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Simple High Performance DC Coupled Class A HPA with sub PPM THD
Simple High Performance DC Coupled Class A HPA with sub PPM THD
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Old 28th July 2018, 11:50 PM   #171
obh is offline obh  Norway
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Simple High Performance DC Coupled Class A HPA with sub PPM THD
i can take one.
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Old 29th July 2018, 01:45 AM   #172
yourownbuzz is offline yourownbuzz  Australia
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ahhh damn flooding sucks. happened to us a few years back because the drainage for our lot was blocked so water cascaded through our yard and basement. muddy electronics, meet the bin, and even pot plants were getting moved around the yard....
good to know the cleanup & recovery is progressing! I'm sure everyone will understand that that has to be your priority at the moment
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Old 29th July 2018, 05:08 AM   #173
xrk971 is offline xrk971  United States
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Simple High Performance DC Coupled Class A HPA with sub PPM THD
GB Status Update:
Quote:
Badboygolf16v - 2 sets, packed and shipping label generated
Dabore84 - 2 sets, packed and shipping label generated
funch - 1 set, packed and shipping label generated
kartk - 1 set, packed and shipping label generated
Yourownbuzz - 1 set plus Aksa Lender Pre TH and 2SA1837's, packed and shipping label generated
Gwrskien - 1 set, packed and shipping label generated
Ernesternest - 1, packed and shipping label generated
Stellarelephant - 1 set, packed and shipping label generated
passive420 - 1 set, packed and shipping label generated
Pinnocchio - 1 set, packed and shipping label generated
vvs7 - 2 sets, packed and shipping label generated
jwjarch - 2 sets, packed and shipping label generated
ermine22 - 3 sets, packed and shipping label generated
Morde - 1 set, packed and shipping label generated
S610adam - 2 sets, packed and shipping label generated
pstech - 2 sets, packed and shipping label generated
Silasmellor - 1 set, packed and shipping label generated
Malvin 1 set, packed and shipping label generated

*ravid - 1 set, Paid, need valid street address for PayPal shipping
*icsaki - 1 set + 1 more, packed and shipping label generated for first order, Invoice #2 sent
*obh - 1 set, Need PP address
only 1 board left

I removed Hallcon83 and BabyDontHertzMe since have not heard back from you for some time now regarding a PP address.
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Last edited by xrk971; 29th July 2018 at 05:15 AM.
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Old 29th July 2018, 05:10 PM   #174
xrk971 is offline xrk971  United States
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Join Date: Oct 2012
Location: Metro DC area
Simple High Performance DC Coupled Class A HPA with sub PPM THD
GB Status Update:
Quote:
Badboygolf16v - 2 sets, packed and shipping label generated
Dabore84 - 2 sets, packed and shipping label generated
funch - 1 set, packed and shipping label generated
kartk - 1 set, packed and shipping label generated
Yourownbuzz - 1 set plus Aksa Lender Pre TH and 2SA1837's, packed and shipping label generated
Gwrskien - 1 set, packed and shipping label generated
Ernesternest - 1, packed and shipping label generated
Stellarelephant - 1 set, packed and shipping label generated
passive420 - 1 set, packed and shipping label generated
Pinnocchio - 1 set, packed and shipping label generated
vvs7 - 2 sets, packed and shipping label generated
jwjarch - 2 sets, packed and shipping label generated
ermine22 - 3 sets, packed and shipping label generated
Morde - 1 set, packed and shipping label generated
S610adam - 2 sets, packed and shipping label generated
pstech - 2 sets, packed and shipping label generated
Silasmellor - 1 set, packed and shipping label generated
Malvin 1 set, packed and shipping label generated
*icsaki - 2 sets, packed and shipping label generated

*ravid - 1 set, Paid, need valid street address for PayPal shipping
*obh - 1 set, Invoice sent
1 board left
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Old 30th July 2018, 04:35 PM   #175
xrk971 is offline xrk971  United States
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Simple High Performance DC Coupled Class A HPA with sub PPM THD
All packages have been shipped today except for orders belonging to ravid and obh. You should have received tracking numbers via email.

