Thank you Tungsten for your kind words.
the problem is that i want to have about 11,5dB and not just 9 db. i do not have a preamp. some titles are nice but with my DAC and the ACA premium it is not possible to get louder.
i compare the normal ACA1
https://www.diyaudio.com/forums/pass-labs/215392-amp-camp-amp-aca-931.html#post6461502
vs ACA premium and then I want to try some filtering and other things at the normal ACA1 to get better SQ. my plan is to be clear which steps are useful to get better sound and power. for power the limit is the housing so therefore more supply voltage or more current is not possible i guess.
so i plan mono block parallel - my speakers are 4R. (NADA). so it is important to know what i have to do to get the same gain.
chris
the problem is that i want to have about 11,5dB and not just 9 db. i do not have a preamp. some titles are nice but with my DAC and the ACA premium it is not possible to get louder.
i compare the normal ACA1
https://www.diyaudio.com/forums/pass-labs/215392-amp-camp-amp-aca-931.html#post6461502
vs ACA premium and then I want to try some filtering and other things at the normal ACA1 to get better SQ. my plan is to be clear which steps are useful to get better sound and power. for power the limit is the housing so therefore more supply voltage or more current is not possible i guess.
so i plan mono block parallel - my speakers are 4R. (NADA). so it is important to know what i have to do to get the same gain.
chris
Thanks Tungsten and thank you dfoulk for the reminder.
yes the 220R is more for filtering the high freq. noise of the SMPS.
and yes for bigger supply the VDS should be re -checked
.
the last 2 days i compared my ACA_p with a F5 clone (with lateral powerFET)...yes the F5 is a different animal...but its nice the realized what a ACA_p can do. still fantastic sound.F5 is more deeper , more body, no fog in lower regions and yes...more power...
therefore i plan my last update for the ACA premium:
1 resistor in the drain circuit
2 filter for my SMPS (meanwell 150W) to get less ripple. i plan to use my 7µH choke as i used for Class D amps and a small cap.
any hint for that? the voltage at the SMPS can be set so some voltage drops is no problem .
chris
yes the 220R is more for filtering the high freq. noise of the SMPS.
and yes for bigger supply the VDS should be re -checked
.the last 2 days i compared my ACA_p with a F5 clone (with lateral powerFET)
...yes the F5 is a different animal...but its nice the realized what a ACA_p can do. still fantastic sound.F5 is more deeper , more body, no fog in lower regions and yes...more power...therefore i plan my last update for the ACA premium
:1 resistor in the drain circuit
2 filter for my SMPS (meanwell 150W) to get less ripple. i plan to use my 7µH choke as i used for Class D amps and a small cap.
any hint for that? the voltage at the SMPS can be set so some voltage drops is no problem .
chris
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Check out the DIY Sony VFET pt 1 thread, first page. Papa has designed a power supply filter especially for SMPS amps. It is small enough to fit inside an ACA. Details are in the DIY SONY VFET pt 1 document.
https://www.diyaudio.com/forums/att...734-diy-sony-vfet-builders-thread-capture-jpg
In addition to this filter, you could also try adding 1000 uF or 2200 uF to the power input of each channel board, which will improve both stereo separation and lower frequency response.
Just a couple new tricks from the latest amp.
https://www.diyaudio.com/forums/att...734-diy-sony-vfet-builders-thread-capture-jpg
In addition to this filter, you could also try adding 1000 uF or 2200 uF to the power input of each channel board, which will improve both stereo separation and lower frequency response.
Just a couple new tricks from the latest amp.
...ACA as preamp...
Hi
one of my plan is to use the ACA as a preamp.
some points are not really clear for me:
thx chris
Hi
one of my plan is to use the ACA as a preamp.
some points are not really clear for me:
- which supply should i choose 12V enough?
- which idle current is enough
- should i try irf610?
