Well, I asked if one can use the store PCB and what needs to be changed there.
There are quite a few components in the original schematic that are not in the one you provide above.
Plus there a few extra components that are not on the original PCB and according to your schematic have to be accommodated somehow.
Maybe you can post a photo of your PCB.
I'm talking about practical stuff, not just theory.
There are quite a few components in the original schematic that are not in the one you provide above.
Plus there a few extra components that are not on the original PCB and according to your schematic have to be accommodated somehow.
Maybe you can post a photo of your PCB.
I'm talking about practical stuff, not just theory.
Go ahead and lay out your own PCB so you can include all the variants and options that you think are worthwhile. www.pcbshopper.com will give you price quotes for manufacturing your board(s) at dozens of different PCB fabs.
I build most of my projects on Vero board - ACA, MoFo, Zen Lite HPA, Pearl I RIAA and so on. Find it a more stimulating mental challenge than learning how to lay traces, vias and pads.
For the others, like M2X, DIY2022FE, ACA Mini I bought the ready made PCBs from the store.
I think Tungsten some time ago posted a vero board layout for ACP+, including one for M2X. Will have to dig through this thread and see if I can find it.
For the others, like M2X, DIY2022FE, ACA Mini I bought the ready made PCBs from the store.
I think Tungsten some time ago posted a vero board layout for ACP+, including one for M2X. Will have to dig through this thread and see if I can find it.
Is anyone able to explain why the additional ground plane board is needed? I'd also like to know the optimal method for using it when casing up the ACP+.
I'm going to put this pre in a metallic box, my thinking was to isolate the amp entirely from the enclosure and have a single connection of the case to safety earth, and possibly to the ACP ground with a small cap / resistor.
Regards the ground plane, the ACP board already has a conductive plane on the top and bottom surface, should these be connected together at all 4 corners with metallic fittings/ toothed washers?
Should the additional ground plane board be used at all? Are 4 grounding planes really the design intent? I'm assuming that this additional board fits on the underside of the main board, or should it be used above?
All seems a bit strange to me.
I'm going to put this pre in a metallic box, my thinking was to isolate the amp entirely from the enclosure and have a single connection of the case to safety earth, and possibly to the ACP ground with a small cap / resistor.
Regards the ground plane, the ACP board already has a conductive plane on the top and bottom surface, should these be connected together at all 4 corners with metallic fittings/ toothed washers?
Should the additional ground plane board be used at all? Are 4 grounding planes really the design intent? I'm assuming that this additional board fits on the underside of the main board, or should it be used above?
All seems a bit strange to me.
Last edited:
@Dan K: "The kit comes with a base plate made up of a circuit board with a ground shield, making for operation without a chassis. It is mounted as a parallel surface below the main board with the 6-32 screws, nuts and spacers provided."
From page 9 of Nelson's original description of this project. You can find it on the First Watt website, under 2019 ACP+.
From page 9 of Nelson's original description of this project. You can find it on the First Watt website, under 2019 ACP+.
To the group,
I come after completing the Mini kit a week back and it seems to work.
But, I have a possible parts snafu in my pre-amp kit I just received,,,
I have scanned the forums, but come up empty. And of course I could just be mistaken and confused.
the BOM indicates that C3 is "gold Nichicon" but my kit has the gold at 10micro farad and C1 at 1000micro farad.
Any help you can provide to make sure I do this correctly would be greatly appreciated. Looks like C1 and C3 are backwards? The other capacitors look like they are ready to be placed. But holding off until I am a little more sure
If this is not the proper place, please forward this note to them. Or let me know where to proceed. I have read many years worth of posts.
thanks
dave
I come after completing the Mini kit a week back and it seems to work.
But, I have a possible parts snafu in my pre-amp kit I just received,,,
I have scanned the forums, but come up empty. And of course I could just be mistaken and confused.
the BOM indicates that C3 is "gold Nichicon" but my kit has the gold at 10micro farad and C1 at 1000micro farad.
Any help you can provide to make sure I do this correctly would be greatly appreciated. Looks like C1 and C3 are backwards? The other capacitors look like they are ready to be placed. But holding off until I am a little more sure
If this is not the proper place, please forward this note to them. Or let me know where to proceed. I have read many years worth of posts.
thanks
dave
Always good to ask. It's likely that parts substitutions were made due to inventories to equally good (or better) parts, but they may not look the same.
