Silly question! Looked at separate cap multiplier boards and the IRF9140 is on a little standalone heat sink 🙄
Amp design plans unaffected 😀
James, Johannes: I have received a 2x18VAC/160VA torroid that I have ordered myself (not to mix up with with 4 x 19VAC / 360VA torroid that I have ordered from BADEL
for Johannes' Active Speaker Project) today.
I have connected this torroid to the current setup and measured the 1st channel (see attached image).
The ACA's operating voltage is about 24VDC. I can easily adjust the quiescent voltage to about 12VDC.
The heatsink - allthough lying on its back - is not getting warm at all.
I will use my RPre to show the temperature of the used heatsink.
You do only need a transformer's secondaries to connect to this ACA - PCB.
I have measured the AC-ripple on the 24VDC power-line of Jason Keutemann's Cap-mulitplier: it is showing an astoundishing low ripple of 81mV.
(Using my HP/Agilent DMM).
I did not yet activate the R15-modification (I only need to set a cap on jumper JP to activate it).
I will go on and test (measure) the 2nd ACA-channel tonight / tomorrow morning.
If it can be as easily adjusted as channel No. #1 (did I do any component- / solder-errors? - I hope not), then I will put the two ACA channels alive for a couple of hours and measure the temperature
of the heatsink with the help of my RPRE and will tell you the results.
Best regards - Rudi
P.S.: My shown RPre is only used to show the temperature of the heatsink! I will give you the results of the temperature-measurement tomorrow.
for Johannes' Active Speaker Project) today.
I have connected this torroid to the current setup and measured the 1st channel (see attached image).
The ACA's operating voltage is about 24VDC. I can easily adjust the quiescent voltage to about 12VDC.
The heatsink - allthough lying on its back - is not getting warm at all.
I will use my RPre to show the temperature of the used heatsink.
You do only need a transformer's secondaries to connect to this ACA - PCB.
I have measured the AC-ripple on the 24VDC power-line of Jason Keutemann's Cap-mulitplier: it is showing an astoundishing low ripple of 81mV.
(Using my HP/Agilent DMM).
I did not yet activate the R15-modification (I only need to set a cap on jumper JP to activate it).
I will go on and test (measure) the 2nd ACA-channel tonight / tomorrow morning.
If it can be as easily adjusted as channel No. #1 (did I do any component- / solder-errors? - I hope not), then I will put the two ACA channels alive for a couple of hours and measure the temperature
of the heatsink with the help of my RPRE and will tell you the results.
Best regards - Rudi
P.S.: My shown RPre is only used to show the temperature of the heatsink! I will give you the results of the temperature-measurement tomorrow.
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Gentlemen: since I need to wait for the arrival of a couple of TO220-heatsinks (used for the MUR820-rectifiers - UPS is telling me that they do not recognise my address?),
I have been thinking about adding some kind of control/comfort to my ACA - PCBs.
The control/comfort will consist of:
1st: my MAINs-Soft-PowerOn - being followed by a Mains-DC-filter
2nd: a temperature-control feature
The MAINs Soft PowerOn will give you the ability to switch ON/OFF the ACA - MAINs AC by your remote contol unit.
The temperature-surveillance will inform you about the fact that the temperature of your ACA-heatsink is exceeding the default pre-programmed degree (60°)
and will activate a fan (for example: one/two ARTIC Silent F8-fan(s).
Do you have any other suggestions?
Is this the way I shall go on and do the final cosmectics of the PCB?
Best regards - Rudi_Ratlos
P.S.: The use of the shown LCD is not mandatory.
I have been thinking about adding some kind of control/comfort to my ACA - PCBs.
The control/comfort will consist of:
1st: my MAINs-Soft-PowerOn - being followed by a Mains-DC-filter
2nd: a temperature-control feature
The MAINs Soft PowerOn will give you the ability to switch ON/OFF the ACA - MAINs AC by your remote contol unit.
The temperature-surveillance will inform you about the fact that the temperature of your ACA-heatsink is exceeding the default pre-programmed degree (60°)
and will activate a fan (for example: one/two ARTIC Silent F8-fan(s).
Do you have any other suggestions?
Is this the way I shall go on and do the final cosmectics of the PCB?
Best regards - Rudi_Ratlos
P.S.: The use of the shown LCD is not mandatory.
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Hey Rudi.
