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Qudelix-5K Bluetooth DAC & Headphone Amp

GaryH

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A quick tip:
Shortly after a firmware update, I began noticing the audio was noticeably sharper, in a bad way.

Turns out the firmware update reset the sampling rate to 96khz. Setting it down to 44.1khz smoothed things out again.

Just set it to the 44.1/48/88.2/96 kHz option so the correct input sampling frequency is always autoselected (in case a source happens to output at something other than 44.1 kHz).
 
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iearhorn

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Hi all - new (posting) here - great info and community!
I have the Q-5K and have been listening via 3.5/unbalanced with my HE400SE, iphone 12 Pro Max with apple camera usb dongle. Sounds great, and the Qudelix app has worked great/consistently. I've recently bought a 2.5/balanced to 3.5 x2 trs for these, and though I've gotten them to 'work', had (have?) issues, so I'll explore them here to suss out what is/might not be user error. I'll enumerate the issues b/c it's easier (for me) to follow:
1. *MY* Qudelix (either HW or APP) does not seem to recognize 3.5 to 2.5 consistently (or as expected), at least when switching from 3.5 to 2.5/bal. I've recreated this using different sequences plugging/unplugging/switching, and starting/closing/restarting the app, as well as the music client (in this case, Apple Music). Is this as-expected behavior for others, with a similar setup- that we need to manually select 2.5 (not rely on 'Auto') for some scenarios (e.g. switching btwn unbal to bal)? If yes, what is a reliable sequence that you use, when switching, either during the same session, or say, using the 'other' connection, for a new session/day?
2. I've on multiple occasions needed to fiddle with the 2.5 end unlike with the 3.5/unbal which works carelessly w/o issue like any other 3.5 audio device. It seems like it's the last fraction of a mm of travel that makes the difference. I'll add that initially it felt fairly stiff to get that last sub mm to seat, even noticing the first few times, the 5k would sort of reject that last little bit, slowly pushing it back out. After reseating a couple more times, it now stays put, the jack body flush to the face of the receptor in the 5k housing. Do these 2.5mm connections sometimes need a bit of 'break-in' where the tip interfaces with the innermost signal ring in the receptor? (my first 2.5mm/bal headphone or cable). Is this a sign (for some) that a connector (male or female) is bad/out of tolerance? Basically, has anyone noticed having to pay extra attention to the last bit of insert of a connector, to seat/keep seated fully?
3. When I successfully switched from unbal to bal - during the same session - while I so notice a difference in volume, it was/is not VERY noticeable. Reading some threads suggests this might be due to a couple of things: the last few decibels would/should present the greatest difference in volume, and using the PEQ (I do) can minimize overall vol output. I use a few EQ presets (thanks to all who contribute there!), and selecting the same (for unbal and bal), I still don't notice a big diff in vol. The last few dB's I DO perceive a more quickly increasing loudness (dB root-power log and all), but, again, overall loudness is never VERY loud. At full power input (iphone) and output (+6dB Qudelix vol IIRC), it's (maybe..) slightly uncomfortable - and almost immediately, the iphone detects too much power draw and disconnects. That's reproducible when maxing out the 5k vol (+6dB). Dropping it back to say +5.X dB and no issue. Is this expected afa loudness? Everything sounds great, I think this is prob my inexperience with balanced boost in loudness, but want to get a sense for other's experiences.
None of this is offputting- I'm really enjoying the sound and convenience, and I (personally) don't mind at all manually switching settings when switching between different headphones/outputs. But I WOULD like to feel confident that I know none of the issues are hardware related, and how to expect the app/5k to act when switching. If there DOES seem to be an issue, say with the (new, bal/2.5mm) cable, I'd rather avoid potentially shorting anything in the 5k, and order a different cable. Thanks in advance!
 

Oso Polar

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Hi!

