magtech amps?

[pjug]

The amp is being tested under the worst condition, which is at just 1 watt. This is tough because crossover distortion is a greater percentage of the total distortion at low power levels than at high power levels.

Also, the S/N will be much lower at high power levels as the noise floor is fixed and greater output will tremendously increase the magnitude of the difference between the noise and the signal. But even at this very low power level you see that the noise floor is about 118 dB below the reference signal. This is a very quiet amplifier.

I don't mean to bash the Magtech amp. It puts out a boatload of power. But that image above looks right about the same as what Amir measured with the $400 Outlaw M2200 at 1W.
edit: brain cramp, Amir's is at 5W. But still I wonder how they compare.

 

[Sir Sanders Zingmore]

Thanks. The cases the owners have shared on the Magtech are amps idling hotter than they should be. The thermal tracking seems like a good idea, but I take it not as straightforward as on the face of it.

I had the issue that you describe. Sanders replaced the devices free of charge (as per his lifetime guarantee).
I'm not sure what they were replaced with, I could open the amp up but tbh I'd have no idea what to look for

 

[Sir Sanders Zingmore]

Thanks @Sir Sanders Zingmore

Someone needs to send one to Amir, so we can compare to other amps. It looks like it will measure well.

I would send mine but postage from Australia would be prohibitive

 

[muslhead]

Thanks @Sir Sanders Zingmore

Someone needs to send one to Amir, so we can compare to other amps. It looks like it will measure well.

i just returned mine before the 30 day trial expired. I used it to drive my salon2s

 

[Sir Sanders Zingmore]

i just returned mine before the 30 day trial expired. I used it to drive my salon2s

That would be a good way to test one.
Someone buy one (perhaps Amir), test it and then return. Although given that they pay shipping both ways, it's probably a bit unfair to buy if you know you intend returning

 

[skypickle]

i just returned mine before the 30 day trial expired. I used it to drive my salon2s

What did you decide on instead?

 

[AudioJester]

i just returned mine before the 30 day trial expired. I used it to drive my salon2s

Didnt think of sending to Amir first?
What was the issue with your salon2s?

 

[muslhead]

What did you decide on instead?

i kept my class d, vtv monoblocks
To my ears the upper end of the sanders was better but the bass was better on the multiple class d amps i tried

 

[muslhead]

Didnt think of sending to Amir first?
What was the issue with your salon2s?

you have 30 days.
Amirs backlog and shipping would work out such that i would have no time for an actual test period. The problem is Amirs backlog, i checked before purchasing.
There is no issue with my salons. what did i say that implied that?

 

[AudioJester]

you have 30 days.
Amirs backlog and shipping would work out such that i would have no time for an actual test period. The problem is Amirs backlog, i checked before purchasing.
There is no issue with my salons. what did i say that implied that?

Ok, makes sense with 30 day limit.

Sorry, meant what was the issue with the Magtech driving the Salons? Why did you send it back?

 

[skypickle]

Which VTV are you driving your salon2s with? I am using a cinepro but want to move to mono blocks. How did you decide which input buffer to order?

 

[muslhead]

Which VTV are you driving your salon2s with? I am using a cinepro but want to move to mono blocks. How did you decide which input buffer to order?

I chose std input buffer on the hypex 1200. IMHO, input buffers are marketing tools to let builders differentiate from each other.
With listening about 10ft away, very loud volumes are achievable with my preamp volume control right around 12 oclock

 

[Addicted to music]

Not enough experience with them from a repair perspective. Very few commercial products I have seen with them in a failed state. In my opinion, once you stray away from standard pinouts (5 pins with TT trs- internal diode) and hybrid/semi hybrid devices, you end up with problems down the track when they are discontinued.

The Sanken darlingtons in a TO3P package seem to have stood the test of time however and have been adopted in mid range gear.

I have replaced a Sanders amp module in a Sanders Dual Channel Power Amp. this is due to a thermal runway in a thermal track device. There seem to be a batch that failed to track normally.....the issue was one channel was getting hotter than the other...
The beauty of this Brand is that Roger Sanders has no issues in sending you replacement modules free of charge on his costs.... Not only that the power supply filter caps used didn’t have voltage headroom and were known to leak if the mains exceeded the input spec. He also sent brand new 120V 8200uf qty of 8 to replaced the 100V 10,000uf all free of charge.... So this owner got 2 brand new amplifier channels and a set of 8 brand new filter caps, no questions asked....
The amp is very serviceable and all modules nicely laid out.... The time consuming thing was replacing the caps, everything else was “plug and play”. With correspondence we didn’t even need to set the bias up, his instruction was do not touch thats already been done before being sent out....
i have compared the Sanders Magtech with the Nc400, the nc1200 wasn’t available at the time so this was the best against conventioval using class D... I went ahead and choose the Magtech, it was in a league of its own....

 

[skypickle]

I chose std input buffer on the hypex 1200. IMHO, input buffers are marketing tools to let builders differentiate from each other.
With listening about 10ft away, very loud volumes are achievable with my preamp volume control right around 12 oclock

Pardon my ignorance, but what does an input buffer do anyway? Does it add noise/distortion?

 

[skypickle]

@Addicted to music did the dead card have any visible signs of failure? I didnt see any charring in your pics.

 

[Addicted to music]

@Addicted to music did the dead card have any visible signs of failure? I didnt see any charring in your pics.

