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Topping L30 Headphone Amplifier Review

somebodyelse

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Please help.

I just bought a (New) Topping L30 from a UK eBay seller. It came in the original box and was well packed.
It has a 201262 number but doesn't have continuity between the channel ground and the back panel screws.
Is it easy to fix with a ground wire or should I send it back?
I'm very suspicious that it's a customer return item that's being resold.
What should I do?
See this post for an explanation. Assuming you made the right measurement you may have one of the ~10% of 2012xx units that shipped before the pogo pin fix for the ESD issue, or the pogo pin may have become detached as I think one person reported - does your L30 rattle if you shake it? The pogo pin is shown here, and there's a picture somewhere of a DIY fix using a bit of wire from the same pad the pogo pin uses, going up around the mounting screw hole, with paint removed to ensure contact. It's an easy fix if you've got the equipment and confidence, but if you want to retain warranty cover I suggest you get the OK in writing from the vendor before attempting it. Alternatively return it and get a replacement.
 

lewis

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Which screws you have picked to measure? The screws closer to the RCA connectors are not connected to ground, those close to case's edges are supposed to be...
None of the screws on the back have continuity with the channel ground. No connection with the circuit board.
 

lewis

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See this post for an explanation. Assuming you made the right measurement you may have one of the ~10% of 2012xx units that shipped before the pogo pin fix for the ESD issue, or the pogo pin may have become detached as I think one person reported - does your L30 rattle if you shake it? The pogo pin is shown here, and there's a picture somewhere of a DIY fix using a bit of wire from the same pad the pogo pin uses, going up around the mounting screw hole, with paint removed to ensure contact. It's an easy fix if you've got the equipment and confidence, but if you want to retain warranty cover I suggest you get the OK in writing from the vendor before attempting it. Alternatively return it and get a replacement.
Just had a look and there's no pogo pin. It must have not got that fix. Thanks for your reply.
Lewis.
 

lewis

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2012 is later than the recalled 2011 range so it should be a new, safe revision. Selling something that's been returned as new is not legal in the UK but I'm not sure how you determine it's a customer return item based purely on continuity.
I have now seen the feedback on the seller and they have had some returns.
 

solderdude

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Any resumen?

It is a measurement error caused by the measurement method Marv used.
He is looking at the back EMF of a headphone falling across a small resistance Marv thought was insignificant.
Simple math says it wasn't.
I already explained this here when Marv started posting his huge findings.
 

deccatree

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Sound is good, but not big step from my resident amps like O2 and SMSL SAP2. Both are able to drive my ATH-R70 (470 Ohms) to a high volume. L30 is not! He has not enough power to drive this can. Lower impedance cans are powered very well ;-)
Update: Yes, he can! But not with the E30 as DAC. ODAC as source and there's plenty of thunder!
 

solderdude

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You may be using the E30 in pre-amp mode and attenuated ?
 

deccatree

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You may be using the E30 in pre-amp mode and attenuated ?
No, definetely not. When running in Pre-Amp-Mode there's no signal on Headphone Socket. Attenuator is on +9 dB. BTW even connected to the same ODAC L30 doesn't drive a ATH-R70x to the same peak level than a O2 HPA. That's what i'm surprised in addition. I expected something different. But it is loud enough!
 

solderdude

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I am talking about the E30 running in pre-amp mode.
Not the L30 in pre-amp mode.

O2 can provide 7V (using adapter) and 5V (on batteries)
L30 (driven from E30, max. volume, gain +9dB) can provide 6V.

The differences you talk about are not power related but gain related.
The O2 and L30 can both driver your headphone equally well. The gain differs and volpot reacts different.
 

solderdude

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Can it be that the E30 needs a TOSLINK etc. for "full power"? I've connected it by USB

When the E30 comes out of the box it is set to variable volume. You have to manually set the E30 in DAC mode.
Give away is:
In DAC mode you will always see the used bitrate.
In Pre-amp mode you will only shortly at the beginning of the song see the bitrate and the display jumps back to the output level indication.

When you want the E30 in DAC mode (so no volume control on the DCA) go to standby mode, press and hold the On/Off button on the touch panel for about 3 seconds until you see “DAC” written on screen, release the button and power it on.
You only need to do this once. It stays in DAC mode until you tell it to go to pre-amp mode again.
 
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solderdude

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In that case the output voltage of the E30 (without software volume control used) the 0dB FS output voltage will reach 2.1V which is pretty 'standard' for RCA out DACs though DACs do exist that have higher or lower output voltages.
The L30 with volume control at max and gain set to H will output 6.25V (2dB higher than O2 amp on batteries and 1dB lower than O2 on mains adapter).
 

solderdude

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The differences you hear are in gain... not power.

Connect the O2 to the E30, connect the O2 out to the L30 in and you can hear how loud the L30 really can go when it would have had a bit more gain.
 

Jimbob54

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The differences you hear are in gain... not power.

Connect the O2 to the E30, connect the O2 out to the L30 in and you can hear how loud the L30 really can go when it would have had a bit more gain.
I still want to know why they find the L30 fed from the odac to be louder than the L30 fed from e30 in full output dac mode.
 
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