1) Can you please explain better what exactly you are doing? I'm not sure what kind of cable is used by your HE400SE - if it is a regular unbalanced cable with a regular 3.5 TRS plug and you got an adapter balanced 2.5 mm TRRS to unbalanced 3.5 TRS and trying to get this way more power into your unbalanced connection - don't do this, you can and probably will damage your amp! You can plug balanced headphone cable into unbalanced output from the amp but not other way round!
2) About "do these 2.5 mm connections sometimes need a bit of 'break-in'" - not in my experience.
3) AFAIR Qudelix user manual states that this is exactly the expected behavior: there should be no difference in volume while switching between 2.5 mm to 3.5 mm connectors - firmware tries to maintain the same volume in order to prevent sudden volume changes. For me the difference in max volume between balanced and unbalanced on the same headphones is huge. And it is quite possible that Qudelix-5K simply doesn't have enough amp power to drive your headphones very loud, especially if an equalizer is enabled with a big negative pre-amp gain. I know that it has barely enough power for my Sennheiser HD600 - it can drive them quite loud (over balanced connection) that is more than enough in 99% of cases (volume stays at -10 -15 dB) but sometimes I wish to raise volume past +6 dB and it obviously can't do this... I'm not sure how difficult it is to drive HE400SE in comparison to HD600.
 

Lunafag

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firmware tries to maintain the same volume in order to prevent sudden volume changes
It compensates for high gain mode but doesn't for balanced/unbalanced. It should be noted that a few versions back qudelix started treating balanced/unbalanced as separate profiles - with their own EQ and volume settings. Doesn't hurt to double check the settings with each output, definitely surprised me when I first saw it.
I'll add that initially it felt fairly stiff to get that last sub mm to seat, even noticing the first few times, the 5k would sort of reject that last little bit, slowly pushing it back out
If the settings are fine I suspect it's still not fully inserted. It might lose power because of that. I haven't encountered such a problem, might be the issue with the plug or with qudelix itself.
 

Oso Polar

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It should be noted that a few versions back qudelix started treating balanced/unbalanced as separate profiles - with their own EQ and volume settings.
Really? That seems to be a good idea, actually! But I don't see settings for such profiles in the app? Where did they hide them? ;-)
The important firmware change arrived to me just yesterday - support for Auto EQ presets. Now we just need to get the same for Oratory ones.
 

Lunafag

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But I don't see settings for such profiles in the app?
That's the surprising thing. It's not displayed anywhere. Settings just change when you plug cable into another output without any notice, and default settings have -30dB volume now.
 
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Bimbleton

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I don’t have the answers to your questions but just wanted to mention that Qudelix have their own forum, and the technicians are actually very helpful and responsive! A great resource if you need additional assistance.
 

iearhorn

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At least one 'issue' is due to the behavior of the EQ - when enabled, switching to the bal input defaults to a profile (?) with very low/no vol. , which seems to agree with what @Lunafag is saying. I say 'profile' but it sounds like it's just a default vol setting. @Bimbleton , thanks I should have started over there - I just find this forum so informative i came straight here! Thanks all
 

iearhorn

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Hi!

1) Can you please explain better what exactly you are doing? I'm not sure what kind of cable is used by your HE400SE - if it is a regular unbalanced cable with a regular 3.5 TRS plug and you got an adapter balanced 2.5 mm TRRS to unbalanced 3.5 TRS and trying to get this way more power into your unbalanced connection - don't do this, you can and probably will damage your amp! You can plug balanced headphone cable into unbalanced output from the amp but not other way round!


2) About "do these 2.5 mm connections sometimes need a bit of 'break-in'" - not in my experience.
3) AFAIR Qudelix user manual states that this is exactly the expected behavior: there should be no difference in volume while switching between 2.5 mm to 3.5 mm connectors - firmware tries to maintain the same volume in order to prevent sudden volume changes. For me the difference in max volume between balanced and unbalanced on the same headphones is huge. And it is quite possible that Qudelix-5K simply doesn't have enough amp power to drive your headphones very loud, especially if an equalizer is enabled with a big negative pre-amp gain. I know that it has barely enough power for my Sennheiser HD600 - it can drive them quite loud (over balanced connection) that is more than enough in 99% of cases (volume stays at -10 -15 dB) but sometimes I wish to raise volume past +6 dB and it obviously can't do this... I'm not sure how difficult it is to drive HE400SE in comparison to HD600.

