September 2019, 04:16 PM   #99
drmaftoon is offline drmaftoon  United Kingdom
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Quote:
Originally Posted by JeffYoung View Post
@thimios,

I haven't built the boards yet, so I'm hesitant to share a design that might not work. There's one build still in the queue in front of it (a DIY Pass HPA-1), and then I'll be getting stuck in to it.

Once it's built and works, I'll definitely post Kicad files, Gerbers, PDFs, or whatever else folks need.

Cheers,
Jeff.
Hi Jeff, have you made any progress on this project yet?
thanks
Sajj
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Old 20th September 2019, 10:34 PM   #100
JeffYoung is offline JeffYoung  Ireland
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Hi Sajj,

No, I got derailed doing a FirstWatt J2 PCB group buy. The HPA-1 is making slow progress though, so we're getting closer.

Cheers,
Jeff.
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