Ti_Leo

@Hrodulf Oh... That makes sense! So it's like half disconnected balanced half as powerful, right? I'll check the cables, thanks!!

I once made a cable that ended up having severe channel imbalance. The culprint was a big solder blob on one channel on the 3.2mm conector (vs the other left cable which had a more even amount of solder). It ends up acting as a resistor and lowers the volume.

@señorhifi Well, that could definitely happen to me, as my soldering skill sucks... But my case should be faulty balanced connection, since at least my preamp used to work just fine.

The ZD SE came with broken right channel, my guess is that the heating circuit was gone, as the big tube barely glowed and not as hot as the working one. So... I decided to apply some thermal isolation onto the right side...

Now it really works! With a little channel imbalance, but bearable. I know I'm definitely a bad bad example of how not to fix your stuff...

IIRC, the OG HE560 sounded quite spikey on treble, didn't like it.
HE560 V2 sounded dull, boring (2.5mm socket).
V3 was just a headband lengthened version of V2 with 3.5mm connection.
Now V4 sounds a bit warm and more... musical? It could use a bit of more subbass, but good enough.

I can't do AB comparison, as my amp is broken, if I swap tube, the right channel will be off.

From my limited time with the 6CG7 (used), it sounds sweeter, a bit wetter, maybe low end rolls off a bit, but it's OK. I just need that bit of sweetness to make ZD SE sounds a bit relaxed. Good!

One of my favorite tubes!

@Azimuth great, now you set my mind at ease, as I don't need to think about tubes in the near future.

But I'm wondering: what if I put or glue a heating desk mat under the DAC? It should speed up the warming up process, right?

I can't imagine this was remotely a design consideration. Read the manual, I'm guessing if this were a good idea it'd be in there.

@GoodEnoughGear Yep, I fully agree, but sometimes I'm a bit naughty...

Modius stuck in the CN customs, can't get a (used) Bifrost 2 here. Only old stuff on used market, like Spring 1, Yggdrasil A1, Gungnir Multibit A1. Otherwise, Audio-GD, Denafrips or some weird DIY stuff if I don't want DS DACs, sigh.

Going on 17 months now! Thanks a lot, COVID!

And as vaccination rates going up, Delta variant enters the chat. Ugh.

@thegunner100 My unit has a different problem I think: The seller broke one of the rectifier tubes, so I guess it took something in the right channel with it. But I can use both of the channels after "warming up" the tubes, and the volume on right channel stays, or even the it sounded a bit loud or brighter to me. Anyway, thank you all the same, and glad to see your amp is working now.

Ahh sorry to hear that. It was worth a try :(

It's OK, I bought this unit hoping it's just a broken tube problem, but planned for much worse, like there's only bricks in the package. (I'm in China, so...) I guess the broken is not toooo big? At least one of the channels still works, so I can use it as reference. Time for me to learn some real electricity!

I stand corrected! I was only thinking of HDMI or DSI displays. SPI displays and parallel rgb displays are blocked, but I2C displays can be used as we have those signals on the 16-pin header on our pi2aes.

@Michael Kelly Probably not what @Ti_Leo had in mind either... but I have one of those dispalys, and it seems to be unusable with any audio HAT.

@Woland Yea, I just wanted get a cheapo small screen from Taobao, normal one is enough for me, and I don't even know what you two were talking about, hahah.

You mean this? https://www.superbestaudiofriends.org/index.php?threads/md-x-airist-x-sosolar-rdac-design-mysteries.6420/

Github is cool

@Biodegraded No no no, the DAC I'm looking at is just a board, I even need to find some psu for it. Which made me hesitated. @Cspirou Yeah, it's like an approval to me, but the board is not 100% copy so I don't know... Sigh.

@Lyander Yes, I thought about HP-3 also, as both of these headphones are (rumored) using Fostex drivers. Yes, HP-3 feels better than NH, but, it's twice more expensive than NH in China, so... I think I'm fine with NH?

Ah true, I'd never have bought the HP-3 for retail price (also, the original pads are USD100... each, BEFORE shipping and taxes). On the upside apart from being excessively murky I did rather like the NH, not to mention they're significantly more comfortable to wear!

Definitely stick with whatever works for you. While I crap on the stock NH a lot personal preferences do matter :P

It's funny that I'm actually having my own NH OG on sale, as I didn't like the OG sound. It's like I had to try very hard to extract the emotion from the bass cloud, but then the slightly peaky treble kicked in and I could only cry for my ears.

Last week I saw a NH Carbon, with the microsuede pads and cheaper than mine, so I "bought the competition", and found the microsuede pads worked surprisingly well.

No good. Did you feel this way about it prior to using the optical input? What is your source? Have you compared it to the USB input?

OK, I found a coaxial cable! So, quick comparison: optical input sounds more two dimensional, mids seems thinner, and the bass seems less also... But coaxial input gives me more congested feeling, seems like it generates some sense of depth by pulling the vocal closer while optical sounds more laid back. I prefer coaxial input on Modius.

Oh, my source is Pi2AES, and I didn't use USB input for long, as it generated noise over time, replugging USB cable resolved the problem for some short time, but it would come back. I guess the problem was more on my PC.

I still listen to a recabled DT880 250 ohm. It may not have the best overall sound signature, but I enjoy it for an everyday open headphone.

Was it loose at the PI2AES side? hopefully it was not an issue with the connectors on our board, but please let us know if it was.

@Michael Kelly No, it's at the DAC side. The connect at Pi2AES is really firm! Great product!!

Ignore my previous impression of Dekoni leather pads. it was made when the polarity was inverted... I bought used unit with after market BAL cable, turned out the cable was poorly made. Now I fixed it, Dekoni leather pads sound quite shouty, hard and V-shaped to me.

Swear you need 2 diametrically opposing DACS, I try to do that.

@Scott Kramer Well, these two DACs are my attempt on this direction, but as I get to know these two more, I found the weakness on each more often...

The softer ones are really softer and squishy, one press and it's all the way to the bottom. The stiffer ones have this slight initial strength against pressing, then there are soft as well. It's like linear mechanical keyboard switches vs tactile ones...

Did yours have the soft ones originally?

Well, I happened to get two pairs recently, so one pair has softer pads and the other pair has stiffer ones. I wouldn't compare them if I didn't buy the latest bunch of Elex pads on Drop, and saw people complaint about soft inferior pads they received (and there's only one pad in the package).

It's not that much of difference, but if I pay attention, it's there.

@gixxerwimp Nah... really not good at serious comparisons... Plus I want to experiment some cheap protein leather pads on it. Now with HD6XX OG pads, this closed-back HD6XX sounds like lower mids recessed, hallower HD600. It's OK, I wouldn't complain, it's much less V-shaped than TH-X00. But switching back to HD600 / HD650 makes me appreciate the fullness of their sound.

In any case, once you get it sorted out, I'm sure others would be interested in your findings. So please do share :D

@gixxerwimp It's so nice of you! I'll post if I can get better result. (Too lazy these days...)