Dx HRII, High Resolution II - now a thread for this veteran

[destroyer X]

The amplifier Dx HRII (High Resolution II) also called HDII by Nordic, never had a thread.

The first presentation was made inside the Dx Amplifier thread, and several folks said interested to buy boards from a group buy, them Nordic, kindly, presented himself to help, and the group buy was created.

The result of that past group buy was 100 boards produced and sold by cost prices, no profit, at least was my instructions, only to have back, the money lost to do this job, the money spent to do that job(main cost), taxes, fares, expenses and so on.

Boards were spread around the world and several friends have built, and i have no complains received.

Also, here in Brasil, i have assembled several amplifiers, my personnal group of Orkut friends have built 12 units and everybody said that felt happy and satisfied with the sonics, they say, even now a days, the sound is impressive.

So, as i have found Dx Blame ES unstable, i decide to keep it on ice and to revisit the HRII.

We have already a site, the Greg Erskine site, with several pages about, also we have board layout, we have decent schematic and a history about the amplifier and pictures that i will search to post.

I think the main things of interest to tell you, dear friends, the Dx HRII was created/copied/designed/inspired by the Dx Amplifier, and this one based in the Aksa 55 from Aspen Amplifiers, was a natural evolution. Also it is very alike the Blameless from Doctor Douglas Self, and the main difference is that i am not using ccs feeding current to the differential long tail...there i am using the traditional zener voltage regulator with 4 to 5 more current than the current used by the differential long tail.

It sounds great, has a lot of punch, tigth and controlled bass and lovely high end, i think it is not so brigth around the high frequencies extremes, not alike the Dx Blame ES, but really, this one does not explode in your face!

Regards,

Carlos

 

[destroyer X]

Dear Mr. Greg Erkine, an Aussie friend, have created and is now a days maintaining

a nice site, having several pages dedicated to Dx Amplifiers..there you have the HRII, the layout, the schematic and more.

Greg in our forum is Gerskine, but since he lost his daddy i could not see him visiting the forum anymore...i am sorry this hurts so much our dear friend.

Greg's Web Site

regards,

Carlos

 

[destroyer X]

The Dx HRII, alike several amplifiers, is tollerant to work with different voltages

some adjustments may be required, and i will be here to help.

You have the option, to remove the rail voltage regulator and to use single rail step down voltage, usually adjusted to reduce 3 to 5 volts, also the voltage regulator loose 5 volts more or less...this can be supressed if needed, or adjusted in a customized way.

Here is a more simple option.

regards,

Carlos

 

[destroyer X]

The HRII can operate using 55 volts, and TAJ has made the beautifull schematic

and he is also preparing his laboratory to test the board during the year of 2010.

The circuit board was not tested, do not build using this board for a while, wait Taj inform was tested.

regards,

Carlos

 

[destroyer X]

The HRII has low distortion, something around 0.003% THD

Down the page you have attached Fourier analisis showing till the 9th harmonic

regards,

Carlos

 

[destroyer X]

I will search for the group buy link, also the HRII debug thread

And this simplified amplifier Multisim 10 file can be sent to your e mail, you have only to let me know that you want it.

carlos.eugenio1951@yahoo.com

regards,

Carlos

 

[destroyer X]

Here is a sample, a recording made using digital camera

the HRII is playing:

YouTube - Dx Amplifier - HRII - sample to compare

If you want to see more, go to youtube and type "destroyersoueu"

regards,

Carlos

 

[lgreen]

Nordic Schematics and Parts List

For those of you who have the original Nordic Boards and cannot find Nordic's original web site dxamp.com (it is not operational), I have located my printout of the Nordic materials: schematics (I think same as the one Carlos posted) and parts list. They are here.

Good luck with the HRII. Hopefully in 2010 there will be boards of the 55V version.

 

[destroyer X]

And here is Igreen page about the HRII

He is too much humble to point those things:

http://www.parttimeprojects.com/audio/diy/DX HRII.php

Enjoy, he made a lovely work.

Thank you very much dear Igreen.

regards,

Carlos

 

[destroyer X]

There are two main schematics, differences are part numbers

One schematic was made by Nordic, using eagle, and he referenced the board he produced using the part number transfered from his eagle schematic.

