I noticed that, too. I was listening and reading at the same time and it kept getting better and better as time went by-- a couple of hours or more. It's quite an amazing little amp that drives horns with a 12" woofer effortlessly and sounds great.
Hi, @getgoin.
Thanks for the update. I am pleased to hear that another recent builder of the DIY ACA Mini amp likes the sound. It seems to work very well with larger, ported speakers. My guess is that the woofers aren't as hard to drive as in bookshelf speakers, especially sealed ones.
Enjoy your new amp!
Thanks for the update. I am pleased to hear that another recent builder of the DIY ACA Mini amp likes the sound. It seems to work very well with larger, ported speakers. My guess is that the woofers aren't as hard to drive as in bookshelf speakers, especially sealed ones.
Enjoy your new amp!
My ACA Mini, which I won in a raffle at this years Burning Amp Festival, does not have C6/R11/J1 or places for them. I would like to try these additional parts with mine. But before I send an order to Mouser for $1.20 for the 3.3F caps, I was wondering how low on C6 I can go. My ACA is used after a 6-24 crossover set at 1200hz. The ACA is used for the high frequencies. So if the lowest frequency of interest is 1200 hz, could I use a smaller cap for C6?
My ACA mini has 22k for R4. Works great!
Ref post #2273.
Ref post #2273.
That is the value listed on the BOM, but looking at he schematic....thanks for the reply! Not that I'll understand 😉 but perhaps someone can educate me as to why this value is being used vs. the schematic showing 6.8?
The value is not critical as when the amplifier is up to operating voltage, the current through the resistor is miniscule. The main purposes of the resistor is to provide power supply filtering in conjunction with the capacitors before and after the resistor, and also to slow the charging of the last capacitor for slow turn-on and thump avoidance. In both cases the larger resistance is advantageous.
The increase to 22k was because some desktop supplies needed more delay on turn on to avoid triggering their fault protection. It was not otherwise a performance issue.
Newbie here... hi all 👋
I have 115db super efficient concentric horns in a tri-amp electronic XO(Sublime audio) system.
Bass section and mid-horn is already sorted mating superbly to a 100W Rogue tube amp(bass) and modified ACA amp or Crayon amplifier(mids).
My main objective now is to find a quality low watt amplifier to drive the tweeters 6300Hz>
Currently using a Marantz PM7001KI integrated where power/gain/input impedance is obviously too great for my situation but still plays quite nice highs.
Initial logical choice for me seems to be ACA-mini... i think..... or.....??
I have read multiple times people stating ACA-mini resembles F5 in design and sound.... albeit much less powerful..... i only need 1 good watt or so.
It is mentioned that F5 plays very nice high frequencies - transparent extended airy refined delicate - nice shimmer on cymbals etc - especially with quality upstream equipment(less edgy) - which i have.
(have good hearing and a lover of percussion and female vocal so beautiful transparent highs is paramount)
Just looking for some opinions..... or if anyone has had some experience with ACA-mini driving tweeters.... or if they have found something that sounds better on tweeters.... ??
One point of reference i have is that i find the original ACA much better suited to my midrange section(very nice in fact) over the tweeter section where i find it too dull/lifeless etc. I also owned a nice PASS XA30.5 in the past(different speakers) with similar findings - i found the highs better - but just too soft.
If ACA-mini was somehow able to give me similar highs to XA30.5 but just more of it - and with more sparkle - that could be close to perfect!
Cost does not matter too much as long as it is not impractical of course....
Any advice/experience here would be very much appreciated!
I have 115db super efficient concentric horns in a tri-amp electronic XO(Sublime audio) system.
Bass section and mid-horn is already sorted mating superbly to a 100W Rogue tube amp(bass) and modified ACA amp or Crayon amplifier(mids).
My main objective now is to find a quality low watt amplifier to drive the tweeters 6300Hz>
Currently using a Marantz PM7001KI integrated where power/gain/input impedance is obviously too great for my situation but still plays quite nice highs.
Initial logical choice for me seems to be ACA-mini... i think..... or.....??
I have read multiple times people stating ACA-mini resembles F5 in design and sound.... albeit much less powerful..... i only need 1 good watt or so.
It is mentioned that F5 plays very nice high frequencies - transparent extended airy refined delicate - nice shimmer on cymbals etc - especially with quality upstream equipment(less edgy) - which i have.
