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Matrix Quattro amp: unboxing and initial impressions - Page 12

post #166 of 229

Some may remember me posting about frying my Quattro when I carelessly inserted an op amp the wrong way around. We also discussed the design of the Quattro and what the benefits (or options) might be for rolling op amps.

 

The following is advice direct from Matrix, but please note they do not recommend or support the changing of op amps as you will instantly void your warranty (like me!)

 

But please note:  After replacing the op-amp must re-adjust the headphone output direct current, adjusting the potentiometer (near four op-amp OPA604), 4 measurement point voltage adjustment to ±0 mv, as small as possible, otherwise, the direct current may damage the headphone.

 

measure point1: the pad in the middle of R49 and R50 

measure point2: the pad in the middle of R53 and R54

measure point3: the pad in the middle of R51 and R52

measure point4: the pad in the middle of R55 and R56

 

What they're referring to here is adjusting 4 little screws inside the amp which regulate the power output to your headphones. I'll take a pic when my amp is back home to make it clearer.

post #167 of 229

Just received my Quattro back from Matrix and am mightily impressed with how well it's driving my HE-500s in balanced mode. I didn't expect it to have the grunt to get the most out of them, but it's holding it's own (running balanced) versus my S.E.X. (running single-ended).

 

Have to say that the service offered by Matrix for damage that was 100% my fault was nothing short of exceptional!!

post #168 of 229

Now that I have the Quattro back, I can also share a quick guide on how to calibrate the amp for non-standard op amps. I'm now using an OPA2107 in the dual slot and a set of 4 x OPA627BP in the mono slots. To calibrate you need to use a multimeter with the earth lead (black) connected to one of the screws on the circuit board like this one (middle of image, bottom right of yellow circuit board, below the big round transformer):

 

 

Next, you need to place the red lead against the pads on each pair of these 8 resistors (little black things with numbers on them running horizontally across the picture):

 

 

Specifically, you place the red probe from the test meter against either of the metal pads in the middle of each pair as per below (inside edges of R49 & R50):

 

 

Finally, while reading your test meter, you need to turn the little metal screw on top of each of these 4 blue potentiometers - anticlockwise reduces the output voltage and clockwise increases the output voltage (IIRC):

 

 

The aim is to reduce the voltage measured by your test meter to as close to zero as possible. It's nearly impossible to get 0 on all 4, but you can get +/- 00.1 or 00.2mV pretty easily.

 

I did find that going over them a second time was beneficial as the first ones adjusted raised a little bit as I adjusted the later ones. 2 passes did the trick though and all are now at no more than +/- 00.2mV

 

I hope this helps anyone contemplating op amp changes and remember that Matrix won't be able to offer any warranty from the moment you pop the lid on your Quattro. They were incredibly helpful, but we do these things at our own risk.

post #169 of 229
Thanks, interesting stuff.
I'm going to have to check back after I get my Quattro amp, which will probably be in June.
Try running the amp for another hour or two or three to let it really warm up, then tweak the pots one more time, assuming the offset has drifted a bit more!
post #170 of 229
Yesterday I tested balanced and rca connection of Quattro to X-Sabre. Its a terrific differences towards to balanced. More clear, wider soundstage and more punchy bass.

Hope to get more improvement from balanced cable with my new HD650.
post #171 of 229
Quote:
Originally Posted by Gibalok View Post

Yesterday I tested balanced and rca connection of Quattro to X-Sabre. Its a terrific differences towards to balanced. More clear, wider soundstage and more punchy bass.

Hope to get more improvement from balanced cable with my new HD650.

 

I found minimal differences between the two inputs using my X-Sabre, but massive only when I realised that the outputs are such different voltages and therefore required that I turn the Quattro up when using the RCA inputs. When I matched the volumes (by ear, not exactly accurate) I found both inputs almost identical.

 

By the way, it's a sign of good gear if the balanced and unbalanced inputs are equally good so this is a good thing.

 

Try bumping up the volume when using RCA inputs and see what you hear... :gs1000smile:

post #172 of 229
Quote:
Originally Posted by Loquah View Post

I found minimal differences between the two inputs using my X-Sabre, but massive only when I realised that the outputs are such different voltages and therefore required that I turn the Quattro up when using the RCA inputs. When I matched the volumes (by ear, not exactly accurate) I found both inputs almost identical.

By the way, it's a sign of good gear if the balanced and unbalanced inputs are equally good so this is a good thing.

Try bumping up the volume when using RCA inputs and see what you hear... gs1000.gif

I do understand what you a reffering to. Its ineed seems that RCA slightly volume below level of balanced inputs. But I think that balanced inputs give some 3d rendering of sound as well. Also I dont exclude that the difference may come from different cables (3m wireworld rca at 70$ and Kimber Kable XLR 0.5m at 150$).

What do you think about improvement using balanced cable with HD650? What cable does worth its money?
post #173 of 229
Just a FYI... directly from their site.

Output:

• RCA Output Level: 0~ 2.0V Adjustable
• XLR Output Level: 0~ 4.0V Adjustable (XLR Interface: 1=ground 2=hot 3=cold)
• Frequency Response: 20Hz~20kHz
• Dynamic Range: 110dB / SNR: 114dB
• Distortion: 0.00056%(1kHz)


Peace OOK
post #174 of 229
Quote:
Originally Posted by Otheronek View Post

Just a FYI... directly from their site.

