[selvakumar]

No noise/hiss at all on both XLR and 6.3mm Jack? Or only on Jack there's no noise?

both i have tested with 6.3mm and balanced xlr both perfect

 

[raoultrifan]

Please tag me when you release the results.

Of course, I will, but I thought @selvakumar already owns both PLAYMATE and C3X, right Selva? Can you pls check the background noise on both devices with your sensitive T5p gen 2 and see if you can spot some hiss on any of those 2?

 

[selvakumar]

Thank you!

Please tag me when you release the results.

tag me i too own play,playmate,c3x

 

[selvakumar]

Of course, I will, but I thought @selvakumar already owns both PLAYMATE and C3X, right Selva? Can you pls check the background noise on both devices with your sensitive T5p gen 2 and see if you can spot some hiss on any of those 2?

already posted playmate has no hiss at all but 3x has hiss in balanced but in 6.3mm is ok less hiss cant hear by many

 

[raoultrifan]

both i have tested with 6.3mm and balanced xlr both perfect

Great, good to know!

I've tested myself the following:
- AKG K550 (balanced and unbalanced) 117.8dB/V: In unbalanced there's a slight hiss that could be heard in a very quiet room, but not impacting listening to the music. In balanced operation some noise can be heard.
- AKG K701 (balanced and unbalanced) 105dB/V: No noise at all in both balanced and unbalanced operation.
- Audeze LCD2 Fazor (balanced and unbalanced) 112.55dB/V: No noise at all in both balanced and unbalanced operation.
- Beats Solo 2 (unbalanced) 118dB/V per Innerfidelity: There's a tiny amount of noise that could be heard, but only if the surrounding is very quiet. Not impacting listening to music.
- Beyerdynamic DT880/600 (balanced and unbalanced) 96dB/V: No noise at all in both balanced and unbalanced operation.
- Fostex T50RP mk3 (unbalanced) 103dB/V: No noise at all.
- Hifiman HE-560 (unbalanced) 100dB/V per specs, 103dB/V per Innerfidelity: No noise at all.
- Grado SR60i (unbalanced) 115dB/V: Couldn't hear any noise out of these cans.
- Superlux HD-662 EVO (unbalanced) 113dB/V: No noise at all in both balanced and unbalanced operation.
- Superlux HD-381F (unbalanced) 121dB/V: There is an audible hiss noise, which is expected from a 121dB/V 16 Ohms pair of IEMs. Probably not the best headamp to drive very sensitive IEM's, but not sure who will purchase a 5000mW amplifier especially to drive 16 Ohms IEMs that with only 10mW can get to 113dB of loudness.
- @selvakumar found Beyerdynamic T5P GEN 2 (117dB/V) that had no noise at all in unbalanced operation, which is good news. However, in balanced operation some noise could be heard, due to the high sensitivity of these cans.

Till now I only found one single pair of headphones that was impaired with C3X and that was Superlux HD-381F (unbalanced) 121dB/V 16 Ohms IEMs specially designed for use with mobile devices. Probably most desk headphones amplifiers will have a slight background noise with such IEMs.

 

[raoultrifan]

already posted playmate has no hiss at all but 3x has hiss in balanced but in 6.3mm is ok less hiss cant hear by many

Idea was to test only the jack plug when comparing PLAYMATE with C3X, otherwise the test would not be fair enough.
Per how a balanced amplifier is designed, it will sound at least two times higher balanced vs. unbalanced.
So, can you please double-check background noise on both PLAYMATE and C3X by using only the jack socket?

P.S.: For me PLAY v2.2 and PLAYMATE and C3X have about same moderate background noise (tested with very sensitive IEMs 121dB/V).

 

[selvakumar]

Idea was to test only the jack plug when comparing PLAYMATE with C3X, otherwise the test would not be fair enough.
Per how a balanced amplifier is designed, it will sound at least two times higher balanced vs. unbalanced.
So, can you please double-check background noise on both PLAYMATE and C3X by using only the jack socket?

P.S.: For me PLAY v2.2 and PLAYMATE and C3X have about same moderate background noise (tested with very sensitive IEMs 121dB/V).

same i have play old version and 2.2 playmate and c3x

 

[raoultrifan]

Thanks Selva. So, @escalibur, I think you have your answer: C3X is on par with PLAYMATE in terms of audible background noise, although C3X has a much more power reserve left and more features.

