and now for something completely different part 3

[skullguise]

I have one of the Pecan Pi Streamers, I actually just got a new case for it where all connectors are on the back and literally this afternoon just re-cased it.  I've had it since last July, so it's not the latest rev of the board.  Not sure if/how much the new boards improve on sound.  I know one new feature is a jumper to override the volume control.  But I set eh control at max, and use DSP through Roon to control volume.

I'm a pretty big fan of the price/performance on this, it's a great streamer (can take Pi 3/3b or 4 boards, but current case is for 3/3b).  The DAC is really quite good as well, and while the unit was bettered by the Lumin T2 I got, that lists for 9x the price of the basic streamer!  Going DIY to build saves even more....

[starcat]

Yes, exactly. I think the 3B would still be best pair for it and this is what Leo recommends as well. Which one have you running? Connection to the DAC is via I2S, so no USB involved at all and then just a single unit for ETH in and XLR out, perfect match for all the head amps with a volume pot. And the roon control is just amazing. I switched to roon a year ago after being an early adopter of LMS for some 15 years or so, and it is so much fun exploring music and being able to virtualize all (remote and local) sources into a single library. 

I expect the GRLV to further improve the sound. Pecan itself draws 0.5A, paired with Pi3B about 1A, sized with 1.5A for more processing load on the Pi.

I think I'll mount the board inside the case via a Neutrik NE8FDP-B so that it is not tied to a specific Pi version due to the cutout on the back.

Edited June 15, 2021 by starcat

[skullguise]

Mine has the 3b Pi board, too.  Great idea for the Ethernet mounting, many don't need/use the USB ports either.

Leo just told me that the latest DAC board has a jumper to disable the volume control, and terminal blocks for the output in addition to the built-in XLR's; so even the DAC can be mounted internally and you can put outputs where desired (though I remember someone in the Orchard Audio group soldered connections direct from the older rev board to external XLR's as well).

Edited June 15, 2021 by skullguise

[starcat]

14 minutes ago, skullguise said:

Mine has the 3b Pi board, too.  Great idea for the Ethernet mounting, many don't need/use the USB ports either.

Yeah, no need for the USB at all, however there is a pass through Neutrik NAUSB3-B for USB3 as well. Eager to hear it soon. Will then custom made the case. 

15 minutes ago, skullguise said:

Leo just told me that the latest DAC board has a jumper to disable the volume control, and terminal blocks for the output in addition to the built-in XLR's; so even the DAC can be mounted internally and you can put outputs where desired (though I remember someone in the Orchard Audio group soldered connections direct from the older rev board to external XLR's as well).

I will put the DAC board to the back panel directly flush mounting the XLRs to keep signal path short and use the terminal blocks for the chinch connectors (to have them just in case). Yes, one can solder directly to the XLR jacks. Using a ribbon cable between the Pi and the Pecan.

[johnwmclean]

Anybody tried the HE6 with a CFA?

[starcat]

Hey John,

I have the HE-6 but not yet 🙂 the CFA (it is on my build list however).

I am ising the HE-6 with RSA The Dark Star atm and it is just magnificent. Compared it to the HD-800 as well but clearly prefer the HE-6 and traded the HD-800.

Edited June 29, 2021 by starcat

[GGW]

On 5/7/2021 at 1:35 PM, starcat said:

Just go 2x CFA3 boards and 2x GRLV (on one or even two transformers). For the amp you do not need to separate the + and - per channel, so 2x CFA3 boards is more than good to go. No need to put the CFA3 boards in separate cases, if you want to separate the L and R channels, put an aluminium divider in the mid of the amp case and use per channel umbilical on the back (off separate GRLVs and transformers in the PSU case), so basically going strict dual mono in two chassis in total. That's already more than overkill. 

You can have the headphone protector as well (for dynamic headphones, stats don't need that) and eventually the ZF/SS selector (which I didn't do). 

Thanks, @starcat - very helpful. 
 

