Chip Amp Photo Gallery - Page 23

FastEddy · 4th December 2006, 10:53 PM

The more power supply cacacitance and filteration, the better the sound.

If 1000 uF makes it better, then 10,000 uF will make it better as well.

My little 150 Watt (x 2) amp has 40,000 uF on each of the rails = and it helps.

http://3dotaudio.com/ampics.html

These newer Class-D amps will also need plenty of power supply capacitance and filtration: http://www.diyaudio.com/forums/showt...20#post1072820

Kooka · 4th December 2006, 10:58 PM

Oh yes, now I got it: that's the idea behind my adding 2 10.000uF Rubycon caps on eachone of my supply units. Since I installed them later (I did not have a lot of room in the case, at that point, but ok...) I could notice the difference: muuuuch better with the 2 extra black cilinders!

superhkm · 5th December 2006, 08:07 AM

Quote:

Originally posted by FastEddy
Those big caps are required for many, nah most amplifier power supplies ...

yeah, most except Gaincards...

Kooka · 5th December 2006, 08:17 AM

Quote:

Originally posted by superhkm

yeah, most except Gaincards...

You mean that the sound of my GC got worse? I had the opposite impression.

VLSI · 5th December 2006, 08:46 AM

My attempt at a compact Bridged LM4780 Stereo amplifier in an old die-cast box, 220mm x 145mm (190mm including heatsinks) x 50mm high.
Made mostly from junk I had lying around.
Home made single sided PCB,s
The transformer is Mu-Metal shielded
4x 4,700uf/50v capacitors + 4x 1000uf/63v caps on PCB (one under each board)
DC protection circuit and relay at rear + Speaker fuses
65 + 65w RMS 8 ohm
85 + 85w RMS 4 ohm
130w RMS one channel driven for 1min test.
Given the transformer is so close I was surprised there is no hum and despite not using hi-end components (would not fit) the sound quality is still very pleasing.

FastEddy · 5th December 2006, 03:37 PM

" ... Given the transformer is so close I was surprised there is no hum ..."

'Cause the transformer is enclosed in a metal case of its own ?? = a quality shield close to the windings =

As long as the mu-metal transformer case remains grounded to the chassis = very little hum.

Q&A: how did you fasted the heat sinks to the case? ... and do the heat sinks ever get warm ??

planet10 · 5th December 2006, 06:17 PM

Quote:

Originally posted by FastEddy
The more power supply cacacitance and filteration, the better the sound.

One of the tenants of the gain-clone concept is that you can have too much C in the PS. 1000-1500 uF/rail seems to be the sweet spot from the experimenting people have done.

dave

Kooka · 5th December 2006, 06:32 PM

Quote:

Originally posted by planet10

One of the tenants of the gain-clone concept is that you can have too much C in the PS. 1000-1500 uF/rail seems to be the sweet spot from the experimenting people have done.

dave

Ok, but my boards sound better with the extra capacitors. I am almost new to GC, but my ears are still good, and have done a long career...

VLSI · 5th December 2006, 07:55 PM

The Heatsinks are attached with 6x screws into taped threads in the case and a strip of copper buss-bar helps spread the heat from the chip.
There is about 5w at idle so the heatsinks are just warm but get quite warm almost hot on hot days when the amp is pushed hard for long periods even into 8 ohm, I think the amplifier would over heat under the same conditions into 4 ohm.
PS rail voltages are +/-42v, I would have liked it a bit lower but I have 12 of these transformers from old computer terminals and wanted to use one.

VLSI · 5th December 2006, 08:01 PM

Should I put these in my next GC?
Came from a bit of telecom equipment I recently trashed (also had in it 12x 47,000/50v capacitors as well)

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4th December 2006, 10:53 PM	#221
FastEddy diyAudio Member Join Date: Jun 2006 Location: North Californie	The more power supply cacacitance and filteration, the better the sound. If 1000 uF makes it better, then 10,000 uF will make it better as well. My little 150 Watt (x 2) amp has 40,000 uF on each of the rails = and it helps. http://3dotaudio.com/ampics.html These newer Class-D amps will also need plenty of power supply capacitance and filtration: http://www.diyaudio.com/forums/showt...20#post1072820

4th December 2006, 10:58 PM	#222
Kooka diyAudio Member Join Date: Jan 2006 Location: Milan	Oh yes, now I got it: that's the idea behind my adding 2 10.000uF Rubycon caps on eachone of my supply units. Since I installed them later (I did not have a lot of room in the case, at that point, but ok...) I could notice the difference: muuuuch better with the 2 extra black cilinders!

5th December 2006, 03:37 PM	#226
FastEddy diyAudio Member Join Date: Jun 2006 Location: North Californie	" ... Given the transformer is so close I was surprised there is no hum ..." 'Cause the transformer is enclosed in a metal case of its own ?? = a quality shield close to the windings = As long as the mu-metal transformer case remains grounded to the chassis = very little hum. Q&A: how did you fasted the heat sinks to the case? ... and do the heat sinks ever get warm ??

5th December 2006, 07:55 PM	#229
VLSI diyAudio Member Join Date: Nov 2006	The Heatsinks are attached with 6x screws into taped threads in the case and a strip of copper buss-bar helps spread the heat from the chip. There is about 5w at idle so the heatsinks are just warm but get quite warm almost hot on hot days when the amp is pushed hard for long periods even into 8 ohm, I think the amplifier would over heat under the same conditions into 4 ohm. PS rail voltages are +/-42v, I would have liked it a bit lower but I have 12 of these transformers from old computer terminals and wanted to use one.