C1 is the 10mF. C3 is the 1000mF. Don't worry about the color of the packaging.
C1 is the 10mF. C3 is the 1000mF. Don't worry about the color of the packaging.
A big thank you to the group for your help Just finished the final touches and PS checks and all looks good. Headphones are awesome with this, been listening for about an hour and all is well.
thanks again to all.
NExt kit may be a Eurorack synthesizer module or two, perhaps some larger scale surface mount - just to see if I can still do it.
melt solder…
thanks again to all.
NExt kit may be a Eurorack synthesizer module or two, perhaps some larger scale surface mount - just to see if I can still do it.
melt solder…
Last edited by a moderator:
Has anybody compared ACP+ with B1K in one very good system ?
I have one B1K and I would like to build the second line pre. I don't need headphones output, just want the best sound quality and thinking about building another B1K or maybe ACP+ ...
I have one B1K and I would like to build the second line pre. I don't need headphones output, just want the best sound quality and thinking about building another B1K or maybe ACP+ ...
If by best sound quality you mean lower distortion, that would be the ACP+. I have both preamps and prefer the ACP+ over the B1K.
It also has the advantage of not reversing the absolute signal polarity IN to OUT... Oh and no microphonics.
Build it and find out for yourself which one you like best.
It also has the advantage of not reversing the absolute signal polarity IN to OUT... Oh and no microphonics.
Build it and find out for yourself which one you like best.
Having build a number of both including variations with different parts and PSUs, I have to agree. The ACP+ is a very nice and quiet preamp especially if you switch the input coupling cap to something closer to 2uF down from the designed 10 (you'll get a far lower bass low end cut off). I've used mine to drive a variety of commercial and Pass DIY amps, and its currently my workshop's main preamp along with the latest AmpCamp mini. I love the sound of the "tube-y" B1K but dealing with the microphonics is a REAL PITA especially if you are using it with a power amplifier that has any decent amount of front-end gain. Look on the B1K thread to see the lengths to which one must go to avoid that, and even then YMMV. I'd imagine that a good pairing for that reason would be with an F4 which has nearly unity V_gain.
All of the kit parts are run past a number of folks and usually Papa and are acceptable replacements based on the varying sands of the supply chain. We always use top-shelf parts in the Pass kits. If you are curious, look up the data sheet for the part in question at mouser / digikey using the markings on the case or DM me and I can help you figure that out. On that note, one of the banes of my existence in building the ACP+ kit has been that "gold" marking in Papa's article. The fact is that %100 of the caps used in the kit are top-shelf and not only work well but sound great. The "gold" here only is to mean to pay close attention to that specific position and use something very high quality, but it doesn't mean that it must have a fold wrapper, referred to as "gold" by the manufacturer or otherwise. In one of the earlier runs we used EPCOS caps that had a rather ugly orange wrapper. Don't let that fool ya - look at the data sheet for yourself and you'll see they measure out very well. Another supply change had me use a slightly different Panasonic cap that didn't have a fold marker on the sleeve and it measures out as well as their model with the gold sleeve. Don't let a the book's cover fool you. 🙂
Yes. They are two different animals. Nelson describes the B1K as a “cartoon dose of negative phase 2nd harmonic” which is exactly what it does... and in many systems, to many people’s taste, it is exactly what they want and like. B1K is never a device where you have to go listening for the changes, it’s very bold with the “tube sound”.
ACP+ is basically a Firstwatt J2, scaled to headphone size and using mosfets as output device and current source. Can drive most any headphones with ease, style, and grace, and happens to be an excellent line amp.
If I had to choose between the two, I’d unquestionably and happily use ACP+ until I get old old and gray… but sometimes you really want what B1K brings.
It’s nice to have both.
Worth note - the Nichicon gold-wrapped capacitors (UKW, UFG, and UKZ muse) are now officially discontinued, so having a literally gold colored capacitor wil become extremely difficult.
Further compounding this heatshrink color issue is the outstanding Panasonic FM series, which used to have a pretty blue wrapper with a gold stripe, are now boring black.