Dx Blame MKIII-Hx - Builder's thread

[Junie]

Testing in progress....Playing music loud and clear.



I will post more photos, camera's batt already exhausted.

[vargasmongo3435]

Originally Posted by Junie

Testing in progress....Playing music loud and clear.



I will post more photos, camera's batt already exhausted.

muy bueno se ve brutal tremendo mano! "translation": awesome!

[BMW850]

@ Rudi, I will definitely make a light bulb tester before I plug in the amplifier.
@ Evette, I appreciate that you've helped me with the components

Regards,
Rudy

[BMW850]

220uF 100 volt 18mm. max 10mm on the board
47uF 100 volt 12mm. max 9mm on the board

I stop now with build because the 100 volt caps do not fit on the board.
I wait or another board is created, or I need to bring the voltage down and buy new transformers.

Regards,
Rudy

[a.wayne]

Originally Posted by Junie

Testing in progress....Playing music loud and clear.



I will post more photos, camera's batt already exhausted.

Nice job Junie ... where did you purchase the panel light ?

Originally Posted by BMW850

220uF 100 volt 18mm. max 10mm on the board
47uF 100 volt 12mm. max 9mm on the board

I stop now with build because the 100 volt caps do not fit on the board.
I wait or another board is created, or I need to bring the voltage down and buy new transformers.

Regards,
Rudy

What voltage are you running?

[canonnica]

Board 'B' was started tonight. Went silk smooth. Couldn't resist making them sign together in unison.

They're built so identical that all initial readings were exactly the same.

DestroyerX; you were right, the sensivity is a bit on the low side with portable devices, even though I'm using an external DAC with a preamp stage. I may reduce the 390 ohms resistor to 270 or 220 to unleash all the guts this monster is having. I'm gonna do this on a single channel first and compare.

Same for the CCS's resistor. I'm gonna increase from 22 ohms to 47 on one channel to compare the heat dissipation reduction. I will report my findings here. Gimme a few days.

Some pics below. It's a mess of wires for now, I'll work my aesthetics in the enclosure.

[BMW850]

Originally Posted by a.wayne

What voltage are you running?

My Transformer is 2x 42Vac 2000Va, I have 2 of them.

Andrew wrote,

42Vac, 3to 4% regulation, on a 220/230Vac mains system must operate very close to 63V. I would not run 63Vcaps.
I think you have made the correct choice going for 80Vdc rating.

Regards,
Rudy

[meanman1964]

Rudi,you could ask Cannonnica how much voltage he has on those caps.My idea is that Alex has a reason for using 63Volt caps there

[destroyer X]

Everyone knows capacitors goes to power supply (mainly)...also everybody knows that mains supply has a variable voltage .... sometimes variation is 10 percent (plus and minus) and sometimes it is 20 percent (plus and minus)....if you have 20 percent plus, then your 44.5 plus 44.5 AC volts from your transformer secondary, increased in 20 percent will go to 53.4 plus 53.4 VAC ..... if you rectify and filter this will turn 75.29 VDC (multiplied by 1.41 because rectification and filtering)... so, you see the increasing in the voltage and the 63 volts will become 75 volts.... of course manufacturers make electrolitic condensers to face much more than that voltage... they produce reliable things because they do not want to close their doors and bankrupt, as they gonna face a lot of complains and devolution of units.

So, if someone could produce a capacitor insulated to exactly 63 volts... and IF this capacitor worked as a zener (It does not work this way) it will be destroyed when mains voltage increase due to natural variations we have in frequency and in amplitude.

Because of that, manufacturers print the "minimum guaranteed insulating voltage" into the plastic case..but in the reality, it can face at least 30 percent more..in my experience, i tried 60 percent more voltage in several capacitor and they worked fine for years long without leakage, over temperature or short circuit..no looses of capacitance, the case was not inflated and the over voltage rubber cap not broken because of excess of internal pressure in the electrolitic fluid.

To use with 63 volts you should use 63 volts capacitors (condensers) not to spend more money than you need.... more insulation and more capacitance increases size and price....waste o money..overkill.... excessive care....non needed exageration.

People believe they should increase to have guarantee...but the factory have concluded that in advance and did that to you...they have a brain too folks....manufacturers, inside their skull, there's a brain too.

- 63 volts capacitors are perfect to 63 volts supplies and you do not need higher insulating voltage units

- 63 volts capacitors can outstand much more voltage than the voltage printed as minimum guaranteed voltage.

- Also, the capacitance is not the value written, it is more than the value printed...that is the "minimum guaranteed capacitance"

In 50 years i never had a destroyed (pop out) condenser using the "minimum guaranteed voltage" printed into the capacitor plastic cap...and also i never had a unit destroyed because working in a over voltage condition ... I said never happened

If people has money to waste...well.... be happy and try 100 volts because they look bigger.

regards,

Carlos

[AndrewT]

Originally Posted by destroyer X

................ manufacturers print the "minimum guaranteed insulating voltage" into the plastic case..but in the reality, it can face at least 30 percent more..in my experience,

I think you are wrong to suggest to anyone, least of all the beginners who are attracted to your DX range of amplifiers that manufacturers either by design or accident apply a Factor of Safety of 1.3 to their electrolytic capacitor voltage ratings.

It is upto the designer of the equipment to ensure by thorough testing that the 63Vdc rating is adequate for all operating conditions and for many fault conditions as well.
Builders should always stay within the 63Vdc rating for all voltage conditions. There is no guarantee that the 63Vdc capacitor can or will survive +30% voltage overload, unless the manufacturers specifications state so.

DX,
in my opinion you are behaving irresponsibly by posting that "overloading is OK" message.