A buffer like the B1 will help with impedance issues. Some amps want to see a low output impedance from the source yet some aren't all that critical. I've no idea what the input impedance of the amp camp mini is but that would likely give you a good idea if the buffer would help.
I can say that the amp camp preamp and the amp camp mini are a very nice combo. Very fine sounding.
I can say that the amp camp preamp and the amp camp mini are a very nice combo. Very fine sounding.
Rin of ACA mini is R2//R3, so 110K
ref to schm given in post #1
no impedance issues there, anything will work as source
ref to schm given in post #1
no impedance issues there, anything will work as source
I've been using my ACA mini with a B1. It sounds very good. I haven't tried it with a non-impedance buffering passive preamp though.
Built a micro (ACAmicro? 😎) version of the ACAmini with 10cm x 10cm PCB. Since my target is smaller form factor with lower Output Power for my small study room (need smaller output power), I use smaller heat sinks and PS and output capacitors (4700 audio grade with lower ESRs). VB is set to 0.25A and temperature on heat sinks are acceptable. Moreover, 2N5458/2N5461 are used to replaced 2SK170/2SJ74. The result is great and love it. Thanks PaPa for this simple and great amplifier.
Looks great! What V+ did you use? Those also look like diifferent baords than I have seen. Is that your layout? Thanks!
Thanks and wall mart DC 24V 2A is used. I layout (but do reference heavily with original board component placement) the board to sink the board size and components are so closed. VB test points are also removed.
Due to a severe case of impatience, and in an attempt to be energetic, resourceful and highly motivated, I have now spent enough late nights learning KiCad to annoy the wife, but I've actually managed to make another near-clone of the MiniACA.
Changes to the original are minor, the board is square, a different color, and I use a different standby switch.
I've built 2 so far. 1 with Harris outputs and Nichicon caps, 1 with Vishay outputs and Epcos caps, and they both sound absolutely amazing.
If you have to pay fifty billion dollars in import-tax for the Harris-parts like I did, just go with the Vishay's instead. They're absolutely fine.
Biggest difference (to me) is the effect of the jumper, which seem to have a bigger impact on the character with the Harris-parts, than it does with the Vishay's.
I understand this can be changed using a different value for R11, I just haven't played with it yet, as I am way too busy listening to my music.
Thank you Papa, for another piece of art, and for many hours of happy listening to come. Jumper ON!
I've previously built the Lottery VFet and the ACA (with premium parts), but so far.. this has got to be my favourite! I absolutely love it!
And this presents an issue to my curiosity. Why this one!? Is it the choice of components, the 'topology', the higher damping factor, or is it actually the negative phase harmonics that plays tricks with my mind?
I'm sorry, but I just have to ask a couple of probably very noob questions:
1: Wanting to compare apples to apples, is it possible to alter the Mini ACA to have positive phase harmonics, or would this require a completely different topology/amp?
If not possible...
2: With ref. to the original BA3FE schematic, would it be possible to modify the BA3FE, lower the voltage to +- 12V, replace Q3/Q4 with IRF520/9520, replace R10/11 with 0,75 ohm, remove R12/13, and have it churm out 2x5W @ 8 ohm with the ability to adjust the phase of the harmonics?
I know I could just build a preamp based on the BA3FE and play around with that, but TBH I really enjoy these little baby-power amps and I am truly amazed by their performance.
Changes to the original are minor, the board is square, a different color, and I use a different standby switch.
I've built 2 so far. 1 with Harris outputs and Nichicon caps, 1 with Vishay outputs and Epcos caps, and they both sound absolutely amazing.
If you have to pay fifty billion dollars in import-tax for the Harris-parts like I did, just go with the Vishay's instead. They're absolutely fine.
Biggest difference (to me) is the effect of the jumper, which seem to have a bigger impact on the character with the Harris-parts, than it does with the Vishay's.
I understand this can be changed using a different value for R11, I just haven't played with it yet, as I am way too busy listening to my music.