As you are relying on a fan to cut in and out ie. A small Heatsink, I would add a thermal cutout in case of fan etc failure
As you are relying on a fan to cut in and out ie. A small Heatsink, I would add a thermal cutout in case of fan etc failure
Gentlemen, I have come so far with the assembly of Johannes' active speaker project (being based on Nelson Pass ACAs for the high and middle tones) today.
Everything still works as designed!
But since I have ordered a 4x20VAC/300VA torroid from BADEL, I need to adjust the ACAs to the torroid listed above (once more, when I will have received the ordered torroid)
and need to tell Johannes to wait with the build of the case ( a small wooden tower case).
Best regards - Rudi_Ratlos
Everything still works as designed!
But since I have ordered a 4x20VAC/300VA torroid from BADEL, I need to adjust the ACAs to the torroid listed above (once more, when I will have received the ordered torroid)
and need to tell Johannes to wait with the build of the case ( a small wooden tower case).
Best regards - Rudi_Ratlos
Attachments
Rudi,
Very impressive build.
Reading your entries in this thread I have decided to thy my ACA with 24V MeanWell SMPS (100W 4.2A). I was previously using two 20V Dell bricks 20V 3.6A.
Indeed 24V might be somewhat better, but my general impression is that ACA sounds darker than my Zen 1994 (ver 1). I was not able to try ACA with a linear PS (as I do not have 20V-24V at hand) so I tried running Zen of the MeanWell. OK Zen is supposed to run with some 35V, but again with SMPS it sounded darker than with its own unregulated power supply.
Can you or anybody comment on this or is it just my Flawed (I admit) test?
Very impressive build.
Reading your entries in this thread I have decided to thy my ACA with 24V MeanWell SMPS (100W 4.2A). I was previously using two 20V Dell bricks 20V 3.6A.
Indeed 24V might be somewhat better, but my general impression is that ACA sounds darker than my Zen 1994 (ver 1). I was not able to try ACA with a linear PS (as I do not have 20V-24V at hand) so I tried running Zen of the MeanWell. OK Zen is supposed to run with some 35V, but again with SMPS it sounded darker than with its own unregulated power supply.
Can you or anybody comment on this or is it just my Flawed (I admit) test?
Gregje, my ACA-build is not impressive at all!
It simply consists of two 190.5 x 300mm heatsinks (ordered from TME.eu) and four of my ACA-PCBs.
I am a "follower" (FACEBOOK-term) of "Rod Elliott - sound.westhost.com"), and when I decided to support my friend Johannes minds to develop a 6-channel active AMP,
I took a look at Rod's pages first.
In one of Rod's PSU pages he is saying that a PSU-CAP-multiplier might be the perfect mate for a small-current ClassA amplifier.
Then I found Jason's CAP-Mulitplier in this forum, asked Jason, if I can use his design - "Sure, you can - Jason" - and this is it!
I do not know the ZEN 1994 amplifier.
The only hint that I have (and it solidifies to come (sound) true (see the attached image) is:
the higher the operating voltage of the IRFP240 the lower the internal capacitances of it and the less (stress) it takes to unload the capacitances ,
and this (...) may contribute to "the better sound of the ACAs at higher voltages" - this is my impression.
Best regards - Rudi_Ratlos
It simply consists of two 190.5 x 300mm heatsinks (ordered from TME.eu) and four of my ACA-PCBs.
I am a "follower" (FACEBOOK-term) of "Rod Elliott - sound.westhost.com"), and when I decided to support my friend Johannes minds to develop a 6-channel active AMP,
I took a look at Rod's pages first.
In one of Rod's PSU pages he is saying that a PSU-CAP-multiplier might be the perfect mate for a small-current ClassA amplifier.
Then I found Jason's CAP-Mulitplier in this forum, asked Jason, if I can use his design - "Sure, you can - Jason" - and this is it!
I do not know the ZEN 1994 amplifier.
The only hint that I have (and it solidifies to come (sound) true (see the attached image) is:
the higher the operating voltage of the IRFP240 the lower the internal capacitances of it and the less (stress) it takes to unload the capacitances ,
and this (...) may contribute to "the better sound of the ACAs at higher voltages" - this is my impression.
Best regards - Rudi_Ratlos
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Hi,
>The only hint that I have (and it solidifies to come (sound) true (see the attached >image) is:
>the higher the operating voltage of the IRFP240 the lower the internal capacitances of >it and the less (stress) it takes to unload the capacitances ,
>and this (...) may contribute to "the better sound of the ACAs at higher voltages" - >this is my impression.
