• Hello and Welcome to HiFiVision.com - an online community for the home entertainment and tech enthusiasts!

    If you would like to ask a question, participate in a discussion and view attachments please Register yourself.

My ACA Amp

Marantz offers at HiFiMART.com

arunlouie

Active Member
Joined
Feb 27, 2009
Messages
294
Points
43
Location
Chennai
This is my first stereo setup and with so much great reviews on ACA, I decided to go with it. Got the kit from Sachin ji ( Thanks again) which was lying idle for months .
Started shopping for parts locally, found these small yet heavy heat sinks. Initially purchased lighter heat sink but long one. Then read somewhere that the horzontal fins have 75% efficiency of vertical. Then exchanged with these smaller ones. Even after 6w mod with little air circulation the amp is running just warm.


Bare board


Drilling threaded holes for the mount screws



Ready for test


First test with FH3


Front , back , top, bottom; all plates. Top and bottom plates are the steel loovers from hardware store.


Stands from harware shop. 50rs per pair.





Too much of filing of aluminium plate to match the het sink height. Shhh one hell of task to manually file a 10mm plate.





Boxed



Inside view. Hard to handle with this small cabinent and poor enclosure plan ( screws only from back. All other screw heads are done internal).




Fully painted





Now singing loud, enough to disturb all the neighbours.

Next to come, K-buffer.


Thanks to Hifivision and Sachin ji!!
 

saikatbiswas82

Well-Known Member
Joined
Jun 24, 2012
Messages
1,305
Points
113
Location
Kolkata
Awesome DIY efforts. It's pretty hard to explain to people what a 5w class a can do really.
Congratulations on your build!

Just a little perspective - I had built the k-buffer prior to my ACA. As all (or most) pass designs have a input jfet buffer (IMHO), you might not get much improvement in overall sq with k-buffer (again IMHO). I had that problem and since my ACA, I've taken k-buffer out of chain. It might gel with my other upcoming builds.

Papa rocks! [emoji4]

Sent from my Nexus 5 using Tapatalk
 
Last edited:

arunlouie

Active Member
Joined
Feb 27, 2009
Messages
294
Points
43
Location
Chennai
Just a little perspective - I had built the k-buffer prior to my ACA. As all (or most) pass designs have a input jfet buffer (IMHO), you might not get much improvement in overall sq with k-buffer (again IMHO).

Thanks Saikat!!
May be. But anyway with my PC being source I will have preamp for volume control and Input selector. Later will try some other pre-amp if not much improvement.
 

saikatbiswas82

Well-Known Member
Joined
Jun 24, 2012
Messages
1,305
Points
113
Location
Kolkata
Thanks Saikat!!
May be. But anyway with my PC being source I will have preamp for volume control and Input selector. Later will try some other pre-amp if not much improvement.

That's the spirit. In audio, everything is relative. But in DIY, one thing is certain - you have to build it to know it. [emoji4]

As your source is different from mine, I guess you might get benefitted with k-buffer.

All the best!

Sent from my Nexus 5 using Tapatalk
 

omishra

Well-Known Member
Joined
May 31, 2011
Messages
2,449
Points
113
Location
Pune
Nice amplifier, excellent build.
I like the cabinet, well executed project.
Congratulations.

Sent from my E6 using Tapatalk
 

sarathssca

Member
Joined
Jul 31, 2014
Messages
111
Points
18
Location
chennai, india
Here how to solder the MOSFET mounted on the heat sink to the PCB board?
As we r using a single side PCB and all the components are on one side and it seems we need to connect / solder the MOSFET (heat sink mounted ) on the opposite side ... How to do this ..
 

arunlouie

Active Member
Joined
Feb 27, 2009
Messages
294
Points
43
Location
Chennai
You have to solder the side along with Mosfet leads (not other side of the board like you do for other components). Its better to solder first and then bend for the heat sink.
 

sarathssca

Member
Joined
Jul 31, 2014
Messages
111
Points
18
Location
chennai, india
Oh ok .. so we need to first solder mosfet along the other components and then fix it to the heat sink ..
So if suppose we need to change any wiring we need to remove heat sink from mosfet , then go the soldering the wires / connections and then put back mosfet to heat sink .??
 

kpsthakur

Member
Joined
Dec 27, 2015
Messages
38
Points
8
Location
Gurgaon
This is my first stereo setup and with so much great reviews on ACA, I decided to go with it. Got the kit from Sachin ji ( Thanks again) which was lying idle for months .

Started shopping for parts locally, found these small yet heavy heat sinks. Initially purchased lighter heat sink but long one. Then read somewhere that the horzontal fins have 75% efficiency of vertical. Then exchanged with these smaller ones. Even after 6w mod with little air circulation the amp is running just warm.





Bare board





Drilling threaded holes for the mount screws







Ready for test





First test with FH3





Front , back , top, bottom; all plates. Top and bottom plates are the steel loovers from hardware store.





Stands from harware shop. 50rs per pair.











Too much of filing of aluminium plate to match the het sink height. Shhh one hell of task to manually file a 10mm plate.











Boxed







Inside view. Hard to handle with this small cabinent and poor enclosure plan ( screws only from back. All other screw heads are done internal).









Fully painted











Now singing loud, enough to disturb all the neighbours.



Next to come, K-buffer.





Thanks to Hifivision and Sachin ji!!



Cool, did you get the 2SKs as part of the kit?? Or did you source them from somewhere
 

kpsthakur

Member
Joined
Dec 27, 2015
Messages
38
Points
8
Location
Gurgaon
Oops, just got trigger happy..I agree this is not a good design for mounting MOSFETs...I may have a pair of Pass ACA v2 pcbs lying somewhere....let me know if you ever get interested
 

sarathssca

Member
Joined
Jul 31, 2014
Messages
111
Points
18
Location
chennai, india
For ACA amp with heat sink of size : 190mm*100mm*30mm each, which of the below options be better:
1. with single 19v 90w laptop power supply for both the channels, without 6w 2.2k R15 mod.
2. with above power supply and with 6w 2.2k R15 mod.
3. with 24v SMPS power supply without 6w 2.2k R15 mod.
4. with 24v SMPS power supply with 6w 2.2k R15 mod.

Will the 2.2k R15 mod be significantly better than normal circuit without it or will it be more of unnecessary heat generated for the given heat sinks?
 

manniraj

Well-Known Member
Joined
Jun 3, 2011
Messages
2,769
Points
113
Location
Bangalore
I have the small red cabinet brought from the group buy of Raghunath for the ACA without 2.2k R15 mod. The cabinet with those small heat sinks are sufficient and I think I have the Dell 19v 90w laptop single power supply. But later I did the 2.2k mod to get to 6w and now the same cabinet with those heat sinks get very hot. Even with Bangalore cold climate it gets pretty hot after 1 hr of playback and you cannot keep your finger more than few minutes. The mod did make a slight difference in terms of able to run less sensitive Mark Audio 7p frugal horns of 87db compared to the 5w. But it does require a bigger heat sink to accommodate almost double the heat for just extra 1w of power output.
 
Top