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Topping D10 Balanced Review (USB DAC)

Blumlein 88 said:
Topping says not to use the D10B this way. Specifically warn you not to do it. With many balanced DACs you can use with an RCA, but not the D10B.

View attachment 367114
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What about using this level converter - >
71EMgCw7rTL.jpg



 
Is it possible to set the TOPPING D10B so that the ***analog output*** is sent at commercial line level (-10dBv) over the balanced output instead of professional line level (+4dBu); while the digital Optical and Coax outputs pass along the signal exactly as transmitted?

For context, all of my audio sources feed into an analog stereo mixer (Ashly LX-308B, +4dBu nominal), which handles both balanced and unbalanced inputs. My other audio sources are currently unbalanced (at commercial line level), and my thought was to incrementally move towards balanced devices as I replace older ones or add new stuff. But during the transition, I will have widely different input line levels. For the initial phase of transition—this D10B is the first—it would be great if I could reduce its +4dBu output level (into the balanced cable) to line level match the other devices that are still unbalanced commercial (-10dBv).

The ability to select between line level of +4dBu/-10dBv into the balanced analog output would benefit two classes of users. First, people like me with a downstream balanced device but need to level match against other inputs that are at commercial line level. Second, anyone who is using a semi-professional downstream device with balanced inputs that is internally designed to operate on a nominal -10dBv. In both cases, the context is setting the line level of the output of the fixed audio (i.e., no adjustment to volume, only changing the output gain between +4dBu and -10dBv nominal level).

Note: the reason I believe the D10 series is absolutely perfect is because it allows me to simultaneously send analog output to my audio mixer, while also passing the original unchanged digital data via S/PDIF output to a separate digital audio chain... and nothing else. (Based on comments in the thread, I may be the only person who selected the D10 because of the dual analog / digital output.) As such, I cannot use the volume control from the PC since that will reduce the audio level on both the analog and digital outputs. Thus, this request is for the D10B fixed analog gain output to be adjusted somewhere in the DAC stage, not at the digital input (UAC2) stage as controlled by the PC.
 
rcstevensonaz said:
Is it possible to set the TOPPING D10B so that the ***analog output*** is sent at commercial line level (-10dBv) over the balanced output instead of professional line level (+4dBu); while the digital Optical and Coax outputs pass along the signal exactly as transmitted?
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Yes, using an analog attenuator between the D10B's Line out and the external amp.

Something like this: https://www.behringer.com/product.html?modelCode=0843-AAF
 
A simple and working solution is to place a -12dB padding circuit at the end of the signal cables from the D10b's outputs. In other words, right at the mixer inputs or whatever balanced input with -10dBV nominal level.
Connecting the D10b unbalanced is not recommended, so one definitely needs a balanced input for these.
1715024025087.png
 
staticV3 said:
Yes, using an analog attenuator between the D10B's Line out and the external amp.

Something like this: https://www.behringer.com/product.html?modelCode=0843-AAF
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Yea. But.... The goal here is not to add another device to the analog input gain chain. Rather, for the Topping D10B—as a bridge device—to select between either of the standard output gain levels (i.e., professional, and also commercial) within the DAC / amplification stage. TOPPING devices sit squarely in the home and consumer-professional space; so this feel like a very natural feature for the D10B to support.

While the use case is not high, such +4/-10 switches (or electronic configuration) have traditionally been quite common on devices that bridge between home and consumer-professional equipment. And ideally, such level selection would be made at the sending (output) device before full gain amplification rather than via in-line attenuation or through gain level reduction at the receiving (input) device.

Edit: and yes, to @KSTR's point, this is entirely within the context of balanced audio output over balanced cables into a device that has balanced inputs. This issue is the nominal line level amplification, not balanced vs. unbalanced connections.
 
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rcstevensonaz said:
Yea. But.... The goal here is not to add another device to the analog input gain chain.
Rather, for the Topping D10B—as a bridge device—to select between both standard output gain levels (professional and commercial) within the DAC / amplification stage. TOPPING devices sit squarely in the home and consumer-professional space; so this feel like a very natural feature for the D10B to support.
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But the D10B doesn't support this feature.

