2. analog
  3. 125972-369

Trafomatic Audio Luna LCR phonostage

These days I am looking into tube phono stages a lot. Especially phonostages which are within $5-6k and that can serve in a serious high end system. While I know that solid state phonostages have traditionally been known for their low noise and high dynamic presentation, I still believe that harmonics that tubes preserve (and SS throw away) can be a great asset to the end result i.e music. And if well designed tubes can do low noise and high dynamic range too.

I know that an all-tube 70db phono gain is a steep challenge and while there are manufacturers who have attempted it (e.g Aesthetix, NVO), the response from the users have been mixed. I am more for the conventional approach of using a top quality tube MM stage with a top quality SUT (matched to the cartridge) or FET stage. In this realm there are not many serious options in the $5k range if I look around. The few that I have looked at are:

Allnic H1500 II SE
Luxman EQ-500
EAR 88PB
Herron VTPH-2 
Leben RS-30EQ

Then there are some full function tube preamps which do have very competitive in-built phonostages like the Shindo Masseto, Manley Steelhead, CAT Ultimate etc.

Here is another one that looks like very good contender for a top quality tube phonostage in this budget:
http://www.trafomaticaudio.com/products/luna/

An LCR design using an all-out tube design with interstage transformers and output transformers, so absolutely no capacitor in the path. MC stage is handled by Lundahl 1941 amorphous cobalt core SUTs. This looks like a no compromise assault for this price category. I have not yet heard it but whenever I have heard Trafomatic products I have always come back with a smile. They have been consistently balanced and musical without any typical voicing artifacts. They never sounded like a product that has been hastily put together or built out of a garage. For a tube amp I have never heard them having any hum or noise issues. In fact I have always found his amps to have a very matured sound. In that regards this is a phono stage I am excited about. If anyone gets an opportunity to hear them, do share your thoughts here.
pani
pani OP
1,219 posts
 
Dear Lewm, like you I too fail to understand why transformers (which involve Kms of wires) would be useful in the signal path however some of the best preamps and power amps I have heard are transformer coupled so I am ready accept that I don't know much. For instance the Wavac PR-Z1 is my reference for tube preamps and it is transformer coupled input to output. Similarly for solid state amplification the First Watt F6 is one of my reference and it too is transformer coupled input to output. I also like the top Audio Note preamps which are again transformer coupled. So I seem to have ample evidence that transformers has a case for itself when done right. 
pani OP
1,219 posts
 
I agree that OTL amps are amazing if properly matched to the speakers. I am not sure what happens in the case of preamp though since most preamps are at the least capacitor coupled. 
tomwh
150 posts
 
Hi Pani

I think you might have answered your own question somewhat.  Besides all the number guys and their theory's you listen to interstage transformers and guess what it sounds like real music.  Lcr same thing.  I did not realize that someone had a interstage phono.  I built my own with with interstage and LCR 3 tubes per channel.  Best thing I ever did.

I have built so many tube phono stages I can not remember.  I have played with almost all variables.  But the latest is by far the best.

I do not know how many stages or which tubes or power supply etc.  But it looks like they have the LCR / interstage going for them.

And if nothing else you know you got some expensive iron under the hood not just some caps and resistors.

Enjoy the ride
Tom
lewm
13,010 posts
 
Pani, I think I was misunderstood.  I did not mean for my comments to imply that transformer-coupling cannot work well and sound great. My point was that using a SUT between a LOMC cartridge and a phono stage per se limits the impedance with which you can load the cartridge. This is only because the turns ratio of the SUT determines the impedance "seen" by the cartridge looking in to the phono input. Case in point, the Luna starts at 100R and goes down from there.  Most LOMCs will work fine into a 100R load, but lately it has been my observation that many LOMCs can sound even better with less of a load.  I spent the last two nights, in fact, listening to two different LOMC cartridges with load 47K ohms. I found that I slightly preferred that to 100R or even 1000R. (Load is selectable on my MP1.)

In the case of the Luna, and without having seen the schematic, I wager that the interstage transformer was necessary for the sole purpose of reducing the output impedance of the stage driving the LCR correction circuit; the impedance has to match that of the LCR module, and most require 600R, although in recent years LCRs that need to see higher impedances have been devised, when the needed inductors can be precisely wound.  This is not necessarily a bad thing; it just is what it is.

lewm
13,010 posts
 
Pani, Also, prepare yourself for the onslaught of the Herron-lovers. There are many of them here, so many that I don’t doubt its excellence. Keep in mind that the Herron uses an "old fashioned" CR type of RIAA correction and no transformers in the signal path. There are many paths to Nirvana.

(I still want to hear the older Trafomatic phono that places the RIAA correction in the plate circuit of the input tube.)

Tom, Have you posted the schematic of your "interstage LCR" phono design? I certainly remain interested in LCR and even LR phono correction.

More to discover