Topping DX9 AKM single ended vs L30 II power

[staticV3]

So a balanced DAC + A70 Pro/L70 should beat my DX9 by a pretty large margin, 7.5dbs is a lot!

7.5dB with regular Balanced DACs like the DX9, and as much as 16.5dB in case of the Topping E50 II DAC with its super high 11.3V output voltage.

Though before you get your wallet, first check if Replay Gain can perhaps solve your gain issue for free.

 

[Tatalor51]

Don't listen from a local library, just Tidal or Spotify. Looked a bit into volume normalisation and should accomplish the same thing. Mostly.

 

[Tatalor51]

Found a good deal for an used L70 and the results are quite surprising, to say the least.
From DX9 High Gain, 0db volume, pre amp out XLR, using HE6se (-6db for eq), L70 ON LOW GAIN is about 4 dbs louder at 0db compared to DX9 0db ON HIGH GAIN.
Switching L70 to high gain, the difference in volume is huge, can't possibly go higher than -10 to -12db.

Even with different gain stages and amplified gain from DX9 pre-out, should the difference (under these circumstances) be around or over 20 dbs? Seems huge. Not saying that I am unhappy about it but. Is there a possibility of some malfunction on DX9 amplifier part?

 

[staticV3]

Found a good deal for an used L70 and the results are quite surprising, to say the least.
From DX9 High Gain, 0db volume, pre amp out XLR, using HE6se (-6db for eq), L70 ON LOW GAIN is about 4 dbs louder at 0db compared to DX9 0db ON HIGH GAIN.
Switching L70 to high gain, the difference in volume is huge, can't possibly go higher than -10 to -12db.

Even with different gain stages and amplified gain from DX9 pre-out, should the difference (under these circumstances) be around or over 20 dbs? Seems huge. Not saying that I am unhappy about it but. Is there a possibility of some malfunction on DX9 amplifier part?

Honestly, just buy a cheap multimeter and you can confirm all voltages and Amplifier gains yourself.

Both to confirm that your gear is in working order, and to get a better understanding of the situation.

 

[Tatalor51]

Will need to learn how to do it

Using Pre amp instead of Line Out is correct I assume? Both seem to be influenced by DX9 volume knob position. Tried Line out with an EHA5 energizer and the volume was very low, lower than E30 Lite Line out. Pre amp worked very well though. Both with volume at 0dbs.

 

[staticV3]

Will need to learn how to do it

1. Plug out all speakers and headphones

2. Play the 60Hz tone on loop

3. Set the Multimeter to V AC, lowest voltage range that covers your voltages

4. Touch the probes to GND+Signal for single-ended, or Positive+Negative for Balanced (doesn't matter which probe goes where)


5. Multimeter will display output voltage

6. If you have DAC output voltage (upstream of Amp) and Amp output voltage, then Gain in dB=20*log10 (Output voltage / Input Voltage)

 

[Tatalor51]

Thank you, will order a multimeter and try.

However, remembering the pre amp vs line out difference, and thinking my past testing of L30 II was done on line out, decided to test again with the entire E30 II Lite/L 30 II stack.

Same as before, high gain, max volume, same 1 minute song fragment, HE6se and HE1000. And, not unexpectedly, L30 II registered around 9-10 dbs louder compared to DX9 BALANCED out. And around 16 dbs louder than DX9 SE. That's basically double the volume and it was, obviously, very audible even with headphones on the table. Can this difference be explained by gain alone or there's a chance I got a somewhat defective unit?

 

[staticV3]

Thank you, will order a multimeter and try.

However, remembering the pre amp vs line out difference, and thinking my past testing of L30 II was done on line out, decided to test again with the entire E30 II Lite/L 30 II stack.

Same as before, high gain, max volume, same 1 minute song fragment, HE6se and HE1000. And, not unexpectedly, L30 II registered around 9-10 dbs louder compared to DX9 BALANCED out. And around 16 dbs louder than DX9 SE. That's basically double the volume and it was, obviously, very audible even with headphones on the table. Can this difference be explained by gain alone or there's a chance I got a somewhat defective unit?

I really don't want to speculate much on shaky data, especially now that you'll be able to confirm all the gains and voltages.