- gain is about 6db (factor 2)
10k to 20k(37k). for me its still not really clear about the 10pF parallel to the feedback resistor - i have a 10k log alps pot
thx chris
...some pics of my ACAp
i wonder that i have with 1,6A each amp a very nice temp management at my Power fets. after an hour without signal and warming up i got just 59 on each power amp. using a ceramic plate is a good idea.
at the 2,3rd pic you will see the correction of idle current and input resistor and my supply caps..its a prototype
i wonder that i have with 1,6A each amp a very nice temp management at my Power fets. after an hour without signal and warming up i got just 59 on each power amp. using a ceramic plate is a good idea.
at the 2,3rd pic you will see the correction of idle current and input resistor and my supply caps..its a prototype
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thanks stanislav for your reply
i avoid to use more then 24V because of my parts - all caps are just 16V(polymer..)
about the gain:
pages before i try with 20k Rin and about 84k RF but i still get not more then 8,6dB, why?
10pF has nothing to do with gain, read ZEN V4 article for clarification.
chris
i avoid to use more then 24V because of my parts - all caps are just 16V(polymer..)
about the gain:
pages before i try with 20k Rin and about 84k RF but i still get not more then 8,6dB, why?
10pF has nothing to do with gain, read ZEN V4 article for clarification.
chris
OK, stay with 24V.
About 10 pF, here's a quote from that article:
"C12, which trims the high
frequency response so as to avoid peaking at high frequencies."
Still a good idea to read the whole article, ACA and Zen V4 share quite a few ideas. You'll find it on the FirstWatt web site, under Articles:
FIRST WATT
About 10 pF, here's a quote from that article:
"C12, which trims the high
frequency response so as to avoid peaking at high frequencies."
Still a good idea to read the whole article, ACA and Zen V4 share quite a few ideas. You'll find it on the FirstWatt web site, under Articles:
FIRST WATT
...first step of modification...
Hi
last days i try a bit around of set up my current to get more juice for my 4R 84DB speakers. finally i found a setup with 2,05Amps at each channel and a temperature of the IRFP240 about 75°C!!
. this is the max of my housing setup (55°C) its HOT ! @24V
in my lab i got: 9,2W@ 4R at 2,4Vrms input and no H2 flat of the sine wave...so that´s nice. as you see the gain is to low to reach the max power, RCA deliver normal 2,0Vrms....so i have to pimp this..
as you know from other post i compare this ACA_p with a F5 lateral clone (not matched components) to have a base of my listening sessions.
yesterday i have my first listening session with this HOT monster and i am happy with the result. the ACA plays more forward and more controlled, not so stoic like the F5 but with a but more texture and the singers are a step in front and it feels more realistic...
next step -- filter noise at the supply rail of my SMPS.
as you can see from my measurement at the amp pcb from my LRS 150-24V
chris
Hi
last days i try a bit around of set up my current to get more juice for my 4R 84DB speakers. finally i found a setup with 2,05Amps at each channel and a temperature of the IRFP240 about 75°C!!
. this is the max of my housing setup (55°C) its HOT ! @24Vin my lab i got: 9,2W@ 4R at 2,4Vrms input and no H2 flat of the sine wave...so that´s nice
. as you see the gain is to low to reach the max power, RCA deliver normal 2,0Vrms....so i have to pimp this..as you know from other post i compare this ACA_p with a F5 lateral clone (not matched components) to have a base of my listening sessions.
yesterday i have my first listening session with this HOT monster and i am happy with the result. the ACA plays more forward and more controlled, not so stoic like the F5 but with a but more texture and the singers are a step in front and it feels more realistic...
next step -- filter noise at the supply rail of my SMPS.
as you can see from my measurement at the amp pcb from my LRS 150-24V
chris
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Hi
next step -- filter noise at the supply rail of my SMPS.
as you can see from my measurement at the amp pcb from my LRS 150-24V
chris
Borrow the filter idea from Mr. Pass' DIY VFET Pt.1, it will clean up most of the garbage.
Or invest in a better SMPS and still employ that filter.
You can construct the filter on a small veroboard and the components are rather inexpensive.