• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

March Audio P452 Purifi Based Stereo Power Amplifier

Status
Not open for further replies.

Wombat

Master Contributor
Joined
Nov 5, 2017
Messages
6,722
Likes
6,459
Location
Australia
OPA1612 in the input buffers the same as the reference (or evaluation) design?

Also, damn if you couldn't have released the stereo Purifi amp a couple of weeks ago so I could have considered it before dropping the funds on a couple of similar French Audiophonics Purifi amps. Which are a little less expensive and made with cheaper cabinets which doesn't bother me because I appreciate the value. I am however going to replace the generic binding posts for some copper posts that your amps already use. Which removes some of the initial value. It's never made sense to me for power amplifiers to use brass binding posts that are much worse conductors than copper.


Electrical Conductivity difference between alloyed brass and plated copper terminals is not particularly significant for audio gear. Gushing marketing blurbs indicate that pure copper terminals are the latest audio fad.


https://www.copper.org/applications/industrial/DesignGuide/selection/conductbrass02.html

The compatibility of materials in contact at connections is a more important consideration.
 
Last edited:

phoenixdogfan

Major Contributor
Forum Donor
Joined
Nov 6, 2018
Messages
3,296
Likes
5,074
Location
Nashville
Here you go Sal. ;)

A pair of Sony TAN-77es the same as mine. Run the pair in mono and get ~600wpc@8R and ~1KW@4R. Each meter is over 6" diagonal. 26.5kg each- 53kg for the pair- you need a decent shelf. I have mine along the top of a solid timber buffet. You don't really want to stack them in summer- they run pretty toasty.

(not my pic)
View attachment 82761
1600116085871.png
 

stren

Active Member
Forum Donor
Joined
Jan 9, 2020
Messages
253
Likes
298
451 and 452 use the same hypex psu I assume?
 

Sal1950

Grand Contributor
The Chicago Crusher
Forum Donor
Joined
Mar 1, 2016
Messages
14,072
Likes
16,605
Location
Central Fl
That's a great FP still, that one goes in my hard-drive, thanks.
I don't ever remember seeing such detail in the meters and it being so obvious how they were made with just a bunch of regular bulbs.
I've got the latest release BD of the movie here, I'll have to run it and check, that's the near final where the ID monster killed Morbius
Beside, I do need an excuse to drool over Anna Francis, she really was a major hottie in that movie and for the time. "those legs, oh my heart" .
All kidding aside, IMO one of the all-time great SiFi movie, it was 1956's Star Wars for me.
poster5 forbidden planet.jpg
anne.jpeg

skin1.jpg

Here Kitty Kitty
forbidden-planet-11-candid-photos_1_8ca6434e893f68aefcfb3b5480f30c50.jpg
 

Sal1950

Grand Contributor
The Chicago Crusher
Forum Donor
Joined
Mar 1, 2016
Messages
14,072
Likes
16,605
Location
Central Fl
You shouldnt use adaptors such as this

index.php


But yes fully compatible with RCA if you use a corretly wired XLR to RCA cable.
So how are we to know if it's correct or not?
Do you have a schematic that we could use to test that adapter with a multi?
2 into 3 or vise versa, it can't be brain surgery. o_O
 

Sal1950

Grand Contributor
The Chicago Crusher
Forum Donor
Joined
Mar 1, 2016
Messages
14,072
Likes
16,605
Location
Central Fl
Hi Sal, sorry I thought people might be bored of me posting this
Probably my problem, if you put it up more than a hour or two ago, it's ancient history to me. LOL
 
Last edited:

HooStat

Addicted to Fun and Learning
Joined
May 11, 2020
Messages
856
Likes
933
Location
Calabasas, CA
That looks great! I have been waiting for this. Once I sort out whether I am going with active speakers or not, this looks like the best amp choice -- kind of a no-brainer. Would be interested in reading about the process of developing this -- I am sure it was harder than it might seem to those of us with no electronics skill.
 

