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Topping L50 Review (Headphone Amp)

jdjung

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Ok, just ran another two tests, ran the Topping E50 DAC by RCA unbalanced to the single ended on the Topping L50 and the ZEN Q usb to balanced out to the balanced input on the L50, switched between them back and forth while listening to Bassnectar Mind Trick. I then volume matched as close as possible than flipped between the two, can't tell a difference. Using Roon to play both to the Topping E50 from my dedicated Roon Core and my desktop playing to the Zen Q monitor outs. Second test for kicks, I then ran my Bottlehead S.E.X. tube amp to see if the bass was more or less from the Topping. Can definetely hear a difference, the Topping is MUCH cleaner then the tube amp, easily able to tell the difference, but the bass level amount was about the same. Tube did sound a teeny bit more, but I believe that's due to the distortion. The monitor outs seem to be working as advertised for me.
 
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Anderlfs

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I'm considering this headamp and I have a question about input impedance, wattage and headphone matching.
I currently use a V-CAN II which has the following in specifications: input 25KΩ and 250mW/32Ω. Headphone is a Grado SR225i (32Ω 98dB).
1) What would that 25KΩ input be? I saw that Schiit shows the same value for the Magni+, but Topping doesn't say anything for the L50.
2) I think the V-CAN II with the Grado is a great match, but I want a 2nd amp. What can we expect from this leap from 250mW/32Ω to the 2.8W/32Ω of the L50?
Thank you.
 

staticV3

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1) What would that 25KΩ input be? I saw that Schiit shows the same value for the Magni+, but Topping doesn't say anything for the L50.
Here's the L50's input impedance (JohnYang is the one that designed it):
2.5k for SE, 2k for Bal. Thank you very much.

You want to use a DAC with low output impedance that won't mind this comparatively high load.

What can we expect from this leap from 250mW/32Ω to the 2.8W/32Ω of the L50?
More volume potential, same sound.
 

Anderlfs

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More volume potential, same sound.
Just to make sure, I also have a Marantz CD6006 CD player that has a headphone output with gains: Low, Medium and High. The manual doesn't say anything about this, only that it should be adjusted according to the impedance. The sound is bad when set to Medium/High. More specifically, is this gain the same phenomenon as increasing from 250mW/32Ω to the 2.8W/32Ω?
 

AnalogSteph

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Amplifier gain is the fundamental ratio of output voltage to input voltage in the linear region.

Now when increasing input amplitude, at some point you will hit either
a) the circuit's output voltage limit (as a result of supply voltages being finite)
or
b) the output current limit
that will ultimately determine how much power can be supplied into a given load impedance without distorting.

The V-CAN II appears to operate on +12V DC with further internal regulation. 250 mW into 32 ohms is 8 Vpp, and given the 5 ohm output impedance the amplfier itself would have to supply 9.25 Vpp at this point. Looks like you're hitting the voltage limit even into 32 ohms. The circuitry is a bit quaint by modern standards, with its single supply and AC coupling throughout, but gets the job done I guess. I'm honestly not sure why it's got a quad opamp and a bunch more parts than I'd normally be expecting... it doesn't appear like anyone has reverse-engineered it so far, so hard to tell.

Grados aren't all that demanding. With a Magni Heretic or the slightly worse performing Magni+, you should be set for the vast majority of headphones that might come your way. A JDS Labs Atom Amp+ should generally be fine, too.

This glorious FU to small screen resolutions is the CD6006's headphone amplifier circuit:
cd6006-hp.png

Would I rely on muting transistors to do my gain switching? I dunno. And while it's nice that they do have a (diamond) buffer, I'm not sure I would have used small-signal transistors rated for a measly 50 mA on the output. And why do they have a 75k/22k voltage divider following the 10k level pot, were they dead-set on needlessly increasing output noise level? Bit of a strange design.
 

Anderlfs

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Thank you for your efforts. Revisiting your answer, I see that I lack a grounding in electronics. Could someone translate for me?
 

IAtaman

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Thank you for your efforts. Revisiting your answer, I see that I lack a grounding in electronics. Could someone translate for me?
Think of an amplifier as a voltage multiplier. You put in 1V signal, it produces 10V signal. The ratio of multiplication (i.e. the ratio of output voltage to input voltage) is called the gain, in this case 10/1=10 times.

If you set the headphone amp of your CD player to medium gain of, say, 10 times, and provide it with a 1V input signal, the amplifier would try to generate a 10V signal across its output terminals. If you have a low impedance headphone connected to to those terminals of, let say 32ohms, then it would need to supply the load with 0.3amps of current to generate 10V across it (V=I.R) If it does not have the capability to provide 0.3amps, it would distort, and potentially sound bad as you experienced. Had you switched to low gain, or used a high impedance headphone that would not require as much current, then you might be back in the range of current and voltage that the amplifier can supply, and the sound might improve.
 