FYI, here are all the values that you should expect:

DX9 RCA Line out max volume	2.1Vrms
DX9 XLR Line out max volume	4.2Vrms
DX9 1/4" HP out max volume Low gain	4.2Vrms
DX9 1/4" HP out max volume High gain	8.5Vrms
DX9 4pin XLR/4.4mm HP out max volume Low gain	4.2Vrms
DX9 4pin XLR/4.4mm HP out max volume High gain	16.6Vrms
E30 II Lite max volume	2.1Vrms
L30 II max volume Low gain	-14dB
L30 II max volume Med gain	0dB
L30 II max volume High gain	16.5dB
L70 1/4" HP out max volume Low gain	0dB
L70 1/4" HP out max volume High gain	13.5dB
L70 4pin XLR/4.4mm HP out max volume Low gain	6dB
L70 4pin XLR/4.4mm HP out max volume High gain	19.8dB

 

[Roland68]

Thank you, will order a multimeter and try.

However, remembering the pre amp vs line out difference, and thinking my past testing of L30 II was done on line out, decided to test again with the entire E30 II Lite/L 30 II stack.

Same as before, high gain, max volume, same 1 minute song fragment, HE6se and HE1000. And, not unexpectedly, L30 II registered around 9-10 dbs louder compared to DX9 BALANCED out. And around 16 dbs louder than DX9 SE. That's basically double the volume and it was, obviously, very audible even with headphones on the table. Can this difference be explained by gain alone or there's a chance I got a somewhat defective unit?

Do you get the same volume level with the L30 II when using the E30 II and the DX9 as the DAC?

 

[Tatalor51]

Not on line out, no. It's way quieter on DX9 line out, around 10 db. But by extrapolating from L70 and EHA5 I think it will be the same volume from pre amp.

 

[Roland68]

Not on line out, no. It's way quieter on DX9 line out, around 10 db. But by extrapolating from L70 and EHA5 I think it will be the same volume from pre amp.

That gives you a possible reason for the discrepancy right there.
Both the E30 II and the DX9 output a maximum of 2.1 volts via RCA.
So, if the L30 II sounds quieter when connected to the DX9, the issue lies upstream of the DX9's own headphone amplifier stage.

Given this, it makes no sense to keep looking for the problem within the headphone amplifiers themselves.
You first need to figure out why the signal level coming from the DX9's DAC is lower than specified—and lower than that of the E30 II (lite).

Measuring it with a multimeter would be a sensible step.

What source and input are you using with the DX9?

I tested a DX9 for a day once, and with my HE6se V2, it was at least as loud as—if not louder than—the L70.

I would rule out a defect in the DX9's headphone amplifier for now. The DX9 has separate amplifiers for single-ended and balanced outputs, and it would be a huge coincidence for both separate amps to have the same fault.
For the moment, I assume the problem lies upstream of the DX9.

 

[staticV3]

Both the E30 II and the DX9 output a maximum of 2.1 volts via RCA.

2.1Vrms for the DX9 is from the RCA Line out

The DX9's RCA Pre out will output 4.2V in Low gain and 8.5V in high gain, both with 0dBFS input and full volume.

 

[Roland68]

2.1Vrms for the DX9 is from the RCA Line out

The DX9's RCA Pre out will output 4.2V in Low gain and 8.5V in high gain, both with 0dBFS input and full volume.

Exactly, @Tatalor51 notes that when using the DX9’s RCA line out with the L30 II, he doesn't achieve the same volume level as he does with the E30 II’s RCA output.
Since both devices—the DX9 and the E30 II—output 2.1 volts, the root cause of the problem lies right there.

The issue must therefore originate either before the DX9 or within the analog circuitry following the DAC chip—specifically in the filter or volume control stage. In any case, it occurs before the headphone amplifier (HPA) stage.

 

[Tatalor51]

That gives you a possible reason for the discrepancy right there.
Both the E30 II and the DX9 output a maximum of 2.1 volts via RCA.
So, if the L30 II sounds quieter when connected to the DX9, the issue lies upstream of the DX9's own headphone amplifier stage.

Given this, it makes no sense to keep looking for the problem within the headphone amplifiers themselves.
You first need to figure out why the signal level coming from the DX9's DAC is lower than specified—and lower than that of the E30 II (lite).

Measuring it with a multimeter would be a sensible step.

What source and input are you using with the DX9?

I tested a DX9 for a day once, and with my HE6se V2, it was at least as loud as—if not louder than—the L70.

I would rule out a defect in the DX9's headphone amplifier for now. The DX9 has separate amplifiers for single-ended and balanced outputs, and it would be a huge coincidence for both separate amps to have the same fault.
For the moment, I assume the problem lies upstream of the DX9.

2.1Vrms for the DX9 is from the RCA Line out

The DX9's RCA Pre out will output 4.2V in Low gain and 8.5V in high gain, both with 0dBFS input and full volume.

