Can DAVE drive power amplifiers directly, and is its DAC mode any different from pre-amp mode at -3 dB?

The practical answer

Watts said Dave can drive power amplifiers directly, and he preferred that to adding a pre-amp. In February 2017 he wrote that "every time I have heard Dave drive valve power-amps direct, it has sounded superb - smooth and refined, with cavernous sound-stage"; he guessed he had done this "about half a dozen times with differing valve power amps", and said he could not comment on all the power amps out there Head-Fi, Feb 2017. In May 2018, writing about his DACs generally in the Dave thread, he said "With the digital volume control, you simply do not need a pre-amp" Head-Fi, May 2018.

DAC mode versus pre-amp mode at -3dB

Each of his Dave statements in this archive (2016, 2018, 2022) says there is no difference. In May 2016 he said the -3dB setting in DAC mode "is the same as pre-amp mode - its just the volume control is permanently set to -3dB" Head-Fi, May 2016. In August 2018 he said "DAC mode is absolutely no difference in the signal path at all"; only the control function changes, with the volume set to -3dB and volume change disabled Head-Fi, Aug 2018. His latest Dave statement (April 2022), agreeing with a poster, was "DAC mode is completely identical to pre-amp mode - it's just fixed to -3dB" Head-Fi, Apr 2022. A September 2021 post in his Watts Up thread says the same of DAC and pre-amp mode but does not name the product Head-Fi, Sep 2021.

Setting the level for your power amp

• From the headphone or RCA outputs, -3dB is 3V RMS and +4dB gives 6.7V RMS, and Dave only clips above +4dB (May 2016) Head-Fi, May 2016. In February 2018 he said -3dB gives exactly 3V RMS with a full-scale input Head-Fi, Feb 2018.
• In January 2016 he said +3dB (6V RMS) is perfectly linear, assuming loads of 33 ohms or easier Head-Fi, Jan 2016.
• For a lower ceiling, in October 2017 he said -6 on the display sets 2.1V RMS maximum Head-Fi, Oct 2017.
• Balanced XLR "doubles the available voltage into a power amp", a change of +6dB (April 2021) Head-Fi, Apr 2021. A March 2018 post gives 6V RMS at -3dB, clipping at 13.6V RMS and a 33 ohm output impedance without naming the output; 33 ohms is the figure he gives for the XLRs Head-Fi, Mar 2018Head-Fi, Dec 2016.

RCA or XLR

In December 2015 he said the balanced drive "has insufficient current drive and is intended to drive power amps only" Head-Fi, Dec 2015. In January 2018 he said a 50 mA current limit applies only to the balanced output, which is for balanced inputs on power amps, not for driving loads Head-Fi, Jan 2018. In May 2018 and March 2021 he said the intent with Dave was to drive amplifier inputs only with the XLRs, which are fed through 33 ohm resistors Head-Fi, May 2018Head-Fi, Mar 2021.

In December 2016 he gave the output impedance as 0.055 ohms on the single-ended outputs (RCA or headphone) and 33 ohms on XLR, and said that for connection to power amps the output impedance is not relevant Head-Fi, Dec 2016. In a February 2017 post mainly about his coming power amp, he added "As to balanced or RCA - it depends on the power amp, but mostly RCA is best" Head-Fi, Feb 2017. The question he was answering is not shown, so it is unclear whether he meant Dave's outputs or the planned amp's inputs. The same month he said a power amp with poor stability margins could go unstable with a low source impedance (the scraped text drops a word here), which he thought very unlikely; if it happens, try the balanced outputs, "as these are 33 ohm outputs" Head-Fi, Feb 2017.

Do you need a pre-amp?

In March 2016 he said "the best sounding pre-amp is non at all", adding that the bandwidth limiting some pre-amps provide is not needed because Dave has no significant out-of-band output Head-Fi, Mar 2016. Earlier that month he said "with Dave, no pre-amp sounds better than an extra pre-amp" Head-Fi, Mar 2016. In May 2018 he said that whenever he removed a pre-amp he got "a big boost to transparency", while pre-amps add a softness and bloom to the bass that some prefer and he does not Head-Fi, May 2018.

Loudspeakers directly

In August and September 2017 he agreed that no analog amplifier can match Dave driving small loudspeakers directly in sound-stage depth, and said Dave powered 88 dB/1W speakers in his office with plenty of volume Head-Fi, Aug 2017Head-Fi, Sep 2017. On power, in January 2018 he said Dave delivers 2.1W into 8 ohms Head-Fi, Jan 2018; in a May 2018 interview he called it 2 watts Darko Audio 2:10.

What he has not said

He named no power amps that suit Dave and gave no input-sensitivity guidance beyond the voltages above; his direct-drive reports name valve amps Head-Fi, Feb 2017. Dave's DX digital outputs are for his own DX power amps, not covered here Head-Fi, Jan 2017Head-Fi, Jan 2018.

Quotes

“DAC mode is completely identical to pre-amp mode - it's just fixed to -3dB. So setting pre-amp mode to -3dB will give absolutely identical performance to DAC mode.”2022-04-28 Head-Fi, Apr 2022

“every time I have heard Dave drive valve power-amps direct, it has sounded superb - smooth and refined, with cavernous sound-stage.”2017-02-05 Head-Fi, Feb 2017

“With the digital volume control, you simply do not need a pre-amp”2018-05-18 Head-Fi, May 2018

“The intent with Dave was to drive amplifiers only with the XLRs.”2021-03-26 Head-Fi, Mar 2021

“Balanced XLR doubles the available voltage into a power amp”2021-04-30 Head-Fi, Apr 2021

Dated positions

Caveats and open points

• All direct-drive listening reports are Watts's own experience with valve power amps and small efficient loudspeakers; he said he could not comment on all power amps.
• Part of the 2017 post on amplifier stability has a gap where the scraped text dropped a word, so that statement is paraphrased, not quoted.
• The March 2018 post giving 6V RMS at -3dB and 13.6V RMS clipping does not name the output; its 33 ohm output impedance matches what he gives elsewhere for the XLRs.
• The September 2021 statement that DAC and pre-amp modes are identical is in the Watts Up thread and does not name the product.
• This archive has no list of compatible power amps and no input-sensitivity guidance beyond Watts's voltage figures.
• The February 2017 'mostly RCA is best' remark comes from a post mainly about his planned power amp, and the question it answers is not shown; it may refer to Dave's outputs or to that amp's inputs, so it is not treated as settled connection advice for Dave.

Topics: Pre-amps, power amps and amplifier choice, Volume, gain and output level