Anderlfs

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Crystal clear. Back to my original question, this leap from 250mW/32Ω to the 2.8W/32Ω of the L50 is the same phenomenon as increasing the gain from low gain to medium gain? Or are they different concepts? As I experienced that my headphones didn’t work well with higher gain in CD6006, I wanna know if the 2.8W/32Ω of the L50 will present the same symptom.
 

IAtaman

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Crystal clear. Back to my original question, this leap from 250mW/32Ω to the 2.8W/32Ω of the L50 is the same phenomenon as increasing the gain from low gain to medium gain? Or are they different concepts? As I experienced that my headphones didn’t work well with higher gain in CD6006, I wanna know if the 2.8W/32Ω of the L50 will present the same symptom.
No. 2800mw / 250mw at 32ohm leap is jump in the amplifier's ability to deliver current and is not a direct consequence of gain as the voltage required would be the same for the same headphone regardless of the amp.

I see you wrote you have Grado SR225i with 32ohm and 98dB sensitivity. Difference between 250mW and 2.8W would be around 10dB higher SPL. If you are not listening very loudly, and the the older amp is still sounding bad, it might not be just due to lack of power, there might be some other issue with the amp as well. L50 will not have any issues driving your headphones to jaw shaking levels.
 

dsnyder0cnn

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Two headphone amps? Interesting.

I have the same setup on my desk (same order and color too), but the third device is a PA5 instead. :)
 

Χ Ξ Σ

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Two headphone amps? Interesting.

I have the same setup on my desk (same order and color too), but the third device is a PA5 instead. :)
I have seen your red stack, looks fire!

One of the L50 was part of my home setup. Since I just bought a Geshelli amp so brought the L50 to my office and expended my E50+L50 combo. Not much practical use but I like how they look.
 

Χ Ξ Σ

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I've also got 2 headphone amps on my desk; the THX AAA 789 & Geshelli Archel3 Pro. I used to have the Archel 2 Pro instead there since I have 3 headphones I listen to frequently.

I just got the Geshelli Archel2.5 XL to replace the L50 at home for the sole reason that it matches the look of RME better.

IMG_7022.jpeg
 

jdjung

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I have two amps on the desk (Topping L50 and Bottlehead S.E.X.) and two under the desk on a shelf (Little Dot mk3 and Drop THX 789). I need help.
 

Jimster480

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I have two amps on the desk (Topping L50 and Bottlehead S.E.X.) and two under the desk on a shelf (Little Dot mk3 and Drop THX 789). I need help.
I've got a bunch of Amps around. I have the THX 789 & Archel3 Pro on my main desk. Topping EX5 on my gaming PC desk... then I have my old DX7 in a box. A30 in a box. JDS Labs O2 custom in a box. Geshelli Archel 2Pro in a box.
Over time as I "upgraded" I haven't really sold any gear as I didn't find it to be really worth anything. I know the Topping A30 for example doesn't have any value anymore (and barely was worth $50 when I stopped using it).. My DX7 has a broken USB interface and a worn screen (probably also not worth anything) and my JDS Labs O2 custom is outdated now and was only around $108 when I first got it..
Maybe the Archel2 Pro has a bit of value but it is their first edition version... not sure if I WANT to part with it as I plan to get another headphone setup going in my bedroom in the future LOL so I'll use the amp over there.
 

Mike710

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Hi folks,

I just got my E50/L50 stack a couple of weeks ago, and a Sennheiser HD560s. I am using the medium selection on the L50, with volume set to 10 o´clock. Is that ok with these headphones? Sorry this Is my first headphone amp.
 

Jimster480

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Hi folks,

I just got my E50/L50 stack a couple of weeks ago, and a Sennheiser HD560s. I am using the medium selection on the L50, with volume set to 10 o´clock. Is that ok with these headphones? Sorry this Is my first headphone amp.
You adjust the volume as you see fit based on what you like to listen to and what's comfortable for your ears. Outside of that, it doesn't really matter.
 

dsnyder0cnn

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Hi folks,

I just got my E50/L50 stack a couple of weeks ago, and a Sennheiser HD560s. I am using the medium selection on the L50, with volume set to 10 o´clock. Is that ok with these headphones? Sorry this Is my first headphone amp.
Less attenuation is slightly better. I would adjust the gain setting so that you can run the volume closer to 3 o'clock.
 
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