The amp module didn’t “fail” the owner reported that that one channel ran hotter than the other, the amplifer was still fine and playing music. so there was no physical/electrical failures to note. The instruction from Roger was to replace the module, but he sent 2 modules so the good one was also replaced as per instructed..
it’s also noted that Onsemi knows there was a bad batch of these thermaltrak devices.... I believe these are the early versions, the later productions have not been an issue... I’ve heard several owners of Sanders Magtech reporting similar issues And have been fixed no questions asked. Of memory and I stand corrected if I’m wrong, these same thermaltrak devices were also used in a Silicon Chip designed power amp, they also had to do some modifications to cater for thermal runway, it’s basically the diode that’s supposed to provide thermal tracking at the die was failing to track properly, the transistor itself are very reliable. I prefer these than negative temp coefficient Mosfets as these are more linear.

 

[Addicted to music]

Pardon my ignorance, but what does an input buffer do anyway? Does it add noise/distortion?

I believe the buffer allows you to roll different Opamps.

 

[restorer-john]

I have replaced a Sanders amp module in a Sanders Dual Channel Power Amp. this is due to a thermal runway in a thermal track device. There seem to be a batch that failed to track normally.....the issue was one channel was getting hotter than the other...
The beauty of this Brand is that Roger Sanders has no issues in sending you replacement modules free of charge on his costs.... Not only that the power supply filter caps used didn’t have voltage headroom and were known to leak if the mains exceeded the input spec. He also sent brand new 120V 8200uf qty of 8 to replaced the 100V 10,000uf all free of charge.... So this owner got 2 brand new amplifier channels and a set of 8 brand new filter caps, no questions asked....
The amp is very serviceable and all modules nicely laid out.... The time consuming thing was replacing the caps, everything else was “plug and play”. With correspondence we didn’t even need to set the bias up, his instruction was do not touch thats already been done before being sent out....
i have compared the Sanders Magtech with the Nc400, the nc1200 wasn’t available at the time so this was the best against conventioval using class D... I went ahead and choose the Magtech, it was in a league of its own....

Those PCBs are having a bet each way with thermal track and standard pinout TO3Ps. Not only that, the standard of soldering is really nasty if you ask me for a commercial offering.

Much as I love Silicon Chip, their amplifier designs over the years have been nothing but poor sounding. And I am talking from the very first designs when Leo Simpson and his friends set up the magazine in 1987 right through to their "ultimate fidelity" amplifiers of later years. Take an ancient ETI David Tilbrook ETI-477 vs anything SC came up with. Even after nearly 40 years, it's still a better sounding (and measuring) amplifier.

 

[Addicted to music]

Those PCBs are having a bet each way with thermal track and standard pinout TO3Ps. Not only that, the standard of soldering is really nasty if you ask me for a commercial offering.

Much as I love Silicon Chip, their amplifier designs over the years have been nothing but poor sounding. And I am talking from the very first designs when Leo Simpson and his friends set up the magazine in 1987 right through to their "ultimate fidelity" amplifiers of later years. Take an ancient ETI David Tilbrook ETI-477 vs anything SC came up with. Even after nearly 40 years, it's still a better sounding (and measuring) amplifier.

The pcb are not done via a soldier bath on a automated machine, if your asking me it’s hand soldered and won’t match the current commercial high production offerings thats done using automated process, nothing wrong with it, its typical of small manufacturing and it’s typical of all things audio. I’ve built and solder myself many projects this way and yet have lasted 30yrs and still going, easy to be a critical. Even if you do go through an automated process, you can still have issues like the Topping DX3 Pro where a device failed to soldered to a pad for proper thermal conductivity, and those Topping Audio Pcbs are done via automated process due to SMDs. the benefit when it’s hand done it’s also visually inspected unlike an automated process that test a sample.

BTW the Sanders Magtech wipes the floor of David Tilbrooks AEM 6000 power amp, i would know because I’ve built and ran it from 1994. If you think the Soldering is below standards for a commercial offering for a Sanders Magtech pcb, well mine is worst and that’s lasted since 1994!

 

[CDMC]

I have replaced a Sanders amp module in a Sanders Dual Channel Power Amp. this is due to a thermal runway in a thermal track device. There seem to be a batch that failed to track normally.....the issue was one channel was getting hotter than the other...
The beauty of this Brand is that Roger Sanders has no issues in sending you replacement modules free of charge on his costs.... Not only that the power supply filter caps used didn’t have voltage headroom and were known to leak if the mains exceeded the input spec. He also sent brand new 120V 8200uf qty of 8 to replaced the 100V 10,000uf all free of charge.... So this owner got 2 brand new amplifier channels and a set of 8 brand new filter caps, no questions asked....
The amp is very serviceable and all modules nicely laid out.... The time consuming thing was replacing the caps, everything else was “plug and play”. With correspondence we didn’t even need to set the bias up, his instruction was do not touch thats already been done before being sent out....
i have compared the Sanders Magtech with the Nc400, the nc1200 wasn’t available at the time so this was the best against conventioval using class D... I went ahead and choose the Magtech, it was in a league of its own....

It is nice to see he supports his products so well. It is a premium priced products, where you would expect good service, but given how poorly I have seen some high end manufacturers deal with issues, it is refreshing to see.