[maty]

Well, $ 895 to both loudspeakers. Different options to the amplification. Like an active monitor, with one or two amps, same or different technology.

Measurements: https://www.audiocircle.com/index.php?topic=167137.msg1774346#msg1774346





It would be interesting to know the phase graph, which Danny never publishes. In this case, being 2-ways, minimum impedance of 8 Ohms and sensitivity of 88 dB is certainly not problematic, but it would be nice to know it.


Power requeriments to obtain certain SPL:

https://www.audiocircle.com/index.php?topic=167137.msg1774352#msg1774352

https://www.doctorproaudio.com/content.php?2273-calculators-proaudio-sound-dmx&langid=1#calc_spl


To 80 dBSPL average + DR15 = 95 dBSPL max

88 dB/W/m, 8 Ohms, random phase, 3 m -> 23 watts at 8 Ohms to have 95 dBSPL max



* 2 m -> 10 watts at 8 Ohms

* 3 m -> 23 watts at 8 Ohms

* 4 m -> 40 watts at 8 Ohms


If you listen to modern commercial recordings, then DR will be < or << 10 dB.

80 dBSPL + 10 dB = 90 dBSPL max

* 2 m -> 4 watts at 8 Ohms

* 3 m -> 7 watts at 8 Ohms

* 4 m -> 13 watts at 8 Ohms


******* ********

Very important.

* SS: watts at THD+N 0.1%

* Tubes: watts at THD+N 1%



Updated the title: GR Research Studio Monitor -> GR-Research NX-Studio

[maty]

Yesterday Archimago published:

An Inexpensive Hi-Fi Class-D Stereo Amp for the 2020's: Hypex nCore NC252MP (DIY Assembly)

http://archimago.blogspot.com/2020/01/an-inexpensive-hi-fi-class-d-stereo-amp.html

The amplifier module was announced back in 2016 and I believe became available in quantity starting in 2017. This single module contains everything in one place for a 2-channel dual-mono amplifier (rated 250W into 4Ω, 180W into 8Ω, at 1% THD, 1kHz signal) including input buffer and power supply. All you need to add is an enclosure with the proper input and output connectors, power switch, and power LED for basic functioning. Already, this component is at the heart of devices like the IOM NCore Pro (€550), the Nord One MP NC252 (£579), March Audio P252 (US$895), and Rouge Audio Studio N-4B (€655.00).

The best deal I've seen is for the Audiophonics MPA-S252NC (€440); not sure how much more it would cost to ship to Canada though if I were to buy it from France and had to pay for border duties...

[Update] Apollon NCMP400 also uses Hypex NC252MP. In a big case, with low mass binding posts: WBT-0703 Cu

[Big IMG] https://www.apollonaudio.com/wp-content/uploads/2019/06/ncmp400-inside-components.jpg


Resized and optimized



Cheap class-D amplifier to the woofer and subwoofers. With tweeter I do not think it is a very good idea if you listen to very good recordings with high / very high DR with acoustic and / or electrified instruments like me. Surely we are very few and to whom we listen to such recordings.


Updated

MEASUREMENTS: Hypex nCore NC252MP Amplifier (+ Subjective opinions around objective testing, and CES2020)

http://archimago.blogspot.com/2020/01/measurements-hypex-ncore-nc252mp.html

A lot of graphs!

[maty]

Like active speakers: https://www.hypex.nl/product/fusionamp-fa252/156



I think with only linear phase filters and not minimum phase filters (my choice without any doubt).

Hypex Filter Design, free soft

https://www.hypex.nl/product/hypex-filter-design/17

From the PDF:

Hypex Filter Design (HFD)

HFD is a free software tool needed to configure the FusionAmp. To protect your valuable drivers, the DSP
does not contain a filter out of the box. A filter needs to be configured and uploaded before the FusionAmp will produce an output signal.

HFD can be used to measure the frequency response of the speaker and this information can be used to
design your filter. 15 biquad filters are available per amplifier channel.

DSP Filters:

15 biquads per channel. A one-way Fusion Amp has 15 biquads, a two-way has 2x15 biquads and a three-way has 3x15 biquads. Amplifiers configured in BTL still have 15 biquads available.

