Dx Blame ST - Builder's thread - post pictures, reviews and comments here please.

[chlorofille]

steady progress...

2nd channel done up. Waiting for 2 items :Two 2X 25V 160W transformers and Multicomp carbon composition resistors.

The suspense is torturous!

 

[destroyer X]

I am sorry, there are a lot of hard work running, contacts with board's manufacturers

collecting prices... negotiation with several folks... so, i cannot be faster.

Soon i will release the schematic.

regards,

Carlos

 

[destroyer X]

Boys!...Uncle Charlie is using a new email adress

Because Yahoo is not working fine anymore.

Please, take note on that:

nanabrother@hotmail.com

Nana means Eliane short form...my sweet sister
Brother means i am her brother...something that make me feel honored.

The brother of Eliane!

regards,

Carlos

 

[Mitchel]

Hello everyone!

This is the link for the groupbuy:

http://www.diyaudio.com/forums/grou...kii-mkii-supercharged-groub-buy-interest.html

We need to know if there is enogh interest in those PCBs, so please let us know by posting on that thread.

 

[destroyer X]

Yep...we need to know because board's price depends on the quantity

We still have the price for 100 units (50 amplifiers), but we need, first, in advance, to know if we gonna have 100 units of order to go on.

Not achieving this quantity... adding Brazilian forum and Internacional forum (this one) we will not be able to order with the price informed.

regards,

Carlos

 

[chlorofille]

DX Blame ES distorting with low level signal

Hi all,

I have wired up the PS and one amp module.
Rails measured to be +/- 32V DC (from a 2X 25V 160W EI tranny).
I installed a 1W 100R resistor in place of the fuses and managed to achieve
4.7V by adjusting the pot. The other rail was also checked and it also showed 4.7V.

DC offset measured to be -5mV which is great. Transistors were checked to make sure they weren't shorting to the heatsink.

I tested with my 82dB 8Ohm 3.5'' vifa fullrange driver. Even when music was playing softly, there is a distorted sound coming through. The full spectrum of music is there; bass, midrange and highs but the midrange distorts first.
On musical peaks there is a "thsskkk" or "thzz" sound.

Power transistors used are : 2SC5200 and 2SA1943
Diode used in the PS PCB are 8A 200V, "damper diodes".

Could the fake transistors or damper diodes cause such distortion?

 

[destroyer X]

This is not normal...check your board till you find something wrong

There's no "tshcc" sound or anything but wonderfull music....amplifier sounds great as several folks reported.

Check everything, first capacitor values, in special the Miller one.

Fake transistor?

Reduce wire length to the transistors...use adaptor

regards,

Carlos

 

[smartx21]

Is R3 a resistor?

I tested with my 82dB 8Ohm 3.5'' vifa fullrange driver. Even when music was playing softly, there is a distorted sound coming through. The full spectrum of music is there; bass, midrange and highs but the midrange distorts first.
On musical peaks there is a "thsskkk" or "thzz" sound.
Could the fake transistors or damper diodes cause such distortion?

Are you sure R3 is a resistor, not an inductor (bobbin, coil)? Maybe a silly question, but it strongly looks like inductors we find here in Brazil.

 

[chlorofille]

Hi,

R3 on the amp board is a 0.5W carbon composite resistor from Multicomp.
I will complete the second channel with some original Sankens and see if the problem can be resolved. Most of the wiring is soldered so there are no loose contacts and all resistors were checked with multimeter before being soldered in place.

 

[destroyer X]

For sure there's something wrong...this amplifier does not produce strange sound

So, check it all till you find something wrong.

regards,

Carlos

 

[meanman1964]

The test wires you're using are too thin ain't they getting hot?
I think the rail voltage is too low check your power-supply.Read my posts about the rail voltage

 

[destroyer X]

It works fine while using 32 volts

He may have a mistake....well, this happens daily at my home...i am deeply impressed that several guys had their boards working at the first try.

Noises, sometimes are bad contact due to bad solder or defective component with an inside crack....despite these cracks are rarities.

One thing we all know and we can guarantee...the amplifier plays a lovely pure sound and have no strange noises.

Maybe the noise is due to a baby Dinossaur inside this very ancient multimeter...ahahahah!

regards,

Carlos

 

[chlorofille]

The test wires are rated at 7A 250V and they're not hot. The power transistors are barely warm(2 degrees over ambient) as my heatsink is large. So you mean the amp will not work with +/- 32V DC ? Will be reading up your posts in the mean time.

Will not rest till this amp sings !

 

[destroyer X]

Works fine with 32 volts without troubles.

Go searching and good luck.

regards,

Carlos

 

[chlorofille]

thanks carlos. I will check it now.

 

[chlorofille]

omg. The second channel with the Sankens are playing like magic. Massive sound, detail retrieval of the highest level. No distortions whatsoever. Didn't realise the tiny 3.5'' could produce such precise bass. Transient attack wow...

To conclude that the first channel transistors were the problem, I have to remove them and add in the Sankens. Tomorrow.

I test all my amps on those little Vifa drivers, but today, they sound like different speakers !!

 

[destroyer X]

Good!

regards,

Carlos

 

[chlorofille]

Alright gents,

I replaced the first channel with the Sankens. All problems are gone. At last I can sleep peacefully hahahha..

Will let the amp be tested on the small speakers for 24 hours before hooking them up to my large speakers.

Thanks for the help and encouragement.

 

[destroyer X]

Gents was nice.... gente (people) in my language

I am glad you are satisfied..you are welcome.

Maybe gents means Gentlemen in your language..but sounds alike our "gente" work..means people, folks, fellows, mate, dude and these friendly words.

I will be waiting for more pictures.

regards,

Carlos

 

[meanman1964]

Alright gents,

I replaced the first channel with the Sankens. All problems are gone. At last I can sleep peacefully hahahha..

Will let the amp be tested on the small speakers for 24 hours before hooking them up to my large speakers.

Thanks for the help and encouragement.

That's good news enjoy the sonics.About the Sankens that's what Rudi suggested to use if you build the Blame ES.