Rabbit
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Post by Rabbit on May 31, 2014 14:19:55 GMT
I borrowed a very cheap amp from a mate and it is amazingly good sounding. It costs around £22 (Yes.... that's all) It has a lithium ion battery so it's rechargable. The chassis is metal and it's about 3 inches by 2. It has a low and high gain switch and claims to work well up to 300 ohm headphones. (It does work too - I'm driving the K612 with it) Comes with rubber bands like the Fiio amps, a little lead and a usb lead. I was really surprised at how quiet it was and how nice it sounded. OPA1611 Output power is 100mW@32 ohm load. THD+N: <0.001% (32 ohm 50mW) 20 - 20kHz Works with 16 - 300 ohm headphones Noise <10UV 58mm X 90mm X 13.5mm 93g weight. The OPA1611 (single) and OPA1612 (dual) bipolar-input operational amplifiers achieve very low 1.1nV/√Hz noise density with an ultralow distortion of 0.000015% at 1kHz. The OPA1611 and OPA1612 offer rail-to-rail output swing to within 600mV with a 2kΩ load, which increases headroom and maximizes dynamic range. These devices also have a high output drive capability of ±30mA. These devices operate over a very wide supply range of ±2.25V to ±18V, on only 3.6mA of supply current per channel. The OPA1611 and OPA1612 op amps are unity-gain stable and provide excellent dynamic behavior over a wide range of load conditions. The dual version features completely independent circuitry for lowest crosstalk and freedom from interactions between channels, even when overdriven or overloaded. OPA1611 is often seen in pro audio gear in broadcast equipment and is also often used in micophone preamps, being very low noise with very little distortion. The OPA1611/1612 are optimized for better distortion figures than the opa211.(apparently, the opa211 is still pretty good in this area)Some people felt that the 1611 were 211 'rejects' at one time, but they work well in audio gear. The result of all that techno stuff is a very clean sounding op amp which runs for a long time on a charge as well. splashurl.com/mfjgfcfA very cheap portable amp from China but being sold from UK. £22 is a great price for what you are getting imo. splashurl.com/lavm9lx |
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Post by Deleted on May 31, 2014 19:46:21 GMT
I think Topping have done a few class D portable amps in the past which got good write-ups. Or I'm maybe getting mixed up. I've not been well recently and I'm still not 100%  |
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Rabbit
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Post by Rabbit on May 31, 2014 19:57:24 GMT
Yes, they have, Jeff. This one caught my attention because of the opamp and the price. It looks like some British company has got a job lot from China and is putting them out at a pretty good price. I'm listening to it now with my K612 and it is a ver 'clean' listen with a well defined bass actually.
On another recording, I felt that it was on the sharp side of neutral, but I think that had more to do with what I was listening to than the amp itself. I quickly switched to a the Fiio Mont Blanc which showed the same toppiness!!
It gets you wondering how low can you go in price before it's poor quality? There is no noise coming from it even at top volume/high gain whch you can get with cheap amps. It's really quiet. It's perfectly loud enough for the AKG which is quite a difficult load and it seems fine. It probably isn't going to give a great deal of headroom at higher volumes, but it sounds good lower down. No sign of it struggling.
You haven't been down with these colds that are flying around have you? Hope you're ok now.
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Post by Deleted on May 31, 2014 20:30:50 GMT
It gets you wondering how low can you go in price before it's poor quality? As you have found out Ian, I think the answer is maybe surprisingly low. As we all know, many companies base their audio philosophy on a signal path that's as short as possible and the use of a few good quality components in a well thought out circuit. If you take that idea to it's logical conclusion, and you can do without all the bells and whistles, you end up with small amps like the Topping. |
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Rabbit
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Post by Rabbit on May 31, 2014 20:55:53 GMT
It is quite a remarkable amp for £22, Jeff. The opamp itself is probably only a couple of quid but I have seen them mentioned before because of their low distortion and noise. Nice to just stick on the headphone out from an Ipad or one of the new Ipods with those daft lightening connectors. Serves a purpose and sounds great.
I've ordered one for myself for when this one goes back!!
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solderdude
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Post by solderdude on Jun 1, 2014 11:22:40 GMT
A few things are rather strange....
They claim to use the OPA1611 BUT the IC that is in there seems to be a 16 pin IC (no markings) where OPA1611/2 are 8 PIN opamps.
