PCB based invert 3886 chipamp assembly and comments

[carlosfm]

digi, the best thing you can do here is to connect your pcb's as you have drawn. Reality will get you the verdict.

Does it hum?

Completely silent => end of discussion.

IMHO a simple drawing without one word of text is not enough.

Hint:
The amp may hum or not with this last drawing depending on the thickness and length of the power ground wires.
And other small details.
It is not enough no have a tight layout on the PCBs.


It is not end of discussion.
For a beginner, following this drawing, a silent amp may just be a question of pure luck.

 

[digi01]

Thank you P-A and carlos.
As to my assembly experience,the amplifier is quiet.What I used is regulated power that has suppressed HUM within the amplifier from the AC.

Yeah, but one my reasons to have as much as possible on one pcb is to get less support questions. Almost every question about Gainclones are about wiring.

good point

 

[Evilsizer]

the resistors used for the gain setting on the amp. 220k and 10k should be what type ? i have done a lot of reading about people reccomending Dale and Halco resistors but cant find anyone that carries them (has anyone)? The 4.7uf cap should it be a certian type?

thanks

 

[moving_electron]

the resistors used for the gain setting on the amp. 220k and 10k should be what type ? i have done a lot of reading about people reccomending Dale and Halco resistors but cant find anyone that carries them (has anyone)? The 4.7uf cap should it be a certian type?

thanks

Mouser carries Dale resistors (Vishay-Dale).

www.mouser.com

Looks like you are looking for Halco resistors. In case you are looking for Holco resistors, Percy audio carries them.

http://www.percyaudio.com/Catalog.pdf

Handmade Electronics has some left on closeout. I picked up some 1/2 watts on closeout for $.40 ea in early Dec. 221k and 10k are still available according to the web page as are a few other values. The half watts are slightly big for the board so the leads have to be bent back under the resistor a bit to fit. But it appears they will work fine.

http://www.hndme.com/storeresistorcloseout.html

 

[Vuamp2]

3886 and regulator PCBs from Digi01

digi01

I still has not recieved any of the 3886 or Regulator PCBs from you. Would you give my an update?

 

[peranders]

It is not end of discussion.
For a beginner, following this drawing, a silent amp may just be a question of pure luck.

... unless the wiring is in the pcb ready made.

 

[carlosfm]

... unless the wiring is in the pcb ready made.

I was talking of this drawing, so...

But even with the "wiring" on the PCB, it would have to be a two-channel complete amp on a PCB, including the RCA connectors, PSU, etc. Everything on board.
This is the only way I can figure out no one would make a mistake with the wiring.

 

[peranders]

But even with the "wiring" on the PCB, it would have to be a two-channel complete amp on a PCB, including the RCA connectors, PSU, etc. Everything on board.
This is the only way I can figure out no one would make a mistake with the wiring.

In my case I everything is on the board except for the rectifiers. This makes it pretty easy just adding fullwave rectified DC only. All other connections are on the board which becomes a bit larger but chances to make mistakes are less.

 

[Upupa Epops]

But " everything on " method is not convenient for these ones, which are permanently dissatisfied with results . Fixed idea " I still don't try all " is for these guys extraordinary impassable .

 

[carlosfm]

But " everything on " method is not convenient for these ones, which are permanently dissatisfied with results . Fixed idea " I still don't try all " is for these guys extraordinary impassable .

Can you elaborate?

What do you want now?

 

[lgreen]

Inverting GC

I've made an inverting GC (not using these boards by the way), there are details on my web page or diy audio thread. You can see the schematic for the amp portion at the bottom of my web page. Anyway, the point I would like to make is that the 220K (R3 in my schematic) and 10K resistors don't give enough gain for many of you with very low level sources. I would increase the 220K to maybe 400K? This has been pointed out to me in the past, just thought I'd share it. I have not looked at digi01's schematic but I think its the same as my own. Seeing someone mention the 220K and 10K resistors jogged my memory. I've got sufficient gain with my preamp with the basic values, so have not changed the circ in my implementation.

I really like the inverting GC, though mine has a buffer and differential inputs, unlike the basic design here.

Anyway, good luck with the boards, they look really nice.