I am aware of this. I guess it woudl be nice to compare like for like: either feed ZEN from 35V SMPS against it sown unregulated PSU or aca unregulated 24v against same voltage SMPS.
@chriscam:
I use my B1 buffer in both setups.
>The only hint that I have (and it solidifies to come (sound) true (see the attached >image) is:
>the higher the operating voltage of the IRFP240 the lower the internal capacitances of >it and the less (stress) it takes to unload the capacitances ,
>and this (...) may contribute to "the better sound of the ACAs at higher voltages" - >this is my impression.
I am aware of this. I guess it woudl be nice to compare like for like: either feed ZEN from 35V SMPS against it sown unregulated PSU or aca unregulated 24v against same voltage SMPS.
@chriscam:
I use my B1 buffer in both setups.
Gregje, I have received the ordered custom wound torroid from BADEL today.
Its specification: 4 x 20VAC / 300VA (meaning: 3.75A per secondary).
I am now easily able to adjust the operating voltage of the ACAs to a value between 24 - 25 VDC.
But I must take care about the heatsink's temperature!
It is now up to Johannes to construct a beautiful case for the 4 ACAs.
Best regards - Rudi_Ratlos
Its specification: 4 x 20VAC / 300VA (meaning: 3.75A per secondary).
I am now easily able to adjust the operating voltage of the ACAs to a value between 24 - 25 VDC.
But I must take care about the heatsink's temperature!
It is now up to Johannes to construct a beautiful case for the 4 ACAs.
Best regards - Rudi_Ratlos
Attachments
Gentlemen, my DIY-friend Johannes and I did not spare any cost and effort to find out, how an ACA#1 sounds at its best in our current active-speaker project.
The used ACAs have the R15-modification implemented (I refer to it as ACA#1.b from now on).
The alternatives:
1) ACA#1.b and a wall AC power-supply (Dell Laptop power supply rated at 19VAC/4.5A):
No way to go. The heights and even the mids are being clipped substantially; the ACA "plays music", but does not follow the rhythm of it nor does it discover its soul.
2) ACA#1.b being driven by a MeanWell - SMPS rated at 24VDC/120VA (see my image in post #13):
Whow: the ACA#1.b "sounds"; the heights and mids are "present, active"; listening only to them (Johannes is using a digital crossover), you feel like you were in another "musical sphere".
3) ACA#1.b being driven by Jason Kuetemann's CAP-Multiplier-PSU (used is a custom-wound torroid rated at 4x20VAC/300VA - see image in the post above):
there are no (very hard to hear) differences when it comes to compare the ACA's sound in the heights and the mids.
But: the ACAs sound "quicker, "on the spot", when it comes to the low tones.
As the conclusion: Johannes and I will stick to alternative 3 (since I have built it already!)
If there is any newbie who heard about the ACA and looks into this thread: I recommend to use the PCB (ACA#1.b plus "standard PSU") together with a 2x18VAC/120-160VA torroid as shown
on the image attached. You will hardly find a "better-sounding" AMP assumed that you are not looking for a "party-amplifier".
Best regards - Rudi_Ratlos
P.S.: In case you are interested in having 2 of the PCBs shown below: tell me.
I will then ask my German friend BIRGER to offer the PCB in his German diy-audio-shop.de
You can mount the rectifier-bridge-diodes (MUR8x0) either vertically or horizontally.
But please take care of cooling them (and of cooling the whole ACA#1.b of course).
The used ACAs have the R15-modification implemented (I refer to it as ACA#1.b from now on).
The alternatives:
1) ACA#1.b and a wall AC power-supply (Dell Laptop power supply rated at 19VAC/4.5A):
No way to go. The heights and even the mids are being clipped substantially; the ACA "plays music", but does not follow the rhythm of it nor does it discover its soul.
2) ACA#1.b being driven by a MeanWell - SMPS rated at 24VDC/120VA (see my image in post #13):
Whow: the ACA#1.b "sounds"; the heights and mids are "present, active"; listening only to them (Johannes is using a digital crossover), you feel like you were in another "musical sphere".
3) ACA#1.b being driven by Jason Kuetemann's CAP-Multiplier-PSU (used is a custom-wound torroid rated at 4x20VAC/300VA - see image in the post above):
there are no (very hard to hear) differences when it comes to compare the ACA's sound in the heights and the mids.
But: the ACAs sound "quicker, "on the spot", when it comes to the low tones.
