Dx Super A - a module to be coupled to Dx amplifiers

[destroyer X]

It can be used with other audio amplifiers that uses emitter follower and needs bias generated reference voltage from 2 to 2.4 volts Dc.

This circuit is adapted, or almost a copy, from the Super A used in the Braziian Gradiente factory (already closed.... factory not operating anymore)....it was used in one of the most famous models of this brand, called Model 366.... it was a license from JVC, the one have created the system down the seventies.

The Super A works setting a high level of bias (300 to 500mA) and switches this current to a lower value (Class AB) when the output power increases above some pre decided level (in our case 4 volts RMS aprox.) ... this way you have a couple of watts in Class A (non switching in the transistor crossover region) and does not have the heat that comes together a Class A amplifier.

This was tested in a Dx Blame ST amplifier, and i did it with one that had 20 plus 20 volts supplies...soon i will be testing together many other models from the "Dx Corporation - the audiophile union"

This circuit is in testing and may receive some modifications...and i will publish the revised schematics.

Here you have the video with the last test made with it:

Dx Blame ST, Super A approved! - YouTube

regards,

Carlos

 

[destroyer X]

Showing you the original Gradiente Model 366

Images attached.

regards,

Carlos

 

[destroyer X]

More images about the Gradiente Model 366 - the SuperA unit

This one is famous and audiophile goes to buy it and pay 500 bucks without discuss.

There's someone in the Brazilian free Market (Mercado Livre....alike Ebay) selling audio power pcboards for this model... a copy from the original Gradiente pcboard.

regards,

Carlos

 

[destroyer X]

Here you have some diagrams...but this is a reference only

Values are being changed in order to adjust the unit to different demands and different power amplifiers.

Just publishing to show you some "standard" of values that may be a start up.

regards,

Carlos

 

[destroyer X]

More images related the unit

attached,

regards,

Carlos

 

[destroyer X]

I have being working on that these last two weeks

And something was posted into the Dx amplfiers thread, also the Dx Blame ST thread and something was said in the Dx Blame MKIII Hx thread too....but just to inform, as i was not sure if i would like it or not.

Now we have a thread and all informs will be here.

I have perceived the sound muffled...but this may be my damaged tweeters..now i will evaluate better...give me a couple of days and i will say what i think about...for a while i am appreciating a lot the advantage not to have all that Class A heat and also the quality in very low levels (1 to 2 watts reproduction).

Well...we listen at this level almost 80 percent of our time.

regards,

Carlos

 

[destroyer X]

I will post a list of videos made about the Dx Super A

This one was made in Portuguese to my people:

Dx Super A in Portuguese language - YouTube

And here you have other ones:

Dx Super A installed and first test done - YouTube

Super A was mufled because tweeter was damaged - YouTube

Dx Super A - 300mA in class A - Supply 40 + 40V - YouTube

Dx Blame MKIII Hx going original again - YouTube

Do not assemble Dx Super A for a while - YouTube

Dx Blame ST playing - it rocks! - YouTube

Dx Blame Rocks II - recorded using Kodak Playfull Ze1 - YouTube

Dx Blame ST - Break for lunch - YouTube

Here you have one of my cameras used to make these videos:

This is the Mitsuca! - YouTube

Pictures attached show the Kodak Playfull Ze1 and the Dx Blame MKIII Hx used together the Dx Super A module (first try)

regards,

Carlos

 

[destroyer X]

Procedures about how to install and adjustments will be provided soon

Sketches, texts and videos will be provided.

I will prepare the unit to operate with 35 plus 35 volts to the Dx Blame ST, then i will prepare it to the Dx Amplifier (Standard one) and will prepare it to Dx Blame MKIII Hx home editions (40 plus 40 volts supplies).

Brazilians wants a dedicated forum to my amplifiers...i may accept their offer.... i am thinking about.

regards,

Carlos

 

[destroyer X]

The idea about the Super A (from JVC) started May, 11th

Here you have videos about:

Dx Super A - starting to prepare the circuit board. - YouTube

Dx Super A prototype board - part B - YouTube

Dx Super A prototype board - part C - YouTube

It shows the way i produce my prototypes...this method i am using since 1960.... i do think it is SMD style.

regards,

Carlos

 

[Bigun]

I like the use of the cpu cooler, very compact and efficient - and these days they are whisper quiet.

 

[destroyer X]

I am glad you like it Bigun..it is easy to find in several repair shops junk

Here you have a new video about the test made with the Dx Super A together the Dx Blame ST operating 40 plus 40 volts supplies:

Dx Super A together Dx Blame ST operating 40 volts - YouTube

Also you have now the correct values applied to the Dx Super A module.

Herman is fixing the schematic and including real values....soon we gonna have them with real values.

regards,

Carlos

 

[Thenno]

Hi Carlos,

I am following the topic, I'm waiting for news in our language.
😀😀😀😀😀😀

Thenno.

 

[destroyer X]

Tomorrow i will do it and will send to Youtube

Keep my channel in your favorites Thenno:

destroyersoueu - YouTube

I will do it when return from work.... at the end of your day you will have it in Portuguese.

Lira is preparing a forum to us...will be Dx forum....do you like the idea?

regards,

Carlos

 

[destroyer X]

Updated schematic and layout

Here you have them attached.

regards,

Carlos

 

[destroyer X]

I do think this pcboard is too much big to be assembled alike floating

Above the power amplifier pcboard....it looks huge to my eyes...can be reduced 50 percent with vertical resistors...i will ask Herman to reduce it.

I want it tiny like a fly landed over a transatlantic.

regards,

Carlos

 

[destroyer X]

The idea started in may

Here you see:

Super A from JVC - future Dx Super A, this one from Gradiente - YouTube

regards,

Carlos

 

[destroyer X]

We are constantly and continuously improving the pcboard

The one is making is Herman...i am giving him suggestions (and terrible demands too).

He does not want me to show the board...because not finished yet....as i do not agree with him...them 50 by 50.... i decide to show half the board.... well...this way i am doing what he wants.... he said not to show the board...i am showing part of the board.

I want him to put transistors in vertical position to reduce board size...it is being a trouble to convince the guy.

heheheheheheh.

regards,

Carlos

 

[destroyer X]

Dx Super A pcboard update, revision, images attached

Here you have values:

Q1 - BD139
Q2 - BC556
Q3 - BC546
Q4 - BC546
Q5 - BC556

R1 - 2K2
R2 - 2K2
R3 - 3k3
R4 - 3k3
R5 - 8K2
R6 - 8K2
R7 - 2K2
R8 - 2K2
R9 - 10K
R10 10K

D1-1N4148
D2-1N4148
D3-1N4148
D4-1N4148

regards,

Carlos

 

[destroyer X]

More images.

Attached,

regards,

Carlos

 

[AndrewT]

............I want him to put transistors in vertical position to reduce board size....... hehehehe........

It is no laughing matter.

I see the pads set out for vertical installation of the transistor.
What is the problem?