I have all the parts from the BOM and shopping cart assembled by Jwarch but need some time to get back into the lab to populate and solder.
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Old 31st July 2018, 03:56 AM   #176
xrk971 is offline xrk971  United States
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Join Date: Oct 2012
Location: Metro DC area
Simple High Performance DC Coupled Class A HPA with sub PPM THD
GB Status Update
Quote:
Badboygolf16v - 2 sets, shipped
Dabore84 - 2 sets, shipped
funch - 1 set, shipped
kartk - 1 set, shipped
Yourownbuzz - 1 set plus Aksa Lender Pre TH and 2SA1837's, shipped
Gwrskien - 1 set, shipped
Ernesternest - 1, shipped
Stellarelephant - 1 set, shipped
passive420 - 1 set, shipped
Pinnocchio - 1 set, shipped
vvs7 - 2 sets, shipped
jwjarch - 2 sets, shipped
ermine22 - 3 sets, shipped
Morde - 1 set, shipped
S610adam - 2 sets, shipped
pstech - 2 sets, shipped
Silasmellor - 1 set, shipped
Malvin 1 set, shipped
icsaki - 2 sets, shipped
*ravid - 1 set, shipped
*obh - 1 set, shipped
No more boards left.
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Old 4th August 2018, 02:40 PM   #177
xrk971 is offline xrk971  United States
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Simple High Performance DC Coupled Class A HPA with sub PPM THD
Default Verification build for PSU

I assembled the PSU and found a few typos in the schematic. The regulators are labeled A211 and A221, The positive rail regulator should be mounted in the position closest to the DC-DC converter (A221) and the negative rail regulator should be mounted at A211. The resistors on the cap Mx R231/R241 should be 10k and not 220R.

I had some trouble because of a bad batch of 7918 regulators. After trying 3 with no luck I installed a 7915 that I knew was good and it worked. So its is surprising at it is an ON Semi MC7918CTG from Mouser.

Anyhow, the circuit works but it looks like ideally we want to use the the nice LDOVR.com regulators with adjustment so that we can dial in the appropriate upstream voltage as there is about a 2.4v drop through the cap Mx.

I have it hooked up to a 10w 100ohm load (circa 150mA on each rail) at present and doing burn in.

Simple High Performance DC Coupled Class A HPA with sub PPM THD-shpa-psu-build-01-jpg

Simple High Performance DC Coupled Class A HPA with sub PPM THD-shpa-psu-build-02-jpg

Simple High Performance DC Coupled Class A HPA with sub PPM THD-shpa-psu-build-03-jpg

So the PSU works if f you follow this revised schematic below.
Attached Images
File Type: jpg SHPA-PSU-Build-01.jpg (268.9 KB, 1899 views)
File Type: jpg SHPA-PSU-Build-02.jpg (315.8 KB, 2066 views)
File Type: jpg SHPA-PSU-Build-03.jpg (259.2 KB, 520 views)
Attached Files
File Type: pdf S-HPA-COMPLETE_001a_page2.pdf (29.4 KB, 90 views)
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Old 5th August 2018, 01:58 AM   #178
xrk971 is offline xrk971  United States
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Simple High Performance DC Coupled Class A HPA with sub PPM THD
One more error found on PSU board silkscreen. Diode V241 has cathode and anode flipped. Need to install with anode to drain of the P channel MOSFET for the negative cap Mx.
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Old 5th August 2018, 07:11 AM   #179
xrk971 is offline xrk971  United States
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Simple High Performance DC Coupled Class A HPA with sub PPM THD
The PSU has now been tested with the amplifier (hand etched proto). Running at about 95mA bias current. The common heatsink for the 7818 and 7918 is at 60C. With adjustable LDOVR.com regs we can adjust voltage to about 3v higher to compensate for the dropout in the cap Mx, so overall dissipation on heatsink for the regulators will be about 50% less. Right now it is dropping 6v from 24v to 18v. Listening to it sounds great. Measured noise at headphone outputs with no signal input is 0.0mV to 0.1mV rms.

Simple High Performance DC Coupled Class A HPA with sub PPM THD-shpa-psu-tested-04-jpg

Ready to move onto building and verifying the main amp board now.
Attached Images
File Type: jpg SHPA-PSU-Tested-04.jpg (443.7 KB, 293 views)
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Last edited by xrk971; 5th August 2018 at 07:13 AM.
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Old 5th August 2018, 06:08 PM   #180
xrk971 is offline xrk971  United States
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Simple High Performance DC Coupled Class A HPA with sub PPM THD
Main amplifier board assembly has begun.
Attached Images
File Type: jpeg 21618FB7-4F93-46BC-BAA1-65E3A33C811C.jpeg (382.7 KB, 58 views)
File Type: jpeg 8E4E95A8-6C8F-425C-A204-A1AC793417DE.jpeg (434.1 KB, 443 views)
File Type: jpeg E6F90D12-E6AA-4866-AEB0-BDD9A4C47F36.jpeg (320.8 KB, 447 views)
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