Dx Precision, finally released... now debugged and better than HRII

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Dear Dexter, welcome to the Dx crew.

This circuit, the protection, is not decided to be included into the board, maybe will be into separate board as provided now a days to the HRII.

www.dxamp.com will provide you the needed informations.

Boards are beeing "coocked" into Nordic Laboratories, and soon will be released, will be made, and sold into Nordic group buy.

I have not informs about how the circuit works, i think detect off set and switch off the unit, have insertion delay and power off delay too and will operate into high current surge switching the speaker off...well..it is Nordic circuit, he can inform those features.

regards,

Carlos
 
Basicaly it is like Carlos described... the detection sits on the output... waits for all DC to be cleared or lower than the value determined by protection resistors, only then will it activate the relay to let the signal out of the amp...

I am again busy with a reworking of the PCB, as there was too much disagreement over small things...

Hopefully it is a little better from that viewpoint afterwards.
Will hold on till it is further developed, to avoid people gettting the wrong ideas...

At the moment it looks like you will need a sink about 10cm tall if you want to mount the boards over them.... that is if I can loose another 4 mm.
 
The Dx Precision I (One) schematic is the one TAJ made for us

He produced a nice schematic using his skills and good software.

Nordic will include, into the board, the protection...other features are under discussion into the Corporation...maybe only protection and switchable VAS protection will be included into the board.

Precision II may have other features than that.

regards,

Carlos
 

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Yes Mihai...thank you very much.

i have prepared the "Speakiller"..... an instrument, not a speaker... it has 1.6 ohms impedance...speakers are in counter phase, opposite..to complicate things, not push pull, not spherical speaker aproach...also i have zeners, power zeners limiting and producing 0.5 ohms shorts into the output, both rails shorting..also i am using coils with ferrite inside...to saturate, low power capacity ferrite.... some milihenries...also have capacitance enougth.

The Speakiller is made for testing purposes.... the amplifier will be tested receiving square waves into input, overdriven, much more than needed, not only subsonic, but also high frequencies will be used...a sweep generator will send sinal to the power amplifier.

It will be tested (was already, but not so hard this way) to be reliable.

Precision II will be able to hold almost all difficult loads people can attach to it.

Precision I (One)...if to four ohms loads (also 8 ohms of course) and nothing more than that....but the other will be made to resist to huge testings.

VAS protection will have switch to put it into the work or not...also the output will have a switch...output will be connected to the NFB, so, generating EMF back to the amplifier and will have the option to be opened, not connected to the NFB, also the mirror, the CCS i am using to feed energy to the VAS and VBE multiplier will have a switch too.... the amplifier will have the condition to operate with CCS and with Bootstrapp.

This will finish with doubts...the one that will have the unit will have a laboratory to test...

What is really better...a CCS or a bootstrapp?

The user will know for sure...also the dinamic disturbance that protectors creates into the VAS...the user will know for sure...also the EMF.

So...we gonna offer the best amplifier we could make, that will eat thousands of others, and a laboratory of experimentation of audio, hahahahahaha...included and for free. (the laboratory is for free, the board will be not...ahahahahah)

No one are offering so good ideas...and if someone copy...i will offer more things.... and faster than the competition will flip their eyes.

There's another 150 watts woofer into the back panel, they are 4 ohms each one.

regards,

Carlos
 

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Re: Transistors are 2N5401, 2N5551 into the differential

destroyer X said:

Also the first VAS transistor.

To VAS output and drivers, use the good ones:

2SC4793 and 2SA1837.

Into the output the Sankens work better, but, the Toshibas 2SC5200 and 2SA1946 can do the job in a confortable way too.



What kind of Sanken do you mean?

Any BOM realeased?
 
Poor nephew.... i did the same.... lost patience and started to put pressure over him

I said:

Do it, do it, do it and do it fast, asap, to yesterday delivery!

He is working hard, 10 hours a day.

The reality is that i cannot wait too.

Also, he is very carefull, will order a sample, will mail it to Brasil, will wait me produce board testings and them will start some group buy.

He is rigth to do this way... but it is really creating me some stress

ahahahaha... i think i am fanatic too.

regards,

Carlos
 

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Neto e falantes da lingua Portuguesa.

to Neto and other portuguese speaking personnel.

I am posting into a Brazilian forum, the HTforum, the Dx amplifiers are there, with schematics and pictures and explanations about how they work.

Here the link:

http://www.htforum.com/vb/showthread.php?p=937280#post937280

Dx Amplifier will have boards made in USA and will be sold into the Brazilian Market... the standard, vanilla, Classic one.

Also i will be visiting another forum:

www.diyaudio.com.br

Now a days i have only to test the Precision II and will spend some time into the brazilian foruns.... Nico will take care of group buy into this forum, and my visits here will be a little bit reduced as people do not need me here now.

regards,

Carlos
 

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They are not to be used with your boards dear nephew

Only to inform him the ones i like....

Our boards are the ones you are producing..near to be ready.

Will use the transistor you have placed there..no modification anymore..when ready to go.... order to produce prototype.

Those beautifull ones are too much big, and also there are many fakes.

I am afraid, Jacco Vermeullen have bougth all stock of those ones.

ahahahahaha!

regards,

Carlos
 
Member
Joined 2004
Paid Member
A PC board question

Hello Nico,

The layout looks very nice.

One question though, why have the output transistors entirely on top of the board? (I.e. board below the transistor bodies) Seems like unused board space. This will also require an angle bracket to mount on a heatsink, or am I missing something?

Francois
 
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