Post by Owen Y on Jul 18, 2018 19:35:34 GMT 12
Chaps - I should mention this relatively inexpensive but v good (IMHO) MM phono stage - for discussion. I bought one of these (US$300 for the basic Lounge LCR) almost 3yrs ago from Lounge Audio (Robert Morin) who designs & manufactures in the Los Angeles area. I already have an all-valve, DIY all-out phono preamp, so why? Well, LCR phono EQ is a sort-of 'holy grail' of phono EQ. Using inductor coils (L) + caps(C) + resistors(R) - instead of the usual RC EQ. My understanding is that: - RC networks tend to be less efficient, there are losses & more gain is needed. - importantly (maybe because of the lower impedance of inductors at mid-lower freqs, I'm not sure) LCR phono sounds good - my experience too is that inductors seem to deliver 'power' well at these freqs, compared to RC circuits or R devices. However because of the extra cost of implementing LCR (eg with high tolerance coils req'd), there are only a few & generally horrendously costly LCR phono preamps - eg. Aurasound Vida, Zanden, Allnic, Ypsilon, AudioNote, Silbatone. The Lounge LCR is the only 'affordable' LCR phono that I know of. Below is the RIAA EQ curve (to flatten the RIAA pre-tailored recorded signal on record): As we know, bass needs to be boosted 20dB(10x) & treble reduced 20dB, in general terms.
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Post by Owen Y on Jul 18, 2018 19:45:30 GMT 12
And here, the Lounge Audio LCR phono. Unboxing.... The unit is not big, measuring 190 x 146 x 76mm approx. Supplied with a 16vac/500mA wall transformer 'powerpack'. (18vac powerpack in USA.)
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Post by Owen Y on Jul 18, 2018 19:57:11 GMT 12
Installed (late 2015): (With Fidelity Research FRT-4 SUT attached behind - for the MC cartridge in use at the time.)
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Post by Owen Y on Jul 19, 2018 12:29:07 GMT 12
Inside (mine is a 'MkI' version, now manufactured in a MkIII version): No tubes, all solid state, lots of PSU stuff, lots of regulators, you can see the RIAA coils at the rear, 2 big framed ones for bass correction, 2 small round coils for the treble pole. The gain device is one class-A biased high speed opamp per channel. The chassis is solid, but utilitarian, with some moderately audiophile touches - ultrafast rectifiers, Panasonic FM, polyprop & silver mica caps, film/foil resistors, careful grounding design. 40dB MM gain. No pF loading options. Pictured with my 'Phi-42' vacuum tube phono stage....
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Post by colinf on Jul 19, 2018 21:46:15 GMT 12
Nice approach to Riaa eq. And it’s affordable!
AMR-iFi R&D
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Post by Owen Y on Jul 20, 2018 12:58:18 GMT 12
Sound: My original intention was just to hear an LCR phono stage & possibly later incorporate LCR into my own DIY tube phono stage. As I was using a MC cartridge at the time + Fidelity Research SUT, this fed the Lounge LCR's inputs. I thought that transparency & soundstage height & width were only average, but LF power & weight was v good - 'visceral' & appealing. System tweaks then took precedence (tonearm, turntable, power amp mods, phono stage PTX failure/replacement, new tweeters....) for a year or two. Just recently, with the introduction of a Decca London cartridge & my tube phono stage undergoing major surgery (separate PSU), the Lounge LCR was brought back in. Firstly fed by the Rega Planar 3 (as recent restoration thread) & MM cartridge, bass again was strong, overall tone was warm, HFs lacking some sparkle (spherical stylus). But the dynamic characteristics that I heard are rare - open & 'expansive', huge 'scale', music 'breathes' easily - like live music does. Now fed by the Decca cartridge, I'm hearing good things - it's a long time since I've heard piano as impressively dynamic, strain-free, powerful. The Lounge plays LOUD with ease, strain-free. (This is a great recording in this regard....)
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Post by Owen Y on Jul 22, 2018 15:44:45 GMT 12
Robert Morin explaining some of the technical features of the Lounge LCR MkIII version of this device: As soon as I get my act together, I'll be intrigued to take up Robert's offer to upgrade my LCR 'MKI' at minimal cost.
