Well gentlemen, here we have a professional artistic impression of my new 6 channel Audiosector LM4780 amplifier.
Hopefully you can see what I have tried to draw, but if there is any questions please ask.
In terms of real world presence I have built the chassis, the Antek Toroidal's are in and I have all the connectors, cable, etc etc. I expect about a days work to finish the build.
The AS-4222 has dual 115v Primaries, so I will use them in series for 250V. There is only dual secondaries which will be split with a terminal block but I got lazy and drew it as is. There is also an anti-static cable coming from the toroidal which I haven't drawn because I have no idea what to do with it.
I look forward to any constructive feedback
and advice.
Cheers
Dean
Hopefully you can see what I have tried to draw, but if there is any questions please ask.
In terms of real world presence I have built the chassis, the Antek Toroidal's are in and I have all the connectors, cable, etc etc. I expect about a days work to finish the build.
The AS-4222 has dual 115v Primaries, so I will use them in series for 250V. There is only dual secondaries which will be split with a terminal block but I got lazy and drew it as is. There is also an anti-static cable coming from the toroidal which I haven't drawn because I have no idea what to do with it.
I look forward to any constructive feedback
and advice.Cheers
Dean
Attachments
There is also an anti-static cable coming from the toroidal which I haven't drawn because I have no idea what to do with it.
I look forward to any constructive feedback
Cheers
Dean
Earth it!
You could have economised on the toroids but its too late now.
Incidentally, I used one common transformer in my similar (5 channel) amp with two sets of rectifier/smoothing.
Frank
Hi Dean, how are you going to mount the toroids? Cable ties through the bottom of the chassis? Not sure if it will be an issue but toroids radiate the most energy out the hole, so three in line like that, may lead to some interference (with each other), It doesn't look from the picture that they could be mounted horizontally in the space. Note that I'm purely speculating here!
The other issue here may be that some of your input jacks may be right in line with the maximum radiated emf from the toroids (it wasn't a problem with my amp which has a vertically mounted toroid and very compact though. I made sure that the inputs weren't "on axis" with the toroid hole ).
Tony.
The other issue here may be that some of your input jacks may be right in line with the maximum radiated emf from the toroids (it wasn't a problem with my amp which has a vertically mounted toroid and very compact though. I made sure that the inputs weren't "on axis" with the toroid hole ).
Tony.
Hey Tony.
I had planed to mount the three as is with a 35mm wooden dowel through the guts and a mounting plate at each end. I would then use thin sheet rubber to wrap the dowel for a snug fit and between the units to keep them separated with support from underneath also. This would all be bolted together so there was no movement. I am going to be installing partitions running the length of the chassis separating the PS stage from the audio stages. I was also thinking about installing a 5mm alloy partition between each toroidal.
Peter Daniel recommended a single 300Va unit for each pair of amps but after franks comment I suddenly started thinking perhaps I could just mount 2 toroidal's flat and run 3 x LM4780's per 400VA transformer.
What do you think.
The only problem I have then is a back panel with 3 switches/fuses installed.
Dean
I had planed to mount the three as is with a 35mm wooden dowel through the guts and a mounting plate at each end. I would then use thin sheet rubber to wrap the dowel for a snug fit and between the units to keep them separated with support from underneath also. This would all be bolted together so there was no movement. I am going to be installing partitions running the length of the chassis separating the PS stage from the audio stages. I was also thinking about installing a 5mm alloy partition between each toroidal.
Peter Daniel recommended a single 300Va unit for each pair of amps but after franks comment I suddenly started thinking perhaps I could just mount 2 toroidal's flat and run 3 x LM4780's per 400VA transformer.
What do you think.
The only problem I have then is a back panel with 3 switches/fuses installed.
Dean
A quick note..
No, all three transformers will not fit unless standing up.
The chassis will be separated into almost equal thirds. The center being the PS section and each outer third containing the audio stages. They will be separated by a 5mm alloy barrier running the length and height of the chassis.
The back panel is arranged in the same manner so no audio connectors will share the same internal space as the PS section.
Dean
No, all three transformers will not fit unless standing up.
The chassis will be separated into almost equal thirds. The center being the PS section and each outer third containing the audio stages. They will be separated by a 5mm alloy barrier running the length and height of the chassis.
The back panel is arranged in the same manner so no audio connectors will share the same internal space as the PS section.
Dean
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The more I look at it the easier it would be to install only 2 of the AS4222 and remake the back panel. This would make the toroidal mounting very easy and I could make a new back panel in an hour or two.
Does anybody know If 1 x AS4222 could power 3 AudioSector parallel LM4780 modules???
Dean
Does anybody know If 1 x AS4222 could power 3 AudioSector parallel LM4780 modules???
Dean
I'd keep the 3 X 300VA's I think 300VA is a good size for two channels. It's what I'm using, and I do still get some PS sag doing low frequency power tests. Having the partitions and only having input connectors on the amp partition allays any concerns I had
As long as the dowel is wooden I think everything should be ok
Are the LM4780's running bridged? I'm using one 300VA for 2 X LM3886's Overkill? maybe, certainly real world music it at normal listening volumes it draws no where near that!! Scarily low in fact. I'll hook up the power meter and check and report back .
edit again: My daughter just asked to go to the park, so will have to be a bit later
Tony.
