Amp Camp Pre+Headphone Amp - ACP+

... I think the rest of the parts could be had for less $100 total, however it's not possible to source everything from one place, so you'll end up paying shipping from several vendors...

This is more or less what I got on the mouser project, and I was able to (at least I think so) source everything but the active devices and the alps pot on mouser.

But it is precisely the multi shipping that kills the deal for those of us that need to deal with import fees. Here, each shipment pays a more or less flat $70 to $80 for any shipment of less than $400 USD or 4Kg in weight.

So, the mouser $100 in parts pays $70. The 4 $50 Jfets and PCBs, another $70. The non-mouser parts, $70 for each thing that ships independently. So very fast this becomes unfeasible.

That’s why store kits are so, so appealing to someone in a similar situation to mine.

That is why, when I ask so many questions about options, and comparisons the usual answer is: “try it, see if it works... build it, try different options”... well, that versatility and playfulness is not as easy for some scenarios as the average US DIYer here.

Was there ever a ACP+ kit besides those in the Burning amp camp? Will there be? My search-fu turned empty on this thread for such info.
 
HD6xx is a great headphone for sure, arguably the best general recommendation for an audiophile headphone around $200. But it's also a 300ohm can. The ACP+ prefers low-impedance loads, (32 ohms is optimal), so I'm not sure HD6xx is the best recommendation here.

peppennino, if you like your Grado SR-60, maybe step up to the SR-225e?

Or possibly look into the Hifiman HE-400i v2020?

Philips Fidelio X2HR is worth considering too if you're a basshead
 
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Audio-Technica ATH-M50x ($145) are my favorite low impedance (38 ohms) headphones at this price point. They are terrific with the Noir headphone amp, haven't plugged them into an ACP+ yet. Discontinued but in stock at B&H Photo, Guitar Center, and many other places.
 
I apologize for the mismatch recommendation regarding impedances of the cans. I failed to add 1 and 1 to cater for that reality.

Actually, I was considering the ACP+ for myself, and my main ones are the HD600, so this may have actually changed my plans 🙁 .

There are lots of great DIY headphone amp deigns that do well with high impedance loads. Kind of getting off-topic for this thread, but head over to the headphone section https://www.diyaudio.com/forums/headphone-systems/ and post a thread that you're looking for a good canamp...include your budget, listening preferences, and favorite headphones and I'm sure there will be lots of good suggestions.
 
Hello Friends!

I was trying to create a project in Mouser to get idea of what is required. The BOM lists all electrolytic capacitors as 25V, but the incredible build guide (as always!) by 6L6 has a picture of a more 'mixed' bag of capacitors:

- 50v 1000uF PS filter caps
- 16v 3300uF C4
- 50v 10uF C1
- 25v 1000uF Audio Grade C3

So, my question is, is 25v only critical on C3? Are these mixed values actually BETTER than having all at 25v, for example?

Thanks for any feedback.

I apologize for the mismatch recommendation regarding impedances of the cans. I failed to add 1 and 1 to cater for that reality.

Actually, I was considering the ACP+ for myself, and my main ones are the HD600, so this may have actually changed my plans 🙁 .

I have HD 650 and sounds fine with the ACP+. You can change the ACP+ Zo if you really want to. I never did on mine.
 
There are lots of great DIY headphone amp deigns that do well with high impedance loads. Kind of getting off-topic for this thread, but head over to the headphone section https://www.diyaudio.com/forums/headphone-systems/ and post a thread that you're looking for a good canamp...include your budget, listening preferences, and favorite headphones and I'm sure there will be lots of good suggestions.

Oh, I have a Whammy that I wouldn’t trade for anything! This was an alternative pre for the sub I have in my main system and headphone amp for the living room (and another fun project with the signature of Papa Nelson).

The first function is still very much valid, but a waste of an incredible pre just for a sub. So I may change my plans a bit, or follow amandarae’s experience and just use it.

Thanks!
 
Hello Rafapolit,


check posts ##322 and following. BenMah gave us the recipe / maths to adjust the ACP+ output-resistors to the demands (resistance) of our headphones. 😉


Greets
Dirk 😀
Great! Thanks! Quick follow up question: the fix mentions R and R16 and only left channel. Are we supposed to replicate another such bridge for R17 with another R for the right channel? Or is this fix needed only in R16? Obviously I don’t know enough electronics to figure this out by myself. Thanks again!
Rafa.
 
Yes, both channels. I was too lazy to show the other channel.

Change R16 and R17 and add "R" to both channels.

I added "R" to the bottom of the board.


799560d1575419777-amp-camp-pre-headphone-amp-acp-82r-signal-gnd-jpg
 
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