Gentlemen, this winter my DIY-friend Hannes and I are aiming for an active speaker project that is partly (66%) based on Mr. Nelson Pass' ACA#1 amplifiers.
Have a look at images 1 and 2.
The music source is a CDP. Its attenuation is done by a 3-way PRE, which is followed by a 3-way crossover.
I have assembled 4 ACA#1s, two of them driving the right and left tweeters and the other two driving the right and left mid-range speakers.
Hannes and I (after browsing the INTERNET, this forum, ...) decided to use an ANAVIEW AMS1000-2600 ClassD amplifier to drive the bass (see image 3).
I myself was very excited to get to know, if the ClassD would in any way "spoil" the performance of Mr. Pass' ACA#1s, if both of these amplifiers are built in close vicinity.
The result: the ClassD ANAVIEW AMS1000 does not spoil at all the "sound" of the ACA#1s. No hum at all.
But, and this is Hannes' and my 1st conclusion: the AMS1000-2600 is not able to "reproduce" music.
It can play loud, it will shake your ears and hairs, moving a lot of air around you:
But showing power over the bass membrans, being precise and being rhythmical and showing soul: no way!
My 2nd conclusion is even more important in my ears than my 1st one:
When I compare the "sound" of the ACA#1s with the "sound" of my "BlackBeauty-SYMASYM" (image 4):
I feel that the sound of the ACA#1s is a little bit "dark", "too warm", just as some of the heights are being cut off.
For example: while listening to a Piano solo.
Is this really, normally so?
Or is this the fact or is it due to my poor (DELL-laptop) PSU?
Can you please tell me?
Is there any way to get crisp and clear trebles out of the ACA#1 (with the R15-mod being active)?
I wonder how.
Best regards - Rudi_Ratlos
Have a look at images 1 and 2.
The music source is a CDP. Its attenuation is done by a 3-way PRE, which is followed by a 3-way crossover.
I have assembled 4 ACA#1s, two of them driving the right and left tweeters and the other two driving the right and left mid-range speakers.
Hannes and I (after browsing the INTERNET, this forum, ...) decided to use an ANAVIEW AMS1000-2600 ClassD amplifier to drive the bass (see image 3).
I myself was very excited to get to know, if the ClassD would in any way "spoil" the performance of Mr. Pass' ACA#1s, if both of these amplifiers are built in close vicinity.
The result: the ClassD ANAVIEW AMS1000 does not spoil at all the "sound" of the ACA#1s. No hum at all.
But, and this is Hannes' and my 1st conclusion: the AMS1000-2600 is not able to "reproduce" music.
It can play loud, it will shake your ears and hairs, moving a lot of air around you:
But showing power over the bass membrans, being precise and being rhythmical and showing soul: no way!
My 2nd conclusion is even more important in my ears than my 1st one:
When I compare the "sound" of the ACA#1s with the "sound" of my "BlackBeauty-SYMASYM" (image 4):
I feel that the sound of the ACA#1s is a little bit "dark", "too warm", just as some of the heights are being cut off.
For example: while listening to a Piano solo.
Is this really, normally so?
Or is this the fact or is it due to my poor (DELL-laptop) PSU?
Can you please tell me?
Is there any way to get crisp and clear trebles out of the ACA#1 (with the R15-mod being active)?
I wonder how.
Best regards - Rudi_Ratlos
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Raise the PSU to ACA to 24V and there goes your smooth highs. Really 19V is absolutely minimum, but 24V sounds MUCH better.
Suggest a decent/Proven lm 3886 Based Amp : My Ref or Modulus 86 as examples.
For your bass one. Actually even try it full range.. as experiment
A Good amp has few parts 😉 as per Mr Pass' designs
For your bass one. Actually even try it full range.. as experiment
A Good amp has few parts 😉 as per Mr Pass' designs
After increasing rail voltage, also try putting 10uf polypropylene cap in parallel with electrolytic.
While in a lower sensitivity passive multiway the ACA's modest output power could result in reduced dynamics & SPLs, but an active system as per your block diagram should be a match made in heaven with the right drivers.
I've used the bone stock DIY Audio Store ACA kits with a couple of different models of Fostex and Mark Audio full range units and didn't find them dark at all.
Andersonix wanted to blame it on the "cheap tweeters", but do we know which those are?
I've used the bone stock DIY Audio Store ACA kits with a couple of different models of Fostex and Mark Audio full range units and didn't find them dark at all.
Andersonix wanted to blame it on the "cheap tweeters", but do we know which those are?