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Post by Owen Y on Jul 23, 2018 11:18:22 GMT 12
The only deficiencies I think I've found are (bearing in mind in comparison with pretty good tube preamp, multiple times the parts cost): - 'transparency' is only so-so, backgrounds perhaps not so quiet or 'empty' (although the tube unit has a bit of PSU hum). - centre images a little less focussed, more 'smeared'. - not so dramatically 'quiet', a little less 'dynamic drama'. - soundstage a little less 'wide' & less sense of depth 'layering'. However, again, dynamic 'headroom' & LF power, 'authority' is especially good, addictive even. Treble clarity is also v good. Rich tone, with lots of 'ambient decay', sustain. Music 'breathed' with this thing.
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Post by Owen Y on Jul 23, 2018 12:46:13 GMT 12
The Lounge LCR is not a phono stage that screams 'detail, detail'. It excels at what inductors are good at, providing low impedance esp. at the lower frequencies, delivering 'power'. Midrange & LFs 'breathe', music 'ebbs & flows', has rhythm, tonal warmth, weight & harmonic richness - that's rare, IMHO in 'hifi' gear. My original plan was to just sample an affordable LCR phono, but this wee box is becoming addictive
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Post by Owen Y on Mar 30, 2019 19:04:48 GMT 12
At long last (with the Xmas delay) the Lounge Audio LCR has arrived back, essentially upgraded to LCR Gold specif (& a bit more), but without the headphone socket or vol control. The interior now almost unrecognisable - stacked with Russian Teflon film/foil & silver/mica caps. Vishay bulk foil resistors in selected positions (Vishay Rs have not been to my taste in the past, but I'll trust Robert's ears). More attention to the PSU power delivery, more direct point-to-point connections, solid silver buss wire, higher current capacity larger format transistors & rectifiers Gain increased from 40dB to 47dB. Also Bass/treble trim pots for trimming LF rumble rolloff + Neumann 4th pole (the latter I've experimented with briefly myself & discarded, but does appear in a few phono stages, eg Sutherland, Aqvox, CH Precision, Gold Note). (The rear now sports a Mono switch.) (Russian teflon /foil caps.) (Russian silver/mica caps.)
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Post by colinf on Apr 5, 2019 18:19:12 GMT 12
Looks pretty busy in there! I’ve been using those nos Russian silver micas for years, they sound transparent. The teflon coupling caps are quite lively sounding. Have you had a chance to listen to it yet?
AMR-iFi R&D
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Post by michaelw on Apr 7, 2019 12:41:49 GMT 12
busy and messy ! hope it sounds better than it looks
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Pundit
Post by belbo on Apr 8, 2019 3:19:50 GMT 12
I did consider the Lounge at some point and looks like the latest iteration is even better. Having said that I think your "Phi" tube phono Owen looks absolutely fantastic (I'm sure it sounds similar too lol)!
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Post by Owen Y on Apr 8, 2019 11:07:53 GMT 12
Yes it sounds like a completely different unit. Whilst the original (MkI) Lounge LCR provided some of the positive sonic characteristics of LCR EQ to an enthusiast, the overall performamnce might not appear 'spectacular' to most punters looking for a impressive phono stage. With the LCR MkIII, Robert Morin up-rated many PSU areas - Hexfred rectifiers, Panasonic FM reservoir caps, Russian polystyrene caps, bulk foil resistors. Then their LCR Gold version adds a headphone socket + volume control. Also lower impedance solid silver PSU supply bus wires higher current regulators, more point-to-point component connections, ultra-direct PSU decoupling caps, better quality foil caps & Rs, 'Neumann 4th pole' RIAA correction. This upgrade has some added features - mono switch, LF & HF trim pots for RIAA EQ, gain increase from 44dB to 47dB. Additionally, heavier gauge silver PSU bus, bulk foil main Rs in the RIAA filter, additional Teflon bypass caps, higher current snubber resistors & recifiers. (If you think the top side PCB looks busy, the underside. with its solid gauge PSU links & point-to-point soldered components, looks equally busy.) Early days yet (the caps take some time to 'run in' they say) but there is much more 'air', openness, more effortless transparency, more nuance, more treble extension, sparkle, detail. Image focus as a result, is of course much improved. As said, early days. (Compared to my original LCR MkI.) Whilst I have a special attachment to my Phi-42 tube phono (& the original intention was to learn about LCR EQ via the inexpensive Lounge LCR unit & later incorporate LCR into a tube cct), I feel no urge to go back to the tube phono at the moment.
