Should I use the RCA or XLR line outputs on TT2 or DAVE into my amplifier?
Short answer
For a short run to your amp, Watts expects RCA to be better: in a 2023 reply that names no device he wrote you are "almost certainly better off using the RCA phono" Head-Fi, Mar 2023. He has said balanced costs a little transparency but can win with long cables, noise or some amps, so compare both volume matched, as XLR is 6 dB louder Head-Fi, Mar 2023Head-Fi, Jan 2021Head-Fi, Apr 2021. On TT2, first check that the amp's XLR input does not short pins 1 and 3 Head-Fi, Mar 2021Head-Fi, Jun 2024.
The practical answer
For short connections Watts expects RCA to be better, but his standing advice is to compare both, volume matched Head-Fi, Mar 2023Head-Fi, Jan 2021Head-Fi, Feb 2019. In a March 2023 Watts Up reply that names no device, he wrote that the balanced output "will result in a small loss of transparency, as an extra amp stage has been added", and that "For short connections, you are almost certainly better off using the RCA phono" Head-Fi, Mar 2023. For long cables, he wrote, "the balanced XLR may be better", and the "Only way of telling is to try with an AB listening test - but remember that balanced has +6dB more gain", so turn the volume down 6 dB when using balanced Head-Fi, Mar 2023. In a 2021 TT2 post: "listening tests must be volume matched" Head-Fi, Jan 2021. In a TT2-thread post of early 2019 (date estimated from the post ID) he wrote that "it's impossible to make a forecast as to whether balanced or SE is best" and that trying each is "my best advice" Head-Fi, Feb 2019.
Why he leans toward RCA
On TT2, he said in 2021 that XLR pin 2 is the same signal as the RCA and the negative leg comes from an inverting amplifier Head-Fi, Jan 2021. The same month he wrote that balanced operation "always involves extra amplifier(s) in the signal path, so there will always be a hit on transparency" Head-Fi, Jan 2021, a loss he described as small and "in absolute terms" Head-Fi, Jan 2021. In 2022 he said TT2's balanced mode measures with the same noise and distortion as the RCA, and put the transparency cost down to added passive components and solder joints in the feedback path, which degrade small signal accuracy that is "impossible to measure" Head-Fi, Aug 2022. In a general October 2024 remark he wrote that single ended "will always have the transparency edge on balanced as it's simpler" Head-Fi, Oct 2024. For Dave, in 2015 he said balanced doubles the analog components in the signal path, so "going balanced will have a cost in transparency" Head-Fi, Jul 2015, and that "Dave is SE as that's the best for SQ; but to do so is much harder, as differential gives measured benefits that hides SQ problems" Head-Fi, Jun 2015.
When balanced may be better
In 2015, writing about Dave, he said balanced "can be better than SE" between a pre-amp and a power amp, and "if SE operation is noisy, try balanced" Head-Fi, Jul 2015. In 2019, on TT2: "some amps and active speakers work better in balanced" Head-Fi, Apr 2019. In 2021 he said balanced can reduce noise on long cable runs and in noisy environments, that he had heard it sound much better into true balanced inputs, but that "most often, single ended is the preferred approach" Head-Fi, Jan 2021. In 2023 the case he gave of balanced sounding a lot better was cables longer than 5 m Head-Fi, Apr 2023. In October 2024 he said he had met power amps where XLR beat RCA, "and of course vice versa" Head-Fi, Oct 2024. In an interview published October 2026 (recording date not stated; its transcript places it before May 2026), speaking of Dave, he said sometimes single ended is better and sometimes balanced; balanced's benefit is common mode noise rejection, mostly with very long interconnects or a poorly designed power amplifier, and with decent cabling and a decent amp "you don't get any of those issues anyway" HiFi Buys 1:08:15HiFi Buys 1:08:33.
TT2
Before using XLR, check that the amp's input does not tie pins 1 and 3 together. He has warned since 2020 that some amp or sub inputs do and that this can damage TT2 Head-Fi, Jul 2020Head-Fi, Jan 2021Head-Fi, Apr 2022, repeated it in 2023 with "Stick to RCA in that case" Head-Fi, Jan 2023, and again in June 2024 Head-Fi, Jun 2024. In 2019 he said to connect pin 1 on TT2 to pin 1 on the amp, otherwise large common mode differences "may damage the electronics for the amp" Head-Fi, Apr 2019. In DAC mode the outputs are fixed at 2.5 V on RCA and 5 V on XLR Head-Fi, May 2018.
