Toroidy makes good stuff.
I'm still puzzled that you had issues with speaker pops on the MOD286. I've built several and they've all powered up and down quietly. Are you using an unbalanced source and pseudo-differential connection by any chance?
Tom
Now this... The Guardian-86 Rev. 2.0 just launched.
Major improvements over Rev. 1.0:
The Guardian-686 will be discontinued once the current stock has sold. I have six fully assembled Guardian-686 in stock and on sale at $169/each (reg. $199/each). I also have a good handful of the bare boards in stock. Shop the sale here: https://neurochrome.com/products/guardian-686
You can read more about the Guardian-86 here: https://neurochrome.com/products/guardian-86
Tom
Major improvements over Rev. 1.0:
- Works without modifications on any amp power by ±15 to ±90 V (or single-ended amps powered by +15 to +90 V).
- Works with all amplifier types: Single-ended and bridged/BTL.
- Smaller footprint (40 x 45 x 27 mm; W x D x H).
- Automatic sensing of the power supply and automatic disabling of the output once the power supply voltage drops to 2/3 of its nominal value. This eliminates clicks and pops on power-down.
The Guardian-686 will be discontinued once the current stock has sold. I have six fully assembled Guardian-686 in stock and on sale at $169/each (reg. $199/each). I also have a good handful of the bare boards in stock. Shop the sale here: https://neurochrome.com/products/guardian-686
You can read more about the Guardian-86 here: https://neurochrome.com/products/guardian-86
Tom
Looks like I should get on with ordering two of those Guardian-686 bare boards since I already have most of the parts for it short of the mosfets.
The new guardian-86 boards look good. For the old ones, does it do the autosensing and autodisabling of the power? What is the older ones voltage range?
The new guardian-86 boards look good. For the old ones, does it do the autosensing and autodisabling of the power? What is the older ones voltage range?
The Guardian-86 Rev. 1.0 and Guardian-686 do not have the auto-sensing of the supply voltage. You set the trip point with a zener diode, but it's not super precise. Basically the Guardian browns out and turns off. In the Guardian-86 Rev. 2.0 there's a comparator that compares the supply voltage with 2/3 of the sensed nominal voltage. Once the power supply crosses that 2/3 threshold, the MOSFETs are turned off and the speaker is disconnected.
The Guardian-86 Rev. 1.0 and Guardian-686 will work without modifications up to 45 V. If you want to go higher than that you need to swap a zener diode.
Tom
The Guardian-86 Rev. 1.0 and Guardian-686 will work without modifications up to 45 V. If you want to go higher than that you need to swap a zener diode.
Tom
Hi Tom,
This is a question regarding the Guardian-86 Rev1.0 for single-ended amplifiers. I'd like to move the boards to a standalone chassis with its own power supply and power button, to provide protection with various amplifiers.
The question is about avoiding ground loops or problems. A lot of North American 110-120VAC CD players, preamps and some amplifiers, use 2-blade universal power cables with no earth ground, and avoid ground loops. They might at most have an RF/ESD filter with a megohms resistor and a few small capacitors. I understand a non-earthed chassis like this could be a shock hazard if a wire from the transformer fell loose, etc. Even so, many consumer electronics are approved this way and operate safely.
Looking at Rev1.0, the IN(J1/J2)/OUT (J3) and the power (J4) share the same ground. Given this, would it be sufficient to use the same practice here, and use the Guardian-86 Rev1.0 with a small current 25-30VDC power supply, without a ground to the mains earth?
This is a question regarding the Guardian-86 Rev1.0 for single-ended amplifiers. I'd like to move the boards to a standalone chassis with its own power supply and power button, to provide protection with various amplifiers.
The question is about avoiding ground loops or problems. A lot of North American 110-120VAC CD players, preamps and some amplifiers, use 2-blade universal power cables with no earth ground, and avoid ground loops. They might at most have an RF/ESD filter with a megohms resistor and a few small capacitors. I understand a non-earthed chassis like this could be a shock hazard if a wire from the transformer fell loose, etc. Even so, many consumer electronics are approved this way and operate safely.
Looking at Rev1.0, the IN(J1/J2)/OUT (J3) and the power (J4) share the same ground. Given this, would it be sufficient to use the same practice here, and use the Guardian-86 Rev1.0 with a small current 25-30VDC power supply, without a ground to the mains earth?
Many consumer audio devices follow electrical safety Class II, which is how they avoid the mains earth connection to the chassis. Class II requires additional insulation and distance between mains and any metal that can be touched by the user. That's why you see the mylar sheets around exposed mains connections and such in that type of equipment.
You can certainly move the Guardian-86 into a separate enclosure, but I wouldn't recommend it. The power supply for the Guardian-86 should be taken from the power supply in the amp. Otherwise you won't get any protection against the turn-on and turn-off thumps and pops. You would still get protection against excessive DC at the output of the amp with the Guardian-86 external, though.