Rudi, my 3-way active system uses the ACA's with the R15 mod to drive midrange and treble compression drivers on waveguides: http://www.diyaudio.com/forums/pass-labs/215392-amp-camp-amp-aca-150.html#post3725314 Since those pics I changed the treble compression driver to a BMS 4540ND that goes up to 30 kHz. Mated to a QSC waveguide that is similar in size to the midrange waveguide in the above pic.
The sound from the ACA amps from 500 Hz on up to my ears is very crisp, but never harsh using subjective terms. I have digitally eq'd my system and the response goes out past my measurement mic limit of 24 kHz: http://i1217.photobucket.com/albums...Speaker at listening position_zpskt56bc5f.jpg
Don't know if you have access to a measurement mic and REW, but if you could take measurement of the frequency response of your speakers, one with the ACA and one with your Black Beauty, you can overlay the measures in REW and check for variations. It would be one place to start or if you can measure the frequency response of the amps...
Hope that helps.
Regards, Mitch
The sound from the ACA amps from 500 Hz on up to my ears is very crisp, but never harsh using subjective terms. I have digitally eq'd my system and the response goes out past my measurement mic limit of 24 kHz: http://i1217.photobucket.com/albums...Speaker at listening position_zpskt56bc5f.jpg
Don't know if you have access to a measurement mic and REW, but if you could take measurement of the frequency response of your speakers, one with the ACA and one with your Black Beauty, you can overlay the measures in REW and check for variations. It would be one place to start or if you can measure the frequency response of the amps...
Hope that helps.
Regards, Mitch
Andersonix, please do not blame the tweeter. The left picture in post #1 is showing any tweeter, just to show you the intention of this project.
In effect we are using a reputable 3-way speaker and have removed its internal crossover.
Kacernator's reply seems promising, and I am now busy looking for / implementing a 24VDC solution.
Best regards - Rudi_Ratlos
P.S.: In my opinion a "good" amplifier should get on well with any brand of tweeters (provided it is a "good" tweeter).
In effect we are using a reputable 3-way speaker and have removed its internal crossover.
Kacernator's reply seems promising, and I am now busy looking for / implementing a 24VDC solution.
Best regards - Rudi_Ratlos
P.S.: In my opinion a "good" amplifier should get on well with any brand of tweeters (provided it is a "good" tweeter).
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3300uF is too big not to ruin the treble quality (you already observed the effect). But sure you can lower the value for the HF section. What value do you plan to use?
I suspect you are clipping the output. more supply voltage will help immensely. As others have suggested, 24V will sound better.
The sound difference isn't the quality of the laptop PSU, but the supply voltage.
OK, got it now: secret but good tweeter....
What is the PS ripple (mVAC) on the rails of the tweeter amp? I would not judge until it's below 5mV.
I have ordered a MeanWell 24 V regulated SMPS and will tell you the results, as soon as I have installed it.
Best regards - Rudi_Ratlos
Best regards - Rudi_Ratlos
Gentlemen, I have received the ordered MeanWell 24V regulated SMPS, have installed it into my intermediate setup and have adjusted the "quiescent voltage" to 12V.
Inserting a disk into my CDP and listening to the ACAs: well - I myself do not hear much of a difference, allthough there definitely is, maybe I was too impatient to let my ears get used to the "new" sound.
I have sent the setup to my DIY-friend today.
I know that he is much more patient with the ACAs and has "better-trained" ears than I have.
The Meanwell-SMPS will only be an intermediate PSU for the ACAs.
In the meanwhile I am dreaming about an ACA-PCB with intergrated PSU for our active speaker-project. (I really begin and like this tiny amplifier!).
The shown PCB-layout will have a size of 100x75mm.
Best regards - Rudi_Ratlos
Inserting a disk into my CDP and listening to the ACAs: well - I myself do not hear much of a difference, allthough there definitely is, maybe I was too impatient to let my ears get used to the "new" sound.
I have sent the setup to my DIY-friend today.
I know that he is much more patient with the ACAs and has "better-trained" ears than I have.
The Meanwell-SMPS will only be an intermediate PSU for the ACAs.
In the meanwhile I am dreaming about an ACA-PCB with intergrated PSU for our active speaker-project. (I really begin and like this tiny amplifier!).
The shown PCB-layout will have a size of 100x75mm.
Best regards - Rudi_Ratlos
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PCB looks promising 🙂 But now I have to put your Amp Camp #1 PCB
in the drawer and have to wait
for your ACA-PCB 😀Micha
I like the integrated cap-multiplier!
