March Audio or Audiophonics?

[March Audio]

Right that's why I was curious because I thought you are only supposed to solder those on the back of the PCB. This is based off my extensive soldering training which consists of several You Tube Videos and a practice kit.

Yes you only solder from one side but you would expect the solder to flow through. Some of those connections carry high current so adequate solder should be fed into the joint. Also lead free solder doesn't mean dull joints, you need the right solder, temp and timing.

 

[DonH56]

To me those look pretty normal for two sided thru-hole components, you don't solder those on top since the board has plated through holes. Lead-free solder usually makes the joints look grey and grainy i.e. crappy.

Right that's why I was curious because I thought you are only supposed to solder those on the back of the PCB. This is based off my extensive soldering training which consists of several You Tube Videos and a practice kit.

Per my training (from the late 1960's through today), which may not match anybody else's (except all of my fellow engineers and techs in the various courses through the years), good practice for through-hole components is (was) to have a smooth solder fillet top and bottom. In general connections (traces) can be at either side of the PCB, most of my work was multi-layer boards (8 to 20 or more) so ensuring good connections all through the via was important, mechanical integrity is better if both sides are soldered, and mechanical or thermal stress (flexure, vibration, expansion/contraction, etc.) is more likely to cause failure if there is not a continuous solder connection top to bottom.

The exceptions I have seen are things like production wave-soldered boards designed for single-sided through-hole connections. Maybe that's the case here, I don't know. I do know I have had to repair the connections on a number of those boards over the years.

There are various grades of lead-free solder. My current company uses it as required; for my previous job (military stuff) we did not as it was not as good a joint as standard leaded solder and rework is harder. The RoHS version we are using now is usually nice and shiny, but I do not claim to be any sort of expert on solder.

Now for full disclosure, except for some rework when our tech was busy or not in yet (I start early), I have not done much soldering the past few years. Those %$#! little SMDs get hard to see, and you lose some steadiness if you are not constantly working on stuff under a microscope. So best practice may have changed for the industry at large. I do know that for us (my workplace) we are required to have good solder joints top and bottom of our boards for through-hole components.

YMMV - Don

 

[Deleted member 2944]

In my younger years I used to teach MIL-STD 2000-soldering courses for the USN.
There's not a single soldered connection on that VTV buffer board that wouldn't be rejected immediately.

Anyways, this was a thread regarding March/Audiophonics......so back to that and sorry for the jacking.

Dave.

 

[restorer-john]

Improper safety grounding is not a minor issue. Especially if a line-based power supply is used where a short can put the chassis at the line voltage. I've had that happen a few times back when I was tech'ing and it is no fun. Hopefully that is not happening on any units shipped now.

I now assume the naysayers will accuse me of being a shill for Alan (@March Audio), and he will of course give me a new set of amps for the publicity.

So when did @March Audio change to correctly earthing his power amplifiers? We had this discussion a while back. They still have the double insulated symbol on them and a three pin IEC.

Don't you think it is a trifle hypocritical to be discussing competitors having "potentially lethal" earthing when his metal cased amplifiers aren't even earthed at all, even though they sport a 3 pin IEC on the back? I have never seen a 3 pin chassis mounted IEC where the earth pin is present, but unused (except in faulty Chinese gear). Gear with the double insulated symbol which uses an IEC style, use a two pin like this one:

(a subwoofer on my floor)

March's implementation:

 

[March Audio]

So when did @March Audio change to correctly earthing his power amplifiers? We had this discussion a while back. They still have the double insulated symbol on them and a three pin IEC.

View attachment 80251

Yep and as you were told then it is not an issue to use the 3 pin socket

The text in your snip tells you all you need to know..

It's also fairly bloody obvious it cannot under any circumstance cause a safety issue. So sorry John it is correctly earthed and incomparable to IEC sockets practically falling out the chassis as we have seen elsewhere.. So not even vaguely hypocritical.

If you think it's problem then what happens when you plug a 3 pin IEC plug into a 2 pin IEC socket as described in the text?

Internally the crimps on the rear of the IEC socket are insulated. The whole socket, crimps and wiring is covered by an insulating boot. The mains wiring is double insulated with locking connector at the far end. The amp module itself is class 2 compliant which means at least 6mm air gap or additional insulation between any live part and the chassis.

 

[restorer-john]

Yep and as you were told then it is not an issue to use the 3 pin socket

It's also fairly bloody obvious it cannot under any circumstance cause a safety issue.

You choose not to correctly earth your metal cased amplifiers, call them double insulated, and yet you continue to fit a three pin IEC that has a non-functional earth pin. Why don't you just buy the correct socket and lead in the first place?

You must be supplying a 3 pin IEC lead to fit that socket which although containing an earth is not earthing the product at all. Any product supplied with a three pin lead must be earthed correctly to standard. If double insulated, it must have a 2 pin lead without an earth pin.

You can tell me all you like that it's "not an issue" but we both know otherwise.

 

[March Audio]

You choose not to correctly earth your metal cased amplifiers, call them double insulated, and yet you continue to fit a three pin IEC that has a non-functional earth pin. Why don't you just buy the correct socket and lead in the first place?

You must be supplying a 3 pin IEC lead to fit that socket which although containing an earth is not earthing the product at all. Any product supplied with a three pin lead must be earthed correctly to standard. If double insulated, it must have a 2 pin lead without an earth pin.

You can tell me all you like that it's "not an issue" but we both know otherwise.

John with respect you either don't understand the subject or you are doing your usual of trying to pick holes where there are none.

It's not a functional earth pin. As the text correctly stated it's perfectly acceptable to plug an earthed 3 pin IEC plug into a 2 pin non earthed IEC socket. That's also an earthed lead that's not earthing the device. Do you have to plug an earthed device into a 3 pin earthed mains outlet? No of course not.

