Topping L70 Headphone Amp Review

[solderdude]

Yes, I had considered that, but then I thought you'd still be able to detect it was somewhat insufficient in bass, and certainly different to say a Stealth played at any volume, so it seemed a surprising statement to me. I also think most headphone amps reviewed on this site would be able to get the HD650 to loud enough levels that the whole Fletcher Munson Curve thing is overcome.

Consider that this is when using tones. In music the mids and treble are much lower in level and thus you need to view the curves that way
In music bass notes are louder than mids and are mixed at average levels (total music energy, not mids or treble) so that is why at louder levels the bass still sounds relatively louder.

There's not much difference between 90dB and the louder levels, and you could probably make the same case for the 80dB curve or at least the curves between 80dB and 90dB that aren't pictured. Pretty much all headphone amps can drive an HD650 to 90dB I would think.

To 90dB sure, even a phone can make it reach 100dB.
It becomes different when you want to play impressively loud (115-120dB peaks).
You must realize.... Amir wants his earlobes to vibrate. You cannot do this with a phone and having the idea (and practice) of going loud with plenty of volume range left makes for a more impressive experience (when cranking it up)

 

[solderdude]

Would it really have been so much trouble to line the headphone sockets up horizontally?

Yes, it requires either mounting sockets with nuts to a subchassis or using extra PCBs or extenders, connectors and extra cables.
Now, the connectors, all different in length and height, are simply soldered onto the PCB.
I reckon the price would go up a bit more than most people want. Topping is about maximum technical performance at a lowest possible price yet still high enough to make a few bucks and giving the dealers some incentive to sell them. They are mass produced (in batches) so that means as little hands are used as possible.

 

[Sokel]

Now, the connectors, all different in length and height, are simply soldered onto the PCB.

That usually reduces longevity isn't it?
Can't compare a nice tight fitted connector with nuts to a PCB mounted one,the stress can't be the same.
Only if it supported by the chassis somehow.

Edit,I have seen supported ones,with screws coming from the outside,can't tell if that is the case here,probably is as I see some screws in the back.

 

[solderdude]

Looks like all connectors are PCB mounted (solder lugs).

A90D:

 

[Ziroz]

I prefer Nixie tubes, they have greater depth.

Nixie tube for volume level display would be a dope feature, I would buy one even if the measurement is crap, worth it just for the look.

 

[solderdude]

It would be quite easy to make such a display. Or even make one with customizable fonts.
I have this clock.
Of course it lack's the depth and 3D experience of the real thing.
Seeing as this is audio real nixie tubes and the idea of depth is a strong thing for placebo.

 

[Ziroz]

It would be quite easy to make such a display. Or even make one with customizable fonts.
I have this clock.
Of course it lack's the depth and 3D experience of the real thing.
Seeing as this is audio real nixie tubes and the idea of depth is a strong thing for placebo.

These ones with multiple layers of acrylic seem more like the real deal in my opinion. But even these can't really capture the glow of real nixie tubes.
New idea: tube amp with nixie tube for display, would be quite a sight.

 

[solderdude]

tube amp with nixie tube for display, would be quite a sight.

and expensive...

 

[Ziroz]

and expensive...

Yeah, probably...
Well since it's already expensive, maybe throw in an r2r dac, and make it a full combo dac/amp.

 

[Dennis_FL]

Excuse my ignorance but for the 12V trigger input control would this be a correct cable ?

You can tell by the number of stripes that it is stereo. I've used those as a trigger cable but you should use a mono cable only as JSmith says above.

 

[vkvedam]

Thanks for the review @amirm, did you measure the imbalance from the volume pot?

 

[solderdude]

Thanks for the review @amirm, did you measure the imbalance from the volume pot?

Channel balance is 0.025% (= 0.0023dB) when outputting 4V in XLR.
It has relay volume control in 0.5dB steps.

see post #95

 

[Robbo99999]

Consider that this is when using tones. In music the mids and treble are much lower in level and thus you need to view the curves that way
In music bass notes are louder than mids and are mixed at average levels (total music energy, not mids or treble) so that is why at louder levels the bass still sounds relatively louder.



To 90dB sure, even a phone can make it reach 100dB.
It becomes different when you want to play impressively loud (115-120dB peaks).
You must realize.... Amir wants his earlobes to vibrate. You cannot do this with a phone and having the idea (and practice) of going loud with plenty of volume range left makes for a more impressive experience (when cranking it up)

I know, but I'm talking about it in context to the Fletcher Munson Curves. If a phone can make the HD650 reach 100dB (sine tone) then that's probably enough to overcome Fletcher Munson for most music, if we say that 85dB Fletcher Munson (in music) is already "best case" or very close to elevating bass to it's most prominent level vs the other frequencies. I just don't think it was a particularly well-founded thing for Amir to say in his conclusion given this, but I'm not gonna go on about it, as it would be silly to devote too much time & space here to one small statement.