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Post by Owen Y on Apr 8, 2019 11:50:42 GMT 12
IMHO, the thing about audio components is that you can have all the technical understanding & innovative ideas, but unless the designer has a good ear.... Every component bears the sonic signature of its designer.
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Post by colinf on Apr 9, 2019 1:39:59 GMT 12
Yes! Although circuit design and topology have a major influence on the sound and the distortion, so do specific parts and grounding layout and quality. I made 2 versions of the same 211 SET poweramp circuit. One was a prototype built roughly but sounded ok. The second one used exactly the same parts but was built using silver grounding. It sounded (and sounds) much better!
AMR-iFi R&D
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Post by Owen Y on Sept 19, 2019 9:34:32 GMT 12
A while back, I contacted Robert Morin (designer/owner of Lounge Audio) about how he sets the RIAA EQ of his LCR phono preamps & why the RIAA EQ is sometimes set slightly different from official RIAA curve. Robert linked me to some videos he's made, explaining his approach to this aspect of the Lounge LCR, LCR Gold phono stages: Of interest are his comments about subjective treble (20kHz) & bass (200Hz) response, & LF rumble (20Hz). And how to adjust the LCR phono EQ, if you can and/or wish.
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Post by colinf on Sept 20, 2019 2:46:42 GMT 12
Interesting that he raises the 20kHz by 0.6dB (ref to 1kHz), asked for by his customers. I’ve been raising the hf slightly too, it seems to be system dependent but generally just a smidge, formed by listening to it. Robert Morin has it nailed to 0.6dB! I wonder how that affects the 50kHz response?
AMR-iFi R&D
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Post by Owen Y on Sept 20, 2019 9:44:30 GMT 12
Robert also implements the '4th Neumann pole' on the LOUNGE LCR & LCR Gold phono preamps. As you'll know, this additional tweak to the standard RIAA curve (arguably to compensate for cutting lathe roll-off above 50kHz) is controversial. I tried it a while back in my DIY tube phono (using Shinkoh Tantalum film resistors + film cap) & did not care for the additional brightness & removed it. However, Robert says to use carefully chosen carbon film Rs & to allow for burn-in of the R & cap. Initially yes, this phono was a bit 'ear-catching', but now with some hours on it (& powered up 24/7), it's a very rewarding phono stage.
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Post by Owen Y on Feb 28, 2020 19:21:04 GMT 12
3 yrs after getting the basic Lounge LCR & a year after upgrading to LCR Gold specif, my interest in this phonostage hasn't diminished. It does well in an area that matters lots to me - dynamic freedom - it 'breathes' & alows delivery of power in the mid-lower spectrum with openness & freedom that sounds 'real'. I'm unconcerned that this is achieved via an opamp chip in this unit (versus tubes as in my previous phonostage).
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Post by Owen Y on Feb 28, 2020 19:33:48 GMT 12
One thing I've been planning to do for a while... These relatively inexpensive Lounge Audio LCR & LCR Gold MM phono stages (now US$340 & $720) are supplied with a small 'wallwart' 16VAC / 500mA AC Adapter (transformer type, not switch mode), which delivers around 19V raw AC to the phonostage, which has its DC rectification & regulation on board. But I have (a couple of) these toroid TXs, scavanged from German HELL printing machines from the 90s. I'm guessing they are 20-30VA TXs - around 5x current capacity vs the wallwart. This one delivers ~21VAC & I figured that the LCR regs would have no problem tolerating a couple more input volts. [Edit: Actually as you can see, a 21-0-21v C-Tapped sec, so I'm using half the output winding.] Wiring up & swapping out the 'wallwart', the result is that the LCR Gold seems to plumb down another 1/2 octave in range - more LF extension, weight, ambience. PSU capacity, impedance-lowering improvements always seem to deliver nice results.
