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

[xrk971]

If your name is on the list here, please PM me your PayPal address with quantity of board sets and country and I will send you an invoice.

Thanks,
X

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

 

[xrk971]

Wow! VERY nice JP and X! Can't wait to get my hands on this one. Any update on the status of the voltage regulator boards?

We looked into making our own TO220 style voltage regulator boards using Texas Intruments' TPS7A400 and TP7A3301 and it just isn't as cost effective as buying ready made ones from LDOVR.COM for $37 a set. These are nicely made units with genuine Murata X7R MLCC caps and are made in the UAE.

TPS7A4700-78XX Ultra Low Noise LDO Voltage Regulator

TPS7A3301 Ultra Low Noise LDO Voltage Regulator

They come with a 5 pin header to allow remote enable (EN) and remote feedback (FB), but to use as 3-pin 78xx/79xx package, cut the two end pins and solder the bridge pads to allow on board EN and FB. Also, what is nice is that in the meantime, you can just use the classic LM7818 and LM7918 (for less than $2) and it will also work quite well. On the positive regulator, several programming solder bridges need to be connected to set 18v. On the negative regulators, two SMT resistors need to be added to set the 18v output. We will provide you exact directions on how to do this.

This is an example of the regulator board mounted to a TO220 heatsink and used a a power supply module.

For our application, the two TO220 daughter boards from LDOVR.com would just mount in the middle of the PSU board, back-to-back with a shared heatsink - like this:

 

[xrk971]

GB Status Update....

*Badboygolf16v - 2 sets, Invoice sent
*Dabore84 - 2 sets, Invoice sent
*funch - 1 set, Invoice sent
kartk - 1 set, need PayPal address
Yourownbuzz - 1 set, need PayPal address
BabyDontHertzMe - 1 set, need PayPal address
Stellarelephant - 1 set, need PayPal address
*passive420 - 1 set, Invoice sent
Pinnocchio - 1 set, need PayPal address
vvs7 - 2 sets, need PayPal address
Gwrskien - 1 set, need PayPal address
*Ernesternest - 1 set, Invoice sent
*jwjarch - 2 sets, Invoice sent
*ermine22 - 3 sets, Invoice sent
*Morde - 1 set, Invoice sent
S610adam - 2 sets, need PayPal address
pstech - 2 sets, need PayPal address
Silasmellor - 1 set, need PayPal address
*ravid - 1 set, Invoice sent

* indicates new activity. Thanks to all who sent me their PP address!
-X

 

[Malvin]

is it too late to join? I'd like 1 set

 

[xrk971]

Not too late at all.

*Badboygolf16v - 2 sets, Invoice sent
*Dabore84 - 2 sets, Invoice sent
*funch - 1 set, Invoice sent
kartk - 1 set, need PayPal address
Yourownbuzz - 1 set, need PayPal address
BabyDontHertzMe - 1 set, need PayPal address
Stellarelephant - 1 set, need PayPal address
*passive420 - 1 set, Invoice sent
Pinnocchio - 1 set, need PayPal address
vvs7 - 2 sets, need PayPal address
Gwrskien - 1 set, need PayPal address
*Ernesternest - 1 set, Invoice sent
*jwjarch - 2 sets, Invoice sent
*ermine22 - 3 sets, Invoice sent
*Morde - 1 set, Invoice sent
S610adam - 2 sets, need PayPal address
pstech - 2 sets, need PayPal address
Silasmellor - 1 set, need PayPal address
*ravid - 1 set, Invoice sent
Malvin 1 set, need PayPal address

 

[xrk971]

GB Status Update

*Badboygolf16v - 2 sets, Paid
Dabore84 - 2 sets, Invoice sent
*funch - 1 set, Paid
kartk - 1 set, need PayPal address
*Yourownbuzz - 1 set plus Aksa Lender Pre TH and 2SA1837's, Invoice sent
BabyDontHertzMe - 1 set, need PayPal address
*Stellarelephant - 1 set, Paid
passive420 - 1 set, Invoice sent
*Pinnocchio - 1 set, Invoice sent
*vvs7 - 2 sets, Paid
Gwrskien - 1 set, need PayPal address
Ernesternest - 1 set, Invoice sent
*jwjarch - 2 sets, Paid
*ermine22 - 3 sets, Paid
*Morde - 1 set, Paid
S610adam - 2 sets, need PayPal address
pstech - 2 sets, need PayPal address
*Silasmellor - 1 set, Invoice sent
*ravid - 1 set, Paid
*Malvin 1 set, Invoice sent

Thanks to those who have already paid, I will be ordering the boards soon after one more careful examination of the schematics and Gerbers for any errors or problems.

For the folks in bold above, please send me your PP address to indicate continued interest in the GB.

Thanks,
X

 

[Morde]

I have a question about the CLC board. According to the attached diagram there is no CLC board presented, but should one still use it?

 

[xrk971]

I think JPS64 (please confirm) made the additional CLC for those wishing to use their own dual rail PSU or for those with extremely dirty mains - as the PSU has a CLC built in, it is mainly to prevent the switching noise from going back and contaminating the mains. Whereas the separate one is for protecting the amp from the noise in the mains.

