CFH7 Amp

[xrk971]

GB shipment status:

So far, here is what I know to be the current status of thee boards shipped and received. Spudbone1098 is in the US so I am really surprised that it has not arrived yet. Kokanee is in Mexico so let's give that one more time. Please update list below if you have received it.

Idefixes = 2 *received*
Hajj = 2 *received*
Rick G = 2 *received*
Kokanee = 2
Overtheairbroadcast = 2 *received*
Spudbone1098 = 2

 

[anatech]

Hi xrk971,
Sorry, your first statement that referenced the offset controls is what threw me. Getting close matches for the diff pair(s) is hugely beneficial.

-Chris

 

[thimios]

CFH9

Late at the party.
Here is what the postman delivered today morning🙂
Thanks X🙂🙂🙂🙂
The other photo is what i have this afternoon.
Several pieces missing and others have similar values🙄

 

[xrk971]

I'm glad the board made it to you safely - you work fast. Looking forward to your review. Use it with a Juma Easy Peasy cap multiplier for best results. 🙂

 

[thimios]

Thanks again for your offer,i will try to end with the amplifier first!😉

 

[thimios]

What is the best value for zobel resistors?

 

[sonal kunal]

2 X 10R/47nF for zobel.

 

[andrewlebon]

Hello Sonal
greetings please can you post sprint lay files for 2 pair version single sided pcb
warm regards
Andrew

 

[AndrewT]

and fit another across the chassis mounted speaker terminals.

I just watched the R.Cordell presentation from the 2016 BA conference.
His sch for the modified DH220 shows the Pi filter with the second Zobel at the speaker terminals. I must have read too much of his interviews series.

 

[BYRTT]

and fit another across the chassis mounted speaker terminals.....

Have couple of nice sounding old Sansui AU-D9's that seems use that schematic.

 

[AndrewT]

I can't see the first Zobel between the output and the decoupling ground.

 

[BYRTT]

I can't see the first Zobel between the output and the decoupling ground.

Uuups you right that was wrong adds i made in a hurry, have changed attachment into post 550 now to correct one.

 

[anatech]

Hi Andrew,
Two zobel networks is overkill and not necessary at all.

-Chris

 

[shaan]

Hello xrk971! Great going with CFH7 and 9!

I was wondering why there is no capacitor in parallel with the 10R + 2diodes network in the second ground on the input side. Is it SMD and mounted under-board?

 

[prasi]

Hi Andrew,
Two zobel networks is overkill and not necessary at all.

-Chris

Hi Chris,
I havent seen two zobels, but have seen parallel zobels on VSSA (Jason layout), seem to work fine... 10R//100nf divided into two 47nF//20R.
reg
Prasi

 

[xrk971]

I did not have 47nF so populated just one side with 100nF and 10R.

 

[xrk971]

Hello xrk971! Great going with CFH7 and 9!

I was wondering why there is no capacitor in parallel with the 10R + 2diodes network in the second ground on the input side. Is it SMD and mounted under-board?

Thanks!

The secondary ground layouts I have seen generally have not had a cap. There are hidden SMT caps but for bypass the big elco's. Maybe Idefixes can comment as he did layout. My initial schematic does not have it.

 

[anatech]

Hi Prasi,
About all that does is increase the stuffing cost of the board, and add to the cost of the BOM. There is zero benefit in doing that.

-Chris

 

[schillg11]

So to get things started off on a round 2 GB:

- Iancortez 2 PCBs
- Jacques Antoine 2 PCBs
- Zman01 (TBC) 2 PCBs

So if we can get 2 more people we can do another one to get 10 minimum. I will probably wait for at least 7 people total though to make it more efficient.

If you are interested please edit this list and repost it.

hi XRK971,

for 2nd GB of CFH9 please add me

- Iancortez 2 PCBs
- Jacques Antoine 2 PCBs
- Zman01 (TBC) 2 PCBs
- schillg11 2PCBs

Best regards
Günni

 

[thimios]

CFH9

Can someone check these measurements?