Magnus Audio MA-300 Monster Amplifier Power Supply Upgrade

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5 жыл бұрын

This absolute monster Magnus Audio MA-300 power amplifier came in for a factory power supply upgrade. Let's take a look!
Capable of 300 Watts per channel into 8 Ohms, this thing will drive any load with no trouble. It's also one of the heaviest amplifiers I've ever had to move around my workshop. At 75 kg, this thing is my entire body weight and definitely a two-man lift, unless you are Arnold Schwarzenegger!
Visit wp.me/p6vB28-5lZ for the article about this Magnus Audio MA-300 amplifier.
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Пікірлер: 79

@user-zh7eo2ul2v 4 жыл бұрын

Magnus Audio MA500 amazing amplifier! 👍 True High-End class!

@TuiCatNZ 5 жыл бұрын

That's crazy that 4 of those little guys have a greater capacity than 1 of the old monsters!

@TuiCatNZ 3 жыл бұрын

Sus

@AMMOPUNK1 3 жыл бұрын

Love the vids, thank you! And this amp is a real beaut!

@bhaverly 5 жыл бұрын

definitely a nice looking amp

@Justplast 5 жыл бұрын

I would not have done this. Good Job

@djvartan 5 жыл бұрын

Great video

@dirtydon8661 5 жыл бұрын

She’s a beauty! Would love to hear it in person. Nice job.

@LiquidAudio 5 жыл бұрын

Thanks for your kind words, much appreciated!

@rvbsoundfactory 3 жыл бұрын

Such a beauty.

@ormocchestandlungclinic3043 3 жыл бұрын

its beautiful!

@peterc3143 4 жыл бұрын

Looks a simple design, Bet it sounds great

@stevesmyth4982 4 жыл бұрын

Looking at the spec sheet it states 550 W idle so the O/P stage is well biased towards class A. Now for a boast... My home made Pass F5 Turbo V3 has a C-R-C PSU, 2 x 220,000 uF, 0.1 R, then 48 x 10,000 uF to give a total of 0.92 F. Rails are +/- 27.5 V, quiescent current is 7 A per rail per amplifier, it is of course class A operation and gives about 70 W audio per channel O/P. And it sounds sweet when driving four pairs of stacked Quad ESL 57s (old & fragile).

@johnstuartsmith Жыл бұрын

If you put a cast iron frypan on those amps, you can make grilled cheese sandwiches while listening to decent audio.

@harryt988 4 жыл бұрын

Never heard of Magnus Very interesting rebuild Mike Cheers !

@MrSteamDragon 5 жыл бұрын

Love the trolley Mike, remember, lift with the legs 😎😂....cheers....Mal

@LiquidAudio 5 жыл бұрын

Ha ha, yes indeed Mal, this thing was painful to move even with two of us on the lift!

@johnbravo7542 5 жыл бұрын

Hi mate,I'm in Perth too,just wondering do you work on point to point tube amplifiers?nice work and video.

@LiquidAudio 5 жыл бұрын

Hi there and thanks for the comment! Yes, I work on all good hi-fi stereo equipment, but this excludes some low-quality tube stuff, kits, things people have made and so on. I'd suggest you contact me via my contact form at liquidaudio.com.au/contact/ and let me know some of the details. Alternatively, give me a call at the number on that page any time during business hours and I'd be happy to assist!

@1968krug 2 жыл бұрын

I imagine The stuff that dreams are made of

@thulinp 3 жыл бұрын

It looks to not have any soft-start circuit. Why? I expect to see that on such large amplifiers. This amount of filter capacitance will dim the house lights on power-on, and may cause issues like PCs rebooting. And wear the power switch.

@vcp93 5 жыл бұрын

Is the "ample" amount of space in the cavity of the amp necessary or just a sign of a higher quality amplifier. I'm certain that it makes life A LOT easier for someone working on an amp like this, but I was just wondering if this is common in high end audio.

@LiquidAudio 5 жыл бұрын

Hi Frank, that's an excellent question. There was less room with the original power supply module, but it's still very generously sized. Partly it allows for large heatsink area, which is necessary with a high powered amplifier. It also allows for easy servicing as you've noted and is generally a good design practice. No doubt it also adds to the scale of the beast which one expects with an expensive and powerful amp. They could have made it smaller, but they weren't making many compromises with this one.

@gino3286 3 жыл бұрын

Very nice video ... as i am very curious i wonder how the sound has changed after the PS upgrade Personally I have a soft spot for the big size caps Maybe it is a mistake Thanks a lot, gino

@LiquidAudio 3 жыл бұрын

Hi Gino, I'm with you, I love seeing big caps in the power supply of a big amp. Having said that, I chatted with the owner recently and he thinks she definitely sounds much better with the new power supply. The power supply impedance is lower with the new supply, plus they are audio-grade caps and there are some other improvements, so it makes sense, but like you, I prefer the look of the big ones!