As long as the dowel is wooden I think everything should be ok
Are the LM4780's running bridged? I'm using one 300VA for 2 X LM3886's Overkill? maybe, certainly real world music it at normal listening volumes it draws no where near that!! Scarily low in fact. I'll hook up the power meter and check and report back
. edit again: My daughter just asked to go to the park, so will have to be a bit later
Tony.
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OK a few things first to set the scene.
* My speakers are fairly efficient probably about 90db in present config (with no BSC).
* They are 4 ohm, and my PS is 28-0-28 with 57oouF per rail per channel
* The power meter is a mains one, it is quite accurate, and samples quite quickly, but may not pick up very short transients. So the power measurements are the total watts the amp was drawing from the mains.
* The room is approx 4 X 10M
* I'm only running my MTM's which have a -3db point around 90Hz (nearfield) so not a lot of bass in this measurement. I might hook up one of my old three ways to get some bass.
* CD used for testing was Pink Floyd the wall CD 1.
* both channels were being driven.
When the amp is on but idle the power consumption is 11W
When the amp is on and playing music at what I would consider a bit louder than normal level it is running at around 12 to 12.5W and peaking at 15.3W
When I really cranked it up (to the point I was worried the neighbours would complain (and enough to make me think I'd over done it because me ears are now hurting) it peaked out at 66W I didn't see the average figure though because I had the meter on the wrong setting.
So what does this mean? Probably in my case 300VA is major overkill and the comments that people make, that "we don't listen to sine waves" are very true
Tony.
* My speakers are fairly efficient probably about 90db in present config (with no BSC).
* They are 4 ohm, and my PS is 28-0-28 with 57oouF per rail per channel
* The power meter is a mains one, it is quite accurate, and samples quite quickly, but may not pick up very short transients. So the power measurements are the total watts the amp was drawing from the mains.
* The room is approx 4 X 10M
* I'm only running my MTM's which have a -3db point around 90Hz (nearfield) so not a lot of bass in this measurement. I might hook up one of my old three ways to get some bass.
* CD used for testing was Pink Floyd the wall CD 1.
* both channels were being driven.
When the amp is on but idle the power consumption is 11W
When the amp is on and playing music at what I would consider a bit louder than normal level it is running at around 12 to 12.5W and peaking at 15.3W
When I really cranked it up (to the point I was worried the neighbours would complain (and enough to make me think I'd over done it because me ears are now hurting) it peaked out at 66W I didn't see the average figure though because I had the meter on the wrong setting.
So what does this mean? Probably in my case 300VA is major overkill and the comments that people make, that "we don't listen to sine waves" are very true
Tony.
Great work Tony.
So, If I have this right...
* Your 2 x LM3886 Draws 66W @ high power into a 4Ohm/90dB load.
* My 6 x LM4780 might draw = 6x66 = 396Watts
* If I use 2 x 400Va toroidal's thats 396/2= 198Watts
* So assuming these very rough calcs I would only be using these transformers at half there rated power when running hard(ish)
I could always hook up 3 units to each tranny and see what happens, I think we have a pretty safe margin here.
A few more pics to help with the idea.
Dean
So, If I have this right...
* Your 2 x LM3886 Draws 66W @ high power into a 4Ohm/90dB load.
* My 6 x LM4780 might draw = 6x66 = 396Watts
* If I use 2 x 400Va toroidal's thats 396/2= 198Watts
* So assuming these very rough calcs I would only be using these transformers at half there rated power when running hard(ish)
I could always hook up 3 units to each tranny and see what happens, I think we have a pretty safe margin here.
A few more pics to help with the idea.
Dean
Attachments
The case is 440x350x150.
The top/bottom/front are 5mm 5005 Alloy, the back is 3mm.
The Heat sinks are Conrad MF35's which may be overkill but the hole thing can be used for my f5 when its ready and I can build this into something half the height if I end up using 2 horizontal toroidals.
Dean
The top/bottom/front are 5mm 5005 Alloy, the back is 3mm.
The Heat sinks are Conrad MF35's which may be overkill but the hole thing can be used for my f5 when its ready and I can build this into something half the height if I end up using 2 horizontal toroidals.
Dean
Sounds like a pretty safe margin to me Dean and that 66W wasn't continuous, it was peak. I was watching with it on peak indicator, it started at around 40W and every now and then went up highest was 66W I didn't switch it back to instantanious to watch so unfortunately didn't get an idea of the range, and didn't want to subject the neighbors (or myself) to those volumes again
My test wasn't hugely rigorous but it
does seem to reflect what others have said regarding power consumption on music compared to sine waves (which are traditionally used for testing power output capabilities).
I'll have to get the dummy loads out and see what the power meter says when pushing it to clipping with a sine wave into an 8 ohm dummy load, probably won't get a chance to do that until tomorrow though.
Tony.
and that 66W wasn't continuous, it was peak. I was watching with it on peak indicator, it started at around 40W and every now and then went up highest was 66W I didn't switch it back to instantanious to watch so unfortunately didn't get an idea of the range, and didn't want to subject the neighbors (or myself) to those volumes again My test wasn't hugely rigorous but it
does seem to reflect what others have said regarding power consumption on music compared to sine waves (which are traditionally used for testing power output capabilities).
I'll have to get the dummy loads out and see what the power meter says when pushing it to clipping with a sine wave into an 8 ohm dummy load, probably won't get a chance to do that until tomorrow though.
Tony.
Hold on,
Those CL60's appear to be across (in parallel with) the AC input.
They should be in series with the input (I'd stick them in the "live" wire.)
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