Phono Preamp. With transformer or fully active

Hi Jeff,
I can’t answer your question directly but have decided on a Zesto Andros Deluxe that uses 4 internal step up transformers for the MC stage. I don’t yet have my Zesto but have well heard the original Andros at RMAF. It uses two transformers internally for the MC stage. The Zesto sound is super clean, warm and natural sounding, Their room was, by far, the best sounding room at the show. And their system was fairly modest. Not expensive at all but the Zesto Andros made the room sound beautiful. I believe SUTs, in general, make for a super quiet and detailed sound. They are, by far, the best way to step up to MC from MM. And it is, by far, preferable to have them built in. The extra IC is problematic and it is safe to assume that when internally built in, they are a perfect match for the MM stage. My vote is for built in and Zesto. The Andros is modestly priced at $4700. And a big plus is that the Zestos are, IMO, absolutely lovely to look at. They are the best looking component there is... IMO.

Mglik;

4 separate transformers as step up for ?   4 inputs ?    All Mc ?

interesting 

jeff

@rauliruegas 

very interesting on the concept of transformers 
it does make sense 

so, As a general rule 
Transformer step up provide softening of transients ? Vs full active ? 
Jeff

Dear @mglik  :  Dear @mglik  : I have no doubt that you love the Zesto unit that's a tube phono stage design.

Why LP analog alternative needs a phono stage? mainly to apply the inverse RIAA curve eq. and in second place to amplify the cartridge signal.

The inverse RIAA curve eq. should mimic the RIAA curve eq. for we can achieve a flat frequency response. This means with no frequency deviations.

The RIAA eq. is a heavy equalization process that goes from 20hz to 20khz and the eq. from around +,-  20dbs ! ! where any single deviation on that curve affects almost two octaves during the inverse eq. phono stage second process.

From some time now a good phono stage design normally comes with an inverse RIAA deviation of: +,- 0.1db but the Zesto comes with higher frequency response deviation: 0.5db that means it has a swing of 1db that's is to high and that puts additional colorations/distortions to the already inherent colorations/distortions generated by tubes.

The inverse RIAA eq. curve is critical to achieve or to stay nearer to the recording. Normally with tubes is extremely hard task to be " there ".

Yes, tube alternative is an option to the SS alternative.

R.

With one SUT you can't use all MC cartridges, such phono stage is not universal for all MC. It will work for some of them nicely, but if your cartridge impedance is very low (2 Ohm) or very high (40 Ohm) you can't use one SUT for both of them.

This statement is false. The use of an SUT depends heavily on how its loaded at its output. This in turn is dependent on the source impedance of the cartridge.  Transformers transform impedance and this goes both ways. So you can indeed use a transformer with a 2 ohm or 40 ohm cartridge, but the loading at the output of the transformer will be quite different! And its important that this is done correctly otherwise the SUT will not sound right to say the very least.

Most SUTs made for a specific cartridge are designed to be loaded at 47K by the phono preamp, with that specific cartridge as the input. That's why they appear to be 'Use specific'. But if you loaded that SUT correctly at its output you could use it with any cartridge. This is why Jensen Transformers (some of the very best made anywhere) can be used with any cartridge, and they have a chart that shows what the loading on the output should be with that cartridge.


I prefer no transformer at all; I find that even the best SUTs seem to take something away from the detail, even if they have plenty of bandwidth (which most do). Since I run an all-tube phono preamp, this requires that I use low noise tubes. Its a simple fact that if you have a phono section with direct-in capability, whether it is solid state or tube the active devices have been hand-picked. I've noticed with our preamps that people think they can just buy a premium tube off the shelf and expect it to work. While that is sometime true its really a craps-shoot; even a premium tube might not be as low noise as you might expect. With any high performance audio equipment you have to hand pick the devices. But the result is great transparency.