The SMPS can become instable from driving such a large capacitive load, I would inquire with the manufacturer what they advise as a maximum capacitance on the output. You see, there are already capacitors added inside, so any outside added capacitance can be fairly small and close up, this doesn't add any quality to the circuit.
I've had a look at the specs, and unless I've missed something, there's no mention of capacitive load limits by Meanwell
http://www.meanwell.com/search/s-350/s-350-spec.pdf
Just in case the smps does go unstable, how will this manifest itself?
Hifimediy increased the power caps for those using toroidals. It is indeed not needed with SMPS which don't need the large energy tank a linear supply requires. With linear, the bigger the better. That's not true with SMPS!
I know of two bad impacts of large capacitors after regulated power supply:
- inrush current needed to load the capacitors at power on. SMPS are usually protected against this with a softstart like circuit.
- regulation issues. Because capacitors hide the real load from the power supply, the SMPS regulation can get confused. Capacitors act as a energy tank in between. Worst case is that the SMPS regulator starts oscillating.
Impact will probably be unregulated output voltage and worst case, SMPS overcurrent protection mecanism stops the power supply!
Intuitively, I think that with music its almost impossible to create conditions for oscillation. I have no clue however how badly large capacitors can impact output regulation. Experience shows (at least with the meanwell S-350 and Connex SMPS) that the additional power capacitors are useless, but do not harm.
I know of two bad impacts of large capacitors after regulated power supply:
- inrush current needed to load the capacitors at power on. SMPS are usually protected against this with a softstart like circuit.
- regulation issues. Because capacitors hide the real load from the power supply, the SMPS regulation can get confused. Capacitors act as a energy tank in between. Worst case is that the SMPS regulator starts oscillating.
Impact will probably be unregulated output voltage and worst case, SMPS overcurrent protection mecanism stops the power supply!
Intuitively, I think that with music its almost impossible to create conditions for oscillation. I have no clue however how badly large capacitors can impact output regulation. Experience shows (at least with the meanwell S-350 and Connex SMPS) that the additional power capacitors are useless, but do not harm.
If someone is really scared about this issue, the eaysiest is to remove one of the caps (the two are paralleled) or replace them by smaller ones.
I am sure Hifimediy would do that custom for you if you ask for it
Hmm...the previous supply cap was 4700uF. Is it too big for the smps too?
Hifimediy should comment when he's back and if this is in any way bad for sonics or there's real risk of failure, offer a separate T3e board for smps. The psu board offers speaker protection so it's good to have. I remember in an earlier post he said 4700uF was a good compromise value for linear/smps so he must have a reason for 10,000uF as the new value.
Otoh, the smps has protection against short, overload and overvoltage so if regulation issues arise or speaker cables are accidentally shorted will it act in time to prevent amp damage?
Hifimediy should comment when he's back and if this is in any way bad for sonics or there's real risk of failure, offer a separate T3e board for smps. The psu board offers speaker protection so it's good to have. I remember in an earlier post he said 4700uF was a good compromise value for linear/smps so he must have a reason for 10,000uF as the new value.
Otoh, the smps has protection against short, overload and overvoltage so if regulation issues arise or speaker cables are accidentally shorted will it act in time to prevent amp damage?
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10,000 ok
I just added 10,000uf to my Sure amp and it didn't cause any problem with the MeanWell S-350-36. It didn't make much difference to the sound other than playing a few seconds longer after switch off but The SMPS starts up and runs no problem.
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I just added 10,000uf to my Sure amp and it didn't cause any problem with the MeanWell S-350-36. It didn't make much difference to the sound other than playing a few seconds longer after switch off but The SMPS starts up and runs no problem.
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That was my experience too.
Virtue Audio Sensation uses 33,000uF(!) on board.
small brick smps.
Standard psu is 24V/65W. Upgraded psu version is 30V/130W for an additional $139
Virtue Audio. We make audio lovers audiophiles. Better sound by design.
It isn't really protected against overvoltage, it just shuts off the output stage to protect the speakers and the output stage itself. This is mainly done for safety, to prevent exploding parts and heavy smoke. Don't kid yourself into thinking this is enough to protect the complete functioning of the amplifier.
Did you try very dynamic, bass heavy music? I expect that's where a diff may be heard, if at all.
I am not the owner but what I can see on their site they offer variety of smps and even battery kits.
So, whatever you choose, 33,000uF stays inside...
I couldn't agree more.
Got my T1 board in a couple of weeks ago, with the Meanwell S-350-27 power supply. Hooked them up, checked the DC offset (no prob). Ran it on a pair of el-cheapo test speakers for a few hours, sounds promising....
Moved the T1 into my main system, speakers are Klipsch Quartet (97.5db) and was frankly a bit underwhelmed. Upper end was pretty good, but I had to listen for the bass, very unbalanced. Overall the sound quality was good, but not much, if any better than the Soundcraftsmen A2502 (120 WPC into 8 ohms MOSFET amp), with the S'men leaving it in the dust on the lower end.
Then an order from Mouser arrived bearing a quad of these:
7447709004 Wurth Electronics Power Inductors
The 4.7uH Wurth's recommended by Sendler. They fit on the board with the addition of some extension leads. They are on their sides, but fit down onto the board pretty well.
Back into the system goes the little T1, and the improvement is almost shocking. What's that? I can actually hear the bass! I'm not good at audiospeak, but it seems that every aspect I read people talking about; dynamics, attack & decay, harmonics, detail, etc are all taken to another level. The sound is rich & full - a real pleasure to listen to.
The bass is much improved, but I still feel there is just not enough brute strength in the T1 to get it done properly. So I split my speaker crossovers, and have the T1 running the mid and tweeter horns, with the Soundcraftsmen humping the woofers. A stellar combo, I'm really liking this setup, the best I've ever had.
Many thanks for the tip, Sendler. I hope I have a chance to buy you a drink someday.
Do the Wurth coils run hot on the T1? I have read that they run quite warm on the Sure board.
Does this or this inductance fit the same as 7447709004 Wurth Electronics Power Inductors ?
I'm interested in freq response of T1, too!
I'm interested in freq response of T1, too!
different
Every coil I tried had a different sound. Even at the same value. The WE-PD are the best.
Every coil I tried had a different sound. Even at the same value. The WE-PD are the best.
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