As the conclusion: Johannes and I will stick to alternative 3 (since I have built it already!)
If there is any newbie who heard about the ACA and looks into this thread: I recommend to use the PCB (ACA#1.b plus "standard PSU") together with a 2x18VAC/120-160VA torroid as shown
on the image attached. You will hardly find a "better-sounding" AMP assumed that you are not looking for a "party-amplifier".
Best regards - Rudi_Ratlos
P.S.: In case you are interested in having 2 of the PCBs shown below: tell me.
I will then ask my German friend BIRGER to offer the PCB in his German diy-audio-shop.de
You can mount the rectifier-bridge-diodes (MUR8x0) either vertically or horizontally.
But please take care of cooling them (and of cooling the whole ACA#1.b of course).
Attachments
Moreover: Johannes asked me to equip his active-ACAs with a setup to power it on/off via his remote-control unit (Grande Seki RFC).
I have done this already and will start with the firmware-implementation right now.
This PCB will do a "Soft-Power-On" (being followed by a Mains-DC-filter) and will monitor the temperature of the heatsinks (by means of a LM35)
and will switch on/off a low-noise fan (ARTIC 80mm low noise), if the given threshold-temperature is being exceeded.
Regards - Rudi_Ratlos
I have done this already and will start with the firmware-implementation right now.
This PCB will do a "Soft-Power-On" (being followed by a Mains-DC-filter) and will monitor the temperature of the heatsinks (by means of a LM35)
and will switch on/off a low-noise fan (ARTIC 80mm low noise), if the given threshold-temperature is being exceeded.
Regards - Rudi_Ratlos
Attachments
I like to report on the status of Hannes and my Active Speaker project.
The ACAs (2 on each side of the heatsinks) are still playing amazingly well.
You don't hear any hum (though I did not implement any common GND scheme), and you will get hooked on their sound.
We are currently thinking about how the case for them could look like.
I have attached 2 CAD-images.
And I took my time to layout a new PIC-µProcessor PCB to do a Soft-Power-On and monitor the temperature of the heatsinks (by means of LM35).
I am then able to switch on (by means of a relay) two small ARCTIC F8 silent fans, in case a given temperature threshold (60°C ?) of the heatsinks is exceeded.
I will keep you informed - Rudi_Ratlos
P.S.: The LCD is not mandatorliy required. The schematic contains a Duo LED to show the status of the heatsinks' temperatures.
The ACAs (2 on each side of the heatsinks) are still playing amazingly well.
You don't hear any hum (though I did not implement any common GND scheme), and you will get hooked on their sound.
We are currently thinking about how the case for them could look like.
I have attached 2 CAD-images.
And I took my time to layout a new PIC-µProcessor PCB to do a Soft-Power-On and monitor the temperature of the heatsinks (by means of LM35).
I am then able to switch on (by means of a relay) two small ARCTIC F8 silent fans, in case a given temperature threshold (60°C ?) of the heatsinks is exceeded.
I will keep you informed - Rudi_Ratlos
P.S.: The LCD is not mandatorliy required. The schematic contains a Duo LED to show the status of the heatsinks' temperatures.
Attachments
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As the result of my findings about the ACA#1-sound in this project, I would like and offer you the following PCB (attached image).
The PCB includes the ACA#1 (with R15 mod.) and PSU.
As PSU you can use:
1) a 19VDC brick: connect it to the GND (=OUT) - and +V - Faston 6.3mm connectors. You need not solder any PSU-component of the PCB.
But I do not recommend to use a 19VDC PSU. The ACA's sound is "dull, without passion, the high tones are clipped", even if the R15-modification is activated.
2) a 24VDC SMPS (for example from MeanWell): same PSU connections.
The ACA's sound is incomparably better. It has life and internal rhythm.
3) a standard PSU, consisting of a 2x18VAC torroid, being followed by the PCB's rectifier and smoothing cap section. Do not populate Jason's CAP-multiplier
and solder a wire between the drain and source of the shown IRFP9140 pass transistor.
Concerning the sound: comparable with the SMPS-version, but "noticeably "quicker and with more control" in the bass.
4) Solder Jason's CAP-Multiplier, giving a very smooth (small ripples) operating voltage.
You will need a transformer rated at about 20VAC though to reach an operating voltage of about 24VDC.
Concernng the sound: if you listen very carefully (for example while you are listening to a piano solo), you will notice that there is an improvement when compared to alternative 3).