Q: What is a “Biquad”?

A: A biquad is a filter section with 2 poles and 2 zeros. All of the biquads are in series so all kinds of filters can be made.

Q: What about the phase of the filters?

A: The biquad filters are all minimum phase, which means that phase is directly linked to magnitude response in exactly the same way as an analogue filter.

Since individual speaker drivers are minimum phase too, EQ'ing them flat also equalises the phase response.

[maty]

For the type of recordings I listen to, I do not want to know anything about OLD class D and high frequencies, that is, amplifying the tweeter.

Maybe the new PURIFI 1ET400A modules with a better input board.

https://www.audiosciencereview.com/forum/index.php?threads/review-and-measurements-of-purifi-1et400a-amplifier.7984/




With the new Universal Buffer from Neurochrome (Tom Christiansen).

https://www.diyaudio.com/forums/class-d/339838-purifi-1et400a-measurements-post6018772.html

https://www.diyaudio.com/forums/vendor-s-bazaar/346956-universal-buffer-achieving-140-dbc-0-00001-thd.html


It is better to let some time pass I think. Let others experience and verify if the sound is as good as its specifications with high quality recordings with acoustic and / or electrified instrumentation and voices without processing with Autotune (vade retro satana).


Will continue with class A and class AB too.

[maty]

Class AB. Chipamp. LM3886.

An amplifier that I have been following for quite some time is Akitika (Dan Joffe). But having only one LM3886 per channel is more appropriate for real and higher 8 Ohms loudspeakers and not for my little coaxials with a minimum impedance of 3.9 Ohms and nominal should be 5 Ohms and not the 8 Ohms that KEF says.

Today it would be my choice if I lived in NA. I would make some modifications to the case (front) and back connectors. With RF /EMI filter, inlet (Schaffner) or inside (ATL audio) of course!

Akitika GT-102

https://www.akitika.com/GT102.html

https://www.diyaudio.com/forums/solid-state/345345-akitika-kits-post5977645.html

https://cheaptubeaudio.blogspot.com/2019/02/akitika-gt-102-power-amplifier.html

https://cheaptubeaudio.blogspot.com/2019/10/micromega-mygroov-mydac-meridian-200.html

https://www.audioshark.org/amplifiers-8/akitika-gt-102-power-amplifier-kit-assembled-16578.html

https://www.stereophile.com/content/akitika-gt-102-power-amplifier

-> https://www.stereophile.com/content/akitika-gt-102-power-amplifier-measurements

[maty]

Neurochrome Modules-x86

https://neurochrome.com/collections/power-amplifiers

Very good specs but much more expensive than Akitika. Modulus-286, with two LM3886 by channel it would not have problems with more complicated loudspeakers than those designed by Danny Richie. But more money!

https://neurochrome.com/collections/power-amplifiers/products/modulus-286

https://www.diyaudio.com/forums/chip-amps/309848-mod-286-build-thread.html

https://www.audiosciencereview.com/forum/index.php?threads/review-and-measurements-of-neurochrome-modulus-286-amp.6443/


Poseidonsvoice built one and is very satisfied with its sound. He could share some photos.

Here, pictures: https://www.diyaudio.com/forums/chip-amps/309848-mod-286-build-thread-post5496246.html

[maty]

Apollon NCMP400 also uses Hypex NC252MP. In a big case, with low mass binding posts: WBT-0703 Cu

[PDF] https://www.wbt.de/fileadmin/content/products/polklemmen/datenblatt/WBT-0703_Cu__E.pdf

[Big IMG] https://www.apollonaudio.com/wp-content/uploads/2019/06/ncmp400-inside-components.jpg

[maty]

Today the measurements, a lot of graphs!

