Driving loudspeakers directly

Analog stage, outputs and amplification

Answers on this topic

• Can Hugo, Hugo 2, Mojo, TT2 or DAVE drive loudspeakers directly from the headphone output, and what load is too low?

Everything he said on this topic (72)

One-line summaries in our words, oldest first. Each link opens the original.

• 2014-04-28Watts says Hugo drove horn loudspeakers loud and transparently; speakers must be 8 ohms or more and efficient given 1W, below ultraviolet volume; he is busy with the QBD upgrade. Head-Fi, Apr 2014
• 2014-06-09Watts revises himself: his PSU test was at line level, but the external PSU sounded better with Hugo driving 8 ohm loudspeakers, by supporting battery voltage. Head-Fi, Jun 2014
• 2014-06-09Watts says there are two 2.2AH Li-ion cells; driving 8 ohm loads flat out sags the voltage, so the charger makes it sound fuller. Head-Fi, Jun 2014
• 2014-07-26Watts says Hugo outputs up to 5V RMS with a 3V preset, advises dropping the pre-amp, and describes damping-factor tests and Hugo's 0.075 ohm output impedance. Head-Fi, Jul 2014
• 2014-09-08Watts says 6 ohm 86dB speakers are too much for Hugo's 0.5A, recommends Hugo over Qute for line use, and describes its Class A discrete hybrid output stage. Head-Fi, Sep 2014
• 2014-09-21Watts says Hugo driving Axjet horn loudspeakers gave extraordinary depth, with a solo violin in The Lark Ascending sounding 40 feet away. Head-Fi, Sep 2014
• 2015-10-11Watts says Hugo driving efficient horn speakers directly beats feeding a linear power amp, which motivated the Hugo amp project: Hugo simplicity with a linear output stage giving enough power. Head-Fi, Oct 2015
• 2017-02-06Watts says he uses ordinary active computer speakers, is looking for portable passive speakers to drive directly from DAVE, and uses AQ NightHawks for serious listening. Head-Fi, Feb 2017
• 2017-03-21Watts says the output into 8 ohms can only be found by measurement, with PSU current the limit, and he will measure it next week. needs context Head-Fi, Mar 2017
• 2017-07-02Watts says Power Pulse Array prototypes are being built with no realistic timeline, release waits until he is satisfied, and DAVE driving small speakers directly gives stunning depth. Head-Fi, Jul 2017
• 2017-07-31Watts says Hugo 2 below white volume is fine with speakers, too weak to damage tweeters, suits near-field efficient 8 ohm speakers, and can fill rooms with 100 dB horns. Head-Fi, Jul 2017
• 2017-08-22Watts identifies an early-1990s design of his, the DPA 200S with a thick-film hybrid Class A amplifier, but says no analog amplifier matches DAVE driving small speakers directly for depth. Head-Fi, Aug 2017
• 2017-09-05Watts says he runs DAVE directly into 88 dB/1W small speakers in his office with plenty of volume and better soundstage depth than his main system. Head-Fi, Sep 2017
• 2018-01-11Watts says Hugo 2 and Dave limit at 0.5A RMS, so Dave gives 2.1W and Hugo 2 1.05W into 8 ohms; the 50 mA limit is the balanced output only. Head-Fi, Jan 2018
• 2018-01-11Watts explains Qutest feeds linear power amps, Hugo 2 suits 1W/8 ohms and Dave 2W, while planned DX amps are pulse array DACs delivering 20W to hundreds of Watts. Head-Fi, Jan 2018
• 2018-02-19Watts explains his discrete single-ended DAC combines I-to-V, filtering and headphone drive in one amplifier with two resistors and two capacitors; DAVE's balanced outputs add an inverting amplifier. Head-Fi, Feb 2018
• 2018-02-23Watts says wood blocks are hard to reproduce, an initial dynamic hit followed by timbre, which he notices when Dave drives efficient loudspeakers directly, plus a huge soundstage. Head-Fi, Feb 2018
• 2018-04-03Watts says the two headphone outputs and the RCA outputs are identical and tracked together, and suggests using the RCA outputs to drive speakers. Head-Fi, Apr 2018
• 2018-05-11Watts gives just over 18V RMS at 1% THD in amp mode and 5V in DAC mode, estimates 98 dB from LS3/5a speakers, and explains why supercaps replace batteries. Head-Fi, May 2018
• 2018-05-14Watts says the supercaps give the output stage ample current; it was upgraded after the TT was found used with efficient loudspeakers, so TT2 can drive them directly. HIFICLUBE.NET JVH 50
• 2018-05-14Watts says the output delivers 18 watts, and 7 watts from the single-ended output, enough to drive efficient loudspeakers; modest 90 dB speakers will do (transcript partly garbled). HIFICLUBE.NET JVH 1:16
• 2018-05-17Watts says all mains-powered DAC/amps have isolation, USB sounds very close to optical, he is amazed 2Qute can drive a loudspeaker, and he explains his single-stage output amplifier. Head-Fi, May 2018
