Amplification ideas to GR-Research NX-Studio

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maty

Re: Amplification ideas to GR Research Studio Monitor
« Reply #40 on: 15 Feb 2020, 09:08 pm »
I think is better idea to post the link of the last Folsom amplifier.

Folsom EC7293: PVI Powered Frontend Amplifier, 60/120w 8/4ohm, 0.0005% THD

https://www.diyaudio.com/forums/group-buys/338275-folsom-ec7293-pvi-powered-frontend-60-120w-8-4ohm.html

Quote
The EC7293 uses 2 chip amps in parallel for high power with a discrete error correction frontend which reduces distortion; and has very low memory distortion. High sensitivity makes it perfect for a variety of sources with 8 ohm and 4 ohm speakers.

Input impedance: 27k
Gain: 32db

Distortion 1 khz; 8 ohm; full power w/Antek AS-3225: <0.0005%




http://www.sengpielaudio.com/calculator-thd.htm

Full power at 8 Ohms -> 60 watts.

At 20 kHz about 0.01% -> -80 dB


I would like to see more measurements and graphs of the Folsom EC7293.

maty

Re: Amplification ideas to GR Research Studio Monitor
« Reply #41 on: 15 Feb 2020, 09:21 pm »
Akitika GT-102, by Dan Joffe

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

Quote
    Output Power: greater than 50 Watts per channel into 8 Ohms
    Small Signal Bandwidth: typically wider than 5 Hz to 100 kHz at -3 dB points
    Slew Rate (typical) 14 Volts/microsecond
    Damping Factor @ 1 kHz wrt 8 Ohms: >80
    Signal to Noise Ratio: typically 136 dB below 50 Watts into 8 Ohms, A-weighted, referred to a shorted input.
    Harmonic Distortion: typically 0.003% at 50 Watts into 8 Ohms at 1 kHz. Clipping occurs at a bit more than 60 Watts into 8 Ohms at 1 kHz.
    Intermodulation Distortion: 0.004% typical, SMPTE 4:1, 60 Hz, 7 kHz
    Separation: >90 dB at 1 kHz, >70 dB at 10 kHz
    Input Impedance: 51 K Ohms
    Sensitivity: 1 Volt RMS input produces 20.59 Volts RMS output
    Dimensions: 15” Wide x 10” Deep x 4.5” Height (includes height of the feet)
    Input Power: 120 VAC 60 Hz, IEC connector (power cord supplied)
    Input Power Fuse Rating and type: medium acting 3 Amps or 3.15 Amps, 5x20 mm
    220-240 Volt operation also possible with the V240 kit, which uses a 1.5 Amp fuse
    Weight: 15.5 lbs
    Shipping Weight: 19 lbs

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

Quote
    Output Power: greater than 50 Watts per channel into 8 Ohms
    Small Signal Bandwidth: typically wider than 5 Hz to 100 kHz at -3 dB points
    Slew Rate (typical) 14 Volts/microsecond
    Damping Factor @ 1 kHz wrt 8 Ohms: >80
    Signal to Noise Ratio: typically 136 dB below 50 Watts into 8 Ohms, A-weighted, referred to a shorted input.
    Harmonic Distortion: typically 0.003% at 50 Watts into 8 Ohms at 1 kHz. Clipping occurs at a bit more than 60 Watts into 8 Ohms at 1 kHz.
    Intermodulation Distortion: 0.004% typical, SMPTE 4:1, 60 Hz, 7 kHz
    Separation: >90 dB at 1 kHz, >70 dB at 10 kHz
    Input Impedance: 51 K Ohms
    Sensitivity: 1 Volt RMS input produces 20.59 Volts RMS output
    Dimensions: 15” Wide x 10” Deep x 4.5” Height (includes height of the feet)
    Input Power: 120 VAC 60 Hz, IEC connector (power cord supplied)
    Input Power Fuse Rating and type: medium acting 3 Amps or 3.15 Amps, 5x20 mm
    220-240 Volt operation also possible with the V240 kit, which uses a 1.5 Amp fuse
    Weight: 15.5 lbs
    Shipping Weight: 19 lbs


Quote
The next measurements show 1 kHz THD+N measurements as a function of output power across an 8 Ohm load. Note the clipping occurs around 63 watts. Both left and right channel measurements are shown. One channel was driven at a time for these measurements. The nice in THD+N at low output power levels is the usual rise that happens at low levels as a fixed amount of noise becomes a greater percentage of the THD+N as power drops.




