I am using my amp with 6W mod. When you put in airy place you shouldn't need to worry. Mine if you see the length wise its small but the fins are larger, its hardly gets heat when my ceiling fan is running .
My ACA Amp
- Thread starter arunlouie
- Start date
I am using my amp with 6W mod. When you put in airy place you shouldn't need to worry. Mine if you see the length wise its small but the fins are larger, its hardly gets heat when my ceiling fan is running .
saikatbiswas82
Well-Known Member
Mine was 300mmX100mmX25mm
sarathssca
Member
Hi .. could u please help with below queries regarding aca amp build .. attached couple of photos of current state ..
1. Can we use cat6 ethernet cable as in the photo .. the cat6 cable has 4 pairs of twisted wires .. I have connected 1 pair (2 individual wires) for each : input positive , input negative , output positive and output negative .. thus both input and output are going in single cat6 cable .. is it ok or do we need to have normal twisted pair cables separately for input and output ?
2. As we r using laptop power supply .. I am planning to use laptop power supply socket/holder as in the photo , so that we may use any laptop power supply directly without tampering it .. is it ok or do we need to have a different type of connection for power supply input ??
3. I am planning to have preamp also to be housed in the same box as this aca amp .. please suggest what type of connectors we may use for connecting input/output/power between the pre amp and main aca amp .. so that if needed we can swap preamps later ie. not to solder wires directly between them and common power supply ..
Attachments
Yes, you can use it tat way. But it is better to use separate cables and try to use thicker wire for output.
No problem in using the socket you are using.
There is no need of pre-amp if your source has decent output, it will help for FM's to answer your question if you let us know about your source.
As for connectors you can use below mentioned terminals for ease of change.
https://diyaudiocart.com/diy-amplifier/connectors-and-terminals/Male-Disconnect-Terminal-6.3mm
you might have to do some modification to this terminal to use it on ACA as the ACA only has single hole, I have cut the one spike from the terminal to mount it with only single spike on the PCB.
Single spike male terminal might also be available however it was not in stock at the time.
https://diyaudiocart.com/diy-amplifier/connectors-and-terminals/Female-Disconnect-Terminal-6.3mm
or
https://diyaudiocart.com/diy-amplif...-Side-Entry-Right-Angled-Screw-Terminal-Block
or
https://diyaudiocart.com/diy-amplif...rminals/2-Pin-Side-Entry-Screw-Terminal-Block
Regards
Bilal
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sarathssca
Member
i am thinking to use with general domestic audio sources like mobile headphone output, laptop/pc headphone output, TV, STB audio out, cd/dvd player etc..
was thinking of preamp in the case if 5w from ACA is not sufficient for the speakers..
have two end speakers for which this may be used for, one is " mark audio alpair 7p" and other is a pair of sony ss-rv900 speakers (i think 100w, 6 ohms each)
Yes, for these sources you might need a preamp to drive ACA at it's full potential.
Alpair should be great for ACA.
If you would like you can also go for 6 watt mod for ACA if you feel 5 watt is not sufficient.
Regards
Bilal
Please use separate pairs of wires for the four connections, preferably shielded twisted pairs (like pro audio balanced cables). You're increasing the chances of cross talk between the inputs and outputs by bunching them all together. A very bad practice, IMO.
But having said that, please note that solid core, high purity OFC copper like Ethernet wires insulated with Teflon has a very good sonic characteristics (which I personally like a lot). The downside is rigid solid core wires are very difficult to solder securely and are prone to dry solder and physical breakage (the reason I stopped using Ethernet wires).
But having said that, please note that solid core, high purity OFC copper like Ethernet wires insulated with Teflon has a very good sonic characteristics (which I personally like a lot). The downside is rigid solid core wires are very difficult to solder securely and are prone to dry solder and physical breakage (the reason I stopped using Ethernet wires).
sarathssca
Member
So shall i take individual twisted pairs from the cat-6 cable outside and twist 4 strands together and out of those 4 strands use 2 for input positive and other 2 for input negative.
And similarly take another 4 strands and twist them together and out of those 4, use 2 strands for output positive and 2 for output negative (so here all will be individual wires without outer protection layers as in whole cat-6 cable)?
any idea how much gain do a preamp need to fully drive ACA
You need to figure out what is the output of your sources then decide, how much gain you need in your preamp.
If I remember correctly then the input sensitivity of ACA is 1.7vRMS, (correct me if I'm wrong) I think something in between 1.7vrms to 2vrms is fine for ACA ( I'm driving my ACA 6 watts modes version with 2vrms without issues)
CAT6 already contains 4 pairs of twisted wires. No need to twist again as they are already twisted together as a pair. Separate the four pairs.
Use one pair each for input left and right and output left and right. Don't bunch or twist the two pairs of inputs. And don't bunch or twist together the two pairs of outputs. Separate the four pairs physically as much as allowable. This will reduce crosstalk.
sarathssca
Member
Just thinking if the single strand of wire be very thin.. so only thought to have one pair for input left positive and one pair for input left negative, one pair for output left positive and one pair for output negative. And similar for right side.. so on left side total 4 pairs and right side 4 pairs..