 

[ejrmathews]

Try using a different USBA to USBC cable. I used this one successfully.
https://www.jbhifi.com.au/products/belkin-duratek-plus-usb-c-to-usb-a-cable-with-strap-black-1-2m

I was able to pick up a new USBA to USBC cable at WholeFoods (Amazon!) on my way home from work. Replaced the supplied cable from my 3X into my Mac Mini, made zero adjustments and it worked perfectly through the USB input. I must have had a bad cable. Thanks again.

Also, I listened carefully for noise using my Sony CD900ST phones and heard none on either gain setting.

 

[Ty116]

I was able to pick up a new USBA to USBC cable at WholeFoods (Amazon!) on my way home from work. Replaced the supplied cable from my 3X into my Mac Mini, made zero adjustments and it worked perfectly through the USB input. I must have had a bad cable. Thanks again.

Also, I listened carefully for noise using my Sony CD900ST phones and heard none on either gain setting.

Same thing with me. The cables they supplied are just not up to snuff.

 

[Ty116]

Is it ok to use the pre-amp output with an unbalanced amp? Basically balanced to unbalanced conversion.

 

[raoultrifan]

Also, I listened carefully for noise using my Sony CD900ST phones and heard none on either gain setting.

Good news! Sony CD900ST are having a sensitivity of 118dB/V, so I suppose you tried them on the jack socket and not to the XLR one, right?

 

[ejrmathews]

Good news! Sony CD900ST are having a sensitivity of 118dB/V, so I suppose you tried them on the jack socket and not to the XLR one, right?

Yes, they are unmodified so I was using the ¼" single-ended output on the 3X.

 

[ejrmathews]

Is it ok to use the pre-amp output with an unbalanced amp? Basically balanced to unbalanced conversion.

I'd be super-careful. If you read the 3X manual available on the Burson site, you must not short one leg of the XLR output. They recommend using a transformer and provide a link in the manual. Also, if you're into DIY, THAT Semiconductor company manufactures an XLR receiver chip that will convert an XLR signal to single-ended. The problem without using one of these tools is that many XLR to RCA cables and jumpers short the negative phase leg of the balanced feed and that could damage your Conductor's output.

 

[raoultrifan]

Is it ok to use the pre-amp output with an unbalanced amp? Basically balanced to unbalanced conversion.

Taken from my post from one page behind:
"Accepts outputs to both unbalanced RCA and balanced XLR connections (with dedicated XLR to RCA transformers or special adapter plugs or cables that do not shorten the audio signal to GND! like is done in this picture)".

I build a short cable few days ago and it worked fine to me. Of course, I did measured with the DMM/multimeter the resistance between the 3 pins, just to be sure it's well done and I'll not short-circuit any of the two outputs from each XLR plug.

O huge NO GOI would be the below picture:

DON'T DO THIS WITH C3X!!! The short-circuit between pins 1 & 3 will kill the opamps inside C3X!
I think that all XLR to RCA adapters are shorting pin 3 to GND (pin1), so either you build one by yourself, either you use a transformer.
​

To do this adapter compatible with C3X you need to remove the short-circuit from pin 1 and 3! To feed C3X correctly just use the Positive (Pin2) and GND (Pin1) pins and leave the Negative signal (Pin3) N.C.. Short-circuiting to GND (pin 1) any of the two pins (2 or 3) may damage irremediable the opamps in C3X and, most likely, void the warranty of C3X! more details about the 3-pin XLR plug could be found here: http://www.clarkwire.com/pinoutxlrbalanced.htm.

Bottom of line: Shorting pin1 with pin3 is a good thing only when you want to feed an amp via an RCA to XLR adapter, because you're shorting to GND the input stage of an unused inverted amplifier from the balanced input. But not in C3X's case where we need a XLR to RCA adapter and not a RCA to XLR one, so pin3 should be left Not Connected to make it work properly!

Removing the short-circuit between pins 1 and 3 should resolve the issue!
This is the cable I've done few days ago and works just fine in feeding an external amplifier without putting stress into C3X's output buffer opamps.
​

P.S.: For warranty reasons, using the recommended balanced-to-unbalanced transformers would be a must!