TomJ

Active Member
Joined
Sep 16, 2019
Messages
129
Likes
177
Location
Palo Alto CA
Alan, when you have a minute, why did you choose a 20kΩ input impedance for the P451 and 452 buffers, vs 94kΩ for your P701 buffer?
 
Last edited:

TomJ

Active Member
Joined
Sep 16, 2019
Messages
129
Likes
177
Location
Palo Alto CA
Alan, also a question about DC protection: does your P452 buffer switch off the SMPS if the amp protection circuit throws a
DCP-latch-off condition? I haven't seen that mentioned but if already addressed, would appreciate the link.
 
  • Like
Reactions: ENG
OP
March Audio

March Audio

Master Contributor
Audio Company
Joined
Mar 1, 2016
Messages
6,378
Likes
9,317
Location
Albany Western Australia
We use the Hypex LM4562 based buffer built in to the NC1200 and it is a slightly different design to our own design of buffer on the P451/P452 which minimises noise and offsets whilst still providing reasonably high input impedance. If a pre or dac cant drive 20k then it needs to be put in a dumpster ;)

Yes if there is a FATAL error the supply gets shutdown and will need to be disconnected from the mains to allow reset. Note also the amp module has a sophisticated monitoring and protective system.

1600413795780.png

1600413833100.png

1600413871189.png
 
Last edited:

jae

Major Contributor
Joined
Dec 2, 2019
Messages
1,208
Likes
1,508
You should put a more attractive photo of the unit on the product page. The current one looks a bit "dirty" and worse for wear. Might put off customers
 
OP
March Audio

March Audio

Master Contributor
Audio Company
Joined
Mar 1, 2016
Messages
6,378
Likes
9,317
Location
Albany Western Australia
You should put a more attractive photo of the unit on the product page. The current one looks a bit "dirty" and worse for wear. Might put off customers
Agreed. The whole web site is due for a revamp and that photo was only put up in a rush as customers were pestering me ( in the nicest possible way :) ) to get the amp in the web shop for sale.

It doesnt appear to have harmed sales, there has been a tremendous response and we have sold out of the first batch, another batch will arrive in about 2 weeks. :)
 
Last edited:

MakeMineVinyl

Major Contributor
Joined
Jun 5, 2020
Messages
3,558
Likes
5,871
Location
Santa Fe, NM

restorer-john

Grand Contributor
Joined
Mar 1, 2018
Messages
12,579
Likes
38,280
Location
Gold Coast, Queensland, Australia
There needs to be a compelling reason to go to the extra effort of implementing a microcontroller which I dont quite see...yet.

Ah come on. ;) That micro can also give you a nice backlit OLED full colour screen with an animated startup display of March Audio's logo, some random icons, status indicators and just for fun, groovy looking VU meters you can toggle between peak, average, VU style or vertical bargraphs!

And all that wonderful time spent debugging the code, sending out firmware updates and warranty service on bricked amplifiers because someone yanked a USB cable halfway through a pointless "feature upgrade" :facepalm:
 

DonH56

Master Contributor
Technical Expert
Forum Donor
Joined
Mar 15, 2016
Messages
7,835
Likes
16,497
Location
Monument, CO
Hardware, at the moment ;).

There needs to be a compelling reason to go to the extra effort of implementing a microcontroller which I dont quite see...yet.

Ah come on. ;) That micro can also give you a nice backlit OLED full colour screen with an animated startup display of March Audio's logo, some random icons, status indicators and just for fun, groovy looking VU meters you can toggle between peak, average, VU style or vertical bargraphs!

And all that wonderful time spent debugging the code, sending out firmware updates and warranty service on bricked amplifiers because someone yanked a USB cable halfway through a pointless "feature upgrade" :facepalm:

Hmph. Alan, don't be the next Emotiva (or insert your favorite FW disaster here)...
 
Status
Not open for further replies.
Top Bottom