If you drive speakers directly instead of an amp, his 2022 advice was not to use the balanced connection for loads under 16 ohms, as it will thermally trip if run loud Head-Fi, Feb 2022; in 2021 he had given 8 ohms or less Head-Fi, Jan 2021 and 10 ohms or less Head-Fi, Mar 2021.
Dave
Dave's XLR is a different circuit. In 2021 he said Dave's XLR outputs go through 33 ohm resistors, the negative output is not high current, and "The intent with Dave was to drive amplifiers only with the XLRs" Head-Fi, Mar 2021. In 2015 he gave XLR as up to 12 V RMS and RCA up to 6 V RMS, and said XLR is not meant for headphones Head-Fi, Aug 2015.
On valve power amps, in 2017 he said Dave driving them direct had always sounded superb to him; for an amp with poor stability margins that goes unstable with a low source impedance, which he thought very unlikely, his suggestion was to try the 33 ohm balanced outputs Head-Fi, Feb 2017. For one owner's ADAM setup in 2017 his "guess" was balanced from Dave, using Dave's volume control to avoid too high a voltage Head-Fi, Oct 2017.
What he has not said
He gives no recommendation of one connection for a named amplifier model, and no figure for how much transparency balanced costs beyond calling it a small loss Head-Fi, Mar 2023Head-Fi, Jan 2021.
Quotes
“For short connections, you are almost certainly better off using the RCA phono.”2023-03-31 Head-Fi, Mar 2023
“See which mode works the best is I am afraid my best advice!”2019-02-05 Head-Fi, Feb 2019
“In short, if SE operation is noisy, try balanced.”2015-07-19 Head-Fi, Jul 2015
“The time when I heard that balanced was a lot better was with cables that were greater than 5m long.”2023-04-01 Head-Fi, Apr 2023
Dated positions
| When | Products | Position |
|---|---|---|
| 2015-06 to 2015-07 | DAVE | Dave is single ended because that is best for sound quality; balanced doubles the analog parts in the path and costs transparency, though it can sound better pre-to-power depending on the setup, and is worth trying if single ended is noisy. Head-Fi, Jun 2015Head-Fi, Jul 2015Head-Fi, Jul 2015 |
| 2018-05 to 2024-06 | Hugo TT2 | TT2's negative XLR output uses the same high-power amplifier design as the single ended output; check that an amp's XLR input does not short pins 1 and 3, which can damage TT2, and use RCA if it does. Head-Fi, May 2018Head-Fi, Apr 2019Head-Fi, Jan 2021Head-Fi, Mar 2021Head-Fi, Apr 2022Head-Fi, Jan 2023Head-Fi, Jun 2024 |
| 2021-03 to 2021-04 | DAVE, Hugo TT2 | Dave's XLR runs through 33 ohm resistors and is meant for amplifiers only; TT2's XLR pins are wired directly to high-current output stages. Head-Fi, Mar 2021Head-Fi, Apr 2021 |
| 2018-07 to 2024-10 | Hugo TT2, DAVE | Single ended is simplest and has the transparency edge, but some amps and long cable runs do better balanced, so he advised trying both volume matched; for short connections he expected RCA to be better (the 2023 posts name no product). Head-Fi, Jul 2018Head-Fi, Feb 2019Head-Fi, Apr 2019Head-Fi, Jan 2021Head-Fi, Jan 2021Head-Fi, Mar 2023Head-Fi, Apr 2023Head-Fi, Oct 2024Head-Fi, Oct 2024 |
| 2026-10 | DAVE | In an interview published October 2026 (recording date not stated) he said that with Dave sometimes single ended is better and sometimes balanced; balanced rejects common mode noise, which matters mainly with very long interconnects or a poorly designed power amplifier, at the cost of doubled circuitry. HiFi Buys 1:08:15HiFi Buys 1:08:33 |
Caveats and open points
- Many TT2 forum post dates are estimated from post IDs; the cited dates are approximate.
- The two 2023 Watts Up posts that carry the clearest RCA advice (Head-Fi, Mar 2023, Head-Fi, Apr 2023) do not name a product.
- His figure for the extra level from balanced is +6 dB in 2021 and 2023 posts Head-Fi, Jan 2021Head-Fi, Apr 2021Head-Fi, Mar 2023, but 3.8 dB in a January 2019 TT2 post about loudspeakers needing extra power Head-Fi, Jan 2019; this archive does not reconcile them.
- Statements about balanced versus single ended made in other products' threads (for example Head-Fi, May 2022 in the Hugo 2 thread, 2022, and Head-Fi, Oct 2024, 2024) are general remarks about his DACs, not advice about a specific line-out setup.
- No statement recommends a connection for a named amplifier model.
Topics: Balanced vs single-ended, Pre-amps, power amps and amplifier choice