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Post by colinf on Feb 28, 2020 20:39:17 GMT 12
Interesting! See if you can play with the length and quality of the AC cable too. I normally use a 16v wall transformer for my own SS phono stage and swapping it for a larger toroidal made it do much the same...more authoritative. A shorter connecting cable made it sound smoother.
AMR-iFi R&D
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Post by Owen Y on Feb 29, 2020 11:06:58 GMT 12
Ah yes, presently this PSU experiment is draped across the floor on a long extension from an across-room power socket, so thanks, yes I'll devise a more tidy, short arrangement.
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Post by Owen Y on Feb 29, 2020 11:10:41 GMT 12
The toroid hums a little, so I'll try the other one that I have. Maybe also insert some rubber under the TX. Do you think that using a half winding would affect vibration-hum?
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Post by colinf on Feb 29, 2020 20:30:06 GMT 12
It’s ok if you use one winding only, the other can be left floating. Toroidal power transformers suffer from having the core magnetically saturate easily from dc on the mains. Any 2nd harmonic distortion on the mains (usual) results in a slight dc bias. The result can be physical hum, sometimes loud, sometimes not too bad but not fixed in level. To help that you can add a small network in series with the primary, consisting of a high value, low voltage cap (say 4700uf) in parallel with two diodes in series connected back to back (four diodes total). That will allow for plus or minus 1.2v of dc offset.
AMR-iFi R&D
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Post by Owen Y on Apr 3, 2020 16:38:59 GMT 12
colinf - I have now done the following: - replaced the temporary extension cord + short 10A mains cord, with a heavier 15A mains cord (to a closer wall socket). - replaced the 2+m 2-core lamp flex output cable (from the PTX to the phono) with a longer 2-core cord which I stripped from its TPS sheath & twisted. The result is a more 'authoritative' overall sound (as you say, slight but noticeable). This was done on an identical PTX, swapped in, but some hum is still there - I tried remounting the toroid on new rubber, but to little effect. Overall, the system now, with the SP-10 TT is playing classical music in particular, sounding the best I've managed to date.... (Achieving a satisfying classical reproduction at home is something I've been working at since the early 90s when I sold my LP12 .) 1) LF power significantly improved. 2) Ambient decay/clues more audible & satisfying (related to the above aspect I think) 3) Instrumental separation within the orchestration much better & maintained at all levels 4) As a result of 3) above, the 'architecture', 'structure' of compositions is much clearer & more readily appreciated (something that is really useful with abstract music like classical). 5) A 'bigger' overall sound, 'scale'. 6) Tonally 'richer' (eg. less dry kick-drums). 7) HF bandwidth, presence, is more 'open' -seemingly enhances image 'height'. Anyways, you get the picture
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Post by colinf on Apr 4, 2020 18:58:15 GMT 12
Glad you’re enjoying it! Interesting the difference a power cable makes. I wonder if you can run the Lounge Audio phono on batteries to avoid cabling altogether? Being opamp-based it would need + and - 12v to 18v, depending on if there is regulation inside.
AMR-iFi R&D
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Post by Owen Y on Apr 4, 2020 19:45:52 GMT 12
Batteries - yes, quite an exercise to implement I'd imagine...charging... Yes rectif & regulator/s onboard.
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Member
Post by gnnett on May 12, 2020 19:32:27 GMT 12
The toroid hums a little, so I'll try the other one that I have. Maybe also insert some rubber under the TX. Do you think that using a half winding would affect vibration-hum? Can I suggest removing the question regarding using half the windings by doubling down on the original phylosophy and halve the load on the transformer secondary, by using both secondaries in parallel? Unless of course you are using the centre tap of a single winding. Cheers Grant
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Member
Post by gnnett on May 12, 2020 19:36:43 GMT 12
The toroid hums a little, so I'll try the other one that I have. Maybe also insert some rubber under the TX. Do you think that using a half winding would affect vibration-hum? Unless of course you are using the centre tap of a single winding. Cheers Grant Which of course looking at the photograph is the case. Sorry for the distraction. 😔
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