completed chipamp pre

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#81
I actually just ordered 10 of them from Mouser the other day. I changed my ordering choices around a little when I found that I could get nearly everything I needed from Futurlec a fair bit cheaper then ordering from Digi-key. My order for Digikey didn't meet the minimum so I thought I'd jsut get the caps from Mouser. Thanks for the offer though.
 
#85
Russ

I need to order some parts from RS and I want to include some components for the Free- and Yardbird. For the Freebird C5, C11 =20pF and C6, C12=10pF. C1, C2, C7 and C9 =47µF/25V. Correct?
For the Yardbird C5, C6, C7 and C8 are also 47µF/25V I presume? But what are the values for C9 and C10? Also not quite sure what types I need for the 47µF/25V cap's. Panasonic FC's?

Cheers
 
#86
GeWa said:
Russ

I need to order some parts from RS and I want to include some components for the Free- and Yardbird. For the Freebird C5, C11 =20pF and C6, C12=10pF. C1, C2, C7 and C9 =47µF/25V. Correct?
For the Yardbird C5, C6, C7 and C8 are also 47µF/25V I presume? But what are the values for C9 and C10? Also not quite sure what types I need for the 47µF/25V cap's. Panasonic FC's?

Cheers
Click to expand...

Hi GeWa,
You correct...

some notes:


On the yardbird:
C10 is there to compenesate the opamp and make it stable, start with 10pf and increase it if the opamp is unstable (you shouldn't have to go over 200pf). Do not omit this cap.

C9 is there as a low pass filter to filter out RF. I usually use 10pf here, but you could go as high as 330pf if you like. You can omit C9 if you choose.

On the freebid:
C5 and C11 are there to compensate finicky opamps at low gains. You can usually omit them. Especially if you are using the opa627.
C6 and C12 are the same RF filter caps as for the yardbird.


Don't order any 47uf LOW ESR electrolytics. I sent you some already, enough for all the boards. But in any case the panasonic FCs would be a good choice. I sent you Nichicons.

I also sent you a PS board, you can discard it if you like. 🙂

Cheers!
Russ
 
#87
Russ

You're simply to kind😀
All I can say is: thank you for all the effort you put in these projects and helping us out with boards and parts. I realy appreciate this.:angel:

Back to the topic at hand: is there any preference for the pF cap's?

Cheers
 
#88
You are welcome GeWa, it is my pleasure. 🙂

For the pf range caps I generally use silver mica(mecause I have tons of them) but I also have used multilayer ceramic and polstyrene as well. 🙂 So really you have a lot of viable choices. The best bet is probably just you standard ceramic cap. The caps do not operate in the audio range, so don't worry about it much. 😉

Cheers!
Russ
 
#92
earsandeyes said:
That must have been a "rich" estate then?
Click to expand...


Well it was a great estate sale find for me. The estate was from the head engineer of on of the larger studio here is Nashville (music city). I got all kinds of cool stuff, including some very rare LPs, and reel to reel stuff. I spent about $1,000 for what I think is about $10,000 worth of stuff. 🙂 Most of the stuff was not store very well (in old oily and marked up boxes) so most of the bidders did not even look in them!!! He he he... So let that be a lesson! Go through all the boxes. even the ones that look like trash. 😀
 
#95
Hé Russ

Guess what the postman delivered today....... YES, an envelope with some cool looking stuff. Those boards look really good, considering the're homemade!:bigeyes:
And if that wasn't even enough, included I found the necessary low ESR cap's. Again, thank you very much for being such a good sport.
As soon as I have the time I will heat up my solder iron and finish those baby's.

Best regards
 

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#96
Excellent! 🙂 I am glad they are there. The copper got a little tarnished before I had a chance to laquer it(I was stupid and left it out in my shop in high humidity over night), but it should work just fine. 🙂 I will be very glad to see what you think of them. 🙂

Cheers! And happy (late) birthday!!! 😀:drink:
 
#97
I bought some ceramic disc cap's in different values for RF filtering purposes, think they will do the job. Now I have to search through my resistor department to see what I need to order extra to finish them of.
My power supply is almost ready. Just need to solder the trimmers and resistors for the adjustable regulator.

Cheers
 

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#99
Maybe a dumb question Russ, but I'll ask it anyway. Can I safely use the image in post #3 and the components list in post #23 to populate the board. I'm asking this because the printing on the component side is a bit unclear for some of the parts.

Regards
 

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#100
Not a dumb question...

Actually it appears I transposed two resistor values..

R3 1K R-EU_0207/10 0207/10 rcl 1
R4 100K R-EU_0207/10 0207/10 rcl 1

Should be

R3 100K R-EU_0207/10 0207/10 rcl 1
R4 1K R-EU_0207/10 0207/10 rcl 1

Otherwise that part list looks correct.

I will submit the corrected partslist when I get home from work. :xeye:

Thanks for making look at that! 🙂

I will fix the component side silk screen too...

Cheers!
Russ
 
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