Buckeye Amps: Hypex NCx500 Official Thread

[christr]

Okey, thanks!

 

[ILoveBeryllium]

Does Micro Audio make SMPS amps for mono configuration?

 

[Buckeye Amps]

Does Micro Audio make SMPS amps for mono configuration?

They do not make amps, but they do make many different models of SMPS'

Our Buckeye Mono Purifi 1ET7040SA uses a Micro Audio SMPS

 

[ILoveBeryllium]

Good to know. I am between the 1ET704 and NCx500 right now.

 

[Espiritiv]

Any such thing as a NCx250 coming out soon? More power for the same cost as the NC252 etc.

 

[Buckeye Amps]

Any such thing as a NCx250 coming out soon? More power for the same cost as the NC252 etc.

Not that I have heard off.

The NCx500 is the “replacement” for for the NC500 and Hypex never had an NC250 during that period.

 

[MusicMan77]

Any feedback as to when you might have a mono unit for Amir to test?

 

[Buckeye Amps]

Any feedback as to when you might have a mono unit for Amir to test?

Not for a while. I can probably get one sent towards end of May

 

[theREALdotnet]

I’d like to ask a question that’s been bubbling in the back of my head ever since the testing and re-testing of a Buckeye amp by Amir. I don’t think I’ve seen the answer in the test/review threads, apologies if I missed it.

The first round of testing of the amp showed increasing distortion from a certain output power onward, and this was confirmed as fixed by the second test. The fix that was alluded to was about the speaker terminals.

What I would like to know is, what was the problem with the original terminals? Was it the type or style of termination? The clamping force? The cross-section of the post? I’d like to understand how a terminal can introduce current-dependent distortion, other than (obviously) through poor contact.

 

[Buckeye Amps]

I’d like to ask a question that’s been bubbling in the back of my head ever since the testing and re-testing of a Buckeye amp by Amir. I don’t think I’ve seen the answer in the test/review threads, apologies if I missed it.

The first round of testing of the amp showed increasing distortion from a certain output power onward, and this was confirmed as fixed by the second test. The fix that was alluded to was about the speaker terminals.

What I would like to know is, what was the problem with the original terminals? Was it the type or style of termination? The clamping force? The cross-section of the post? I’d like to understand how a terminal can introduce current-dependent distortion, other than (obviously) through poor contact.

The original terminals were steel (so magnetic) as opposed to what was listed as brass (non magnetic) when I ordered them.

 

[theREALdotnet]

The original terminals were steel (so magnetic) as opposed to what was listed as brass (non magnetic) when I ordered them.

Ah, I see. What is the presumed mechanism of action for causing the distortion, though? Does being ferromagnetic affect the flow of current through a material? I would have thought that if anything, a higher conductive material (like copper or brass) would be more affected, for example through eddy currents.

I know that when there is sufficiently high magnetic flux in a ferromagnetic material (like in a transformer core) one can get crackling Barkhausen noise, but surely that’s not what we see in speaker terminal posts?

 

[Buckeye Amps]

Ah, I see. What is the presumed mechanism of action for causing the distortion, though? Does being ferromagnetic affect the flow of current through a material? I would have thought that if anything, a higher conductive material (like copper or brass) would be more affected, for example through eddy currents.

I know that when there is sufficiently high magnetic flux in a ferromagnetic material (like in a transformer core) one can get crackling Barkhausen noise, but surely that’s not what we see in speaker terminal posts?

@Rick Sykora did a deeper dive into this issue and if he is willing may be able to explain better what is happening when using a ferrous material.

 

[RickS]

@Rick Sykora did a deeper dive into this issue and if he is willing may be able to explain better what is happening when using a ferrous material.

Did not delve into the physics of it, but some smart folks at Purifi claim that hysteresis distortion can occur when iron is in the signal path. The distortion also reminded me of what happens with an oxidized contact. Ran this by some experienced electrical engineers I know and they said a good solder connection should resolve. I tried this with the steel tab and it did not fix.

 

[theREALdotnet]

Did not delve into the physics of it, but some smart folks at Purifi claim that hysteresis distortion can occur when iron is in the signal path. The distortion also reminded me of what happens with an oxidized contact. Ran this by some experienced electrical engineers I know and they said a good solder connection should resolve. I tried this with the steel tab and it did not fix.

Thanks Rick, my prime suspect would have been the quality of the contact, too. There are many types of steel, or course, but stainless steel can be difficult to solder. On the other hand, plated steel contacts are commonplace in electrical installation.

I’ll add it to my list of things to read up on

 

[DonH56]

Ah, I see. What is the presumed mechanism of action for causing the distortion, though? Does being ferromagnetic affect the flow of current through a material? I would have thought that if anything, a higher conductive material (like copper or brass) would be more affected, for example through eddy currents.

I know that when there is sufficiently high magnetic flux in a ferromagnetic material (like in a transformer core) one can get crackling Barkhausen noise, but surely that’s not what we see in speaker terminal posts?

It's complicated, and I claim no expertise as it has been a while since I have dealt with this (though have spent a lot of time dealing with the effects of ferrite beads in RF and power supply circuits). It is not (or not just ) Barkhausen noise, but actual distortion (nonlinearity) that is added. IIRC, ferrous materials introduce nonlinear effects on current flow including hysteresis. The effects are small, but at higher current are enough to add distortion, especially when we are looking at the very low distortion levels here. In the real world, as @Rick Sykora noted, similar (e.g. voice coil/magnet modulation and hysteresis, etc.) and other effects (e.g. other hysteresis, nonlinear suspension flexure, cone breakup, etc.) from the speakers will dominate the distortion you hear by several orders of magnitude.

HTH - Don

 

[goryu]

@Buckeye Amps

Do you have the specs for the 3 channel Micro power supply? Can you give it's current rating at max output per channel at 2ohms? Thanks...

 

[3ll3d00d]

Some detail on sustained power would be useful too

 

[Buckeye Amps]

@Buckeye Amps

Do you have the specs for the 3 channel Micro power supply? Can you give it's current rating at max output per channel at 2ohms? Thanks...

Some detail on sustained power would be useful too

Sustained power is 1.8kW @ 120VAC / 2kW @ 240VAC
Peak power is 2kW @ 120VAC / 2.2kW @ 240VAC

 

[goryu]

Sustained power is 1.8kW @ 120VAC / 2kW @ 240VAC
Peak power is 2kW @ 120VAC / 2.2kW @ 240VAC

Sustained power is 1.8kW @ 120VAC / 2kW @ 240VAC
Peak power is 2kW @ 120VAC / 2.2kW @ 240VAC

What is the max current output? The NCx500 is limited at 2ohms to 26amps. Will this power supply handle that or is it going be the limit? What is the output voltage? Thanks.

 

[Buckeye Amps]

What is the max current output? The NCx500 is limited at 2ohms to 26amps. Will this power supply handle that or is it going be the limit? What is the output voltage? Thanks.

It will be more than capable to handle the NCx500 into 2ohms...the whole premise of having this custom made by Micro Audio was to handle the NCx500 down into 2ohm for up to 3ch configs (and also 2ch Purifi 7040SA builds eventually)