Not sure they are so good than thin Mica+good thermal grease, considering thermal resistance ?
~ 0.75 - 1.0 VS ~ 0.9 - 1.5
Aluminium (0.4) or Beryllium (0.25) oxyde ones are fragile the best of all isolators on my opinion.
Don't eat Berillium pads, because they are toxic 😀
Last edited:
Hi LC,
Which one sounds better, a singe FO or a bridged FO (sound wise and not DB wise), with power hungry speakers ?
Thanks
Which one sounds better, a singe FO or a bridged FO (sound wise and not DB wise), with power hungry speakers ?
Thanks
Despite all our efforts, and because N & P Mosfets or Tranies are never exactly symetrical, a bridged amp will always be better, on a distortion point of view.
Apart for X2 Bass damping factor.
The other advantage is you will reduce power supply ripple influence as well as common mode noise from input's connections, if you use symetrical ones.
The currents (so errors voltages) in the ground returns of each amp is reduced, because no ground connection to the speakers, this is the last advantage.
On my opinion, and if you can go for it, and as long as your DC speaker resistance is >= 6 Ohms, you will prefer-it.
Last edited:
Hard anodized aluminum heat sinks provide a good enough isolation by themselves, as aluminum oxide is a good isolator. They will provide the best thermal resistance of all solutions with no added washer. Some precautions have to be taken: do not screw too firmly the tranies on them, use washers to isolate the screws, verify carefully the perfect isolation once they are mounted, better twice than once.
Ensure no oscillation witch could occurs because the height capacitance between the body of the tranies and the radiator due to the thickness of the oxide.
Of course, you need a good non conductive thermal paste, in all the cases, and use this solution at your own risks..
Last edited:
I tried functionality only, not compared them directly. As Esperado explained there are certain advantages, certainly worth to try. 😉
I've used the Bergquist K10-104 kapton insulators, easy to work with and not fragile (don't break)
Thermal Resistance °C-in²/W: 0.2
Thermal Conductivity, W/m-K: 1.3
Recommended 🙂
Don't believe blind those 1.3, danny_66, verify and compare once mounted. ;-)
Micas are really as simple to use and give better average results, on my experience. DIYers are not in the same situation than manufacturers and can afford little more precautions when they mount their beloved baby to get the best of them 🙂
About speakers impedance and efficiency, i wonder why so many people are using 4 Ohms speakers. They can go down to <3 ohms in their impedance curves, and are just good for cars, on my point of view.
I wonder too why so many people are using low efficiency speakers. They reduce instant dynamic, whatever you try.
I will never use a speaker <95 dB/W ( <90 in the worst case) if you ask me , or mount a Ferrari engine in a tank or an armored car ;-)
Last edited:
Apart for X2 Bass damping factor.
damping factor is 1\2 because each amp see half the impedance.
damping factor is 1\2 because each amp see half the impedance.
Hi Esperado,
The Bergquist K10 are flexible and easy to work with, they work fine in my F5.
For best results: polish the surface of the heatsinks with sandpaper (400-600) and add a very thin layer of thermal paste.
Agree on the speaker high sensitivity = dynamic, mine are 93db, High sensitivity makes it also much easier for the amp 🙂
4 ohm is a design choice, often two woofers are used for BSC, there are not many reasonable sized woofers (8-10") with sensitivity >90db at <100Hz.
Regards,
Danny
The Bergquist K10 are flexible and easy to work with, they work fine in my F5.
For best results: polish the surface of the heatsinks with sandpaper (400-600) and add a very thin layer of thermal paste.
Agree on the speaker high sensitivity = dynamic, mine are 93db, High sensitivity makes it also much easier for the amp 🙂
4 ohm is a design choice, often two woofers are used for BSC, there are not many reasonable sized woofers (8-10") with sensitivity >90db at <100Hz.
Regards,
Danny
Last edited:
Normally yes,
but for best results I've added a very thin layer of thermal paste and polished the surface of the heatsinks with sandpaper (400-600).
That's what i mean, of course. A single amp have a X2 damping factor compared to the same in bridged mode.
Or, if we prefer, the internal amp output impedance is, of course, X2 in the bridged configuration, because they work in serial while the speaker remain the same.
Sorry if i was not clear enough and thanks for this precision.
Note too that the output power will be X4 in bridged mode, if each amp can afford the X2 current, and that, each time you double the output power, you just add 3dB to the acoustic level.
Last edited:
What about canceling of even-order harmonics created in the amp, in bridged mode ?
Can this influence the sound quality ?
Can this influence the sound quality ?
To answer this question we should need to know if those harmonics were audible in single mode 🙂
I fear you will have to make your mind by yourself ;-)
Even if you had found advantages on 99 amps with bridged mode this does not imply it will be the same on the hundredth one.
I don't know, but i'm quite sure that L.C. will not resist to try-it soon... may-be the Second One, or the FirstTwo ?
Last edited:
Such 😀.
Thanks this afternoon experience/knowledge sharing for bridged mode Christophe, sorry it produces quistions because lack of knowledge. Should one forget bridged mode if not present having high end balanced pre signal. I mean if one only has what one thinks very good single ended pre signal (lack of balanced mode), does trafo or active circuit to add balanced pre signal eat up benefits you descriped for power amp, or should pre signal be designed from start to end to be balanced. Prefer to keep singel ended at start in chain if possible because of simpler cheaper volume control (using at least two or more mono amps for each speaker). Next question is if good balanced pre mode signal can be diy, where to find 🙄.
Last edited:
I'm sure not ;-)
Too many various situations for unique and simple answers. Of course, balanced links are always better, more and more benefit with distance and cable's lengths.
To feed a bridged amp, you need a symmetrical signal. It seems more clever to build a symmetrical output in your preamp than a asy/sym converter in the amp itself, as your link between preamp and amp will benefit of symmetry., including for ground loops and leakages from AC between preamp and amp.
Converters ? Active or transfo ? Well, Active can be more transparent and have better transients... Trasfos (good ones) are expensive, simple, and can give more natural results and perfect rejection in difficult environments ?
Filtering HF evils as well.
Volume control ? Asymmetrical is more simple and better in most cases. But you can use shunt ones in a symmetrical design, just the two serial resistances to pair.
You can reach very good results with asymmetrical system, but it will require lot more efforts in tuning and evils hunting.
If you can run in symmetry all the system path, of course, go for it 🙂
Uuuh i turned on that you needed to write so many lines sorry for that. Giving the time explaining deeper the possibilities ups and downs so one understand, you are a unique value library in sound systems reproduce/produce, big thanks 🙂.
Taken from your advise i see future/curiousity/hobby for my local sound system will go for symmetry all paths, though this maybe means years. In meantime i enjoy asymmetrical and what it presents, though hehe tuning and evils hunting has been done for some time and mostly learnt from this domain, asymmetrical not so bad at all.
Last edited:
First One Stereo Connection
Hi GB members
Improved schematic for stereo connection in a single chassis. GND potential of each channel is lifted from chassis earth potential, meaning connection is done via 1 k resistor and anti-parallel diodes. In this way Earth potential interference currents are isolated from GND potential. At the same time GND potential of each channel also isolated in between.
This stereo connection gives best sonic results. 😎
Hi GB members
Improved schematic for stereo connection in a single chassis. GND potential of each channel is lifted from chassis earth potential, meaning connection is done via 1 k resistor and anti-parallel diodes. In this way Earth potential interference currents are isolated from GND potential. At the same time GND potential of each channel also isolated in between.
This stereo connection gives best sonic results. 😎
Attachments
Concerning the new "grounding schematic", should I use half of this when making 2 mono amps? Or should I use another way for grounding?