The General Advice/Questions Thread

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I think I may have a misunderstanding about what an OTG cable is? I thought they were simply very short (6”ish) USB cables that connected a smartphone or DAP to an external DAC/AMP. I have one that came with my iFi Micro iDSD black label, and another that I ordered. When I mentioned the “OTG” 3.5mm TRS, I was referring to a very short dual ended 3.5mm cable (90 degree) that also came with the iFi, meant for much the same type of connection, only analog.

At the heart of my question is a basic lack of knowledge of how a digital coax cable transfers its signal, and wondering why the provided digital DAP cables (3.5mm to coax) have a TS on the 3.5mm end. I guess it’s no different to how a USB transfers digital data, but I wasn’t fully clear on why the same or similar cable could act as both a digital and analog interconnect.

I did a bit more reading on TS, TRS, and TRRS and feel a little bit smarter, but not much. :slight_smile:

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“OTG” is a reference to USB On-the-Go, which is just a cable that lets devices, such as cell phones, that usually act as USB devices act/connect as USB hosts.

And yes, one use for such a cable is to let a phone act a host for a USB DAC.

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TS, TRS and TRRS are just connector types. They can be used in many ways, the most common probably being for analog audio signals. Sometimes they are used as power connections, sometimes for digital connections, triggers, or other situations in which you need two, three or four (respectively) separate wires in a single connector.

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“Digital” coax cables, at least for S/PDIF (the standard digital audio protocol), simply carry a train of timed analog voltage levels indicating either 0 (0V) or 1 (0.6V). These are organized as frames and blocks, of fixed length, using bi-phase clocking.

USB uses packets of data, with specific sub-protocols and data frames for different purposes. The “digital” data is still transmitted as analog voltage levels (for USB 1.1 it’s a +/- 3.3V signal level, for USB 2.X and later it’s +/- 0.4V), but the data structures involved are MUCH more complicated.

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Other than things like characteristic impedance, which for digital signals helps suppress signal reflections on the cable, there is nothing stopping you sending “digital” data down a wire instead of “analog”, since the only real difference is what voltage levels are used and how they are sent.

Digital will be discrete voltage levels for 0 and 1, where as analog will be a continually varying voltage. But both are simply voltages on a wire.

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89

Thanks for the info @Torq! :smiley:

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90

thank you Ian!

this should be pinned somewhere
I never read a so highly informative, clear and easy explanation about all the OTG (On-the-Go) connections

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91

Let me preface by saying I know virtually nothing about tubes (what little experience I do have is related more to bass amplifiers)…

I was wondering if someone could explain to me how a single tube preamp works (either a standalone or one found in a hybrid amp)?

I always thought that tube channels were mono but if they can preamplify 2 channels and keep them separate, then either they are not mono or there is something else that I don’t grasp.

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A single tube can have multiple sections (that’s what they actually called). Something like the 6SN7, which is what you’ll see in a Lyr 3, is what’s called a dual-triode - because it has two independent triode’s (6J5 in this case) inside that can be accessed separately.

With dual tubes that have the same type of triode (or pentode) for both sections, you can use one section for each channel. And when doing this, and actually buying tubes, you want to make sure you get “matched sections” to they have gain that matches as closely as possible.

Some tubes have multiple sections that are different, such as the 13EM7, and those are not suitable for driving two channels from a single tube.

You’ll see dual-tubes mostly in small signal tubes, but they do exist as power tubes as well, such as the 6080/6AS7 dual-power-triode used in the Bottlehead Crack (which also uses a 12AU7 dual-triode).

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Thank you @Torq, as always, for taking the time to explain!

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94

I’m looking for the best sounding headphones in the 200 dollar range. I don’t mind getting a used pair.
Anyone have a sugestion?
Thanks

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Drop Sennheiser HD-6XX. For another $100 add a headphone amplifier such as the JDS Labs Atom or Schiit Heresy. The amp and model of amp does matter.

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this is a good first recommendation

if you get the 6xx used - you could have to invest in new pads… which set you back the difference between used and new.

So you could get a new for 195 and really have to add a amp to this headphone.
My first headphone was a HD600 which is very similar and I had no amp for 2 years with it, which was my biggest audio mistake.

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or are you into closed backs?
Do you need to be isolated from the surroundings and don’t want your sound leak out of the headphone?

Tell us a bit about your situation you plan to use it and maybe the music you like

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If you don’t already have an amplifier, then this would be better than the HD6XX, IMO:

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@Sohotthisday I agree with what the gang has said the Drop 6XX or 58X are awesome starting headphones, my first good pair of headphones was the 6XX which I still have and absolutely love. If you don’t want to get deeper into this hobby right away I would agree with @ProfFalkin the professor, and get the 58X as they are less amp picky and actually sound decent from most devices however if you are looking at a set that can scale up and improve in sound as you improve your amps/dacs over time then the 6XX are a better buy as to me they sound better than the 58X. My 2 cents!

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I am just wondering if the HE-4XX is worth the current price of $130 on Drop?

I am not wanting it as a main headphone, just as something to have a different flavour in the office (currently in the office I have HD6XX, Custom Studios, Porta-Pros and H12’s) running from either the Loxjie P20 or JDS Labs atom.

Other current offerings from drop would be the HD58X or the HE-35X (not heard good things about the latter).

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I’ve never listened to them, but I know Hifiman’s build is questionable.

What about the AKG 371’s?

@metal571 really likes these, and they’re in that price bracket. It’s pretty neutral (Harman Target), and it may be different enough. (I have not listened to them either)

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102

Would go for the 4xx over the 58x for some variation- reading you have the 6xx.

Not sure about quality control with the 4xx though

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Thanks for the suggestion, I was only really mentioning the Drop models as I will be in the US shortly and it’s a pain to get Drop models shipped to Spain (well, more than a pain it’s a cost).

I can pick up the K361 or K371 here at any time for about the same price as the US.

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What do you miss the most out of your existing headphones?

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I wouldn’t say I really miss anything, it’s just for a variation in flavour. I mean, I don’t miss anything from my main bass guitar but I still have a dozen of them :wink:

(And thanks to whoever moved the thread/posts to the correct thread)

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Your budget is around 150?

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