So, to assemble Nordic board you need board schematic to check things, because of that i have asked Nordic to print the values over the board, values printed directly in the silk screen.

Greg site has other schematic, offered by a friend, if not Greg the one could be Sparkle.... and the part numbers are different, but no board there, so, that schematic we have at Gerskine site has not pcboard matching the part numbers.

I think i may have the copper side inside my backup HD, when found i will post it, the one matches this board made by Nordic.

Maybe we will have board from Taj, and this will be even better, because Nordic is unreachable, he has disappeared, i am afraid he has passed away, i hope i am wrong about that.

regards,

Carlos

 

[destroyer X]

Dx amplifiers!, if they are good for China, may be good for you too

A diy amplifier, i am not exploring the amplifier as a business.

Dx Corporation exists only in my dreams.... maybe in the future will come true.

regards,

Carlos

 

[destroyer X]

Now i have solder... a lot...so, amplifiers!..wait for me

I will build more hundred!

Solder brand Cast, made in Brazil, 1 milimeter diameter wire, triple fux, 60 percent of lead (Plumbum, Chumbo) and 40 percent of Stain (Estanho), 255 feet length of solder wire, weigth is 1 pound, price was 11 USD

regards,

Carlos

 

[destroyer X]

Nordic boards, Nordic schematic, here the parts list

Called BOM, Bill of Material

regards,

Carlos

 

[destroyer X]

More pdf files, now the board layout, and the schematic

with the part numbers used into the Nordic boards.

regards,

Carlos

 

[destroyer X]

If you want the original images captured from Nordic files

a zipped package, then follow this link:

4shared.com - online file sharing and storage - download DXHRII alta fidelidade.zip

regards,

Carlos

 

[destroyer X]

I have a special passion by the Dx Amplifier, the standard one, but,

All Brazilian folks, at least the ones have build the Dx Amplifier, the HRII, the DHR Turbo, Precision 1 and Trust....well, those ones say the HRII is the best in sonics.

regards,

Carlos

 

[Ultima Thule]

... i am not using ccs feeding current to the differential long tail...there i am using the traditional zener voltage regulator with 4 to 5 more current than the current used by the differential long tail...

Hi Carlos,

I have a question if you mind... you see the quote above, I am now relating to the schematic in post #1.
You say you use the zener for CCS, and it is filtered with capacitor C10 and C11 to ground, now I wonder why you make a split on the LTP resistor by using two, R5A and R5B, from there you have a capacitor C6 of the value 2,2 nF which also goes to ground.
Can you explain what is the reason for using this, if I am correct this will lower the LTP current source impedance for high frequency, are you using it for creating the following sound experience, see your words below:

...lovely high end, i think it is not so brigth around the high frequencies extremes, not alike the Dx Blame ES, but really, this one does not explode in your face!

Cheers Michael

ps: I received your kisses and hugs in your other thread, sorry I don't have any daughter yet so I have to save your 'gift' for the future..

ps2: I almost forgot to tell, but Merry Christmas Carlos!

 

[destroyer X]

Zener for voltage stabilization dear Ultima, it is not a constant current source

It is just a voltage reduction and a filter, to provide stable voltage (not current) to feed the differential long tail.

The main idea is to provide 0.6 volts to both differential transistor emitters and to filter oscilations as soon as they appear.

Reduced a little the impedance, maybe the losses in high frequency came from this.

Well my dear, the amplifier is ready, but, you can fix that, or improve in your own board..

Will you build?

Merry Christmas.

Carlos

 

[destroyer X]

A friend sent me this image.

This one was made by Nordic i think.

Well, Nordic (Nico Daneel) has disappeared, i would be more happy watching someone alike Taj to produce pcboard (layout) and schematic..... sadly Taj is really busy with his family.

regards,

Carlos

 

[destroyer X]

I have made the HRII, the worst way i could, to force unstabilities

The circuit is the one posted in the schematic, i have installed a CCS, and will search a micro switch to listen zener voltage regulator OR, ccs.

The bad focus was made intentionally, too much ugly, wires crossing...all the bad things to unstabilize.

It is running very well.

I am having fun...

Merry Christmas folks.

regards,

Carlos