How much current is it capable of (peak and steady)?
My DIY-friend Johannes has received my parcel with the "new ACA" (now being operated by a 24V MeanWell - SMPS) and has written me:
"... enormous progress, the heights are clear and bright, the stage has widened, ... - in one word: awesome."
So this is an advice that I like to pass to those, who are planning to build the ACA:
Use a 24V PSU to get the best sound out of the ACA!
Best regards - Rudi-Ratlos
"... enormous progress, the heights are clear and bright, the stage has widened, ... - in one word: awesome."
So this is an advice that I like to pass to those, who are planning to build the ACA:
Use a 24V PSU to get the best sound out of the ACA!
Best regards - Rudi-Ratlos
Gentlemen, when I have listened to the sound of the ACA#1 for the 1st time, I have been disappointed a little (a lot).
Well, I thought, this is how "ClassA" sounds - no "joie de vivre", the internal rhythm has been missing.
I has not been until I have been told to operate the ACA#1 from a 24VDC(!) PSU that I have changed my mind (my ears) to listen to the ACA#1 more closely, and: this advice has been perfect!
Operating the ACA#1 from a MeanWell +24VDC SMPS has shown me the way to go (to listen to - refer to post #13), but since I feel that it is a shame to drive a ClassA amplifier from an SMPS,
I did a new PCB-layout and have given my ACA#1 the Jason Kuetemann CAP-Multiplier - PSU.
I have not yet finished my ACA#1s yet, but will keep you informed.
Best regards - Rudi_Ratlos
Well, I thought, this is how "ClassA" sounds - no "joie de vivre", the internal rhythm has been missing.
I has not been until I have been told to operate the ACA#1 from a 24VDC(!) PSU that I have changed my mind (my ears) to listen to the ACA#1 more closely, and: this advice has been perfect!
Operating the ACA#1 from a MeanWell +24VDC SMPS has shown me the way to go (to listen to - refer to post #13), but since I feel that it is a shame to drive a ClassA amplifier from an SMPS,
I did a new PCB-layout and have given my ACA#1 the Jason Kuetemann CAP-Multiplier - PSU.
I have not yet finished my ACA#1s yet, but will keep you informed.
Best regards - Rudi_Ratlos
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Gentlemen, James, Johannes,
I myself do not own an active crossover. But my friend Johannes, who asked me to think about a 3-way active speaker concept, owns two of them: a Mini-DSP and a Thel-Audio crossover.
But do not ask me, which parameters Johannes is using for the adjustment!
I have finished the 1st of Johannes' ACA-PCBs yesterday and have evaluated the CAP-multiplier, designed by Jason Kuetemann, which will drive the ACA.
I have ordered a 4x18VAC / 100VA each torroid from BADEL several weeks ago, but did not yet receive it and therefore connected the new ACA to a 18VAC R-Core that I had at hand.
I connected a set of resistors to it resulting in a load of about 500mA.
My DMM is showing a ripple of about 55mV with the output voltage being adjusted to 24VDC.
I will go on with the 2nd ACA-PCB tonight and have to wait, until the ordered torroid will arrive.
Best regards - Rudi_Ratlos
P.S.:
Looking at the 2nd picture above: I have had a mishap, my tapper broke during my 1st attempt and I had to restart tapping the holes.
The used heatsink is 300mm high and 190mm broad.
I myself do not own an active crossover. But my friend Johannes, who asked me to think about a 3-way active speaker concept, owns two of them: a Mini-DSP and a Thel-Audio crossover.
But do not ask me, which parameters Johannes is using for the adjustment!
I have finished the 1st of Johannes' ACA-PCBs yesterday and have evaluated the CAP-multiplier, designed by Jason Kuetemann, which will drive the ACA.
I have ordered a 4x18VAC / 100VA each torroid from BADEL several weeks ago, but did not yet receive it and therefore connected the new ACA to a 18VAC R-Core that I had at hand.
I connected a set of resistors to it resulting in a load of about 500mA.
My DMM is showing a ripple of about 55mV with the output voltage being adjusted to 24VDC.
I will go on with the 2nd ACA-PCB tonight and have to wait, until the ordered torroid will arrive.
Best regards - Rudi_Ratlos
P.S.:
Looking at the 2nd picture above: I have had a mishap, my tapper broke during my 1st attempt and I had to restart tapping the holes.
The used heatsink is 300mm high and 190mm broad.
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