Gb: F5 Pcb

[jwor]

Thanks.

 

[ENSen]

Hi ndtran and BadassBob, you can order F5 boards on diyAudio's store. If you also need psu boards, you can get those on my site: GB order page for cviller , but I am not very fast in terms of shipping speed.

I can not get the link to the order page to work.

 

[blue lander]

Is the BOM for the psu posted anywhere? The old links don't seem to work. Basically I just need to know if all the resistors are .47 ohm

 

[labjr]

Is the BOM for the psu posted anywhere? The old links don't seem to work. Basically I just need to know if all the resistors are .47 ohm

8 x .47
2 x 2.2k
all 3w Panasonic

 

[Fcrawley]

count me in for 4 boards

Thanks,
Fred

 

[cviller]

As you probably guessed, I had a server breakdown, so all the stuff I had in the audio and gb sites is gone. I have not had time to see if I have an acceptable backup yet, but can probably find most of it scattered around in different places...

 

[cviller]

I have made a new order-site for the remaining PSU and rectifier boards, if anyone is interested. The new url is here: cviller order site

And for the psu bom, I found it here:
http://www.diyaudio.com/forums/group-buys/134554-gb-f5-pcb-11.html#post1683288

 

[cviller]

Before organising a new batch of F5 v2 boards, I would like to hear if someone would share some listening and building impressions of using the cascoded and dual mosfet options?

I would like to know if there are things I should change before the next batch.

 

[bobodioulasso]

Your board is great, easy to use, i would'nt change anything.

Or, may be the cascoding scheme, as per Nelson, using 3 resistors and one cap, no reference to ground.
Works perfect as it is, though.

 

[Sergelisses]

Hello

Look at the image .i have added capacitors for the power supply +24,-24v

I don't know if it's necessary 😱😱 it's a suggestion

Serge

 

[cviller]

Hi Serge,

I know it is tempting to add decoupling, but Nelson Pass actually tells us not to do it. If you do it, the amp will be more at risk of oscillating.

 

[Sergelisses]

Nelson Pass actually tells us not to do it

I have the good answer

Thanks
Serge

 

[h_a]

I know it is tempting to add decoupling, but Nelson Pass actually tells us not to do it. If you do it, the amp will be more at risk of oscillating.

Do you have by chance any link to that?

As these do not directly affect stability margin I would be curious for the reasons.

Hannes

 

[cviller]

He has mentioned it many time in the f5 monster thread, but here is an example:
http://www.diyaudio.com/forums/pass-labs/121228-f5-power-amplifier-447.html#post1876930

I believe the problem is that you will create an LC oscillator by the supply interacting with the signal gnd on the amp board.

 

[h_a]

Thanks for the link, interesting, might be due to the current feedback design (huge bandwidth) and/or board layout.

Hannes

 

[Nikon1975]

Is a new batch of V2 coming ? I did a stereo F5 using V1, and I want to do another one to have balanced monoblocks. If you are doing a new batch of the V2, I am going to wait to get the boards for the second one.

Thanks,

Davide

 

[cviller]

The next batch will be in the diyAudio store (DiyAudio PCB Bank) - but it normally takes quite a while for boards to be ordered and produced. I think the boards will be ready late spring.

 

[viki_v2]

Guys i need pcb files of f5 for etching , Please help

 

[Nikon1975]

Thinking about changes, there are things that could be useful, although they can be accommodate in other ways, like:

1) Extra pads to parallel a second resistor to the mosfet source resistors (R11 R12)
2) pads to add the extra resistor for EUVL degeneration trick
3) pads to allow the connection of two boards together for balanced
4) pads to parallel a second resistor to R1 R2

I understand it's not a big deal to do all the optimization with the actual design, and if it's complicated just forget it, but I think they would make a very versatile board, potentially capable of the monster F5 parallel+balanced.

D.

 

[lhquam]

While you are adding pads, consider pads for a 6 pin header for bias adjustment connections to a ribbon cable.

I learned the hard way, that it is possible to accidentally short something and smoke an amplifier while making probe connections during bias adjustments. To prevent this in the future, I directly soldered 6 wires of a CAT5 cable to my cviller boards, using 1k resistors in series with the connections to prevent possible problems. The cables connect to a 2 pole x 6 position rotary switch. The 2 outputs of the switch connect to a multimeter for adjusting bias. The CAT5 pairs connect to each end of R11, R12, and output/gnd. Everything other than gnd was isolated with a 1k resistor. I will post pictures if you like.