Ah, OK. Yeah. Tomato, tomato. 
I'm referring to the harmonics of the mains frequency not the mains frequency itself. In one of my recent power supply review videos you'll see those components extending well into the kHz range and creating all sorts of IMD products.
Tom
I'm referring to the harmonics of the mains frequency not the mains frequency itself. In one of my recent power supply review videos you'll see those components extending well into the kHz range and creating all sorts of IMD products. Tom
I got to the point where I concluded that the Micro Audio SMPS has higher switching noise than I'd like. Sami suggested that I try filtering, which I will.
The Connex SMPS300 uses an additional LC filter on the output. The Micro Audio doesn't have that ... yet.
What has also happened is that Mean Well released the LOP-600 series, which looks incredibly promising. If it works well, Micro Audio will be a tough sell. It is vastly more convenient to have a single supply rather than having to mess with two supplies in series, but would that be worth the 20-25% added cost compared to the LOP-600. Then again, the Mean Well RPS-400 and LOP-600 share the same underlying topology, and about 50% of builders had issues with the RPS-400-36, so maybe the LOP-600 isn't so hot after all.
Decisions, decisions.
As noted elsewhere, I have my hands full at the moment. I remain committed to finding a quality alternative to the Connex SMPS300, even though it'll be at a significantly higher price.
Tom
The Connex SMPS300 uses an additional LC filter on the output. The Micro Audio doesn't have that ... yet.
What has also happened is that Mean Well released the LOP-600 series, which looks incredibly promising. If it works well, Micro Audio will be a tough sell. It is vastly more convenient to have a single supply rather than having to mess with two supplies in series, but would that be worth the 20-25% added cost compared to the LOP-600. Then again, the Mean Well RPS-400 and LOP-600 share the same underlying topology, and about 50% of builders had issues with the RPS-400-36, so maybe the LOP-600 isn't so hot after all.
Decisions, decisions.
As noted elsewhere, I have my hands full at the moment. I remain committed to finding a quality alternative to the Connex SMPS300, even though it'll be at a significantly higher price.
Tom
Another pair of Modulus-86s are alive! No pictures yet as it is just roughed in my old F5 case for testing.
My initial assessment is that I can finally understand why so many builds here involve expensive cases and speaker protection circuits. This is a quality amp.
I had been a bit worried about the output power, because one of my other amps (60W) sounds strained and loses a lot of clarity when I turn the music up. This one does not and I'm currently only running it on 24V rails.
When we recover financially from recent vet bills a Dissipante 2U 300 seems like it would look really slick.
My initial assessment is that I can finally understand why so many builds here involve expensive cases and speaker protection circuits. This is a quality amp.
I had been a bit worried about the output power, because one of my other amps (60W) sounds strained and loses a lot of clarity when I turn the music up. This one does not and I'm currently only running it on 24V rails.
When we recover financially from recent vet bills a Dissipante 2U 300 seems like it would look really slick.
Not a bad temporary home. Even though it's only temporary I would still do something to brace at least the front edge of the board. I often use some long standoffs, screws, or threaded rod for this. Just 'tune' it to the right length. All you need is something to fight gravity so the chip doesn't do all the work. Of course, once yo find a permanent home you'll secure the boards by all corners.
Tom
Tom
Depends... If the sub has a plate amp with a high-impedance, speaker voltage input then you can connect it in parallel with your speakers. But if the sub is just a speaker driver then I'd hesitate to simply hook it in parallel for a number of reasons.
Personally I would rather take the sub output at line level, i.e., at the output of the preamp.
Tom
Personally I would rather take the sub output at line level, i.e., at the output of the preamp.
Tom
After several 16 hour days, I have to say I'm impressed. I was worried it might sound harsh but it just sounds like the music. With my last couple SS amps I used a preamp that had a bass boost option that would lift up everything below 500hz and with this I don't need that. There is nothing lacking from the bottom to the top in the music. Even running it at 24V I don't run out of power. I have fallen asleep listening to it fairly loudly a couple of times and to me, that is a good sign.
Having started out with a DIY tube amp I kept gravitating towards amps that were described as being 'sweet sounding'. But in all honesty I think my SE tube amp ran pretty clean. It probably helped that I had a 21st Century Maida Regulator in it
The only thing that is annoying is I will have to build at least one more, so I can have one in my home office too. And maybe another as a gift for the person I built a different LM3886 based amp for a few years back.
Having started out with a DIY tube amp I kept gravitating towards amps that were described as being 'sweet sounding'. But in all honesty I think my SE tube amp ran pretty clean. It probably helped that I had a 21st Century Maida Regulator in it
The only thing that is annoying is I will have to build at least one more, so I can have one in my home office too. And maybe another as a gift for the person I built a different LM3886 based amp for a few years back.
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barossi,
I tried only one SMPS with the Modulus-86 - it is a Connex Electronics SMPS300R.
If I am not wrong Tom did his initial testing with the Connex SMPS and published measurements; so I followed suit and got the SMPS300R, albeit at a lower voltage than Tom's. If I am not wrong Tom used a +/-30V DC unit, and the one I ordered was +/- 24V DC with option to increase voltage by 10%. Highest I can get is +/- 25V DC.
I also have a 2x22V AC transformer for building a linear power supply for the Mod-86 that should give ~+/- 30V DC output; however never got to building that power supply, and been using the amplifier powered by the SMPS unit only.
I tried only one SMPS with the Modulus-86 - it is a Connex Electronics SMPS300R.
If I am not wrong Tom did his initial testing with the Connex SMPS and published measurements; so I followed suit and got the SMPS300R, albeit at a lower voltage than Tom's. If I am not wrong Tom used a +/-30V DC unit, and the one I ordered was +/- 24V DC with option to increase voltage by 10%. Highest I can get is +/- 25V DC.
I also have a 2x22V AC transformer for building a linear power supply for the Mod-86 that should give ~+/- 30V DC output; however never got to building that power supply, and been using the amplifier powered by the SMPS unit only.
I started with the Connex SMPS300RE and have since then used the SMPS300REh. They appear to be identical electrically, but the added metal mounting plate of the 'h' version has definitely increased the reliability of that supply in my experience.
I've always used ±30 V with the Modulus-86, though I have tested up to ±36 V. I recommend ±30 V for a "load-invariant" design (to borrow a Doug Self term) and ±36 V for 8Ω-only operation.
There's nothing wrong with going lower in supply voltage. The Modulus-86 will work down to ±20 V, but naturally the max output power scales with the supply voltage. But so does the amount of power dissipated. There's a plethora of SMPSes available for ±24 V, so that's attractive. You can expect about 28 W into 8 Ω and about twice that into 4 Ω with that supply voltage.
Tom
I've always used ±30 V with the Modulus-86, though I have tested up to ±36 V. I recommend ±30 V for a "load-invariant" design (to borrow a Doug Self term) and ±36 V for 8Ω-only operation.
There's nothing wrong with going lower in supply voltage. The Modulus-86 will work down to ±20 V, but naturally the max output power scales with the supply voltage. But so does the amount of power dissipated. There's a plethora of SMPSes available for ±24 V, so that's attractive. You can expect about 28 W into 8 Ω and about twice that into 4 Ω with that supply voltage.
Tom