So, please explain the difference in electrical terms between an earth terminal being unconnected in the front of the socket to being unconnected at the rear.

 

[restorer-john]

John with respect you don't understand the subject.

Are you chassis earthing your amplifiers in any market?

 

[March Audio]

Are you chassis earthing your amplifiers in any market?

In which markets is class 2 a problem?

 

[restorer-john]

Here's some class II fused 2 pin IECs to consider for the future, the bottom one may just be a drop-in to your cutout

 

[March Audio]

Here's some class 2 fused 2 pin IECs to consider for the future, the bottom one may just be a drop-in to your cutout

View attachment 80261

Thanks for the info.

 

[Massimo]

John with respect you either don't understand the subject or you are doing your usual of trying to pick holes where there are none.

It's not a functional earth pin. As the text correctly stated it's perfectly acceptable to plug an earthed 3 pin IEC plug into a 2 pin non earthed IEC socket.

Please explain the difference in electrical terms between an earth terminal being unconnected in the front of the socket to being unconnected at the rear.

I understand that the Hypex NC252MP is a Safety Class II device and IEC to chassis earth is not required if meeting minimum safety distances to the enclosure but why not just connect the IEC earth to the chassis for additional safety? Potential issues with sources with RCA only?

 

[March Audio]

I understand that the Hypex NC252MP is a Safety Class II device and IEC to chassis earth is not required if meeting minimum safety distances to the enclosure but why not just connect the IEC earth to the chassis for additional safety? Potential issues with sources with RCA only?

Correct. Same with their other modules, they are class ii compliant.

In simple terms the mains cabling is double insulated with heatshrink. This also keeps the cable tightly twisted. As mentioned the crimps are insulated, the IEC connector rear is fully booted so there is no exposed mains. The mains cable goes direct to the amp module where it is secured by a locking insulated connector, it doesnt go via a power switch. The minimum safety distances are observed, or additional insulation is implemented.
So its just not necessary

Yes it will minimise the potential for issues with RCA.

 

[DarthVince]

Same with the other modules.

In simple terms the mains cabling is double insulated so its not necessary. As mentioned the crimps are insulated, the IEC connector rear is fully booted so there is no exposed mains. The mains goes direct to the amp module, doesnt go to a power switch.

Yes it will minimise the potential for issues with RCA.

A very sensible and well thought out implementation.

 

[firedog]

@March Audio
Question about Purifi monos: I contacted Purifi and they confirmed to me that they see no technical/performance need for anything other than a stereo amp: i.e., one Hypex SMPS1200A400 and 2 Purifi 1ET400A boards. The said that stereo config is what they send out as a demo EVAL1 amp.

Do you agree?

I'm curious to why you are selling just monos and no stereo version? Or is it simply using the case you have available and it's not suitable for a stereo version?

 

[ririt]

I'm curious to why you are selling just monos and no stereo version? Or is it simply using the case you have available and it's not suitable for a stereo version?

According to what I saw on another thread, a stereo version from March Audio is expected soon....

 

[Matias]

@March Audio
Question about Purifi monos: I contacted Purifi and they confirmed to me that they see no technical/performance need for anything other than a stereo amp: i.e., one Hypex SMPS1200A400 and 2 Purifi 1ET400A boards. The said that stereo config is what they send out as a demo EVAL1 amp.

Do you agree?

I'm curious to why you are selling just monos and no stereo version? Or is it simply using the case you have available and it's not suitable for a stereo version?

Interesting info, thanks.

Monos are prefered for shorter speaker cables, although in this case, quite expensive for doubling the power supply for no gain.

 

[March Audio]

@March Audio
Question about Purifi monos: I contacted Purifi and they confirmed to me that they see no technical/performance need for anything other than a stereo amp: i.e., one Hypex SMPS1200A400 and 2 Purifi 1ET400A boards. The said that stereo config is what they send out as a demo EVAL1 amp.

Do you agree?

I'm curious to why you are selling just monos and no stereo version? Or is it simply using the case you have available and it's not suitable for a stereo version?

The major thing with Monos is it allows you to place the amp next to the speaker and have short as possible speaker cables. Much better to do that and have long interconnects. Otherwise there is an improvement in crosstalk. Also whilst the A400 PSU has enough power to manage two amps, the load will still modulate the voltage. This effect is less pronounced with a single channel. Also with mono the PSU wiring (PCB tracks) is more optimised.

Our stereo version is released next week, just had the enclosures arrive. The cases are designed by us and manufactured to our spec so thats not an issue, we dont use off the shelf ones. However we have changed the format with the stereo amp. Firstly because we did need a little more room to fit both modules, but also as we need the extra rear panel space for the upcoming matching pre amp to fit socketry.

 

[GD Fan]

The major thing with Monos is it allows you to place the amp next to the speaker and have short as possible speaker cables. Much better to do that and have long interconnects. Otherwise there is an improvement in crosstalk. Also whilst the A400 PSU has enough power to manage two amps, the load will still modulate the voltage. This effect is less pronounced with a single channel. Also with mono the PSU wiring (PCB tracks) is more optimised.

Our stereo version is released next week, just had the enclosures arrive. The cases are designed by us and manufactured to our spec so thats not an issue, we dont use off the shelf ones. However we have changed the format with the stereo amp. Firstly because we did need a little more room to fit both modules, but also as we need the extra rear panel space for the upcoming matching pre amp to fit socketry.

View attachment 80818

View attachment 80819

Apologies if this has already been asked and answered but do you have any plans to add a multichannel amp to your lineup, say a 5 channel configuration?

 

[Mnyb]

Apologies if this has already been asked and answered but do you have any plans to add a multichannel amp to your lineup, say a 5 channel configuration?

Buy 5 mono amps