Quote
It's also handy to get a look at the spectrum of the harmonics. The following graphs show the harmonics of a 1 kHz fundamental. They are shown in dB relative to 53 Watts into 8 Ohms. Note that the largest harmonic, the 3rd, is almost 100 dB below the fundamental. The remaining harmonics are typically more than 120 dB below the fundamental.




From other source: Stereophile.

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



Quote
Fig.6 AkitikA GT-102, THD+N (%) vs frequency at 8.95V into: 8 ohms (left channel blue, right red), 4 ohms (left cyan, right magenta).

With one LM3886 by channel... But Studio Monitor is 8 Ohms and, if I am not wrong, cuts at 70 Hz at -3 dB.


http://www.sengpielaudio.com/calculator-thd.htm

At 20 kHz, 8 Ohms, 10 watts, THD+N= 0.04% -> -68 dB

maty

Re: Amplification ideas to GR Research Studio Monitor
« Reply #42 on: 15 Feb 2020, 09:39 pm »
Folsom EC7293

Full power at 8 Ohms -> 60 watts.

At 20 kHz about 0.01% -> -80 dB

Jaytor

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Re: Amplification ideas to GR Research Studio Monitor
« Reply #43 on: 16 Feb 2020, 01:51 am »
@maty - Have you built one of these? I just ordered a set of boards to give it a try.

maty

Re: Amplification ideas to GR Research Studio Monitor
« Reply #44 on: 16 Feb 2020, 08:04 am »
Nope.

After ruling out several DIY class A designed by Hugh Dean for lack of power (KEF Q100: true 85 dB and minimum 4 Ohms) and excess heat, I focused on the DIY PURIFI 1ET400A. I am not in a hurry because I enjoy a great sound. Let others be the ones who first count the problems and weaknesses, if any. Of course, without Hypex SMPS. DIY Cresnet SMPS probably.

It is the only class D that really interests me because it does not suffer from the usual problems that of the technology, specially in the HF. The criticism I have received in other forums for reporting these deficiencies!

maty

Re: Amplification ideas to GR Research Studio Monitor
« Reply #45 on: 16 Feb 2020, 08:34 am »
Akitika

I was about to buy the first Akitika model, the GT-101. I did not do it because I wanted more power for my little coaxials, 3 meters away. Keep in mind that I usually listen to excellent recordings with very high dynamic range, usually excellent 24/192 or 24/96 vinyl rips. I have a multitude of tracks with DR > 15 dB.

Then I discarded the successor, the GT-102. Why? Because the Q100: 49 Hz at -3 dB, and really is like 5 Ohms nominal (KEF says 8 Ohms, as LS50, false).

It is a chipamps problem, for slightly demanding speakers, they require two per channel.

Studio Monitor: 88 dB and true 8 Ohms nominal, and about 70 Hz at -3 dB. Stereophile graph OK with it, even if the impedance was lower.

maty

Re: Amplification ideas to GR Research Studio Monitor
« Reply #46 on: 16 Feb 2020, 08:37 am »
Neurochrome

The same restrictions. Only Mod286 (two chipamps by channel) or Mod686 (six chipamps).

Two inconvenients.

* Expensive (I would like more watts) or very expensive using chipamps.

* I do not have a good relationship with Tom Christiansen.

maty

Re: Amplification ideas to GR Research Studio Monitor
« Reply #47 on: 16 Feb 2020, 08:40 am »
Folsom EC7293

I want more measurements! And reviews too. Maybe in the future but not just now. That they are others who boast of their new acquisition, I prefer to bet on insurance or, in other words, reduce the risk of error in the purchase, that is my usual practice.

maty

Re: Amplification ideas to GR Research Studio Monitor
« Reply #48 on: 16 Feb 2020, 08:55 am »
To finish,

I have always been a very questionable person, of those who preferred to sit in the front row.