MEASUREMENTS: Hypex nCore NC252MP Amplifier (+ Subjective opinions around objective testing, and CES2020)

http://archimago.blogspot.com/2020/01/measurements-hypex-ncore-nc252mp.html

[maty]

To finish with modern class D amps designed by Bruno Putzeys, maybe the new Purifi1 ET400A modules. The key, will be a good input board + buffer / gain with very good clean power.

https://www.diyaudio.com/forums/class-d/347137-brainstorming-purifi-1et400a-amps-post6045723.html

by mocenigo

...While I cannot do a direct comparison, the little Purifi amp with the stock buffer NOT yet bypassed sounds so much better than the NC500 mono blocks (with hypex smps and a buffer with Sonic Imagery opamps) that I find it quite likely that it is not due to the amplification board alone.

[Captainhemo]

Yeah, have heard the  Purifi  numerous times in my system  now.
Exellent  amp  with   new Mivera  gain stage implemented into an all in one 

jay

[Tyson]

Here's my amplification idea (haha, I just got this as a new toy so had to post it somewhere):









EL84 push-pull, 17 watts.  $750.

[howard1818]

nice where did you find that? a kit?

[Jmitchell3]

Here's my amplification idea (haha, I just got this as a new toy so had to post it somewhere):







Sexy AF

EL84 push-pull, 17 watts.  $750.

[Tyson]

nice where did you find that? a kit?

It's a prototype build from VTA (tubes4hifi.com), sort of a modern update of the Scott 222C, I believe.  Even fresh out of the box it sounds great.  Similar levels of clarity and immediacy as my Type 45 SET amp but with more power and punch.

[corndog71]

I built a pair of EL84 monoblocks but I want to rebuild them into a stereo amp.  Essentially, a modified Dynaco ST35.


EL84 Monoblocks

I built a stereo version for my brother.  I came up with layout and hoped it would work.  It had zero noise when I turned it on.

ST35 v3

[maty]

Off topic

Amps, like loudspeakers, there are a lot of. I focus on those of which we have measurements, especially if they are independent.

Measurements -> necessary condition but not sufficient to ensure quality sound. Let us say I understand it as a way to minimize the error risk in the purchase.

Unless the seller allows a 30-day trial period, like AVA and others. And live in that same region of the world (my problem: shipping + taxes to Europe).

- End off topic -

[Tyson]

Off topic

Amps, like loudspeakers, there are a lot of. I focus on those of which we have measurements, especially if they are independent.

Measurements -> necessary condition but not sufficient to ensure quality sound. Let us say I understand it as a way to minimize the error risk in the purchase.

Unless the seller allows a 30-day trial period, like AVA and others. And live in that same region of the world (my problem: shipping + taxes to Europe).

- End off topic -

True, but it's easier to end up with a bad sounding SS amp than it is a tube amp.  Especially at the lower end of the price spectrum.

[maty]

Yeah, have heard the  Purifi  numerous times in my system  now.
Exellent  amp  with   new Mivera  gain stage implemented into an all in one 

jay

The key is the input board and very clean power. Purifibuffer:

https://www.diyaudio.com/forums/class-d/339838-purifi-1et400a-measurements-post6016119.html

They also have 6 ultra low noise power supplies built in to power all the various sections of the Purifi modules to perfection. Everyone else uses the dirty power from the Hypex supply, and shares the power regulation between multiple sections Yuck!

BTW, Mivera thread is closed now. Then it was freely available, hence I shared the image and the comment on diyaudio.com

[maty]

LJM L12-2

Re: I need a $300-$400 amp (new or used) to go with JBL Studio 530 Speakers.

https://www.audiocircle.com/index.php?topic=166640.msg1771784#msg1771784

-> https://www.audiosciencereview.com/forum/index.php?threads/chinese-jl-hood-1969-class-a-amplifier-off-aliexpress.3372/post-269888

-> https://www.audiosciencereview.com/forum/index.php?threads/chinese-jl-hood-1969-class-a-amplifier-off-aliexpress.3372/post-269889







https://calvins-audio-page.jimdo.com/ideas-and-circuits/power-amplifiers/

https://sites.google.com/site/stevesstuffproject/l12-2-power-amplifier


***** https://calvins-audio-page.jimdo.com/ideas-and-circuits/power-amplifiers/ *****

https://sites.google.com/site/stevesstuffproject/l12-2-power-amplifier

[bodhiboy]

How about Dodd 120s?