Therefore, the solution would have to be external, unless you're willing to modify the D10B's PCBA.
 
staticV3 said:
But the D10B doesn't support this feature.

Therefore, the solution would have to be external, unless you're willing to modify the D10B's PCBA.
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This is where my being a Comp Sci rather than EE major may be a liability :cool:

The D10S and D10B largely use the same underlying DAC and OPAMPS that are both capable of supporting either +4 or -10 output. From a Comp Sci perspective, I assume there is a register or control signal somewhere that specifies what the output stage should be. In which case, such selection could be controlled by changing the register or sending a command to adjusts the setting. Hence my question about whether that could (in theory, or in practice) be done.

However, it is very possible the EE person will respond back and say "can't you read the circuit boards?", and tell me that the output level is clearly hard coded by the resistors embedded on the PCB board itself so the +4 setting can't be changed without making major physical changes to the device itself.
 
rcstevensonaz said:
This is where my being a Comp Sci rather than EE major may be a liability :cool:

The D10S and D10B largely use the same underlying DAC and OPAMPS that are both capable of supporting either +4 or -10 output. From a Comp Sci perspective, I assume there is a register or control signal somewhere that specifies what the output stage should be. In which case, such selection could be controlled by changing the register or sending a command to adjusts the setting. Hence my question about whether that could (in theory, or in practice) be done.
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I think that if you'd like to change the analog output amplitude w/o affecting the digital out, then you'd have to modify the analog output stage that's between the DAC chip and the Line out ports.

By changing some resistors, you should be able to change the output voltage. Add a toggle switch to the chassis and you may even be able to make your -10dBV/+4dBu dream a reality.

It would be quite the undertaking though. Definitely not a project for beginners.
 
staticV3 said:
I think that if you'd like to change the analog output amplitude w/o affecting the digital out, then you'd have to modify the analog output stage that's between the DAC chip and the Line out ports.

By changing some resistors, you should be able to change the output voltage. Add a toggle switch to the chassis and you may even be able to make your -10dBV/+4dBu dream a reality.

It would be quite the undertaking though. Definitely not a project for beginners.
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Yep, if the output gain is set by hardware rather than by electronic settings, it is absolutely beyond anything I would undertake.
 
rcstevensonaz said:
And ideally, such level selection would be made at the sending (output) device before full gain amplification rather than via in-line attenuation or through gain level reduction at the receiving (input) device.
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Well, no. Technically, it is usually best to make use of any available high level on the cables and attenuate at the input of the receiver, for best signal-to-noise ratio and low interference. The passive "pad" has an ever so slight noise penalty which is usually insignificant.

One sure could mod the D10b directly, the output stage is extremely simple, I/V opamps per (+) and (-) leg of a channel, followed by a simple passive RC-filter. No signal combiner present, it depends on a proper balanced input to combine the "raw" (+) and (-) leg outputs by subtraction.
To change the I/V's, reduce the feedback R to 1/4th and increase the integrator cap to 4x... and loose a good amount of the signal-to-noise ratio... passive attenuator inside the device is also not ideal, we'd like to have a buffered low-impedance outputs.

At this point the modding project sort of explodes ;-)
Passive Attenuation at the receiver is simple and effective and also easy to DIY.
 
KSTR said:
Well, no. Technically, it is usually best to make use of any available high level on the cables and attenuate at the input of the receiver, for best signal-to-noise ratio and low interference. The passive "pad" has an ever so slight noise penalty which is usually insignificant.
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Thanks for that clarification. I (obviously) assumed the opposite.

KSTR said:
One sure could mod the D10b directly, the output stage is extremely simple, I/V opamps per (+) and (-) leg of a channel, followed by a simple ...
Click to expand...
Easy for you to say (and thanks for the explanation). But I think you missed the part that said I was Comp Sci and not EE... I was lost from "I/V" onward. o_O
 
@rcstevensonaz , the laconic explanation for the mod of the D10b was actually meant to discourage people from trying it unless it is fully within their comfort zone, and even then it is not that great an idea.
 
The D10B is on sale at Apos, Amazon, etc. for $118.15. Google search for coupons from Apos could further reduce price by 5%, 10%, etc.
 
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