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Simple High Performance DC Coupled Class A HPA with sub PPM THD

Founder of XSA-Labs
Joined 2012
Paid Member
So the to220 adapter is if we want to solder the finicky regulator ourselves otherwise the option is to use the ones you linked from ebay?

I think JPS64 was planning on getting them made pre-populated. The point is to provide you a regulator that you do not have to solder as most people do not have the equipment to reflow a 0.5mm pitch quad flat pack with no legs and a power pad on the bottom. It's quite tricky without a hot air gun for reflow.
 
Well sign me up for a pair as well. I guess that becomes:

Badboygolf16v - 1 pair
Dabore84 - 2 pair
funch - 1 pair
kartk - 1 pair
Yourownbuzz - 1 pair
BabyDontHertzMe - 1 pair
Stellarelephant - 1 pair
passive420 - 1 pair
Pinnocchio - 1 pair
vvs7 - 2 pairs
Gwrskien - 1 pair
Ernesternest - 1 pair
jwjarch - 1 pair
ermine22 - 2 pairs
Morde - 1 pair
S610adam - 2 pair
pstech - 2 pair
dabore84 - 2 pair
Silasmellor - 1 pair
 
Founder of XSA-Labs
Joined 2012
Paid Member
Hey cool! that's better than what I thought!
Out of curiosity how is he planning to get them pre made? Are there places that do these kind of small production run boards?

Or it may be that JP was thinking that I would do the reflow of the LDO regs in batches for the GB as I am getting pretty good at soldering them. It takes some practice.

I just soldered another pair on another project and those hidden pins actually line up quite nicely - they sort of self-align with the reflow solder surface tension.
 
Member
Joined 2016
Paid Member
Well sign me up for a pair as well. I guess that becomes:

Badboygolf16v - 1 pair
Dabore84 - 2 pair
funch - 1 pair
kartk - 1 pair
Yourownbuzz - 1 pair
BabyDontHertzMe - 1 pair
Stellarelephant - 1 pair
passive420 - 1 pair
Pinnocchio - 1 pair
vvs7 - 2 pairs
Gwrskien - 1 pair
Ernesternest - 1 pair
jwjarch - 1 pair
ermine22 - 2 pairs
Morde - 1 pair
S610adam - 2 pair
pstech - 2 pair
Silasmellor - 1 pair

*Correct List*

I'm already on the list 2nd from top :)
 
Founder of XSA-Labs
Joined 2012
Paid Member
More progress from JPS64... The HPA is now also a very capable preamplifier with optional multiple input selector board. What type of RCA connectors do folks like? If you have a good one to suggest please do. The ones shown here are rather pricey at about $12ea (per jack).

If you do not need the multi-input preamp feature, simply skip the sub-board.

I was thinking of these from Switchraft, gold plated copper alloy, no shared grounds:
PJRAN2X1U01AUX Switchcraft | Mouser

An externally hosted image should be here but it was not working when we last tested it.


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Badboygolf16v - 1 pair
Dabore84 - 2 pair
funch - 1 pair
kartk - 1 pair
Yourownbuzz - 1 pair
BabyDontHertzMe - 1 pair
Stellarelephant - 1 pair
passive420 - 1 pair
Pinnocchio - 1 pair
vvs7 - 2 pairs
Gwrskien - 1 pair
Ernesternest - 1 pair
jwjarch - 1 pair
ermine22 - 2 pairs
Morde - 1 pair
S610adam - 2 pair
pstech - 2 pair
Silasmellor - 1 pair
ravid - 1 pair
 
Founder of XSA-Labs
Joined 2012
Paid Member
Simple Class HPA and Preamp Production Data

Many thanks to JPS64 for his untiring efforts to produce a magnificent set of professionally-done layouts and uniquely flexible design for either a HPA or a Preamp.

Here is a block diagram showing how the single panel with 8 sub-boards can be mixed and matched to produce either a HPA or a Preamp with multiple input selector jack:
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The panel includes following boards:
  • input and source switch board (only preamplifier version)
  • crossfeed board (with defeat Xfeed ON/OFF switch)
  • headphone jack output board (6.35mm stere TRS output jack)
  • volume potentiometer board (with the possibility of three different types of pots)
  • PSU (includes CLC, DC-DC dual rail step up, cap Mx, CRCRC filter to produce battery-like rails from simple 12v wall-wart)
  • CLC filter board (in case you want to use your own PSU)
  • ON/OFF switch board
  • amplifier board

For the preamplifier version, the following boards are not used: the crossfeed, headphone jack output board, and volume potentiometer.

For the preamplifier version, use the potentiometer built-into the main amp board; for the headphone version, use the separate volume potentiometer board.

Of course, you could use the external volume pot board for the preamp if you wish. The panel offers a wide range of possibilities.

Here are 3d renders:
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The detailed schematics and stuffing guides are attached below as PDF's.

Comments/feedback welcome. If no more changes we can move to actual GB and I will start collecting payments via PayPal invoices.

The PCB's will be 2mm thick, with 2oz copper and gold ENIG finish and blue solder mask as depicted in renders.

Cost will be $28/panel (a stereo "set" as terminology was used when we originally thought we were using separate mono boards).

Shipping costs will be $5 in USA, $10 for Canada, and $15 everywhere else.
 

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Founder of XSA-Labs
Joined 2012
Paid Member
Simple HPA GB List:

Badboygolf16v - 1 set
Dabore84 - 2 sets
funch - 1 set
kartk - 1 set
Yourownbuzz - 1 set
BabyDontHertzMe - 1 set
Stellarelephant - 1 set
passive420 - 1 set
Pinnocchio - 1 set
vvs7 - 2 sets
Gwrskien - 1 set
Ernesternest - 1 set
jwjarch - 1 set
ermine22 - 2 sets
Morde - 1 set
S610adam - 2 sets
pstech - 2 sets
Silasmellor - 1 set
ravid - 1 set