Do you know where I can find the Gerbers for the ZF/SS selector and the headphone protector?

[GGW]

Hi guys,

 

Is the "protect3.zip" the headphone protector gerber that is used in some of the CFA3's posted here?

 

Does anyone have any leads on where I can find out more (Gerbers, BOMs, reading material) on the ZF / SS selector?

 

Thanks!

[johnwmclean]

^ I have protector boards, pm me if interested

[starcat]

On 3/12/2021 at 8:19 PM, kevin gilmore said:

the 47uf caps have to be populated. the 600pf caps are optional, paradoxper decided not to populate them

What are the specs for the 600pF caps, ceramic for how many volts?

And as they are optional, should one start with or without them? 

Edited August 5, 2021 by starcat

[starcat]

For the 4.7uF cap, would you use the WIMA 4.7uF/63V or the Murata MLCC 4.7uF/50V?

[Pars]

Most use the Wima

[starcat]

This 10000uF 63V electrolytic will be pretty overkill but just fits into the GRLV. 

[starcat]

Looking through my stock I only have BC546C, shouldn't be a problem using them with BC556B, or am I better waiting for the BC546B to arrive? 

Using in the lates CFP3 boards.

[audiostar]

I don't see many implementing the SS/ZF switching, I think beside one amp or so -- do most of you prefer and set it fixed to one of the modes and if so, which is it?

Cheers guys.

[Pars]

This was only on the one which I repaired for tkam, but I couldn't really tell much difference between them. I think tkam liked the zf better.

[audiostar]

Hi all, anyone have a p/n for the 600pF cap optionally used in the CFA3? The closest I can found is a 620pF MLCC Kemet, but no 600pF... 

[bbest]

On 6/29/2021 at 4:50 PM, starcat said:

Hey John,

I have the HE-6 but not yet 🙂 the CFA (it is on my build list however).

I am ising the HE-6 with RSA The Dark Star atm and it is just magnificent. Compared it to the HD-800 as well but clearly prefer the HE-6 and traded the HD-800.

I am using modified HE-6 with balanced beta22. Sounds also great.

[dill3000]

Hi Guys,

Can someone please point me in the right direction for me to getting hold of all I need to build a CFA  - is the CFA3 the all in one balanced version by the way?  Is the usual plan for guys to make up their own boards with the Gerber files? I have seen version 1.2 on the thread. I would need the PSU section also, is this the GRLV? I would like to build a dual mono version.  I'm excited, the amp builds on this thread looks great! This will be my first ever KG amp build, I have built various Pass amps on diyAudio etc. 

Thanks a lot Dill

[kevin gilmore]

bc546/bc556 starting to get very hard to get even though onsemi says they are going to make more, so this which needs massive amounts of checking.

 

[audiostar]

Kevin, this looks beautiful! 
What are the dimensions of that PCB, still the same?

[kevin gilmore]

that one is identical sized.

[audiostar]

I see you have switched here to 50k feedback resistors and 4.2k ZF-resistors. 
The 20pF cap alongside the feedback resistor you left. 

Like the new name much more as well, Current Mirror Amplifier!

[mdr30]

On 10/26/2021 at 10:23 PM, kevin gilmore said:

bc546/bc556 starting to get very hard to get even though onsemi says they are going to make more, so this which needs massive amounts of checking.

 

Anyone order the boards? I'd be interested in a pair.

[Pars]

Kevin,

A couple of questions. I have a pair of thru-hole boards which I am planning on building.

1. The BC546/556: Is the C variant still preferred, or is B acceptable?
2. Should any resistor value, etc. changes present on the new PZTA board be used in place of what is shown on the thru-hole boards?

Also, I'm noting a bunch of new vendors in the TO92 space since on-semi and I presume nxp are discontinuing much of this. Taiwan Semiconductor, Central Semi, Diotec, Micro Comm. Components (MCC), etc. Are these all equivalent, or would one prefer to use on-semi if available?