Post by Owen Y on Apr 23, 2020 10:51:21 GMT 12
LUXMAN's new flagship preamp - reviewed by STEREOPHILE's Art Dudley. Possibly Art's last component review? Features: - Vacuum tube design with output transformers, SS PSU - Phonostage, MM & MC, 38-66dB overall gain - Tranaformer attenuator (dual 34-step) volume control (relay switched). - 24.4kg wt - Cost US$20k An other-worldly costly product, but interesting to see what design features that LUXMAN consider important in their best preamp. And an interesting sonic comparison with the SHINDO Montbrison preamp (US$12,500?)  
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Post by colinf on Apr 23, 2020 18:19:20 GMT 12
Wow now that’s a volume control!
AMR-iFi R&D
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Post by cartridgeguyonline on Apr 23, 2020 19:26:29 GMT 12
Never gonna fit that inside your preamp bud !
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Post by Owen Y on Apr 23, 2020 19:31:09 GMT 12
Look at all those relays  (As I think I've mentioned, my experience with relays, G5V? small signal Omrons, wasn't good, it put me off using relays in the signal path. There may be better ones to use, I don't know.)
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Post by michaelw on Apr 24, 2020 12:43:54 GMT 12
damn... that monster eclipses the lyra connoisseur volume control.
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Post by Owen Y on Apr 24, 2020 13:51:54 GMT 12
Not too dissimilar to my Transformer Vol Control implementation in my original linestage  ...  
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Post by Owen Y on Apr 24, 2020 14:19:06 GMT 12
You'll note that LUXMAN provide in-built 'demagnetisation' of the transformers inside this preamp - automatically at turn-on, or via a front-panel 'Articulator' button... " Our deep experience in signal path transformers has alerted us to a significant downside: residual magnetic fields in the cores. For this reason, the CL-1000 oscillates and demagnetizes the transformer cores every time you turn the power on. For an even higher degree of sonic purity, you can perform manual demagnetization using the Articulator switch. " See LUXMAN CL-1000 webpage.  Demagnetising MC cartridges, yes, but I haven't thought about demagging say TVCs or OPTs. Or 'system demagnetising', not since I last used the The Exorcist: 
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Post by colinf on Apr 24, 2020 18:44:18 GMT 12
That’s a first in a preamp TVC afaik.
AMR-iFi R&D
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Post by michaelw on Apr 25, 2020 12:58:56 GMT 12
i've seen built-in demag in phono stages (aesthetix, luxman) but don't recall any full function preamps with this feature.
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Member
Post by chilli on Apr 30, 2020 14:28:58 GMT 12
That's some interesting preamp vol control there. I think I better catch up on my stereophile reading. This looks like an interesting product!
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Post by deano1974 on Apr 30, 2020 16:42:28 GMT 12
What a beautifully engineered pre amp, I would happily be able to live with that Misses might shot me when she asked how much it cost lol
Manager & Product specialist at Rapallo AV & HI-FI
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Pundit
Post by raveydave on Apr 30, 2020 18:45:17 GMT 12
Misses might shot me when she asked how much it cost lol I had the pleasure of spending some time listening to the Luxman LX-380 last year, while auditioning some Living Voice speakers. This little 6L6 amp was quite impressive, and also incorporates that fancy LECUA volume control... but it didn’t come cheap!!!
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Member
Post by chilli on May 4, 2020 20:54:38 GMT 12
Look at all those relays (As I think I've mentioned, my experience with relays, G5V? small signal Omrons, wasn't good, it put me off using relays in the signal path. There may be better ones to use, I don't know.) Owen. You attempted to make a resistor relay volume control? I have seen some attempts with using Omron G5v. However, I had a look at the luxman website for better pics and it looks like they're using Takamisawa. I have seen quite a few cheap and expensive Chinese vol controls using this brand. Mostly DIY mass produced, but a couple of expensive smaller places as well, some using jfets with them and even dsp and ways to avoid the clicks. Recently, I saw that Gustard has produced a preamp using Nexem (prev NEC). Sorry, I realise this doesn't really relate to the Luxman that much but couldn't find a post to put this.
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Post by Owen Y on May 4, 2020 21:08:56 GMT 12
Hi chilli - sorry I could have explained that, on my first line preamp build, I used relays for input switching. I used a rotary switch to switch the 5v relays on/off. The idea was to avoid taking the signal from the rear input sockets up to the front panel Input Selector switch, before feeding the 1st preamp stage. ie Shorter signal path. However, I found that a rotary selector switch (just a regular Lorin silver contact job), sounded better, the relay robbed significant dynamics from the sound. (The relays were 'small signal' types, but I did not try any others.)
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Post by michaelw on May 4, 2020 23:19:00 GMT 12
i loved the feel of the stepped attenuator (using vishays) in the pureaudio control preamplifier, beautifully precise with a very satisfying click, click. i once asked gary if it could be fitted to my integrated. the answer was no, it's a hugely expensive piece ($100's per channel) and there's no room in the one chassis. 
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Post by Owen Y on May 5, 2020 10:26:10 GMT 12
If it was a full 'ladder' attenuator, there would be 2 x resistors at each volume setting & thus 50 - 100 resistors in the attenuator - per channel! Yes, prohibitively expensive. Even a 'series' attenuator would have say 25 - 50 Rs per channel - but series attenuators are disadvantaged by having many Rs in series in the signal path. The best resistor attenuator I've tried was a DACT ladder attenuator using SMD Rs (I was surprised at how much better SMD Rs sound vs traditional Rs (with end-caps & wire leads).
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Post by colinf on May 5, 2020 19:57:29 GMT 12
You can make an 8 bit shunt volume control with 256 positions with only 9 resistors and 8 relays per channel. And digital control circuitry of course. I’ll be designing one shortly. I agree, SMD resistors generally sound better in the signal path, and are far cheaper. Accurate ones are now the industry standard and are made in vast quantity which makes them far less costly too. They have much smaller power ratings than normal through-hole resistors though, a consideration when used in dc positions.
AMR-iFi R&D
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Post by Owen Y on May 5, 2020 20:47:35 GMT 12
This is a DACT stereo attenuator that I had back then, with SMD Rs, built on nice Swiss Elma gold-plated switches. (Possibly one for the I-wish-I'd-never-sold file )
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Member
Post by chilli on May 5, 2020 22:56:16 GMT 12
Thanks for clearing that up, Owen. Interesting that the relays had an effect on the sound. Not sure whether I'll pull the trigger on trying a volume control this way. My integrated has a relay and has the old clicking sound. Sound is good though.
Hearing the way you guys talk about the steps in your volume controls reminds me of my tvc. Very satisfying springiness in the dial movements. Perhaps we could all empathise with the late author, when he said the Luxman didn't have a remote..
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Post by Owen Y on May 6, 2020 9:10:07 GMT 12
Oops, forgot to add pic of the DACT ladder attenuator: 
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