MFA Luminescence MC Reference preamp

Hello Mike. As an owner of a luminenscence, a few things should be addressed if you are thinking of acquiring one.First:If your system is biased toward vinyl; as mine is,retubing becomes a very important issue as the currently made octal based tubes are a total waste of time sonically in the Lumi, acquiring quiet nos 6sn7's and 6dn7's are not only a very expensive investment but a giant crap-shoot at best.The Lumi is extremely critical to the tubes used "especially" the 6sn7's.That particular type of tube is very very prone to microphonics,so much so that more than half of them are unacceptable in the Lumi.I have another preamp[the supratek syrah] and two amplifiers that employ the 6sn7 and most of my nos tube stash sound terrific in the syrah, whereby when used in phono stage of the Lumi...they just don't cut it. The syrah uses the 6sn7 for gain in the line stage only and the amps mentioned above employ it only as a driver stage for an 845 triode.Phono gain is another animal altogether as noise becomes paramount when driving low output moving coils!Re-tubing can become a very frustrating experience.The highly regarded Kenrad black glass vt231...while it is my tube of choice in the syrah,does not seem to like the lumi!The early 50's Sylvania gt versions sound fabulous in the lumi and mediocre in the Syrah.Go figure? That being said:When optimized with low noise tubes-- I personally believe the lumi to be one of the finest preamps ever made and one that can compete with ANYTHING out there, regardless of price.As TWL mentioned,when updated with caps,gain pots and a few reistors here and there, it then becomes next to impossible to beat.Further more... its circuit topology is a very straight-forward and lends itself to updating its passive parts- the circuit does not use any boards and is all wired point to point with lots of room in the chassis for changing caps or any other passive parts.I am currently using a shelter 501mc and I can honestly say that the 501 sounds more organic through the Lumi and potrays a larger volume of space on the stage than the Syrah.I am anxiously waiting for the return of a Koetsu rosewood that I have sent to Japan for a rebuild. I am speculating here, but I believe that the lower the output of the cartridge,the more difficult it will become to optimise the preamp. Hope this Helps! Cheers David

Ecclectique- it shouldn't be surprising that the Syrah using 6SN7s in a transformer coupled line stage is less demanding on tube quality. The 6SN7 has less gain than
6SL7/5691 used in the phono section of the Lumi.

The best tubes I found for the Luminescence phone/line sections were the brown base RCA 5691/5692s.

Good luck with your Koetsu

Great technical informations from everyone, thanks to all.

I'm considering purchasing a new preamp that I'm familier with, and the ones that I've heard and liked are: Hovland HP-100 and MFA MC Reference.

Since I'm a big analog guy(4,000 lps and counting...)MC Reference is my first choice due to the great phone/line stage it has(as you all mentioned) and can be modified/repaired easily locally.
But on the other hand Hovland has more of the modern appeal with pretty good phone stage of its own and is quite affortable on this site(around $4K).

Decisions, decisions........

Hi Mike.I would have to concurr with Kana as well.No miniature triode based preamp I have ever heard seems to capture the "soul" of the music quite like a well designed octal tube preamp.I have owned the CAT sig mk2,various versions of Audio Research preamps... from the sp-3a,on up through to the sp-10 mk2,[still in use] the Klimo Merlin as well as the new supratek syrah.ALL of them very highly regarded and while they all make beautiful music.....the Lumi is still "THE reference" in my rig[phono only].Of all the above mentioned preamps-the Klimo Merlin was the closest overall to the Lumi through the phono stage and I want to point out that my observations are based on the phono stage ONLY.Cheers

Hello fellow audio-nuts. While you have most of the facts right, you've got some of them wrong. There was a preamp from MFA called "Luminescence" (I have two. One early pre-production A and a heavily moded B1), with various versions (A, B, C etc). There was a "Venusian", and an "MC Reference", both of which were NOT Luminescences. Lumi was the only one to my knowledge to use octal base tubes, and was dropped only for the reason of unavailability of inexpensive low-noise octal bases for the phono. MC Reference was actually a hybrid (technically speaking) design with heavy solid state regulation. Very rare and expensive in $5k range for a used one. Venusian I've never heard nor seen but I don't believe it used octal bases, I may be wrong here, but it was definitely not called a "Luminescence Venusian". Thanks for the forum, Mark