• 2018-05-20Watts explains TT2's 18V RMS balanced output, estimates power into 6 ohms, describes the supercaps and second-order analog noise shaper benefits, and says the output is protected. Head-Fi, May 2018
• 2018-05-23Watts links a 4mm in-line socket cable set for TT2's balanced 18W output and calculates that 100 dB SPL at 1m needs 88 dB speaker sensitivity. Head-Fi, May 2018
• 2018-05-24Watts says TT2 would reach 103 dB on a 91 dB speaker, the balanced output has double the impedance, and SE would give 114 dB with an LCD-4. Head-Fi, May 2018
• 2018-05-24Watts says TT2 drives 1 ohm loads fine and should give 27W RMS into 4 ohms from the balanced XLR output. needs context Head-Fi, May 2018
• 2018-05-25Watts says TT2's output stage uses emitter degeneration and safety resistors, and will not clip at or below +6dB with CD into 8 ohms SE, or +12 dB with Blu-ray. Head-Fi, May 2018
• 2018-05-25Watts says TT2 addresses headphone power (external amps mostly add coloration) and DAVE driving efficient speakers directly; its 18 watts drives any headphones, and he drives speakers from headphone sockets. Darko Audio 50
• 2018-05-25Watts describes his power pulse array amplifiers in development (200 watts to a kilowatt, single global feedback) and says TT2 uses their output stage, delivering five amps into headphones. Darko Audio 2:10
• 2018-06-17Watts says BluDave cannot voltage clip at +6dB but can current limit into 8 ohms (4.1V RMS, 2.1W), making +5dB the danger zone; quiet recordings may explain the poster's level. Head-Fi, Jun 2018
• 2018-07-03Watts says he drives his B&W 803 D3 from TT2's single-ended output with more than enough volume in a moderate room. Head-Fi, Jul 2018
• 2018-10-27Watts says TT2 drives his 802 D3 from the SE output, lists upcoming events, and says Dave remains well ahead of TT2 in depth and detail resolution. Head-Fi, Oct 2018
• 2018-11-01Watts says 320k MP3/AAC softness is more apparent via TT2 and M Scaler, single-driver speakers are transparent but flawed, and 7W SE suffices for his 803 D3. Head-Fi, Nov 2018
• 2018-11-08Watts says whether TT2 drives the speakers depends on room and volume, noting his 803 D3 work with only the 7W SE outputs. Head-Fi, Nov 2018
• 2018-11-11Watts says his adaptors allow balanced (18W/8) or single-ended (7W/8 ohms) speaker drive, with the green terminal as ground. needs context Head-Fi, Nov 2018
• 2018-11-11Watts says TT2 can drive B&W loads dipping to 3 ohms thanks to supercap reserves and a 10A current limit, and suggests trying 7W SE before balanced. Head-Fi, Nov 2018
• 2018-11-20Watts says the setup should be OK, as the SE amp will see currents from the sub and full-range speakers, fine if both are 8 ohms; XLR gives +6 dB more output. needs context Head-Fi, Nov 2018
• 2018-12-12Watts says TT2's linear output current suits efficient speakers; it gives 7 W, or 18 W into 8 ohms balanced, and has a low-noise low gain mode for IEMs. Pursuit Perfect System 39:38
• 2019-03-28Watts says he is not unhappy with TT2, drives his B&W 802s from it, and was surprised DAVE's lead was so large, from factors other than noise shaping. Head-Fi, Mar 2019
• 2019-08-05Watts says TT2's SE outputs dissipate fine driving his B&W 803 D3 at +6 dB or +12 dB, but balanced quadruples internal loss, risking thermal trips at 8 ohms or less. Head-Fi, Aug 2019
• 2019-10-03Watts explains clipping versus distortion rising with current, says TT2 avoids crossover distortion and current limiters, drives his 803 D3, and display noise is LED multiplexing. Head-Fi, Oct 2019
• 2019-10-17Watts guesses 1W for Hugo 2 and 0.75W for Mojo into 6 ohms, noting Hugo 2 measured 1.05W RMS into 8 ohms at 1% THD. Head-Fi, Oct 2019
• 2020-01-06Watts says TT2 got huge headphone power after complaints about Hugo 2, helping drive speakers, that DAVE and Hugo 2 drive almost any headphone, and no DSP is fully transparent. Head-Fi, Jan 2020
• 2020-07-07Watts says TT2's real PSU is internal (inductor, supercaps, RF filters), recommends XLR pins 1 and 2 for speakers, and warns some subs short pins 1 and 3. Head-Fi, Jul 2020
• 2020-11-13Watts says 4 ohms is too much for Dave unless the volume is at -6 dB or below. Head-Fi, Nov 2020
• 2020-11-23Watts says TT2's balanced output into 4 ohms may thermally trip, restarting once cool, single-ended into 4 ohms won't trip, and Dave would have no problem with the Voxativ. Head-Fi, Nov 2020
• 2021-01-08Watts says TT2 drives efficient speakers single-ended, but XLRs thermally trip into 8 ohms or less; 16 ohms is fine, and amps shorting pins 1 and 3 risk damage. Head-Fi, Jan 2021
