BAF 2015 Coverage

[generg]

(Chorus)

You need 30V on the ampside of the cap...... 🙂

 

[Soundhappy]

The +4.7 is what's on the schematic, connected to a 10k. There was no +30 marked on the schematic that I have. Here is what I am working from:

Probably you have ready connected 4N37 optocoupler with missing connection i see on schematic ?
Was pointed by Generg 🙂
I like it very much your diy work and fell it's good time on bench.
Curious about sound

 

[2 picoDumbs]

(Chorus)

You need 30V on the ampside of the cap...... 🙂

https://www.youtube.com/watch?v=76RrdwElnTU

Hehehe

 

[flocchini]

pico is on this

Reminds me of setting up F2J - half the input voltage before the output cap zero after.
As he says adjust for 30V

Does the voltage before the cap drop as you lower bias?

 

[flocchini]

Not to be redundant but is the a connection between pin 1 and pin 5 of opti- coupler?

 

[ci11]

You need 30V. (For extra emphasis)

OK - I get the 30V. I see 28V on the schematic also.

But I am not getting 30V at either side of the 2 0R2's. Even more strange:

1. Varying the bias from +4.7 with the probe at the 0R2 results in NO change - it measures 55.5VDC.

2. Varying the rail from +60 to +30 shows 25.7VDC.

soundhappy, generg.

Please see picture of 4N37. It's upside down, and floats above the terminal block. The schematic was wrong but I connected it correctly, I think!

 

[ci11]

Not to be redundant but is the a connection between pin 1 and pin 5 of opti- coupler?

No. Please see picture from last post. The 4N37 is upside down, with Pins 2 and 4 connected only.

 

[flocchini]

I think NP's schematic from BA2015 shows a connection between 1 and 5 - I'm sorry if I missed a change in that schematic

 

[ci11]

I think NP's schematic from BA2015 shows a connection between 1 and 5 - I'm sorry if I missed a change in that schematic

Generg pointed out the error on NP's schematic. It's on page 14, post #137.

 

[generg]

http://www.diyaudio.com/forums/pass-labs/280950-baf-2015-coverage-14.html#post4492245

🙂

 

[flocchini]

Sorry guys and thanks

Totally missed it

 

[Soundhappy]

4n37 🙂

 

[ci11]

4n37 🙂

Yes, Sir - this is the exact one I used.

Next I am going to retrace all connections and make sure I did not make any stupid mistakes.

 

[Soundhappy]

Thanks Sir Generg we need 4N37 wiring clarifications.
Schematic corrected now all is OK on the righ picture.
Cool

 

[generg]

in the right picture is the fault again, no connection from the collector to the anode of the LED diode is right!

 

[Soundhappy]

in the right picture is the fault again, no connection from the collector to the anode of the LED diode is right!

Thanks again Generg 🙂

 

[Michael Rothacher]

Gerd's corrected pdf should be at audiohobby.com now as well. Let me know if it's not coming through.

🙂

http://www.audiohobby.com/download/baf-slides-nelson-pass/

 

[Soundhappy]

Gerd's corrected pdf should be at audiohobby.com now as well. Let me know if it's not coming through.

🙂

BAF Slides Nelson Pass | Audiohobby.com

It´s coming perfectly dear Uncle 😀
Thanks and best regards

 

[2 picoDumbs]

Yes, Sir - this is the exact one I used.

Next I am going to retrace all connections and make sure I did not make any stupid mistakes.

Very nice to see you build it. Great work.
Be patient, you'll find the problem.

I might check your photos later if you are still not having any luck.

 

[2 picoDumbs]

OK - I get the 30V. I see 28V on the schematic also.

But I am not getting 30V at either side of the 2 0R2's. Even more strange:

1. Varying the bias from +4.7 with the probe at the 0R2 results in NO change - it measures 55.5VDC.

2. Varying the rail from +60 to +30 shows 25.7VDC.

soundhappy, generg.

Please see picture of 4N37. It's upside down, and floats above the terminal block. The schematic was wrong but I connected it correctly, I think!

It's not easy to tell the orientation of the device but Only 4 pins should be electrically connected