Dan Joffe (Akitika). I haunted him (e-mail) with many questions and doubts I had. He always responded with good manners and giving the explanation I was looking for. It is very important to know that you are going to have a good after sales service, just like Danny Richie or Frank Van Alstine (AVA Hifi), at least for me.

tomchr

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    • Tom Christiansen Audio
Re: Amplification ideas to GR Research Studio Monitor
« Reply #49 on: 16 Feb 2020, 06:11 pm »
Neurochrome

* I do not have a good relationship with Tom Christiansen.
That's unfortunate. I hear he's a really nice guy... ;)

You're right, though. You and I don't see eye-to-eye. Part of that is that I've pointed out the fallacies in your arguments and refused to take your word as gospel. I approach audio design from a perspective rooted in science and engineering. I also have the perspective of someone who has designed circuits for mass production. The circuits I designed for National Semiconductor and Texas Instruments have been produced by the millions. I apply this perspective and the learnings from my experience in my designs. I have no plans to change that.

It's sad that you find it necessary to trash my reputation both here and on DIY Audio (https://www.diyaudio.com/forums/class-d/347137-brainstorming-purifi-1et400a-amps-post6079964.html), but that is your choice. (BTW, those who know Maty and his communication style may find my response insightful, if not quite entertaining. It also outlines the root of our disagreement: https://www.diyaudio.com/forums/class-d/347137-brainstorming-purifi-1et400a-amps-post6080256.html).

I have always been a very questionable person, of those who preferred to sit in the front row.

You and I actually have something in common then. However, in my experience, such students tend to fall into two categories: 1) Those who reflect on the topic taught and ask questions to test their understanding; and 2) those who crave the attention of the instructor and want the lecture to be about them and their issues. I've always preferred students who fell in the former category and do my absolute best to be a member of that category as well.

He always responded with good manners and giving the explanation I was looking for. It is very important to know that you are going to have a good after sales service, just like Danny Richie or Frank Van Alstine (AVA Hifi), at least for me.

It's interesting you mention that, actually. In my market surveys, a vast majority of my customers find me to be polite, honest, and to the point. Many also commend me for my ability to deal gracefully with the various noise makers in forum threads (one guy referred to this as my BSRR, which I found to be a fitting term). I tend to get around 100 participants in my surveys before they close, so I think I'm reaching a representative sample of my customers.

That said, my communication style does tend to be pretty direct, fact-based, and science-based, which rubs some the wrong way. Also, while I do my best to be patient, my patience is finite. So I probably become a bit rough around the edges when someone forcefully argues that I should change my products to suit their pet ideas - in particular when they completely lack perspective and it becomes impossible to reach them with fact- and science-based arguments. See this discussion for example: https://www.audiosciencereview.com/forum/index.php?threads/review-and-measurements-of-neurochrome-modulus-286-amp.6443/post-143471

It's unfortunate that you don't like my direct, no-BS approach. I have no plans to change. I would rather sell my products with evidence-based arguments than with sappy marketing verbiage. You're free to disagree.

Now back on topic: Here is one review of my Universal Buffer + Purifi 1ET400A: https://www.diyaudio.com/forums/class-d/347137-brainstorming-purifi-1et400a-amps-32.html#post6064187 with further clarification here: https://www.diyaudio.com/forums/class-d/347137-brainstorming-purifi-1et400a-amps-post6064216.html. Here's a summary:

Quote
The first impression is that it is smoother and the sound more "plastic" than with the EVAL1 buffer, or bypassed. Plastic as in plastic arts, in particular sculpture, not as in the synthetic material. [...] [T]he soundstage is very precise and natural, wide and deep, with very precise layers and everything has the right size and placement. As if sculpted.

The noise floor is also lower (my test was not too scientific but it is still a measurement: I bypassed the autoformer on the tweeter of the B&C coaxial so that it has a 110Db sensitivity, then measured the noise with my umik microphone and, with gain matched, I get a measurement of the hiss which is almost 10Db lower).

With the gain at unity it sounds relaxed and with slightly understated dynamics – with the gain at 7.3 or 13 it is much more dynamic. I chose to keep 7.3. I matched the level with the DAC's control, so this may also be due to the DAC behaving in a different way at various attenuation levels, but I would consider this case unlikely.

It's good to know that at least one person in the world likes my circuits and is willing to work with me. :) He and I are currently working on a buffer designed specifically for the Hypex NC500 and Purifi 1ET400A.