@gino3286 3 жыл бұрын

@@LiquidAudio Hi ! thank you very much indeed for your very kind and valuable reply. I have no reason to doubt about the outcome. For sure they must have done a lot of design and testing. And above all if sounds better is better Nice amp indeed in any case. Kind regards, gino

@summerforever6736 Жыл бұрын

Could be a very strong placebo effect

@dontcare563 5 жыл бұрын

I live in Northern California where this is made and I'm an audiophile and I've never heard of this company. With regards to that transformer, I really doubt that is a 1500-2000 KVA. Much smaller that that. I would like to hear this though.

@LiquidAudio 5 жыл бұрын

Definitely not 1500 kVA, 1.5 kVA for sure! It has to be of course, based on its power output of 600 Watts per channel into 4 Ohms, core losses etc...

@johnbravo7542 5 жыл бұрын

Don't Care,I have tried to find videos on KZfaq about this amplifier,nothing there.

@friedmule5403 4 жыл бұрын

Nice video and well made!:-) I am thinking, what power supply (V / A) do you use in such a situation, lets say you had to power that amplifier, to see if anything else was wrong and the Magnus power supply did not work?

@LiquidAudio 4 жыл бұрын

A big one! I use a 1500 Watt variac which handles most situations.

@friedmule5403 4 жыл бұрын

@@LiquidAudio Thanks for your reply! Okay as replacement for the PSU in the amplifier? I saw that that amplifier did deliver 54V and how many ampere? What would you reccommend as a PSU for a repair shop?

@LiquidAudio 4 жыл бұрын

@@friedmule5403 Ah, I see what you were getting at, no, if the amplifier supply is dead that raises all sorts of other questions. Generally, we want to find out why it died, is it safe to apply rails to the amplifier itself and so on. If there are no high current faults and the main supply is dead, we have to then work out what the rails are, what the current draw is on those rails and then rig up enough power supply channels to feed the thing. Amps like this typically have +/- high voltage rails, +/- low voltage rails and then maybe a logic supply, so say +5V. So, you need enough clean power supplies to handle that. There are many options but you always want good equipment, so older HP, Agilent etc power supplies are some of my faves.

@friedmule5403 4 жыл бұрын

@@LiquidAudio Yes that sounds logical:-) I have just a hard time to find units that I can use for that task, first do I not know how many voltage and how many amps, and if it has to deliver +/- ??V it do make it even harder:-) I do also intend to use the PSU while designing an amplifier, in that way can I apply higher voltage until signal / noise and clipping is where I find it okay. Without having to go trough complicated math, just turn and measure and listen:-) Agilent, HP and those sounds as a great idea. I know that I am asking about much here but do you know of any power supply's that can give +/- rail in the amount of V / A as you find useful? :-)

@LiquidAudio 4 жыл бұрын

@@friedmule5403 You will need some math, there is no escaping that and measurements are essential when designing amplifiers, so other test and measurement gear is needed. There are many good power supplies, but much depends on your use case - what are the voltage and current requirements? See the catch 22? You need some math to be able to take the next step. I can't remember the model numbers, but you want dual rail power supplies capable of delivering up to 50 or 60V, at the current you require, probably several amps per rail. You can series or parallel the channels to increase voltage or current and you want linear, not switching power supplies for amplifiers.

@barryp9463 4 жыл бұрын

do you know how much watts it does?

@LiquidAudio 4 жыл бұрын

This amplifier outputs 300 Watts per channel into 8 Ohms, specs are on their webiste I believe.

@DrBroncanuus 4 жыл бұрын

can you talk about Chord Amps and their unique power supply

@LiquidAudio 4 жыл бұрын

I will definitely look at doing a video on some Chord gear if a piece comes in for service or repair. It's a good sign that the brand seems to be very reliable at this point!

@DrBroncanuus 4 жыл бұрын

@@LiquidAudio as Chord , do not use transformer power supply...could you talk about if their solid state equip would sound Tube like as aresult...thank you

@LiquidAudio 4 жыл бұрын

@@DrBroncanuus This sort of commentary is not really what I do on my channel but the best solution is always to go and listen for yourself. Generally, switching power supplies are not conducive to good sound. There are a number of technical reasons for this, but having said that, it's always about the design and implementation. Chord is obviously doing something right with their SMPS designs for the gear to sound good. Go and audition the unit you are interested in and see what you think!

@summerforever6736 Жыл бұрын

How many watts it has?

@LiquidAudio Жыл бұрын

300 Watts a side into 8 Ohms, 600 W into 4 Ohms.

@summerforever6736 Жыл бұрын

@@LiquidAudio sounds good! Thanks

@dannyilaya8432 3 жыл бұрын

Can I buy the old power supply ?

@LiquidAudio 3 жыл бұрын

Where are you located Danny?

@user-im3ry3it7e 3 жыл бұрын

did you know bias current for Krell kav 2250 ??

@LiquidAudio 3 жыл бұрын

Not off the top of my head, service manual is the best place for this data.

@user-im3ry3it7e 3 жыл бұрын

@@LiquidAudio they dont have service msnual, only give me schematic - can you find proper bias if see schrmatic?

