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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

Showing 4 responses by tomwh

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
tomwh
150 posts
 
Lewm

I do not schematic software.  But a quick over view.  It is a 3 stage with the Riaa correction between the 1st and 2nd tube.  The 3rd tube can be 2a3 1 to 1 out and still have low output impedance.  Or your use a higher gain tube 2 to 1 step down to get a lower impedance. On the first 2 tubes I am using diode bias and the 3rd is fixed.  Each tube has its own choke tube power supply.  And separate filament power supply for each tube.

I am using Dave Slagle 7k chokes for riaa so opens up many tube options.  In regards to sut loading I have a separate box with 4 pair of different suts and replaceable resistors to load before after or both.  So I can go from 0 to anything.

The reason I posted here is it sounds like Pani is looking for something that has body and soul.  If hi fi was his thing the options are endless.  I realize pretty much no one wants to be over the top like what I built but I think the interstage/lcr is going get you pretty close to a home run!!!

Enjoy the ride
Tom
tomwh
150 posts
 
Lewm

It is fun to go through a mental process and or research.  But when it is all said and done we have to listen to our decisions.  The only reason I I posted was from Pani post it sounded like he could hear what interstages could do.

If you need to prove to your self that interstages are a waste of money without listening to them;  besides the band width issues your can not hold the riaa adjustment as close as with a r/c circuit.
Maybe Dave Slagle non LCR phono stage.  I am pretty sure he is using lower impedance tubes so he can reduce load resistor values.  He thinks you can get pretty close to a LCR unit.

If you are interested on how build and or understand phono stages Morgan Jones second or third ed. Valve Amplifiers is a must have.  He is very much a numbers guy but is very through.

Once you get a understanding of tube amps you will see there are not that many variations as the marketing department would lead you to believe. In fact in all the experiments I have done the simple circuit is the best.  No ccs tube or transistor.  No cathode followers.
No grid stop resistors.  No cathode bias caps you get the idea.  Been there done it more times than I like to remember.

So if Pani is interested if he can find out how many stages and who's chokes and transformers.  Also tube types.  Maybe it will help you with your concerns.

Enjoy the ride
Tom




tomwh
150 posts
 
Pani 

Loading a cartridge has to be done regardless of sut.  Most people add one on a mm phono which normally has a 47k load.  So the transformer is now loaded on the secondary.  So now the load on the cart is affected by the turn ratio of the transformer.

So with out getting into the math or theory let's just say most carts sound different when you change the loading. If the phono stage does not have a adjustment for this I would find out what it is and see if the cartridges you use match up pretty close. 

Enjoy the ride
Tom
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