Also they wave their magic wand with OPA specs that are 100x better than the specs they give.
The PCB design would have to be real crappy to reduce the THD to those levels.... unless they aren't using the OPA1611.
Specs are all over the place though and a fleabay seller quotes:
Distortion: <0.00005%(10mW)
Frequency response: 10Hz to 100KHz
Output power: 150mW(16 Ohms), 16mW(300 Ohms)
To reach that the battery voltage must be at least 6.5V, yet it is charged directly from 5V ?
Topping themselves does not seem to offer this amp in their webshop.
For the price you can't go wrong though and would recommend it over the PA2v2
With a power supply voltage of 3.7V (I reckon the battery is that voltage as it can be charges from 5V) a maximum Vout can be created of around 1.2V.
About the same as the PA2v2 and most other portable devices b.t.w.
When connected to a 300 Ohm HP it will put out just 5mW (so no idea where the 16mW comes from, maybe under heavy clipping ?)
in 120 Ohm it will give 12mW which is still a respectable 102dB SPL peak in the K601 for instance (about 95dB average) which is above decent.
The fact it looks smart, recharges fast, last 100 hours on a charge, has a gain switch and volume control still makes it a good bargain.
Will it drive orthos and difficult headphones? no, but it will work well on most headphones and drive them to decent levels.
The batteries from the DAP it is connected to will last a bit longer than when driving them directly.
It will seem louder as well (because of the gain) but output power won't be that much higher.
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Rabbit
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Post by Rabbit on Jun 1, 2014 15:45:02 GMT
Yes, there are some 'odd' claims on the site and English isn't great either. One that tickled me was comparing it to 50 years of Steinway pianos. (Very odd)
The PAV2 is more noisy than this one. One thing I never liked about the PA was the hiss levels as well as the too warm sound. Great for something like a Grado I guess, but the Topping (or whatever it is) seems cleaner sounding and has a more crystal like top end.
It just about drives the K612 to a reasoanble level on low power setting.
It's nice and small too and way easier to cart around than the PA. It's flatter and the body is metal so it is a bit tougher. Plus it's cheaper too.
I quite like it as a cheap run around portable amp. It 'feels' good too with a nice vol pot and quite smooth jack sockets. One thing about the O2 from USA I never liked was the sockets - they are cheap and clanky. Even to the point of not liking Beyer plugs. (The Beyers seems to have a bigger edge after the tip of the pin which can play up) Nice and smooth on the Topping.
This bit made me smile:
NX-1 has achieved in the best balance between high quality and reliable lasting dyrability, which is equipped with a selection of high quality audio devices such as WIMA capacitance, ALPS potentimeters. The part of the power supply adopts high frequency low resistance capacitance with is very low loss and resistance, NX-1 voice is as brilliant as steinway piano which is with 50 years history.
The English is a bit odd!!
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solderdude
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Post by solderdude on Jun 1, 2014 17:13:52 GMT
I quite liked these remarks:
- Humanized function Indicators (the indicators seem be humanized, whatever that may be)
- Portable, small and exquisite (ah... exquisite)
- In order to perfectly match with different resistance and sensitivity headphones, NX-1 upgraded with gain control and bass boots functions. You can adjust by needed
(Bass boost ? where can that be set ?)
- Exquisite workmanship (ah... more exquisite)
- Metallic style, aluminum shell, small and smart (ah it's smart too, does it have access to internet?) .
- Logo in the panel embossed by laser engraving and never fadeless. (never fadeless ? or never fades or never fades less than...)
- NX-1, which is equipped with a selection of high quality audio devices such as WIMA capacitance, ALPS potentimeters. (Ah, so you use 4 capacitors and the rest is cheap SMD ceramics and at least you can say you use WIMA.. and those small ALPS pots are cheap, that's why they use them)
Main Features:
0.000015% distortion (oh wow that's a lot better than the 0.001 in the specs)
Splendid combination of amplifier (combination of amplifier with what ... uuuooh with splendid)
The topping NX-1 use high performance chips OPA1611 (where is it ?)
Opa1611 designed by TI CO, Ltd which is for audio amplification and can lead to reach the extreme distortion degree index of 0.000015% almost zero distortion.
