For the output I am using Nichicon KW. I have always like them. Bridging them with a 1uF MKP might be fine.
Once I can solve the noises problems I have right now (a Hum when I connect a source in the right channel).
I also planned to try the inputs with coupling capacitors, something like Mundorf 10uF.
Once I can solve the noises problems I have right now (a Hum when I connect a source in the right channel).
I also planned to try the inputs with coupling capacitors, something like Mundorf 10uF.
As far as PSU’s internal and external. We decided to switch from 19v generic laptop PSU’s
to 24v MeanWell “bricks” because 24v PSU’s have gotten cheaper and the generic ones were sometimes less reliable. W e asked Nelson to test the generics again and they were noisier than we thought they were.
Upgrading to the MeanWell bricks is worthwhile. They are very well made, the amp puts out 25% more power, and they are quiet and reliable. We do stock them individually so people can get them for upgrades. And it’s an absurdly easy upgrade if you have one of the no-name supplies. Just plug it in and then adjust the pot to 12.5v instead of 10v (see Build Guide) and you’re done. Obviously the old monoblocks would need one for each channel.
Pass says he prefers not to use 2 supplies with a single chassis because the frequencies are never exactly the same and sometimes interfere with each other and “beat”. This isn’t always a problem.
Also, the external supplies could be considered a “feature” not a “bug” because external PSUs keep any high frequency noise out of the chassis. I mean, some high end amps brag about their external power supplies, right?
to 24v MeanWell “bricks” because 24v PSU’s have gotten cheaper and the generic ones were sometimes less reliable. W e asked Nelson to test the generics again and they were noisier than we thought they were.
Upgrading to the MeanWell bricks is worthwhile. They are very well made, the amp puts out 25% more power, and they are quiet and reliable. We do stock them individually so people can get them for upgrades. And it’s an absurdly easy upgrade if you have one of the no-name supplies. Just plug it in and then adjust the pot to 12.5v instead of 10v (see Build Guide) and you’re done. Obviously the old monoblocks would need one for each channel.
Pass says he prefers not to use 2 supplies with a single chassis because the frequencies are never exactly the same and sometimes interfere with each other and “beat”. This isn’t always a problem.
Also, the external supplies could be considered a “feature” not a “bug” because external PSUs keep any high frequency noise out of the chassis. I mean, some high end amps brag about their external power supplies, right?
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We, 5 of us. tried alot of output cap when playing with sansui for over a year. So we had alot of reference.
Elna gives the nicest textured and dynamic sound. Goldtune is one of best result we tried. Kw and kg.. Might be too dark.
Input cap 10uf.. Mkt might have a better tubyness, meat and texture. Good results with ecq. Mmk. Vishay 1822..mkp is more clean and better hi extention. Mkc also helps with hi Airy textured extention but bass can suffer I can see why zenmod likes them very much for bypass.
If possible... No bypass. It will sound more coherent and relaxed.
Hope our time spent messing around helps to decide.
Elna gives the nicest textured and dynamic sound. Goldtune is one of best result we tried. Kw and kg.. Might be too dark.
Input cap 10uf.. Mkt might have a better tubyness, meat and texture. Good results with ecq. Mmk. Vishay 1822..mkp is more clean and better hi extention. Mkc also helps with hi Airy textured extention but bass can suffer I can see why zenmod likes them very much for bypass.
If possible... No bypass. It will sound more coherent and relaxed.
Hope our time spent messing around helps to decide.
currently i measure my cambridge audio cxa 80 amp rated 90watt 8 ohm,
its not even 1 V measurement. is there any wrong with it and differences with this aca 10 V?
Will ACA power my KEF LS50's?
I'm considering the ACA to power my KEF LS50's. They are 85dB efficient. Am I going to be ok with one or should I run two of them as dual mono blocks? Or, is there a better amp kit for me? My listening room is small (at best). I'm a noob at hi end audio but have experience with soldering. Thanks in advance for any help.
I'm considering the ACA to power my KEF LS50's. They are 85dB efficient. Am I going to be ok with one or should I run two of them as dual mono blocks? Or, is there a better amp kit for me? My listening room is small (at best). I'm a noob at hi end audio but have experience with soldering. Thanks in advance for any help.
I'm driving a pair of JR149s (old but good) which are about 85-87db. Sounds superb in my smallish workshop. The build manual is very good (downloadable as PDF) and there are videos too. Along with these pages you cant really go wrong.
If you only measure 1V at power amp output and you are satisfied with sound level then ACA amp is not the problem. ACA can deliver much more than 1V out in 8 ohm (at least 10V peak). I think the problem may be that your preamp don't amplify "enough".
Some preamps may not "voltage amplify" but just act like a buffer like Pass B1 buffer?
how to check whether my pre amp has volt amplify ? its integrated amp with built in pre amp function.
