Hi Casiomax...
Yes it is the same design from Alex...
It's the kind of PCB that he offers for those who want to install the PCB on the big chassis... not the slim one like I have... which then Alex suggested me to re-drill the heatsink so that the PCB ca be installed within the slim chassis...
As for toroid rewinding... sorry, I don't know any....
But probably you could check with Alex?
Yes it is the same design from Alex...
It's the kind of PCB that he offers for those who want to install the PCB on the big chassis... not the slim one like I have... which then Alex suggested me to re-drill the heatsink so that the PCB ca be installed within the slim chassis...
As for toroid rewinding... sorry, I don't know any....
But probably you could check with Alex?
hmmm ok no problem.... i know it's take risk n time hehehe
btw can't u share what component u used/merk/type that i can follow like:
C1 (2,2-4,7 Bipolar) ? Tipe/merk?
C2 220 PF? Tipe/merk?
C3a,3b,5? merk/tipe?
Resistor ? merk/tipe?
where u buy Vishay Telefunken SF4007 n
2.2 uF Polyfilm? i'm difficult to find that part, maybe someday i need ur help to buy same parts as you.
btw:
6. I glued some of the AC cables to the chassis...?
u mean grounding, right? or fire/netral hihihi
what glue u use? (lem bakar?)
btw can't u share what component u used/merk/type that i can follow like:
C1 (2,2-4,7 Bipolar) ? Tipe/merk?
C2 220 PF? Tipe/merk?
C3a,3b,5? merk/tipe?
Resistor ? merk/tipe?
where u buy Vishay Telefunken SF4007 n
2.2 uF Polyfilm? i'm difficult to find that part, maybe someday i need ur help to buy same parts as you.
btw:
6. I glued some of the AC cables to the chassis...?
u mean grounding, right? or fire/netral hihihi
what glue u use? (lem bakar?)
casiomax said:
Please find attached... I hope it's not confusing as I re-draw it based on an available schematic...
sneih said:
C1: 2.2uF cap is not polycap.. my mistake.. those are MKP made by Audiophiler China, cheap.. IDR 4500 a piece..
C 220pF: I decided not to instal it... (cause I didn't buy it.. hehe)
C3a, 3b and C 5: all are Nippon Chemicon 100uF/50 V
Resistors: for the feedback resistor I use Riken Metal Film others are generic Metal Film...
(but actually I want to try with Holco resistor.. as I like the other GC LM3886 I built for my friend.. using the Holco resistors and it sound different.. well.. probably on my next GC...)
SF4007 diodes: bought via Singapore website (forgot... its either Farnell or RSonline..). Was actually leftover from my previous DIY project: replacing the diodes of my NAD CDP. Later I found out that these diodes are available in the city... silly me
Glue?: It's the usual hot glue (lem bakar...) no, I applied them on the loos cable between the AC inlet and the Power On/Off switch.. initially applied this approach just to have a tidy layout.. hehehe...
Thanks.... and Happy DIY!!
Dino-Indo said:Hi Sneih...
Feedback Resistor is installed next to LM3886 chip.. it's the R5 on the PCB... (see attached) I used Riken Metal Film 22K 0.5 Watt
om Dino,
does your configuration produce a slight hum? i dont use PCB from om Alex, but instead, I solder components directly to LM3886 pin, and make a start ground from pin7.
I powered the amp with +/- 32volts, btw I am using a standard 3amp CT transformer.
Hi Casiomax,
Yes.. it did produce very slight hum on the left channel.. but I only can hear this when I put the potentiometer fully open and I put my ear very close to the speaker....
But then I re-do the grounding and the hum has gone...
If possible, I suggest you to apply put a grounding cable from the ground of your power supply capacitor, then solder this grounding cable at the same point in the Chassis with the Star ground of your LM 3886 chip
If it still produce hum, then probably you should check and try the approach that I did as I mention in this post:
http://www.diyaudio.com/forums/showthread.php?postid=1451754#post1451754
Hi Sneih,
I live in Menteng Dalam, Tebet area, Southern Jakarta...
Yes.. it did produce very slight hum on the left channel.. but I only can hear this when I put the potentiometer fully open and I put my ear very close to the speaker....
But then I re-do the grounding and the hum has gone...
If possible, I suggest you to apply put a grounding cable from the ground of your power supply capacitor, then solder this grounding cable at the same point in the Chassis with the Star ground of your LM 3886 chip
If it still produce hum, then probably you should check and try the approach that I did as I mention in this post:
http://www.diyaudio.com/forums/showthread.php?postid=1451754#post1451754
Hi Sneih,
I live in Menteng Dalam, Tebet area, Southern Jakarta...
Hi Andrew,
Geeez.. what I did was just making sure that the 'flow of the signal' right from the input to the output did not produce 'ground loops'...
See, on my first attempt of my GC I used many cables to 'channel' the grounds of each LM3886 PCB to arrive at the same star ground at the chassis...
But on my second attempt GC (with the new PCB) I use only one cable from the speaker output ground to the chassis
On both approach.. I applied the grounding circuit as suggested by Rod Elliot on his website (http://sound.westhost.com/project04.htm) .. my big thanks to Rod !!
Hi Sneih!! Thanks !!
Geeez.. what I did was just making sure that the 'flow of the signal' right from the input to the output did not produce 'ground loops'... See, on my first attempt of my GC I used many cables to 'channel' the grounds of each LM3886 PCB to arrive at the same star ground at the chassis...
But on my second attempt GC (with the new PCB) I use only one cable from the speaker output ground to the chassis
On both approach.. I applied the grounding circuit as suggested by Rod Elliot on his website (http://sound.westhost.com/project04.htm) .. my big thanks to Rod !!
Hi Sneih!! Thanks !!
http://www.diyaudio.com/forums/showthread.php?postid=1475396#post1475396
recently I have been playing with using both the before and after Zobel forming a Pi filter. Setting the Ca = Cb = 47nF seems to give good values. R2 = R1b = 4r0 and R1a = 8r0
recently I have been playing with using both the before and after Zobel forming a Pi filter. Setting the Ca = Cb = 47nF seems to give good values. R2 = R1b = 4r0 and R1a = 8r0
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