If you do put the Guardian-86 Rev. 1.0 in a separate chassis, feed it with a 12 V Class II wall wart and make zener diode D4 a wire link.
Tom
You can certainly move the Guardian-86 into a separate enclosure, but I wouldn't recommend it. The power supply for the Guardian-86 should be taken from the power supply in the amp. Otherwise you won't get any protection against the turn-on and turn-off thumps and pops. You would still get protection against excessive DC at the output of the amp with the Guardian-86 external, though.
If you do put the Guardian-86 Rev. 1.0 in a separate chassis, feed it with a 12 V Class II wall wart and make zener diode D4 a wire link.
Tom
@wcwc
Vzener ≥ VCC-35 (absolute min)
Vzener ≤ VCC-7.2 (absolute max)
For 57 V rails I’d go with a 39-43 V zener. Get a 1.3 W type. Go with a 39 V type in DO-41 format. 1N4754 will work. Allowing for mains voltage variations and all.
And specifically speaking, I am talking about D4 on the Guardian-86 Rev1.0.
Best,
Anand.
Vzener ≥ VCC-35 (absolute min)
Vzener ≤ VCC-7.2 (absolute max)
For 57 V rails I’d go with a 39-43 V zener. Get a 1.3 W type. Go with a 39 V type in DO-41 format. 1N4754 will work. Allowing for mains voltage variations and all.
And specifically speaking, I am talking about D4 on the Guardian-86 Rev1.0.
Best,
Anand.
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The shutdown speed depends on how much DC voltage is applied at the input of the Guardian-86. I don't have the numbers memorized, but it's in the µs to low-ms range for common rail voltages. I'm sure it wouldn't sound awesome, but the speakers would experience no worse trauma than a good bass thump played with the peaks near clipping. In fact, the bass thump could be worse.
I'll run a simulation to figure out the shutdown speed. That seems like good data to have.
I have a few other priorities right now, so I won't promise a video anytime soon. My top priority is to find myself another car as I was T-boned yesterday by a guy running a deep red light (as in: it had been green in my direction for several seconds before I even approached the intersection). He was going 50-70 km/h (says police). So I got to spend my afternoon in the ER getting a CT scan of my head (precaution!). The good news is that they found my brain (yay!) and also that I don't have any bleeding within it. But I have a bit of a concussion so I'll lay low for a little bit. I'm also pretty sore, but I'm pretty sure that's muscular. The car is a write-off.
Pay attention when you drive. Those cat videos can wait. Oh... And also stick around after the accident. The guy took off. Classy move. Witnesses gave a good description of the vehicle and a partial license plate. So there's hope that the police will catch up with him. Felony hit & run is taken seriously.
Oh, well. This too shall pass.
Tom
I'll run a simulation to figure out the shutdown speed. That seems like good data to have.
I have a few other priorities right now, so I won't promise a video anytime soon. My top priority is to find myself another car as I was T-boned yesterday by a guy running a deep red light (as in: it had been green in my direction for several seconds before I even approached the intersection). He was going 50-70 km/h (says police). So I got to spend my afternoon in the ER getting a CT scan of my head (precaution!). The good news is that they found my brain (yay!) and also that I don't have any bleeding within it. But I have a bit of a concussion so I'll lay low for a little bit. I'm also pretty sore, but I'm pretty sure that's muscular. The car is a write-off.
Pay attention when you drive. Those cat videos can wait. Oh... And also stick around after the accident. The guy took off. Classy move. Witnesses gave a good description of the vehicle and a partial license plate. So there's hope that the police will catch up with him. Felony hit & run is taken seriously.
Oh, well. This too shall pass.
Tom
Glad you got out relatively unscathed. Hope they get the bastard.
Regarding concussions, my advice is to pay attention to the symptoms. Everyday you have a headache or feel disoriented, please take an analgesic (ibuprofen is fine, since you don’t have a bleed). I would lie low as far as hockey is concerned until a few days (say 48 hours) have passed and you don’t have a headache and without analgesics. Thereafter, you can resume your usual intensive aerobic activities. But walking is fine. Regarding work, try to avoid long periods staring at a monitor, like you are doing now. More sleep, rest, and casual, non stressful activities.
Best,
Anand.
Regarding concussions, my advice is to pay attention to the symptoms. Everyday you have a headache or feel disoriented, please take an analgesic (ibuprofen is fine, since you don’t have a bleed). I would lie low as far as hockey is concerned until a few days (say 48 hours) have passed and you don’t have a headache and without analgesics. Thereafter, you can resume your usual intensive aerobic activities. But walking is fine. Regarding work, try to avoid long periods staring at a monitor, like you are doing now. More sleep, rest, and casual, non stressful activities.
Best,
Anand.