Destroyer x Amplifier...Dx amp...my amplifier

[Nordic]

I just follow the 20% overrating rule, because I too have too little knowledge on the topic, to dismiss the innitial safety guidlines I was taught...

...as much as I love and respect uncle Carlos.



For HV caps you can take two lower voltage caps and run them in series... obviously they need to be double the intended capacity...

then If you want to accommodate for a worst case scenario where you received 4 caps that were absolutely at the bottom of their tollerance rateing... i.e. -20%

Two marked as 400V but are actualy 320V
The other marked 500V but are actualy 400V

Lets say you detirmined you need an 750V cap, clearly you can see that the 400V caps COULD fall short... I say COULD, in the same sense that lightning can hit you, it is just not very likely... most of us goes through our lives without getting hit...but some are less lucky...

I have a saying "Things happen because they can" which means the inverse... If you don't want something to happen, take away the pillars upon which this thing happeining stands...make it "not possible"

Further I have other concerns...

Capacitors have a lifespan rateing normally rangeing from a few hundred hours to several thousand... Would this lifespan rateing still stand if the cap is used above its RATED voltage?

P.S. I am busy with a valve project now... haveing much fun... my hybrid DX guitar amp... front end is 2 nice Electro Harmonix 12AX7 tubes, run at about 250V.

Tonight I am makeing the heater supply.. 6.4V from a 5V v-reg referenced to ground via two diodes, wit a 5A current rateing provided by a MJ2501 transistor....

[destroyer X]

Will you make rectification and filtering into your heater supply.... i do not understand about tubes, but i have suspections this may be good.

If you decide to do that...5000 uf to each ampere.... into 12 volts the condensers are not expensive

regards,

Carlos

[Nordic]

Yep, I bought a 16V 4700uf one, as well as 1uf tantalum for after the regulation...

To be honest Carlos, I can not believe you do not know tubes...
MUCH easier to understand how they work, and to design with I think, than transistors... Some call them the perfect gain device...

For sure more dangerous voltages but I am most scared of the little 6V heater supply, drawing a constant 1.2A, that one stings like hell. the first triode (think of it like a transistor biased in class A), The first triode is biased with only half a milliamp at about 123V, so, very easy for minutely small signal to overcome the bias... inside the signal path we can swing to 250V leaving small noises way below in the noise floor... and at the very end in conventional tube amps is an output transformer, normally with a ratio of 20:1 or something high like that to step the voltage down for the speakers...

To bias a transistor for your diffirential, you need a whole string of components... to do the same for a triode tube (which is like a dual opamp) you basicaly need 1 or 2 resistors...

See if you can spot the DX

[Nordic]

and the other side of the regulator... still under construction...

[destroyer X]

have the main PC supply oscilating frequency entering the power amplifier and beeing measured into the output...give a check on that....good construction...nice things those tubes.
I do not have experience...have build very few things using tubes...do not like them...too much hot.

regards,

Carlos

[billabong]

Carlos, thanks for your comments. Your experience has shown that 50V electrolytics can withstand higher voltages - I accept that. Even having that information, being the over? cautious type that I am, I would still make allowance for the manufacturer's +/- tolerance specification.

Nordic, nice work. You are a busy bee! Years ago I could do five tasks together in quick time - nowadays I do only one and it takes an age.

billabong.

[space2000]

hi,

first i have to say, i am not good in electronics as like you all. so i can't make very nice. here is my "DX precsion I" circuit. you can see the meter, it is the only meter i have for checking. transformer, i have two but here is showing one. you can see with lcd too, it is using microchip 16f877 for lcd ,switch and to control output protechtion for speaker. i am still doing program for it. last you can see my rose garden..

amp is still under construction.

thank you.
michael

[es44]

Originally posted by billabong
Years ago I could do five tasks together in quick time - nowadays I do only one and it takes an age.

billabong.

I'm happy to hear i'm not the only one feeling this way

Somehow i always find an excuse to lay down the soldering irom. The latest excuse is, that my daughter gave birth to this little beauty 7 weeks ago

[destroyer X]

I have appreciated, a lot your construction, it shows me and prove to everybody that our worries and concerns about boards and parasitic capacitances, inductances, coupling and all stuff is some kind of over worries.

Those wires, distances, kind of building is all people believe as wrong and dangerous....and all my life i could perceive that in audio this do not makes any difference...i have build this way, and them i have made pretty high tecnologically made boards and sounded the same...so..... this is something usefull to us to see the differences of real world and our worries.

Thank you Space.... i am now a days discussing with a dear friend from Croatia, the man is "apocalipthic" and he believes each condenser brand may sound specifically different from other, and each transistor brand may sound different...and each board layout will sound different...and each enclosure vibration will be different...well..... he sees a tragedy that i am trying to clarify to him and to myself...because if my friend is rigth, we will never find a good solution as Mathematical combinations of wrong or rigth possibilities will be enormous..... will be alike to win a Lottery game to build something with excelency.

Was good that you came with that picture for me...will show my tragic dear and beloved friend, that this works too.

regards,

Carlos


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Ebbe

Nothing more beautifull than a son.... in special when is a daugther i think...... i think life would be very empty without any happyness without a baby in our lives.... i would be happy to produce one each year...but unfortunattelly i am not finding women that wants to give me more children.

ahahahahah

Carlos

[Nordic]

Morning Carlos, no, I am not useing a computer supply,only the box as a shield...

Haha who would believe you can build a 500W amp on veroboard... in fact who would even try... nice one.