peranders industry gainclone assembly progress

[jleaman]

how much ( again ) are these board's going for ?

 

[peranders]

Look in your mailbox, emailbox 🙂

 

[digi01]

here is a very useful article for SMD soldering.
http://www.infidigm.net/articles/solder/
by Infidigm

 

[Saibot]

digi01,

did you get your amp to work using only one transformer and the wiring shown in the beginning of this thread ?

I have 6 QRP-02 I want to build but I don't want to use a transformer for each of them. It gets too expensive buying a lot of MUR3020:s and transformers...

Anyone else has a solution to grounding problems that may show if only one transformer is used ? There's got to be a solution...

/Tobias

 

[peranders]

You must in some way got the star grounding concept to work.

1: Loose all rectifiers on board

2: Drop the big smoothing caps

3 Use "fat" ground wire

4: Get a rectified and smoothed DC voltage

5: Make a very serious star ground point, maybe use a copper block, like a cube or something. You must see to it that the ground currents don't interfere with each other.


There are reasons why multichannel amps have separate power supplies. This is the reason.

 

[greatestbestest]

Looking to split C1

I am trying to avoid buy a PPS .1uF capacitor for C1 alone because with min quanity it is $14. There has to be others out there with extra ones I could buy off you. Anybody?
Possible canidates:
Evox Rifa PPS 65-557-59 from Elfa
dimensions 5.7x5.0

from digikey
Panasonic ECH-U PPS film
none fit exactly but I assume will work
2416 6.0x4.1
2820 7.1x5.0

PCF1167CT-ND 2416 .12uf $1.01 2%tol
PCF1158CT-ND 2416 .12uf $0.96 5%tol
PCF1506CT-ND 2820 .1uf $1.41 2%tol 100VDC
PCF1489CT-ND 2820 .1uf $1.31 5%tol 100VDC

Mouser
AVX SMD FILM MKI
581-CF042D0334J 2220 .33uf $.77 polyester and significantly lower fc (but min quanity 1)

Please throw me some ideas or some parts. Thanks

 

[greatestbestest]

Fuses

Another quick question:
What size fuses are you using?
On the supply rails I assume fast blo would protect amp best, but slow blo would allow transformer inrush current on primary.
secondary fuses ~ output current limit?
for LM3886 this would be 7-12A which seems large for 50W amp
primary fuse
This would vary with number of channels on power switch. For 2 channel 3A slow blow seems good.
Any info on this topic?

Paul

 

[digi01]

the amp is completed🙂

ZANG

 

[digi01]

front panel,power on.

 

[digi01]

inner connections.

 

[digi01]

the detail of poti.

 

[peranders]

Have you fired up the amp yet? No hum? Sounds good?

 

[jleaman]

Look's Killer NICE NICE NICE keep it up..

 

[Franz G]

Looks very professionally, digi01!

- how does it sound, no hum with just one tranny?
- did you produce the smoke recently with this amp?

Regards
Franz

 

[digi01]

thank you.
The amp was finished yesterday,I am listening it at whole night.
Through burn up of 8 hours,the sound is perfect.quality of mid-range left the deepest impression on me,good soundstaging and details.bass control is tight but a tad lightweight.
But I have been already very satisfied,if the power is a bit larger(80W or 100W each channel),then very ideal🙂

P.S.
the amp is not hum & hiss when there is not input.even I close up my ears on the loudspeaker,can only hear very faint white noise.
the dc offset of Rch is 5mv,Lch is 12mv.

ZANG

 

[digi01]

Re: Fuses

Another quick question:
What size fuses are you using?
On the supply rails I assume fast blo would protect amp best, but slow blo would allow transformer inrush current on primary.
secondary fuses ~ output current limit?
for LM3886 this would be 7-12A which seems large for 50W amp
primary fuse
This would vary with number of channels on power switch. For 2 channel 3A slow blow seems good.
Any info on this topic?
Paul

Hi Paul,
On the supply rails I use a fast blo 250V1.5A fuse.chinese home is 220VAC.the transformer is 250VA 2x22VAC.I have not set up secondary fuses,just short them.

FYI,main parts list:
C23,28, nippon 3300uf/50v
C22,27, empty
C4, elna cerfine 100uf/35v
C6,C7,wima 1uf/63v
C10,12, elna rjh 100uf/50v
C14-C21,ero 0.1uf/63v
R8(mute resistor)33K
D7,8,9,10,15,16,17,18, BFY6A200V(made in china)
thanks P-A offer all 0805 parts and C1.

ZANG

 

[digi01]

Re: Looking to split C1

I am trying to avoid buy a PPS .1uF capacitor for C1 alone because with min quanity it is $14. There has to be others out there with extra ones I could buy off you. Anybody?
Possible canidates:
Evox Rifa PPS 65-557-59 from Elfa
dimensions 5.7x5.0

from digikey
Panasonic ECH-U PPS film
none fit exactly but I assume will work
2416 6.0x4.1
2820 7.1x5.0

PCF1167CT-ND 2416 .12uf $1.01 2%tol
PCF1158CT-ND 2416 .12uf $0.96 5%tol
PCF1506CT-ND 2820 .1uf $1.41 2%tol 100VDC
PCF1489CT-ND 2820 .1uf $1.31 5%tol 100VDC

Mouser
AVX SMD FILM MKI
581-CF042D0334J 2220 .33uf $.77 polyester and significantly lower fc (but min quanity 1)

Please throw me some ideas or some parts. Thanks

I think C1 can be short.or you can use standard film caps,warp the legs.the attached photo is a illustration,wish that helps.

 

[peranders]

Good to hear that you didn't get any hum.

5 mV and 12 mV at the output, was that without DC servos?

 

[peranders]

digi, some time has gone now. What is your impression now?

 

[XELB]

my overkiller case.is the inner layout all right?

Where did you find that case

I'm looking for a nice case and I only find rubbish