Amp Camp Pre+Headphone Amp - ACP+

[ernesternest]

Yes, that is the one. I also found out at BAF that Hi-Fi 2000 who supply the enclosures for diyaudioastore accept these files. They ship from Italy.

Thanks for informing about that. I wasn't aware of this as this files usually are for Frontplattendesigner from Schaeffer AG. Good to know!

Have a good Sunday.

 

[toto34]

Good morning, everyone.
To power this preamp (headset and line), what voltage?
Thank you in advance for your answers.

 

[2 picoDumbs]

Anywhere between 19V and 24V should be fine.
I think they are using laptop switching power supplies

 

[toto34]

The Pcbs will be sold by the DIY AUDIO STORE?

 

[6L6]

Yes.

And perhaps a kit of parts as well.

No idea on exact dates, but the ball is rolling.

it’s a fantastic project, you’ll love it!

 

[toto34]

Merci encore 6L6

 

[toto34]

Thanks also 2 picoDumbs

 

[Nisbeth]

Yes. There is also a European company affiliated but I cannot remember the name (begins with an "S"). Would be cheaper to have it shipped from Germany.

https://www.schaeffer-ag.de/en/ - and it's actually the other way around: FPX is the name of Schaeffer's US operation

 

[2 picoDumbs]

Thanks also 2 picoDumbs

This is what is listed in the parts list TRIAD WSU240-0500.
This one is a 24V switching powersupply.

 

[RafaPolit]

This is indeed a fantastic project! Thanks as usual to Mr. Pass for his generosity and genius and to 6L6 for all the support!

As one that has built the Whammy, how does this fare against it?

I know that the best answer is: build one, enjoy, and you will have your answer! Some of you already know that availability of parts where I live is really precarious, so a small question up front helps a lot in decision making.

Thanks for any insight... and again, thanks to this community! Those building this on the burning amp workshop must have had a blast!

Best regards,
Rafa.

 

[2 picoDumbs]

Build it and give either one as a gift.

 

[bajjisw]

This is indeed a fantastic project! Thanks as usual to Mr. Pass for his generosity and genius and to 6L6 for all the support!

As one that has built the Whammy, how does this fare against it?

I know that the best answer is: build one, enjoy, and you will have your answer! Some of you already know that availability of parts where I live is really precarious, so a small question up front helps a lot in decision making.

Thanks for any insight... and again, thanks to this community! Those building this on the burning amp workshop must have had a blast!

Best regards,
Rafa.

After spending time with both as a headphone amp, I like them both. They sound different to me. I have opa2134 in whammy. I was looking to modify whammy to add preamp. I'll use acp+ for that instead.

 

[Dennis Hui]

I haven't tried the ACP+ as a preamp. Recently I listened to it through an old pair
of AKG701 headphones and the source was an old (mid 90's) portable cd player with
fixed out. The music was a few Blue Coast Records sampler tracks.

The ACP+ literally jumped out and grabbed me. Very engaging and enjoyable.

 

[toto34]

In order to achieve the ACP+ at best , the two 2SJ 74 which Idss?
Thank you in advance.

 

[Nelson Pass]

They run at about 4.5 mA, depending on the Vgs of the IRF610, so 6+ mA will be
fine. High Idss might require some adjustment of the 1K Drain resistance. to put
the output DC test voltage at midpoint of supply and ground.

 

[toto34]

Thank you Mr Pass for your clear explanations

 

[aspringv]

I've some 2sk214 here that I thought might be appropriate to use here. That said their Vgs(on) is a lot lower than the irf610.
I would imagine the solutions are either to reduce the value of R15, and/or the current running through the LTP. But! The bias of the out put stage is being controlled by the optocoupler, so I'm unsure if any of what I've described is even relevant.
Could anyone let me know what I'm missing?

 

[EUVL]

Both Vgs and Yfs too low, wrong pin assignment.


Patrick

 

[aspringv]

Roger that! Cheers for the answer.

 

[Nisbeth]

They run at about 4.5 mA, depending on the Vgs of the IRF610, so 6+ mA will be
fine. High Idss might require some adjustment of the 1K Drain resistance. to put
the output DC test voltage at midpoint of supply and ground.

Wouldn't it make sense to make this adjustable (trimpot)? The same would apply to R4 to make the CCS-current adjustable (as some people discussed a few pages back?