Amp Camp Pre+Headphone Amp - ACP+

[Nelson Pass]

I am starting the ACP+ build thread.

I have posted the documentation for the ACP+ preamp/headphone amp
which is the subject of the DIY build session on Saturday Nov 9 at the
Burning Amp Festival.

FIRST WATT

I have assembled a total of 55 kits for the occasion, of which I
understand 30 will be built on site and the rest distributed in some
fashion.

Our member 6L6 has been working on his build guide as well.

As with the ACA, I anticipate it being available in the store soon.

 

[dewdrop]

Papa, love another project from you!

Unfortunately, I am based in Singapore and can't make a trip to BAF 2019 due to the distance. I tell myself i will make the trip some day. ;-)

If the kits are ever available to the greedy boys in the Far East before the store, let me know.

Ed
P.S.: did you sign off the year as 29 on purpose?

 

[Dennis Hui]

Obviously, it's a design from the future.

 

[gl]

Nelson,

On the schematic the input connects straight to ground through a 1k resistor. The layout seems to tell the real story.

Graeme

 

[Nelson Pass]

Thanks, I'm looking forward to all the corrections.

 

[Vix]

Nice

Fulfills three audiophile wishes:

1.Has the right amount of H2 (so, no need for H2 generator)
2. It is a hi-end headphone amp
3. And, can also serve as 1 Watt amp

 

[Zen Mod]

 

[Nelson Pass]

OK, I fixed the schematic and the reversal of the name.....

Moderators, could you please change the thread name to ACP+ ?

 

[2 picoDumbs]

Noooooooo
I was in San Francisco a week ago.

I want one now.

Please please please please please

 

[hirscwi]

I had hoped to be able to make this my first BAF but alas, someone else in our household had other ideas...

I am in the market for a new headphone amp so I'll look forward to availability of this one. It appears to be superb from the write-up.

Thank you, Mr. Pass, for another of your fine creations and generous donation to this community!

 

[PKI]

Thank you so much Nelson, this looks amazing!

Will boards be available for those of us who can’t make it to the event?

 

[wg45]

Thank you, Papa! I appreciate your generosity to our community.

I’m looking forward to the build and paring the preamp with my two ACA’s.

 

[PRR]

Input impedance for each channel is about 20 Kohms.

Looks like 76k to me.

Have I slipped a cog? (Again?)

In solid-state work this does not matter. But there are some tube and passive sources which may strain mildly in 20k and be fine for >47k.

OTOH: why not R2 R3 = 1Meg? The JFET won't care. Rin now 500k. Then a 0.1uFd film-cap for C1 to reduce kneejerk reaction to an electrolytic (not that I care about an ample e-cap). I suppose price is a goal?

 

[carsten.witt]

@NP,

Thumbs up, nice project.

 

[Zen Mod]

Looks like 76k to me.

Have I slipped a cog? (Again?)

In solid-state work this does not matter. But there are some tube and passive sources which may strain mildly in 20k and be fine for >47k.

OTOH: why not R2 R3 = 1Meg? The JFET won't care. Rin now 500k. Then a 0.1uFd film-cap for C1 to reduce kneejerk reaction to an electrolytic (not that I care about an ample e-cap). I suppose price is a goal?

ALPS

 

[dBel84]

To all who are going to BA, have enough fun for all of us not able to make it.

 

[El Reino]

Thank you Mr.Pass

 

[indra1]

... Please please please please please

Be very much alert on the "distributed in some fashion" part.

 

[6L6]

Photos of the not-quite-final BAF'19 Workshop PCB, but close enough that it's fine for illustration.

 

[MEPER]

Looks good. Think I will try it when available in the DiyStore.
Is a dedicated chassis also made for it?