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Lundahl Sound VC2361 6-Channel Volume Control Review

Rate this volume control

  • 1. Poor (headless panther)

    Votes: 2 1.5%
  • 2. Not terrible (postman panther)

    Votes: 8 5.9%
  • 3. Fine (happy panther)

    Votes: 44 32.4%
  • 4. Great (golfing panther)

    Votes: 82 60.3%

  • Total voters
    136
Regarding use case, it might be nice to have a transparent volume control downstream of a DSP X-over, which would help solving any noise problem at low volume in an audiophile's 3-way active system.
In fact this seems to be the intended use, together with other components from the brand, and should work with a Behringer DCX as well - the noisier, cheaper PA processor, the more benefit.
 
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Over 1 grand for a passive attenuator? Only if it is fitted with Lundahl transofrmers...is it the same company by the way?
 
Regarding use case, it might be nice to have a transparent volume control downstream of a DSP X-over, which would help solving any noise problem at low volume in an audiophile's 3-way active system.
But this VC is passive; how much help would it provide if the "noise problem" starts at the DSP X-over, (that will pass through this VC-2361), en route to the 3-way active system?
 
But this VC is passive; how much help would it provide if the "noise problem" starts at the DSP X-over, (that will pass through this VC-2361), en route to the 3-way active system?
The DAC is receiving the full scale unattenuated digital signal at 16/24/32bit depth and VC is handled after signal processing. Slightly better scenario for the signal chain depending on your hardware/software.
 
Yes, my reasoning might be flawed but as I see it, if the volume setting is handled in DSP-Xover, output DAC noise is constant while signal is variable, so SNR worsens as volume setting decreases - whereas if signal is handled near 0 dBfs during the digital processing, then output as an analog signal at a healthy voltage, SNR is optimized and, signal and noise being equally attenuated, untouched through the subsequent phase of analog attenuation - inasmuch as the VC device is audibly transparent.
Or am I wrong ?
 
Where is the HF roll-off coming from ? .... given it is only a relay attenuator.
It suggests there is a 500pF on the output (I assume the AP input is much smaller) on one channel and a smaller one on the other measured channel.
 
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Where is the HF roll-off coming from ? .... given it is only a relay attenuator.
It suggests there is a 500pF on the output to ground (I assume the AP input is much smaller) on one channel and a smaller one on the other measured channel.

~250pF per leg (3.5k output R) would do it to be -3dB at ~91kHz. Not hard on a PCB with that many switched relays/resistors. A bunch of parallel tracks...
 
Where is the HF roll-off coming from ? .... given it is only a relay attenuator.

Seeing that it affects the two tested channels differently I’d say wiring, PCB layout and/or parasitic capacitances?

I still reckon that digital attenuation done in 24 or 32 bit is the way to go, as long as you don’t have to go down like 60dB for normal listening levels.
 
Digital domain "volume control" should be used if possible at or above 75% of full level for the volume you use to counter any problems (if the system gain allows it).
Wadia knew this, and why they incorporate "analog output gain setting links" of their output buffers on their top models, so then you set the annalog buffer gain so then digital domain volume control is use above 75% to counter those problems.

Cheers George
 

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~250pF per leg (3.5k output R) would do it to be -3dB at ~91kHz. Not hard on a PCB with that many switched relays/resistors. A bunch of parallel tracks...
And probably a ground plane too... + cables that might add a bit to this capacitance as well.
Hoping the input capacitance of the following amp isn't that range either.
Would be 1.75k per leg output resistance (3.5k total).

30kHz -0.5dB is enough of course... still...
 
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Digital domain "volume control" should be used if possible at or above 75% of full level for the volume you use to counter any problems

What is 75% of the range from -∞…0dBFS?

In any case, I think the worries about loss of resolution or excess noise stem from the 16bit era. With 24bits or more you have numeric accuracy to spare until you attenuate a lot.
 
24 bit resolution for relay control requires an enormous amount of relays (per channel) and a really fine grained encoder and would make attenuation with the remote a lengthy procedure.
128 steps (0.5dB/step) is probably already more than enough (so twice that of this device which does 64 steps) and adds just one relay but requires another encoder (or ADC if done this way) and takes double the time on the remote, although you could make the remote receiver a bit smarter by making the pulses shorter while continuing to press the remote control.

24bit or 32bit would be fine in the digital domain to make it step-less but for volume control 0.5dB/step is already pretty close to stepless. 1dB/step is already fairly usable.
 
Really looking forward to see what the full system and speakers do.
Hopefully they send to Amir to measure
 
24 bit resolution for relay control requires an enormous amount of relays (per channel) and a really fine grained encoder and would make attenuation with the remote a lengthy procedure.
128 steps (0.5dB/step) is probably already more than enough (so twice that of this device which does 64 steps) and adds just one relay but requires another encoder (or ADC if done this way) and takes double the time on the remote, although you could make the remote receiver a bit smarter by making the pulses shorter while continuing to press the remote control.

24bit or 32bit would be fine in the digital domain to make it step-less but for volume control 0.5dB/step is already pretty close to stepless. 1dB/step is already fairly usable.

Sorry, I meant 24bit for digital volume control. For analog, like this device, I’d be perfectly content with 24 x 2dB steps. That’s exactly what I used to have in a transformer volume control some years ago. The steps were meaningfully different, and I never once wished for finer control. In Audirvana I set the volume control steps to 1dB, because the 0.5dB steps annoy me.
 
They also have a DSP active crossover and a PSU,can't get to the product page to see if they have something more.
A lot of subjective wording though.
Would be interesting to see the specs and measurements. six-channel DACs are rare and with the volume controller it may be a nice setup for active 2x3 speaker system.
 
I am trying to figure out what the use-case for this balanced 6-channel VolumeControl (VC) could be; even if not for consumer applications.
Adding y six channel amp you can activate a three way stereo speaker.
 
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