 

[passive420]

Invoice paid X, many thanks to you and JP for the excellent project development

 

[JPS64]

Hi X,

confirmed: for dirty wall switching supplies.

JP

 

[xrk971]

GB Status Update

Badboygolf16v - 2 sets, Paid
Dabore84 - 2 sets, Invoice sent
funch - 1 set, Paid
kartk - 1 set, need PayPal address
Yourownbuzz - 1 set plus Aksa Lender Pre TH and 2SA1837's, Invoice sent
BabyDontHertzMe - 1 set, need PayPal address
Stellarelephant - 1 set, Paid
*passive420 - 1 set, Paid
Pinnocchio - 1 set, Invoice sent
vvs7 - 2 sets, Paid
Gwrskien - 1 set, need PayPal address
*Ernesternest - 1 set, Paid
jwjarch - 2 sets, Paid
ermine22 - 3 sets, Paid
Morde - 1 set, Paid
S610adam - 2 sets, need PayPal address
pstech - 2 sets, need PayPal address
*Silasmellor - 1 set, paid
ravid - 1 set, Paid
*Malvin 1 set, Paid

 

[xrk971]

GB status update

Badboygolf16v - 2 sets, Paid
*Dabore84 - 2 sets, Paid
funch - 1 set, Paid
*kartk - 1 set, Invoice sent
Yourownbuzz - 1 set plus Aksa Lender Pre TH and 2SA1837's, Invoice sent
BabyDontHertzMe - 1 set, need PayPal address
Stellarelephant - 1 set, Paid
passive420 - 1 set, Paid
*Pinnocchio - 1 set, Paid
vvs7 - 2 sets, Paid
*Gwrskien - 1 set, Paid
Ernesternest - 1 set, Paid
jwjarch - 2 sets, Paid
ermine22 - 3 sets, Paid
Morde - 1 set, Paid
*S610adam - 2 sets, Invoice Sent
pstech - 2 sets, need PayPal address
Silasmellor - 1 set, paid
ravid - 1 set, Paid
*Malvin 1 set, Invoice Sent

 

[pinnocchio]

Invoice paid yesterday

Thanks
Do

 

[yourownbuzz]

I've paid but paypal said payment pending so not sure what's going on..

 

[xrk971]

Thanks for the update, gentlemen.

I've paid but paypal said payment pending so not sure what's going on..

I see that too - let's give it a few days to clear.

 

[xrk971]

GB status update

Badboygolf16v - 2 sets, Paid
Dabore84 - 2 sets, Paid
funch - 1 set, Paid
*kartk - 1 set, Paid
*Yourownbuzz - 1 set plus Aksa Lender Pre TH and 2SA1837's, Paid
BabyDontHertzMe - 1 set, need PayPal address
Stellarelephant - 1 set, Paid
passive420 - 1 set, Paid
Pinnocchio - 1 set, Paid
vvs7 - 2 sets, Paid
Gwrskien - 1 set, Paid
Ernesternest - 1 set, Paid
jwjarch - 2 sets, Paid
ermine22 - 3 sets, Paid
Morde - 1 set, Paid
*S610adam - 2 sets, Paid
pstech - 2 sets, need PayPal address
Silasmellor - 1 set, paid
ravid - 1 set, Paid
*Malvin 1 set, Invoice Sent

Thank you to everyone for quickly paying. I am ready to place order now for boards.

 

[xrk971]

GB Status Update

Badboygolf16v - 2 sets, Paid
Dabore84 - 2 sets, Paid
funch - 1 set, Paid
kartk - 1 set, Paid
Yourownbuzz - 1 set plus Aksa Lender Pre TH and 2SA1837's, Paid
BabyDontHertzMe - 1 set, need PayPal address
Stellarelephant - 1 set, Paid
passive420 - 1 set, Paid
Pinnocchio - 1 set, Paid
vvs7 - 2 sets, Paid
Gwrskien - 1 set, Paid
Ernesternest - 1 set, Paid
jwjarch - 2 sets, Paid
ermine22 - 3 sets, Paid
Morde - 1 set, Paid
S610adam - 2 sets, Paid
pstech - 2 sets, need PayPal address
Silasmellor - 1 set, paid
ravid - 1 set, Paid
*Malvin 1 set, Paid

 

[xrk971]

Order for PCB's has just been placed. 2mm FRP, 2oz copper, gold ENIG finish, blue solder mask just like shown below:

 

[silasmellor]

X, apologies if this was already covered previously, but can you say a bit more about the cross feed?

I am toying with the idea of running double duty, preamp with Headphone out. How would you use the creed in that case?

 

[xrk971]

The Xfeed is based on the modified Danyuk design and has a defeat switch, so if in preamp mode, just defeat the Xfeed, and in HPA mode you have a choice of it in or out.

Here is the original (active) Danyuk crossfeed.
(PDF) Adjustable crossfeed circuit for headphones
But since we have a high impedance input with JFETs, the crossfeed can be driven passively before the pot.