• 2021-03-25Watts says TT2's XLR used single-ended into a high-impedance input is fine, but some XLR inputs short pins 1 and 3; avoid balanced loads at or below 10 ohms. Head-Fi, Mar 2021
• 2021-04-05Watts says the DAC's single-ended output drives his B&W 803D3s with ample volume, and describes making speaker cable from twisted solid-core silver-plated wire annealed at 200 deg C. needs context Head-Fi, Apr 2021
• 2021-08-17Watts says 4 ohm speakers on TT2 single-ended are fine, as it suits loads like his 3 ohm B&W 803 D3, giving at most 95 dB SPL at 1m. Head-Fi, Aug 2021
• 2021-08-26Watts says for cabling to loudspeakers use the headphone outputs, or the RCA phono outputs with loudspeaker cable. needs context Head-Fi, Aug 2021
• 2021-09-11Watts says TT2 at +0H gives about 2.25W into 8 ohms, +7H 7W; CDs clip above +7H, but sources with 6dB margin allow +12H, even +18H on his 803D3s. Head-Fi, Sep 2021
• 2022-02-06Watts says he considered an M Scaler mode for DAVE/TT2, TT2's 7W beats DAVE plus power amp, NFM-free treble sounds natural, and he has not started a DAVE replacement. Head-Fi, Feb 2022
• 2022-02-17Watts says TT2 should not use balanced outputs into speakers or loads under 16 ohms as it will thermally trip; single-ended drives his B&W 803 D3 loud enough. Head-Fi, Feb 2022
• 2022-03-08Watts describes his first orchestra recording with a ribbon mic into a Focusrite Scarlett, matching live volume on Hugo 2 and Stealth at blue, and TT2 driving his 803 D3s. Head-Fi, Mar 2022
• 2022-04-12Watts gives the XLR pin standard, says speakers should use the single-ended connection, and warns that pin 3 shorted to pin 1, as some amp inputs do, may damage TT2. Head-Fi, Apr 2022
• 2022-04-12Watts says TT2 will thermally shut down driving 8 ohm loads or less in balanced mode, and anyone not seeing shutdowns does not need the extra power. Head-Fi, Apr 2022
• 2022-07-02Watts clarifies he meant not to drive speakers from TT2's balanced XLR output; using XLR pins 1 and 2 to drive speakers is fine. Head-Fi, Jul 2022
• 2022-07-19Watts says TT2 has no line output: single-ended is volume-adjusted from 0 to 9V RMS and XLR doubles that to 18V, so a sub can be fed from either. Head-Fi, Jul 2022
• 2023-01-03Watts says TT2's XLR outputs trip thermally into 8 ohm speakers, leaving the 7W single-ended outputs, and Hugo 2's second-order noise-shaper amp eliminates crossover distortion. Head-Fi, Jan 2023
• 2023-01-21Watts says he drives small efficient speakers directly from Hugo 2's headphone output when traveling, getting plenty of volume in hotel rooms at a low blue volume setting. Head-Fi, Jan 2023
• 2023-01-23Watts says 8 ohm speakers above 90dB suit direct near-field drive, considers the Mixcube for his office, and credits full-range crossover-less design for its soundstage depth. Head-Fi, Jan 2023
• 2023-02-04Watts says TT2 gives 7 watts into 8 ohms; DX outputs are for future 100 to 400 watt DACs driving speakers directly, a program that has stalled. Dusty Audio 1:01:31
• 2023-03-28Watts says his loudspeakers are B&W 803s, driven directly from his TT2's 7 W output. The Headphone Show 57:24
• 2023-09-29Watts says 7W from TT2 should not damage speakers unless clipping, and a stereo ADC in design will offer SRC-based external word clock sync and possibly Dante. Head-Fi, Sep 2023
• 2023-10-01Watts says he drives directly with TT2s and the Stealths, following his answer that he uses B&W 803 D3s. The Source AV 39:47
• 2024-10-05Watts says TT2's single-ended output drives his B&W 803 D3 speakers directly with its 7W output, which DAVE cannot do, with enough volume even for movies. Head-Fi, Oct 2024
• 2024-10-06Watts says the best pre-amp or power amp is none, cites TT2 sounding the same into an 8 ohm load, and says the large-power DX DAC concept is not dead. Head-Fi, Oct 2024
• 2025-02-25Watts warns that a 0.29 ohm load may damage TT2 before protection acts, and any nominal load under 4 ohms is a no-no. Head-Fi, Feb 2025
• 2025-03-18Watts says it was designed for the B&W 803 D3, lowest impedance 3 ohms, so a speaker is fine if it stays above 4 ohms nominal and 3 ohms minimum. needs context Head-Fi, Mar 2025
• 2025-03-19Watts says a speaker sounds fine to use because its lowest impedance matches his B&W 803 D3. needs context Head-Fi, Mar 2025
• 2025-03-27Watts says TT2's balanced outputs should not drive 8 ohm speakers, as above 7W it thermally trips; balanced is for low-sensitivity 32 ohm headphones or balanced amp inputs. Head-Fi, Mar 2025