(Yes, that's correct, the OPA1611 is designed by TI and is for audio amplification and indeed can reach the extreme distortion numbers of 0.000015% (-136dB) at 1kHz with a source resistance of 0 Ohm with 0dB gain and in a 2kOhm load when powered on +/-15V with 3V output voltage.
but... IF they should have used it would have been much less in distortion numbers as the source resistance > 1kOhm, there is more than 1x gain, the voltage rail is +/- 1.5V (specified down to +/-2.5V) the load of a 32 Ohm is 62x higher oops...
Hilarious from an engineers POV.
They just 'grab' a number from a spec sheet of an op-amp they didn't use and IF they had would be using it under circumstances that are very far from the 'ideal' lowest value specs from that datasheet.
- 220V working voltage can give full play to the op-amp and guarantee the good performance.
(hmmm does that mean it needs to be connected to a 5V power supply to reach the specs ?, most likely it is, on 3.7V it is hard to defend those numbers)
Still..... for the money it looks like a nice device but the Bravo/Indeed thingies looked nice too.
And it does show you do not need to spend a lot of money when something is made in China in bulk.
IF you were to buy the used components and have to make a PCB in low numbers the same amp would likely cost 3 to 4 times more.
That alone is reason enough to buy one.
All kidding aside... I am all for cheap and good sounding audio products so this one (as well as Zigis stuff etc.) fits that bill nicely and will be very hard to beat VFM wise.
Do not expect top-notch performance that will drive anything though.
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Rabbit
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Post by Rabbit on Jun 1, 2014 18:08:32 GMT
 Reading your post really made me laugh!! |
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Post by Rabbit on Aug 12, 2014 16:20:13 GMT
I've been using this little amp for a while now, in a nice soft carrying case, and I have to say, it really does work well. and goes for a remarkably long time between charges. Noise is very low and it does give quite a bit of gain. I tend to use lower impedance headphones with it like the Senn HD595 and now, the AKG Y50. It's clean sounding and is a really much better alternative than the cheaper Fiio amp. It is less noisy and at the price I paid, I think it was a real gem. You don't see a great deal around about Topping but this is fine. It's small and really tough, with low noise and a decent amount of power for easier loads. www.head-fi.org/t/696825/lightbox/post/10790907/id/1169831Regarding Ebay descriptions - they are all over the place, but someone on HF reckons - "By the look of the circuit, it seems to be a simple MAX9722 design, and actually I just posted a review of similar amp, the SMSL sAp4s"(over at In ear Matters). datasheets.maximintegrated.com/en/ds/MAX9722-MAX9722B.pdfStill £22. www.ebay.co.uk/itm/Topping-TP-NX1-Portable-Headphone-Amplifier-USB-Rechargeable-Battery-UK-Stock-/400669802110?pt=UK_AudioTVElectronics_HomeAudioHiFi_Amplifiers&hash=item5d49c7fe7e |
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Post by Deleted on Aug 12, 2014 21:02:44 GMT
Looking at the eBay link you give I note it has been upgraded with "voice quality enhancement functions".
This has got me quite interested.
Does this mean it will make Kylie sound like Kate?
Or One Direction sound like Steely Dan?
Or would I need a considerably more expensive amp to achieve that level of enhancement??
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solderdude
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Post by solderdude on Aug 12, 2014 21:12:13 GMT
This is because:
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Rabbit
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Post by Rabbit on Aug 12, 2014 21:27:37 GMT
 5 amps for £100?
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Rabbit
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Post by Rabbit on Aug 13, 2014 21:02:54 GMT
Here's a curious thing.....
The nx1 is way louder than the Mont Blanc into a 32 Ohm load. The Mont Blanc is quoted at 16x but it matches the nx1 at low power. It reminds me of the time when I found the k 601 worked brilliantly with a cheap CMoy. Well matched.
It seems that the nx1 likes a 32 ohm load.
It's quoted at 130mW per Channel into 32Ω.
Mont Blanc Output Power:
>880mW@32Ω
What on earth is going on?
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Rabbit
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Post by Rabbit on Aug 14, 2014 16:26:15 GMT
Mystery solved. Lucy has been using the e12 and managed to switch it to low power!! I was beginning to think I'd lost the plot. (Again)  It seems that the description is also wrong as far as the op amp goes. There is a Max9722 in there! |
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