You do not need the R15-modification in cases 2-4).
On the contrary: the R15-modification will produce an excessive amount of heat then.
I recommend to solder a small (for example 4.7µF) MKT parallel to C1 (3.300µF) .
The size of the PCB is 100 x 75mm.
A pair of PCBs incl. worldwide shipping will cost 12€.
Tell me, if you are interested.
Best regards - Rudi_Ratlos
The PCB includes the ACA#1 (with R15 mod.) and PSU.
As PSU you can use:
1) a 19VDC brick: connect it to the GND (=OUT) - and +V - Faston 6.3mm connectors. You need not solder any PSU-component of the PCB.
But I do not recommend to use a 19VDC PSU. The ACA's sound is "dull, without passion, the high tones are clipped", even if the R15-modification is activated.
2) a 24VDC SMPS (for example from MeanWell): same PSU connections.
The ACA's sound is incomparably better. It has life and internal rhythm.
3) a standard PSU, consisting of a 2x18VAC torroid, being followed by the PCB's rectifier and smoothing cap section. Do not populate Jason's CAP-multiplier
and solder a wire between the drain and source of the shown IRFP9140 pass transistor.
Concerning the sound: comparable with the SMPS-version, but "noticeably "quicker and with more control" in the bass.
4) Solder Jason's CAP-Multiplier, giving a very smooth (small ripples) operating voltage.
You will need a transformer rated at about 20VAC though to reach an operating voltage of about 24VDC.
Concernng the sound: if you listen very carefully (for example while you are listening to a piano solo), you will notice that there is an improvement when compared to alternative 3).
You do not need the R15-modification in cases 2-4).
On the contrary: the R15-modification will produce an excessive amount of heat then.
I recommend to solder a small (for example 4.7µF) MKT parallel to C1 (3.300µF) .
The size of the PCB is 100 x 75mm.
A pair of PCBs incl. worldwide shipping will cost 12€.
Tell me, if you are interested.
Best regards - Rudi_Ratlos
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Micha, the minimum amount of PCBs to order is 10.
I will wait a couple of days (at most one week), until the limit is reached.
Best regards - Rudi
I will wait a couple of days (at most one week), until the limit is reached.
Best regards - Rudi
Thank you for your interest, gentlemen.
I am even thinking about offering you the "hard-to-get-parts" for my ACA-revision.
For example (have a look at the attached image showing my current ACA-PCBs):
1) the 0R47 / 0R68 MPC7x resistors (the white ceramic "bricks": they are the best "emitter-resistors" that I know)
2) the used ZTX450
3) the used 2SC1845- and 2SK170- transistors
4) the 4.700µF smoothing caps, the big light-blue capacitors.
The used grid of my PCB is EB20D. But it is only Vishay that I know to offer a suitable capacitor with this grid (https://www.buerklin.de/default.asp?search=12D4858&event=ShowSE()&l=d&ch=11759&suggestion=)
I have added the schematics of the ACA#1 and Jason's CAP-Multiplier at the bottom.
If you want me to change anything concerning the layout: please tell me!
Best regards - Rudi_Ratlos
P.S.: You do not need to activate the R15-mod, if you are going to give the ACA#1s an operating voltage of >= 24VDC.
This will not contribute to a sound-improvement in this case (in my ears).
You do not need to further cool-down the rectifier's diodes as shown on image 1 then.
I am even thinking about offering you the "hard-to-get-parts" for my ACA-revision.
For example (have a look at the attached image showing my current ACA-PCBs):
1) the 0R47 / 0R68 MPC7x resistors (the white ceramic "bricks": they are the best "emitter-resistors" that I know)
2) the used ZTX450
3) the used 2SC1845- and 2SK170- transistors
4) the 4.700µF smoothing caps, the big light-blue capacitors.
The used grid of my PCB is EB20D. But it is only Vishay that I know to offer a suitable capacitor with this grid (https://www.buerklin.de/default.asp?search=12D4858&event=ShowSE()&l=d&ch=11759&suggestion=)
I have added the schematics of the ACA#1 and Jason's CAP-Multiplier at the bottom.
If you want me to change anything concerning the layout: please tell me!
Best regards - Rudi_Ratlos
P.S.: You do not need to activate the R15-mod, if you are going to give the ACA#1s an operating voltage of >= 24VDC.
This will not contribute to a sound-improvement in this case (in my ears).
You do not need to further cool-down the rectifier's diodes as shown on image 1 then.
Attachments
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