Tom Christiansen
Neurochrome - www.neurochrome.com
Tom Christiansen Audio - www.tomchr.com

HT cOz

Re: Amplification ideas to GR Research Studio Monitor
« Reply #50 on: 16 Feb 2020, 06:55 pm »
Tom you are a class act and a valued member of the diy community.  Please filter out the noise and continue to support us!!!

poseidonsvoice

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    • 2 channel/7 channel setup
Re: Amplification ideas to GR Research Studio Monitor
« Reply #51 on: 16 Feb 2020, 06:58 pm »
Tom you are a class act and a valued member of the diy community.  Please filter out the noise and continue to support us!!!

+ gazillion!  :green:

Best,
Anand.

tomchr

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    • Tom Christiansen Audio
Re: Amplification ideas to GR Research Studio Monitor
« Reply #52 on: 16 Feb 2020, 08:24 pm »
Tom you are a class act and a valued member of the diy community.  Please filter out the noise and continue to support us!!!
Thank you. I appreciate it. I'll do my best. :)

Tom

maty

Re: Amplification ideas to GR-Research NX-Studio
« Reply #53 on: 21 Feb 2020, 10:22 am »
YouTube GR-Research NX-Studio, NX-Otica and NX-Treme Sound Clips

Clarified and optimized



If I had a very large room and, above all, for my enjoyment, the two Big NX-Treme with the same two Big subwoofers would be my choice without hesitation.

In smaller rooms, NX-Studio, with at least two subwoofers.


PS: updated title thread: Amplification ideas to GR-Research NX-Studio

maty

Ron Brenan (New Record Day) audio "arsenal"
« Reply #54 on: 21 Feb 2020, 02:50 pm »
As a curiosity, here you are Ron Brenan (New Record Day) audio "arsenal"

https://www.youtube.com/post/UgxqOemUxaI7A8knbR54AaABCQ



[Big IMG, link] https://yt3.ggpht.com/YNLXlKZebXYj0X8GVUg4QJakuPu_kVDs_o7sQVesx261zWiLbolLlt_T6EhA8jwlOJdbvdZVqZowIvo=s1600

You know, you always have to go well equipped if you travel to Texas to visit Danny Richie :D
« Last Edit: 21 Feb 2020, 03:56 pm by maty »

studley

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Re: Amplification ideas to GR Research Studio Monitor
« Reply #55 on: 24 Mar 2020, 11:46 pm »
+ gazillion!  :green:

Best,
Anand.
Anybody who has heard any of Tom’s designs knows how good they are.  In a word, outstanding.

Captainhemo

Re: Amplification ideas to GR Research Studio Monitor
« Reply #56 on: 25 Mar 2020, 12:09 am »
Quickly browsing i did like the Stratos Stereo from Odyssey Audio.
I could stick with Schiit Ragnarok Amp since it does have L&R balanced pre outs. I would like to pair the studios with the servo sub kit2 (stereo subs) but those don't seem to have a balanced input, just the servo sub kit 1. (that's what i can make out from the low quality picture) am i correct? or do my eyes deceit me?

For a DAC maybe Cambridge Audio?

(CXN V2)

or



(Azur 851C)


Any thoughts on the combos? Will it be feasible for the stereo subs?

You  can get  any  amp   you want withthe  kit,  just  let  Danny  know  what you need.  TA370PEQ has  SE, Balanced, and a  LFE  input  I believe.  Likely a very small upcharge.

jay

bdp24

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Re: Amplification ideas to GR-Research NX-Studio
« Reply #57 on: 26 Mar 2020, 02:37 pm »
If you can find one, a Music Reference RM-10 Mk.2. 35w/ch from a single pair of EL84's per.

Sonicjoy

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Re: Amplification ideas to GR-Research NX-Studio
« Reply #58 on: 31 Mar 2020, 01:47 pm »
I can recommend and amp for the Studio Monitors. I am using two Emerald Physics EP 100.2SE class d amps in my system and they are currently powering the Studio's. These are great little amps that are under appreciated in my view. They are a great value also. They can be had second hand for around $600. $700. Check HiFi Shark. There are a few listed now.

They come in black or silver.







    Special Edition version of 100.2
    Fully balanced design
    100 watts RMS @ 8 ohms
    150 watts RMS @ 4 ohms
    275 watts RMS mono operation
    450 watts in mono @ 4 ohms

I'm running these as mono blocks in balanced mode. They sound great with NX Studios. They have none of the harshness of early class d designs. I also liked it so much when I got the first one that I bought a second one. Very happy with these.

My preamp is a Wyred 4 Sound STP-SE with stage 2 upgrades Very Very nice Preamp. True reference grade.