You might be unto something here. I thought line out is like that on purpose, compensated by the fact that pre amp seem to send a lot of power downstream. And that I read somewhere that it's normal.

So if the L30 II (and EHA5) are lower volume from DX9 line out compared to E30 Lite line out (assuming max gain/volume on DX9 as I noticed line out is also influence by volume), the most probable explanation is some kind of fault somewhere between the DAC and line out/headphone out? I will test again but at the start of this thread I measured L30 vs DX9 BAL and they were roughly the same. And I am pretty sure I used line out. Measuring again with L30/E30, the difference was quite huge, almost 10 dbs in favor of L30.

Also, I assume it's perfectly possible that only line and headphone outs to be affected, since pre amp seems fine, L70 is roaring while connected to pre amp.

Again, thanks a lot for all the help guys, this is very useful both as a learning experience and debugging the damn thing!

 

[Tatalor51]

Just tested L30 again. From E30 and DX9 pre amp it's about 10 dbs louder compared to DX9 line out. What I also noticed is that Gain setting makes on difference on line out as opposed to pre amp. But I assume that's normal.

 

[Roland68]

Just tested L30 again. From E30 and DX9 pre amp it's about 10 dbs louder compared to DX9 line out. What I also noticed is that Gain setting makes on difference on line out as opposed to pre amp. But I assume that's normal.

That’s how it should be; the line out ought to be independent.
However, the significant difference between the DX9’s line out and the E30 II’s clearly indicates where the problem lies.

The easiest next step would be to use a multimeter to measure the voltage at the line out of both the DX9 and the E30 II Lite.

Is it possible that your source is sending a signal to the DX9 with the volume already reduced? I’ve encountered some bizarre issues with this, especially when using Windows via USB.

Do you have a source with S/PDIF (RCA or Toslink) available so you can test the devices using a different input?

 

[Tatalor51]

That’s how it should be; the line out ought to be independent.
However, the significant difference between the DX9’s line out and the E30 II’s clearly indicates where the problem lies.

The easiest next step would be to use a multimeter to measure the voltage at the line out of both the DX9 and the E30 II Lite.

Is it possible that your source is sending a signal to the DX9 with the volume already reduced? I’ve encountered some bizarre issues with this, especially when using Windows via USB.

Do you have a source with S/PDIF (RCA or Toslink) available so you can test the devices using a different input?

Dont have such source but tested with bluetooth, if relevant. Same volume. Don't think its Windows, if that was the case I think i would not get huge volume out of L70. Also, would probably interfere with E30 too.

A friend will visit next week and bring a multimeter so I'll measure then.

But from what you remember from when you had it, @Roland68, you're inclined to think there's an issue, right? 10 dbs less on Balanced vs L30 II can't really be explained by different by a different gain structure, I think. And my measurements, as crude as they are, are ok to tell the db difference.

And L70 from pre amp goes around 20dbs over so there's that too.

How should I approach the issue with the store where the guy I bought it from made the initial purchase?

 

[Roland68]

Dont have such source but tested with bluetooth, if relevant. Same volume. Don't think its Windows, if that was the case I think i would not get huge volume out of L70. Also, would probably interfere with E30 too.

A friend will visit next week and bring a multimeter so I'll measure then.

But from what you remember from when you had it, @Roland68, you're inclined to think there's an issue, right? 10 dbs less on Balanced vs L30 II can't really be explained by different by a different gain structure, I think. And my measurements, as crude as they are, are ok to tell the db difference.

And L70 from pre amp goes around 20dbs over so there's that too.

How should I approach the issue with the store where the guy I bought it from made the initial purchase?

Windows remembers USB settings and device drivers, and there have been many cases on the forum where the volume was reduced for this very reason.
See if you can find someone with a Mac to test the DX9 and E30 II with the L30 II via USB.
Alternatively, try using a CD, DVD, or Blu-ray player with an SPDIF output.

Comparing the volume levels of the L70 and L30 II when connected to the DX9's pre-amp output doesn't really tell you anything, as the output voltage is far higher than what is needed to reach maximum output.

After all, it makes no sense to send the unit in for repair if there might not actually be a fault.

 

[Tatalor51]

No Macs but I have couple older Windows laptops around. And my son's desktop. None had a Topping device ever connected to them. What if I connect it to those?

 

[Roland68]

No Macs but I have couple older Windows laptops around. And my son's desktop. None had a Topping device ever connected to them. What if I connect it to those?

That would be one possibility, at least.
What do you use for playback?