@LiquidAudio 3 жыл бұрын

@@user-im3ry3it7e Yes, it can be calculated based on the output devices, emitter resistors and looking at the design. It's beyond the scope of what I can offer here though. I'd be chasing the service manual. I work with Krell quite often, they will have it, or it will be available somewhere.

@user-im3ry3it7e 3 жыл бұрын

@@LiquidAudio huoh((( So i measured 5.3mV across 0.68ohm emmiter resistor, value vary per another resistors but not by much 4.7,5.1,4.8 and etc so problem if i push amp hard, it's get hot, around 70C degrees. How it can be with so low bias value? Dc offset 0.01 to 0.2mV both channels - seems right.

@user-im3ry3it7e 3 жыл бұрын

Output devices Sanken LAPT C4886 and A1860. 7npn and 7pnp devices per channel rails 84V, 2kw toroid.

@hifijohn 4 жыл бұрын

We use to call them computer grade capacitors.

@onlinevideochannel1349 Жыл бұрын

You know that if we look at the ends of board with end power transistors, and found what theirs electric board lines and wiring are very cose to each other - its not good to the sound (very small distance between electric lines on board with power transistors). So other good power amp items have bigger distance between these power lines and also they have even air space betwwen them but not the pcb as in this case. Thats dRAMMATICALLY enchancethe sound stage music field. Also it is not have onboard power supply lines for the end power transistors so it acrually mount on the board and these power supply lines are actually huge on the pcb near ends power transistors and they actually made from pure copper. It helps to supply power to power transistors stable and fast All these issues from electric engeneering field and they not implemented at this item.

@LiquidAudio Жыл бұрын

Yeah, perhaps you could show us what large commercially available power amplifiers you have designed? You could also contact Magnus Audio and tell them how you could improve their power amplifiers.

@beslemeto 3 жыл бұрын

My fridge is certainly smaller than this thing!

@user-mi8so5fj1v 5 жыл бұрын

Можно новых 3 платы поставить в 3 этажа!

@BoudewijnvanHouten 3 жыл бұрын

Not according to Nelson Pass. This amp is over ten years old so this blue Mallory's could have been replaced with filtercaps of the same size and voltage rating but approx. double capacitance.

@LiquidAudio 3 жыл бұрын

I'm not sure what you are talking about here, my customer ordered the replacement power supply capacitor bank which I installed here, as per his request.

@BoudewijnvanHouten 3 жыл бұрын

@@LiquidAudio Yes, you're 100% right of course. I was not criticizing your work at all, I'm actually quite surprised and happy with your video's about the repairs/refurbishing you do. I just remembered that Nelson Pass favors those old school large can capacitors for his designs, but that's not an argument at all for doing something else as the customer wants to install a factory update. So I'm sorry to imply something different here and I'm curious to see your next video.

@LiquidAudio 3 жыл бұрын

@@BoudewijnvanHouten Hey no problem, we love Nelson Pass here, and huge capacitors! Massively parallel capacitors really are an excellent technical solution to achieving super-low impedance power supplies though. Stay tuned and visit my website too, there's a ton more over there.

@BoudewijnvanHouten 3 жыл бұрын

@@LiquidAudio Thanks, I will!

@stevesmith3033 2 жыл бұрын

Mallory's are THE best electrolytics and the most expensive of the large scale manufacturers. Unless they're bad I wouldn't swap them out for cheap Elna's. The sound degradation will be noticeable. I see vintage Mallory's that are still good 60 years later. Cheap Asian caps can blow in less than two years.

@LiquidAudio 2 жыл бұрын

Not quite, RIFA are better and there are a few on that level like Sprague, but yes, Mallory are excellent and likewise, I see them often still perfect after 50+ years. This was customer ordered work. I had no input into whether he should do it or not. He bought the new board and asked me to install it. Technically, this new board will deliver lower source impedance though, which is good.

@stevesmith3033 2 жыл бұрын

@@LiquidAudio I can't confirm that Rifa are better as we don't see them much in North America but here I'd rank them Mallory, Cornell Dubilier then Sprague. You do great work btw. I enjoy your content.

@LiquidAudio 2 жыл бұрын

Thanks Steve, really appreciate that! I can confirm that RIFA, now Kemet, are technically the very best and most expensive in that form factor. That being said, most of these big computer grade caps last a long, long time as you will know. People replace them when they don't need to and this was indeed one of those cases, but the customer reported a significant sonic improvement, no doubt due to the aforementioned lower power supply impedance. I still have the old power supply!

@stevesmith3033 2 жыл бұрын

@@LiquidAudio Very cool. I use some smaller axial electrolytic Kemet/Rifa caps in tube amps. the also make a great metalized paper box style capacitor. Curious what you use for solder there? The alloy and flux type? Cheers!

@LiquidAudio 2 жыл бұрын

It varies according to job type but always lead-based, sometimes alloys with copper and/or silver, AIM, Multicore etc.