March Audio P451 Purifi 1ET400A Mono Blocks

[Zoomer]

XLR/TRS combi jacks

Nice touch!
Will they be for sale in Europe through Purite?

 

[Matias]

Nicely built. Interesting choices of touch power button, XLR combi and 20A IEC. My amp also has the ETI speaker connectors, I like them.

 

[March Audio]

Nice touch!
Will they be for sale in Europe through Purite?

Yes, sending Keith his first pair next week

 

[AudioSceptic]

Hi

Our P451 Purifi MonoBlocks are now ready, will be on the website this weekend.

They follow the form of all our amplifiers, compact enclosure milled from aluminium block with tough anodised finish.

Features:

• OPA1632 based fully differential input buffer with very low noise LT3045/94 voltage regulators. These are particularly suited for regulating the SMPS output as they have high PSRR at high frequencies where most of the SMPS noise resides. These also feed the analogue sections on the 1ET400A module.
• Separate regulated supply for the 1ET400A digital section (for info its actually missing on the prototype board shown below).
• Solid copper ETI Research speaker binding posts.
• Balanced XLR inputs (XLR/TRS combi jacks) also fully compatible with single ended RCA with adaptor cable.
• Audio input RF filter
• Touch switch power control
• Mogami balanced signal cable
• Speaker cable tightly twisted
• Mains input booted, cabling twisted, double insulated and routed away from speaker/signal wiring/boards as far as practicable.
• Power Supply is significantly over specified for a single channel amp.
• All the lovely Purifi technical performance and sound

Piccies

Just for info the bottom plate actually fits the other way round (psu to front) in the top shell.

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Very nice. I take it that touch switch power control means that this uses a relay? Looks nice and compact but what are the dimensions? One more question: do you have the cases made locally or abroad?

 

[kaka89]

Clean and neat!

Will there be a stereo version?

 

[March Audio]

Very nice. I take it that touch switch power control means that this uses a relay? Looks nice and compact but what are the dimensions? One more question: do you have the cases made locally or abroad?

It toggles the main SMPS, part of its control logic. The main SMPS does have a relay.

 

[March Audio]

Clean and neat!

Will there be a stereo version?

Eventually, it will require a new case.

 

[Purité Audio]

They look great Alan, can’t wait to try them.
Keith

 

[kaka89]

Eventually, it will require a new case.

Oh, that is a great news for me!
I found the current case's width-depth ratio quite odd.
A more squareish case would look better in my opinion. Looking forward to its release.

Thanks.

 

[Matias]

Oh, that is a great news for me!
I found the current case's width-depth ratio quite odd.
A more squareish case would look better in my opinion. Looking forward to its release.

Thanks.

It is because you need 2 monos, put them side by side and they look squarish.
Or the source/preamp in the middle and each of them on the sides, also looks good.

 

[digitalfrost]

This looks to be best implementation yet. Will you send one to Amir for review and/or can you share measurements of your own?

 

[JimB]

Thanks

Yes, fairly big but they allow for good access for large CSA cable and large spades. Plus bananas of course.

Nice. But my one significant concern is the connection for getting the output off the board!

 

[JimB]

Hi

Our P451 Purifi MonoBlocks are now ready, will be on the website this weekend.

They follow the form of all our amplifiers, compact enclosure milled from aluminium block with tough anodised finish.

Features:

• OPA1632 based fully differential input buffer with very low noise LT3045/94 voltage regulators. These are particularly suited for regulating the SMPS output as they have high PSRR at high frequencies where most of the SMPS noise resides. These also feed the analogue sections on the 1ET400A module.
• Separate regulated supply for the 1ET400A digital section (for info its actually missing on the prototype board shown below).
• Solid copper ETI Research speaker binding posts.
• Balanced XLR inputs (XLR/TRS combi jacks) also fully compatible with single ended RCA with adaptor cable.
• Audio input RF filter
• Touch switch power control
• Mogami balanced signal cable
• Speaker cable tightly twisted
• Mains input booted, cabling twisted, double insulated and routed away from speaker/signal wiring/boards as far as practicable.
• Power Supply is significantly over specified for a single channel amp.
• All the lovely Purifi technical performance and sound

Missing from my wish list: 12V trigger in (not out).

 

[deafenears]

20A IEC

Where are you seeing this? Looks IEC C13 to me.

 

[Matias]

Where are you seeing this? Looks IEC C13 to me.

Rectangular shape, looks like 20A to me.

 

[March Audio]

Standard IEC

Wouldnt be any need/benefit for larger.

 

[AudioSceptic]

It is because you need 2 monos, put them side by side and they look squarish.
Or the source/preamp in the middle and each of them on the sides, also looks good.

One big advantage of mono amps is that you can put them really close to, or hidden behind, the speakers and use really short speaker cables.

BTW why do some call mono amps "monobloc(k)s"?

 

[AudioSceptic]

Clearly not @solderdude , what were you thinking? The soldering is in a whole other league of excellence.

Rectangular shape, looks like 20A to me.

IEC C20 has horizontal pins. <https://en.wikipedia.org/wiki/IEC_60320>

 

[March Audio]

The P451 is now available in our web shop

https://www.marchaudio.net.au/p451

 

[March Audio]

Very nice. I take it that touch switch power control means that this uses a relay? Looks nice and compact but what are the dimensions? One more question: do you have the cases made locally or abroad?

Sorry I didn't reply about the dimensions:
330mm x 180mm x 75mm

Cases are made in China, its the only economic option. Have to say the quality and service from the company has been excellent.