(have good hearing and a lover of percussion and female vocal so beautiful transparent highs is paramount)
Just looking for some opinions..... or if anyone has had some experience with ACA-mini driving tweeters.... or if they have found something that sounds better on tweeters.... ??
One point of reference i have is that i find the original ACA much better suited to my midrange section(very nice in fact) over the tweeter section where i find it too dull/lifeless etc. I also owned a nice PASS XA30.5 in the past(different speakers) with similar findings - i found the highs better - but just too soft.
If ACA-mini was somehow able to give me similar highs to XA30.5 but just more of it - and with more sparkle - that could be close to perfect!
Cost does not matter too much as long as it is not impractical of course....
Any advice/experience here would be very much appreciated!
I'm trying to set the VO/VB and understand that it is easier to use 2 meters. Any recommendations for attaching the probes?
https://www.amazon.com/HiLetgo-3Pai...hook+multimeter+probes&qid=1702476583&sr=8-15
If you know you're in it for the long-haul something like these is pretty nice.
https://www.amazon.com/Pair-Multime...6700&sprefix=parrot+test+leads,aps,109&sr=8-4
Lots of options. I find the "J-hook" type easier to use than "Alligator" clips.
For an attachment point ... I sometimes make a little loop with a piece of left over resistor lead or similar to craft a "test point". Solder the loop to the board.
If you know you're in it for the long-haul something like these is pretty nice.
https://www.amazon.com/Pair-Multime...6700&sprefix=parrot+test+leads,aps,109&sr=8-4
Lots of options. I find the "J-hook" type easier to use than "Alligator" clips.
For an attachment point ... I sometimes make a little loop with a piece of left over resistor lead or similar to craft a "test point". Solder the loop to the board.
Okay, after re-reading your reply I think I got it. The J hooks don't attach at the thru holes but to fashioned loop.
I was expecting a difficult time adjusting bias, but with 2 meters it was pretty simple! Just waiting for some female banana to wire adapters due anytime now, a bit too lazy to make something. Although, I am champing at the bit, so if they don't arrive soon....
Figure out a way to hook it up now. You're going to be impressed.
🙂
🙂
I just drove down the road 10 minutes ago and saw the UPS truck very close so I'm giving them another 30 minutes. I have a variety of options for making something, but something worthwhile is worth waiting for. Just not too long 😜
Banana adapters just arrived, who could wait that long! For the time being I am running Revel F226Be, so not the best match but that's a tale for another time., or perhaps a F5M 😉. The Mini is taking the place of my Supernait 3 w/ outboard PS, being driven from a Bluesound Node power thru AQ Niagara 3000.
First up was Blind Faith I Can't Find My Way Home, MoFi, not the best recording but enjoyable as the amp warms up.
Next Boz Scaggs w/ Duanne Allman, Buddy Can You Loan Me A Dime, Wonderful. The organ, Boz's voice and of course Duane!
Followed by The Persuasions, We Came To Play, Don't It Make You Want To Go Home, the LP is much better, but wonderful
Muddy Waters Folk Singer My Home Is On The Delta MQA, here is where it starts to really shine!
One of my favorite tracks was up next, Nils Lofgren Acoustic Live Keith Don't Go, absolutely beautiful!
All in all most impressive indeed!!
I am curious as to what input level would overload the amp, and if it isn't too much to ask perhaps some explanation as to how one determines that.
First up was Blind Faith I Can't Find My Way Home, MoFi, not the best recording but enjoyable as the amp warms up.
Next Boz Scaggs w/ Duanne Allman, Buddy Can You Loan Me A Dime, Wonderful. The organ, Boz's voice and of course Duane!
Followed by The Persuasions, We Came To Play, Don't It Make You Want To Go Home, the LP is much better, but wonderful
Muddy Waters Folk Singer My Home Is On The Delta MQA, here is where it starts to really shine!
One of my favorite tracks was up next, Nils Lofgren Acoustic Live Keith Don't Go, absolutely beautiful!
All in all most impressive indeed!!
I am curious as to what input level would overload the amp, and if it isn't too much to ask perhaps some explanation as to how one determines that.
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Just popped on Nojima Plays Liszt, La Campanella at low volume, terrific delineation, timbre, harmonic structure and of course soundstage/image!