Thank you Papa, for another piece of art, and for many hours of happy listening to come. Jumper ON!
I've previously built the Lottery VFet and the ACA (with premium parts), but so far.. this has got to be my favourite! I absolutely love it!
And this presents an issue to my curiosity. Why this one!? Is it the choice of components, the 'topology', the higher damping factor, or is it actually the negative phase harmonics that plays tricks with my mind?
I'm sorry, but I just have to ask a couple of probably very noob questions:
1: Wanting to compare apples to apples, is it possible to alter the Mini ACA to have positive phase harmonics, or would this require a completely different topology/amp?
If not possible...
2: With ref. to the original BA3FE schematic, would it be possible to modify the BA3FE, lower the voltage to +- 12V, replace Q3/Q4 with IRF520/9520, replace R10/11 with 0,75 ohm, remove R12/13, and have it churm out 2x5W @ 8 ohm with the ability to adjust the phase of the harmonics?
I know I could just build a preamp based on the BA3FE and play around with that, but TBH I really enjoy these little baby-power amps and I am truly amazed by their performance.
Attachments
Interesting fidings... what loudspeakers are you using when comparing these fab amps?
Happy Easter
Claude
Happy Easter
Claude
I like to get my hands on a ACA mini pcb and semis kit. I’m looking forward to news from DIY Store.Assuming that store management wants it, I will supply the boards and matched semis as a kit.
Estimated cost through the store would be about $30. I think it could be available next month.
We have someone standing by to create the optional "completion kit", although everyone is free
to buy the parts on their own or through group buys.
aha ......... as Casey said to (my fave Kido) Vale - "your ambition out-weighted your talent"
your first mistake (shown to us) is - buying those speakers
now, feel free to buy at least PL XA60.8, if you want any music squeezed from them
hm, that is giving me an idea to name my next amp "Tesla"
though, modest as I am, I'm certain that amp will more deserve it's name than their call to Maestro Stradivari
your first mistake (shown to us) is - buying those speakers
now, feel free to buy at least PL XA60.8, if you want any music squeezed from them
hm, that is giving me an idea to name my next amp "Tesla"
though, modest as I am, I'm certain that amp will more deserve it's name than their call to Maestro Stradivari
Thanks... I have only the VFET and not (yet) the ACA Mini, just wondering why you prefer the latter.
Perhaps one reason you prefer the small amp is indeed related to DF. Your speakers are quite demanding below 200Hz re complex impedance... is your benefit with ACA mini related mainly to drive / bass response and possibly soundstage depth, and not really in other areas?
Just thinking out loud
Claude
Perhaps one reason you prefer the small amp is indeed related to DF. Your speakers are quite demanding below 200Hz re complex impedance... is your benefit with ACA mini related mainly to drive / bass response and possibly soundstage depth, and not really in other areas?
Just thinking out loud
Claude
@zm: I suspect Casey was describing one of his own crashes to Vale!? 😝
I have seen every single one of his races since he started with Aprilia in 125cc. I kinda hoped he would have taken his 10'th title with Aprilia. Would have been the perfect finish! 🤯
I totally agree with regards to power and the Cremonas, (they do come to life with a pair of SA/2's), but that just makes this little one even more impressive. 🧐
@ClaudeG: It clearly has better control of the bottom-end, but there is just so much more detail everywhere, and more space around the instruments, than I have ever heard before. 😳
I am curious to find out if this is due to the negative phase harmonics, or simply because this is an insanely good amp. 🥸
I have seen every single one of his races since he started with Aprilia in 125cc. I kinda hoped he would have taken his 10'th title with Aprilia. Would have been the perfect finish! 🤯
I totally agree with regards to power and the Cremonas, (they do come to life with a pair of SA/2's), but that just makes this little one even more impressive. 🧐
@ClaudeG: It clearly has better control of the bottom-end, but there is just so much more detail everywhere, and more space around the instruments, than I have ever heard before. 😳
I am curious to find out if this is due to the negative phase harmonics, or simply because this is an insanely good amp. 🥸