The cables are 2.5 balanced to 3.5 trs balanced. However, they're boutique and so without dismantling them i can only assume they're wired correctly, hence my interest in ruling them out as a source of issue(s). It sounds like the vol difference you hear btwn unbal-bal is much more noticeable than mine. Could a miswired cable account for just volume differences or would it always introduce other audible effects? My headphones aren't particularly hard to drive but they're not the easiest.
 

mrbungle

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I was looking for something like a Hidizs S9 Pro, but with internal battery to not drain the iPhone quickly. Is this still one of the best choices? Will exclusively use with IEMs. Balanced would be nice because I have a 2.5mm cable.
 

Morpheus

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[QUOTE="bobbooo, post ....pretty much the same performance as the Qudelix 5K, but the latter is smaller and lighter, with a longer battery life and a parametric equalizer (that can also be used over LDAC), so I don't see a good reason for getting the BTR5 over the 5K really.[/QUOTE]

Hi, what is the typical battery life of this..? I am eying this as a super cheap quality bluetooth PEQ preamp for active speakers, on a shoe string budget system for a friend, and wonder if this could fill the bill, battery, or mains operated.
 

Jimbob54

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[QUOTE="bobbooo, post ....pretty much the same performance as the Qudelix 5K, but the latter is smaller and lighter, with a longer battery life and a parametric equalizer (that can also be used over LDAC), so I don't see a good reason for getting the BTR5 over the 5K really.

Hi, what is the typical battery life of this..? I am eying this as a super cheap quality bluetooth PEQ preamp for active speakers, on a shoe string budget system for a friend, and wonder if this could fill the bill, battery, or mains operated.[/QUOTE]

Its pretty good actually. I can walk around with it for an hour a day for a week without charging but you can plug it in to charge and still use BT and cap it to an 80% charge to protect the battery. So should work as you propose.
 

Oso Polar

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what is the typical battery life of this
Battery life is good, it lasts many, many hours in general but really it depends a lot on the load: what headphones it is driving and how loud, also on what Bluetooth codecs are used etc. Here are the official battery specs: https://www.qudelix.com/blogs/5k-dac-amp/battery
Their numbers are probably based on maxed out volume - in practice battery lasts longer for me. For IEMs battery lasts several times longer than for HD600 - which is logical.
 

Morpheus

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Battery life is good, it lasts many, many hours in general but really it depends a lot on the load: what headphones it is driving and how loud, also on what Bluetooth codecs are used etc. Here are the official battery specs: https://www.qudelix.com/blogs/5k-dac-amp/battery
Their numbers are probably based on maxed out volume - in practice battery lasts longer for me. For IEMs battery lasts several times longer than for HD600 - which is logical.

Its intended use would be as an also portable, but 95% stationary Bluetooth enabled PEQ DAC / Preamp for active speakers ( I am refurbishing a cheap pair of B&O Pentas I found and they need EQ ), for my friends first and foremost inexpensive system, and that's in that capacity I am looking at this as a possible solution, and worrying about the power management...
 

Cahudson42

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worrying about the power management...
Apologize if off mark, but I use the Qudelix with a common 3 wire OTG cable that is always 5v USB powered. With mine, one microUSB goes to my TracFone wifi 'streamer', one with adapter to Q USB-C, and the third to 5V.

Power management in the Q is great. Battery remains fully charged, but not overcharged. TracFone also remains charged. Been using this way maybe a year...
https://www.amazon.com/dp/B07B6CRW6D/
 
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Morpheus

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Apologize if off mark, but I use the Qudelix with a common 3 wire OTG cable that is always 5v USB powered. With mine, one microUSB goes to my TracFone 'streamer', one with adapter to Q USB-C, and the third to 5V.

Power management in the Q is great. Battery remains fully charged, but not overcharged. TracFone also remains charged. Been using this way maybe a year...
https://www.amazon.com/dp/B07B6CRW6D/

Thanks a lot for the input..Nice high quality and functionality low budget setup, by the way, its an interesting setup for my purpose too..
 

Rottmannash

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Just received mine from Amazon. So far loving it. Can't believe the quality from LDAC. Stupendous, especially w/ the preloaded PEQ profiles for HP's and IEM's. It's worth the price for those. The balanced out sounds very close to the E1DA.
 

fbfranco

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Noob question: are there specific setting(s) for using the Qudelix as DAC only with an external amp?
I couldn't find a "DAC only" mode in settings.
Thanks!
 
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