Output:

• RCA Output Level: 0~ 2.0V Adjustable
• XLR Output Level: 0~ 4.0V Adjustable (XLR Interface: 1=ground 2=hot 3=cold)
• Frequency Response: 20Hz~20kHz
• Dynamic Range: 110dB / SNR: 114dB
• Distortion: 0.00056%(1kHz)


Peace OOK

I alwaus thought that xlr connection brings more quality than rca. What is the reason to put xlr instead cheaper second rca both to X-Sabre and Quattro?

Since i beleive in better world I think that xlr is better. And i hear more clarity. But again the reason can be in different clarity and length of cables in my case
post #175 of 229

Quote:

Originally Posted by Otheronek View Post

Just a FYI... directly from their site.

Output:

• RCA Output Level: 0~ 2.0V Adjustable
• XLR Output Level: 0~ 4.0V Adjustable (XLR Interface: 1=ground 2=hot 3=cold)
• Frequency Response: 20Hz~20kHz
• Dynamic Range: 110dB / SNR: 114dB
• Distortion: 0.00056%(1kHz)


Peace OOK

 

Are those stats for the Quattro DAC? I think we are talking about the X-Sabre DAC with the Quattro amp. The X-Sabre DAC has the following specs (notice the voltages from the outputs):

 

  • RCA Output Level: 2.2Vrms at 0dBFS
  • XLR Output Level: 6.8Vrms at 0dBFS (XLR:1=GND,2=hot,3=cold)
  • Frequency Response: 20Hz-20kHz +/-0.1dB
  • SNR: 124dB 0dBFS Unweighted
    127dB 0dBFS A-weighted
  • THD+N: 0.0003% @1kHz 0dBFS
    0.0003% @1kHz -1dBFS
    0.0003% @1kHz -3dBFS

 

Quote:
Originally Posted by Gibalok View Post


I alwaus thought that xlr connection brings more quality than rca. What is the reason to put xlr instead cheaper second rca both to X-Sabre and Quattro?

Since i beleive in better world I think that xlr is better. And i hear more clarity. But again the reason can be in different clarity and length of cables in my case

 

The main benefit of balanced (XLR) connections is their ability to reject noise (much more so than simple RCA), but the actual output itself is not necessarily of higher quality (depending on the gear). In the case of the X-Sabre, I actually find no difference between the 2 which is great because it means you can happily run devices from both outputs with no loss of quality. Certainly cables may influence the sound as well so it's worth considering that too.

 

Quote:
Originally Posted by Gibalok View Post


I do understand what you a reffering to. Its ineed seems that RCA slightly volume below level of balanced inputs. But I think that balanced inputs give some 3d rendering of sound as well. Also I dont exclude that the difference may come from different cables (3m wireworld rca at 70$ and Kimber Kable XLR 0.5m at 150$).

What do you think about improvement using balanced cable with HD650? What cable does worth its money?

 

I would highly recommend running your HD650s balanced from the Quattro. The balanced output (even when volume matched) is vastly superior to the unbalanced connection. You could simply have your stock HD650 re-terminated if you wanted to. Otherwise take a look around at brands like Toxic cables, Double Helix Cables (DHC), and Forza Audio Works (in Poland so possibly a good option for you being in Russia) to name a few. You don't need to spend a fortune to get a great sound from a balanced cable for the HD650s.

post #176 of 229


Yes they were...sorry I stand corrected.  Serves me right for not thoroughly reading the post.  But there still is a difference as you listed them, which is typical for a balanced and unbalance signals.   At least in the pro gear verses consumer gear I deal with....


Edited by Otheronek - 5/9/14 at 7:15pm
post #177 of 229

Could anybody please explain/show pictures how to connect HD650 in balanced mode to Matrix Quattro. 

 

Thanks a lot

post #178 of 229
Quote:
Originally Posted by Gibalok View Post
 

Could anybody please explain/show pictures how to connect HD650 in balanced mode to Matrix Quattro. 

 

Thanks a lot

 

You need a cable with some form of balanced termination (common options are 2 x 3-pin XLR or 1 x 4-pin XLR). The Quattro uses a slightly less common 2 x TRS jack interface so I have personally made adapters (2x TRS to 1 x 4-pin XLR) for my setup, but you could buy an adapter lead or a dedicated HD650 cable.

 

The cable wiring is explained in the Quattro manual, but basically, the active for each channel (L/R) goes to the tip contact of the TRS and the ground for each channel goes to the ring contact. The sleave contact (normally used for the earth or shield connection) is left disconnected and serves as a trigger to tell the Quattro that it's running balanced. In other words you'll end up with a stereo 6.3mm TRS plug for the right and a stereo 6.3mm TRS plug for the left.

 

I hope this makes sense.

post #179 of 229

Well, thanks

 

So im considering to buy some Chinese cable like that 

 

http://www.ebay.com/itm/Upgrade-Cable-For-SENNHEISER-HD580-HD600-HD650-DUAL-MALE-XLR-BALANCED-PLUG-/221339993442?pt=US_Audio_Cables_Adapters&hash=item3388e44562

 

Is it worth the money?

 

 

Also I can order hand made cable made from Western Electric 20th cuprum cable for 150-200$. 

 

http://www.avito.ru/moskva/audio_i_video/kabel_naushnikov_hd_650-western_electric_4h0.5_335679764

 

 

 

To connect XLR's to Quattro Im going to buy 2 x Neutrik XLR to Jack 

 

http://www.allcables.ru/neutrik_NA3FP.html 

 

Should it be Mono or Stereo Jack?

 

Thanks for help. 

post #180 of 229

I personally enjoy "upgraded" cables, but it's all personal preference.

 

As for the jacks, they must be stereo because you need the non-connected sleeve contact to trigger the auto-detection of balanced mode in the Quattro.

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