 

[MCH]

Nixie tube for volume level display would be a dope feature, I would buy one even if the measurement is crap, worth it just for the look.

Your best chance is to pay attention to Douk Audio releases, they are almost there.
If there is one dope experience is to check out their AliExpress shop

https://www.aliexpress.com/item/33015907576.html?spm=a2g0o.store_pc_allProduct.8148356.19.56d428f1hYihuJ&pdp_npi=2%40dis%21EUR%21%E2%82%AC%20197%2C49%21%E2%82%AC%20138%2C24%21%21%21%21%21%402100bde116704359517684027e730b%2167194372110%21sh

 

[Lambda]

So as expected there is not mush more to wish for performance wise.

just a view features i don’t like and a view i'm missing.

1. DC (USB C(PD)) powered i don't like AC Powered low power Equipment.
There is especially no reasons to put a big (IEC 60320) C14 on a low power device.

2. Don’t like the potted electronic this makes repairing unnecessary hard but it helps little to nothing with reverse engendering.
getting a small X-ray/CT costs little to nothing in SZ. Or Just Laser the Plastic away.

3. Devices shuld not try to obfuscate the schematic. we had Had manuals including Schematics till the early 90s for all sorts of HiFi and TV devices.

4. The Propitiatory 4.4mm headphone plug is the MQA of connectors. it has no benefit but you pay licensing fee for it.

5. The connectors are the first ting to ware out/off so i would like to see them on separate board or connected with cable

6. GaAs Leds and instead of O-LEDs

The performance is good enough that this is would be the last headphone amp you ever need but i don’t think quality longevity and repairability is there.

 

[solderdude]

I know, but I'm talking about it in context to the Fletcher Munson Curves. If a phone can make the HD650 reach 100dB (sine tone) then that's probably enough to overcome Fletcher Munson for most music, if we say that 85dB Fletcher Munson (in music) is already "best case" or very close to elevating bass to it's most prominent level vs the other frequencies. I just don't think it was a particularly well-founded thing for Amir to say in his conclusion given this, but I'm not gonna go on about it, as it would be silly to devote too much time & space here to one small statement.

Amir's remark made perfect sense to me and did not evoke any 'synergy' things but.. I understand what you meant and some folks may read that into it.

When one is a Harman bass fan then no matter how loud one plays the HD650 is not going to have enough bass.

 

[don'ttrustauthority]

$ 349?!? Amazing quality for the price of grocery and 93 octane fill-up. Impeccable review, thank you Amir!

Good work, but Schiit produces a nearly identical product with identical SINAD numbers in xlr and 1.5x to 4x more power. If you don't use unbalanced headphones, the Schiit sells their Magnius at $200 and gives their employees seriously better benefits, if you care about that sort of thing.

This topping outperforms with unbalanced loads.

It's $200 vs $350.

Under warranty you're better with Schiit.

Out of warranty they fixed a $500 dac for me for $150. No experience fixing cheaper stuff out of warranty.

Warranty service was fine the one time I used it, two week turnaround.

 

[VariousArtists]

Good work, but Schiit produces a nearly identical product with identical SINAD numbers in xlr and 1.5x to 4x more power. If you don't use unbalanced headphones, the Schiit sells their Magnius at $200 and gives their employees seriously better benefits, if you care about that sort of thing.

This topping outperforms with unbalanced loads.

It's $200 vs $350.

Under warranty you're better with Schiit.

Out of warranty they fixed a $500 dac for me for $150. No experience fixing cheaper stuff out of warranty.

Warranty service was fine the one time I used it, two week turnaround.

Do the newer Schiit HP amps have ESD protection now?

 

[staticV3]

When one is a Harman bass fan then no matter how loud one plays the HD650 is not going to have enough bass.

 

[Robbo99999]

View attachment 248422

Why is it that the 60dB line is the only one that looks correct? (slight rhetorical question) Have you just arbitarily set 60dB to be frequency response baseline (measured frequency response of HD650), and then you've charted the difference between a 60dB Fletcher Munson Curve and a 100dB Fletcher Munson Curve - and then applied that difference to the 60dB blue line? If so I think that's misleading, because you're assuming the HD650 "sounds like the blue line" when only playing at 60dB. I think it would be more useful/representative to set whatever dB level the Harman Curve was designed to be played at by the Harman creators of that research - so I don't know - what volume in dB did they set their headphones to during the study? You'd set the blue line to whatever dB that would be - that would be your baseline (the HD650 measurement), then you'd chart your 100dB Fletcher Munson Curve extrapolation on top of that......but the way you've done it I think is very misleading. That's my interpretation based on my understanding.