If your integrated has a separate preamp output then it is hard to believe that it is only a buffer. Which means you should have enough voltage gain and should be all right.
Yes, try to make the same measurement when you play using ACA. If you need to turn volumen to max then something is probably wrong. Then measure RMS AC at both ACA input and output. Having these two values we can get closer to the problem......if there is a problem.
FWIW, I decided to hook up my standard ACAs to ESL57s (+ REL Strata II) on the assumption that OneThingAudio widgets would protect each from the other if necessary.
Having recently heard a band called 'Scotch, No Soda' at a blues festival, I picked up a cd at the same time. Playing it now with my eyes closed, the sound (and in particular the vocal) is so close to my memory of the performance, it's uncanny.
I've several projects in the pipeline, including a Neurochrome HP-1 and Korg NuTube B1 (to compare opposite philosophies) an M2X plus a commercial DAC and a VFET amp, but right now I could happily relax and settle for this. Given that these were a beginner's project the sound really is outstanding
(Current ancilliaries are nothing special - a Dell laptop running JRMC, s/h MyDac and elderly Cyrus pre-)
Having recently heard a band called 'Scotch, No Soda' at a blues festival, I picked up a cd at the same time. Playing it now with my eyes closed, the sound (and in particular the vocal) is so close to my memory of the performance, it's uncanny.
I've several projects in the pipeline, including a Neurochrome HP-1 and Korg NuTube B1 (to compare opposite philosophies) an M2X plus a commercial DAC and a VFET amp, but right now I could happily relax and settle for this. Given that these were a beginner's project the sound really is outstanding
(Current ancilliaries are nothing special - a Dell laptop running JRMC, s/h MyDac and elderly Cyrus pre-)
First Watt J2 power amplifier | Stereophile.com
for those who wan some idea how many watts needed and comparison between speakers.
i guess this review as reference is something good?
for those who wan some idea how many watts needed and comparison between speakers.
i guess this review as reference is something good?
Am I missing something?
I have had my 2 ACA for a few months, I now have them connected to a pair of PMC twenty5 26 speakers (sensitivity 86db). I sit about 2 metres from the speakers. I am very pleased with the sound, I can play the music too loud for me. I have compared the amps to an older Crown D-75 power amp and the ACA units win. Why would I consider anything else? Even a bigger amp from the DiyAudio store. Is there something that can make a significant difference? thanks
I have had my 2 ACA for a few months, I now have them connected to a pair of PMC twenty5 26 speakers (sensitivity 86db). I sit about 2 metres from the speakers. I am very pleased with the sound, I can play the music too loud for me. I have compared the amps to an older Crown D-75 power amp and the ACA units win. Why would I consider anything else? Even a bigger amp from the DiyAudio store. Is there something that can make a significant difference? thanks
Hi,
I am currently waiting for boards and heatsinks on ACA amps that i will be building the chassis for. I am hoping/plotting/planning on putting the amps under my speakers in a hole in my speaker stands and doing ACA monoblocks.
the area in the stand is only 7" wide, 11" tall, and 8-9" deep.
i am curious about the group opinion on what the best way to orient the pair of heatsinks in the monoblock will be to not fry anything. The heatsinks are going to be 8"X1.5"X5" so they are slightly oversized for the ACA.
Here are various flavors i have come up with (looking at the amp from the front, with the black area, the heatsinks)
A is basically two monoblocks stacked on top of one another,
B is amp in "normal" position with heatsink on each side, but only 3-4" between heatsinks due to narrowness of stand
C is stacked monoblocks, with upper heatsink offset
D is normal ACA amp configuration with amp basically on its side on the bottom of the stand.
.
all of these have beauty, heat flow, and build issues. what do you guys think?
thanks for your time
Tim E - in Seattle
I am currently waiting for boards and heatsinks on ACA amps that i will be building the chassis for. I am hoping/plotting/planning on putting the amps under my speakers in a hole in my speaker stands and doing ACA monoblocks.
the area in the stand is only 7" wide, 11" tall, and 8-9" deep.
i am curious about the group opinion on what the best way to orient the pair of heatsinks in the monoblock will be to not fry anything. The heatsinks are going to be 8"X1.5"X5" so they are slightly oversized for the ACA.
Here are various flavors i have come up with (looking at the amp from the front, with the black area, the heatsinks)
A is basically two monoblocks stacked on top of one another,
B is amp in "normal" position with heatsink on each side, but only 3-4" between heatsinks due to narrowness of stand
C is stacked monoblocks, with upper heatsink offset
D is normal ACA amp configuration with amp basically on its side on the bottom of the stand.
.
all of these have beauty, heat flow, and build issues. what do you guys think?
thanks for your time
Tim E - in Seattle
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