Briangt LM3875 kit rev 3 0705 confusion

[ransom peek]

I purchased a basic briangt lm3875 kit last year and am just building it now. But I cant figure out how to build it because it didnt come with documentation and the current documentation on brians site, although for rev3, is different.

These boards (different layout) are marked LM3875 rev 3 with a date code of 0705.



Where can I find instructions, a schematic, and /or a photo of these boards assembled?

FOR THE AMP:

I am guessing that I need to populate R1, R2, and R3, C1, C2, and the LM3875. I have C1, C2, and the LM3785s but dont have an R1 220 ohm resistor. But it does have 1K ohm low wattage resistors - could this be it?

My kit has two 2.9 ohm higher wattage resistors - is this supposed to be for the Rf or Rz slot on the pcb? Is the Rf, Rz, and Cz slot unused?

FOR THE RECTIFIER PCBs:
Kit has the 8 rectifiers.

My kit does not have (2) 4.7 uf 100v Panasonic FC capacitors, but it does have (2) unmarked blue plastic 2 leaded rectangular parts .28 inch x .23 in x .42 in. Kit also has (2) 10uf 50v electr caps.

Since I am buiding 2 rectifier boards, need 2 sets of these parts...

Kit also has 5 high wattage resistors: 6.8k, 4.7k, 3.0k, 1.1k, and 680 ohm. What would these be for?

Should I throw this kit out and buy a new one?

[jleaman]

Originally posted by ransom peek
I purchased a basic briangt lm3875 kit last year and am just building it now. But I cant figure out how to build it because it didnt come with documentation and the current documentation on brians site, although for rev3, is different.

These boards (different layout) are marked LM3875 rev 3 with a date code of 0705.



Where can I find instructions, a schematic, and /or a photo of these boards assembled?

FOR THE AMP:

I am guessing that I need to populate R1, R2, and R3, C1, C2, and the LM3875. I have C1, C2, and the LM3785s but dont have an R1 220 ohm resistor. But it does have 1K ohm low wattage resistors - could this be it?

My kit has two 2.9 ohm higher wattage resistors - is this supposed to be for the Rf or Rz slot on the pcb? Is the Rf, Rz, and Cz slot unused?

FOR THE RECTIFIER PCBs:
Kit has the 8 rectifiers.

My kit does not have (2) 4.7 uf 100v Panasonic FC capacitors, but it does have (2) unmarked blue plastic 2 leaded rectangular parts .28 inch x .23 in x .42 in. Kit also has (2) 10uf 50v electr caps.

Since I am buiding 2 rectifier boards, need 2 sets of these parts...

Kit also has 5 high wattage resistors: 6.8k, 4.7k, 3.0k, 1.1k, and 680 ohm. What would these be for?

Should I throw this kit out and buy a new one?

No need to throw out your kit. I have just message briangt for you to show him this thread so he can help you. Have you tried to email him ?

[edjosh23]

Originally posted by ransom peek
These boards (different layout) are marked LM3875 rev 3 with a date code of 0705.



Where can I find instructions, a schematic, and /or a photo of these boards assembled?

I have taken a couple of pictures for you of my old boards. Everything should be the same as from his websites. You can also check out pictures from the photo gallery. From my understanding this should be the information you need.

Originally posted by ransom peek
FOR THE AMP:

I am guessing that I need to populate R1, R2, and R3, C1, C2, and the LM3875. I have C1, C2, and the LM3785s but dont have an R1 220 ohm resistor. But it does have 1K ohm low wattage resistors - could this be it?

My kit has two 2.9 ohm higher wattage resistors - is this supposed to be for the Rf or Rz slot on the pcb? Is the Rf, Rz, and Cz slot unused?

From the pdf you see that R1 is infact a 1kohm .5w resistor.

The Zobel network does not have to be used, some people decide not to use it. Your welcome to test out the differeneces and find what you like best. But for the zobel there is supposed to be a 2.7ohm 2w resistor. Brian may have found that he prefered a 2.9ohm resistor more.

Originally posted by ransom peek
FOR THE RECTIFIER PCBs:
Kit has the 8 rectifiers.

My kit does not have (2) 4.7 uf 100v Panasonic FC capacitors, but it does have (2) unmarked blue plastic 2 leaded rectangular parts .28 inch x .23 in x .42 in. Kit also has (2) 10uf 50v electr caps.

Since I am buiding 2 rectifier boards, need 2 sets of these parts...

Kit also has 5 high wattage resistors: 6.8k, 4.7k, 3.0k, 1.1k, and 680 ohm. What would these be for?

Should I throw this kit out and buy a new one?

First off, don't throw away the kit. I measured the caps, the blue recatangles are caps, for my kits they are used in the zobel. On one of the sides of the cap that is .28"x.42" it says the cap value. It is written on there, but very hard to see, and quite small. It should be 100nf. In my picture you can actually read the cap if you zoom in.

The resistors, I'm a bit confused. about as well.

Hope this helps.

Josh

[BrianGT]

Originally posted by ransom peek
I am guessing that I need to populate R1, R2, and R3, C1, C2, and the LM3875. I have C1, C2, and the LM3785s but dont have an R1 220 ohm resistor. But it does have 1K ohm low wattage resistors - could this be it?

My kit has two 2.9 ohm higher wattage resistors - is this supposed to be for the Rf or Rz slot on the pcb? Is the Rf, Rz, and Cz slot unused?

FOR THE RECTIFIER PCBs:
Kit has the 8 rectifiers.

My kit does not have (2) 4.7 uf 100v Panasonic FC capacitors, but it does have (2) unmarked blue plastic 2 leaded rectangular parts .28 inch x .23 in x .42 in. Kit also has (2) 10uf 50v electr caps.

Since I am buiding 2 rectifier boards, need 2 sets of these parts...

Kit also has 5 high wattage resistors: 6.8k, 4.7k, 3.0k, 1.1k, and 680 ohm. What would these be for?

Should I throw this kit out and buy a new one?

Sorry for the confusion. The 220 ohm resistors were replaced with 1k ohm resistors for the rev3 kit. The 2.7ohm and 0.1uf components are for the optional zobel network, with is shown as Rz and Cz on the pcb.

For the power supply board, the 4.7uF capacitors were replaced with 10uF capacitors.

Let me know if there is any more confusion.

--
Brian

[ransom peek]

Yes the cap says 100n GR very small faded print.

The picture on your link is the correct parts list! Your boards unfortunately are different, but helpful to see the blue 100nf cap.

Now, how about a schematic for this puppy!

Thank you so much for your help so far, the pieces are coming together...

I havent emailed Brian, but thank you for sending him a note. Maybe he will help....