Could you please suggest how shall i proceed wiring these..
Don't worry about thinness. A CAT6 wire is 24 AWG thickness and adequate to carry line level signal.
However, my experience is thicker wire can give more bass weight. So feel free to experiment with two wires per lead instead of single wire per lead. But make sure that the twisted pair used as negative lead is properly twisted with the twisted pair used as positive lead.
You will however face a challenge of inserting together two CAT6 wires into PCB holes. You could simply solder both on the PCB solder pad.
Do be also aware that solid core wires tend to roll off highs a bit compared to multi stranded wires. This may or may not be a good thing depending on your system and taste. Suck it and see, in a manner of speaking
sarathssca
Member
But make sure that the twisted pair used as negative lead is properly twisted with the twisted pair used as positive lead.
Do be also aware that solid core wires tend to roll off highs a bit compared to multi stranded wires. This may or may not be a good thing depending on your system and taste. Suck it and see, in a manner of speaking
but a wire would be resistive in nature .. how would it roll off the highs..
so basically we need to twist the positive and negative wires irrespective of how many strands we use for each (and whether they themselevs are twisted or not)??
Regarding roll off, I don't know why but have heard it on both small signal applications like amp internal wiring or equipment interconnect cables, as well as speaker cables.
Yes to your second sentence.
The dry soldering issue could be because of the smooth surface of the Copper lead. You can try scraping the bare copper lead all around the length before inserting into the PCB hole and soldering for better results.
saikatbiswas82
Well-Known Member
A couple of things I'd rather do for my builds. Please note that these are not practical or measured solutions. I'm a bit skeptical and that's the reason -
1. I'll never house pre and power in same cabinet
2. I'll shield transformer with iron/aluminium cover (however for aca trafo is not necessary)
3. I'll house the amp and preamp in metal cases only.
4. For power supply and speaker terminal connection I'll use finolex 2.5sqmm or 4sqmm wires only.
5. For line level signal I'll use coax cables only.
I don't have any justification why I'll follow the above steps. Again I'm a bit skeptical.
Thanks,
Saikat
1. I'll never house pre and power in same cabinet
2. I'll shield transformer with iron/aluminium cover (however for aca trafo is not necessary)
3. I'll house the amp and preamp in metal cases only.
4. For power supply and speaker terminal connection I'll use finolex 2.5sqmm or 4sqmm wires only.
5. For line level signal I'll use coax cables only.
I don't have any justification why I'll follow the above steps. Again I'm a bit skeptical.
Thanks,
Saikat
sarathssca
Member
what is the reason for the above
is it the head from power amp effecting pre amp or any other issue??
why do we need to have only metal cases..
and also why cove transformer (if used) with metal ?
sarathssca
Member
I have separated the cat-6 cable outer cover to get the individual strands separated as in photo .. so now one pair of strands for each input positive and negative and output positive and negative .. is it ok now ..
saikatbiswas82
Well-Known Member
The main reason for covering with metal is - electromagnetic interference. However, every point ive mentioned earlier may not be necessary.
sarathssca
Member
Finally assembled and got the amp sing ..
- no thump sound at power on or off .. it's smoothly starting and stopping ..
- finally used 4 strands of cat-6 cable for each output positive and negative on one side.. my soldering job little ordinary only
- I couldn't get the bolt/connectors for mounting the board and MOSFETs on the heatsink as in other aca builds here .. I have used normal screw and nuts for this as in photos but faced difficulty in properly fitting the board and MOSFETs. Needed to put the screws from behind the heatsink and put the bolt on top as I couldn't put the bolt behind the heatsink .. also the holes for MOSFETs and PCB were not properly aligned as my heatsink has horizontal fins ..
- my heatsink r of size 190mm *95mm *33mm.. is it ok .. while running it's getting very very hot .. i haven't done any mod and these r running on 19v 90w power supply.. do I need to use bigger heatsink or small fan or another additional heatsink and fix it over these 2 heatsinks ..
- volume out of the alpair 7p speakers r coming little less only .. current volume is ok for near field .. now need to run these to break in the alpair 7p drivers
..
- no thump sound at power on or off .. it's smoothly starting and stopping ..
- finally used 4 strands of cat-6 cable for each output positive and negative on one side.. my soldering job little ordinary only
- I couldn't get the bolt/connectors for mounting the board and MOSFETs on the heatsink as in other aca builds here .. I have used normal screw and nuts for this as in photos but faced difficulty in properly fitting the board and MOSFETs. Needed to put the screws from behind the heatsink and put the bolt on top as I couldn't put the bolt behind the heatsink .. also the holes for MOSFETs and PCB were not properly aligned as my heatsink has horizontal fins ..
- my heatsink r of size 190mm *95mm *33mm.. is it ok .. while running it's getting very very hot .. i haven't done any mod and these r running on 19v 90w power supply.. do I need to use bigger heatsink or small fan or another additional heatsink and fix it over these 2 heatsinks ..
- volume out of the alpair 7p speakers r coming little less only .. current volume is ok for near field .. now need to run these to break in the alpair 7p drivers
..
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