Step Up Transformer Question

@rmdmoore A VAS Cartridge as you are investing in, is a bespoke built Cartridge. It is being produced by an individual who's reputation is recognised for both Cart' Overhauls and Scratch Built Cart's across the Globe.

Taking time for selecting the SUT or Head Amp to support it in use will be a worthwhile experience.

Adding to your considerations for a preparation, the general consensus is to keep connecting cables between the SUT / Head Amp and Phon', as short as possible.

As you have made known, the PA 2 has a inbuilt SUT used in combination with Tubes.

My experiences had with both owned and loaned SUT's and Head Amps is that the SUT can create a range of effects to impact on the perception of the Tone being produced. The SUT depending on model in use, can be perceived as creating an increase in Richness, ranging from a subtle influence, through to a very noticeable Bloated bottom end of the frequency range.

I have less experiences with Head Amp Models, and from what I have experienced, I am able to describe the effect of the Head Amp as being much more transparent as a influence in a comparison to a SUT. A Head Amp's influence in relation to certain SUT's could be described as the Anti Thesis of such models of SUT. 

All the above is based on my experiencing a variety of Models/Designs in the home system.

The Company Sculpture A has a range of SUT's, that are offered with a broad range of winding ratio's. I have been demo'd a few Sculpture A SUT's in a system I am very familiar with and one that shares similarities to my own. 

On the day of the Demo's a Sculpture A Copper and Silver Winding SUT was loaned for the experience. The Copper Winding was a perfect match for a 0.2mv Cart', which is the resident Cart's output.

The impact this SUT had on the system in comparison to the resident SUT was quite something, the transformation of the sonic has been notable and well worth making known to others.

The Silver Winding SUT was more aligned as a match to a 0.5mv Cart', but was still able to off something quite special and as well notable for what it could present.

I am left with two questions, as new to me electronic encounters had been had. 

1, How much does the Cart' matching offer to create such an impressive demo'.    In general this will be the suggestion that will be off the most importance

2, How much does the use of a Nano Crystalline Core Metal add to the impressive sonic produced.                                                                                                        As it is not a commonly experienced material in use, it is difficult to tie this one down. 

The overall outcome is that, Sculpture A SUT's are devices on my short list to be a home trial.  

I got my 1254's as apart of a Group Buy during COVID. The report was these were Hand Wound Versions due to the workforce being very limited. I got these for approx' $300 shipped to the door. The final build was approx' £400 inclusive of Pure Copper Low Eddy RCA's used on the chassis. 

The Hashimoto SUT built to a very similar Spec' was short of £500

Both prices are in keeping with the monies the OP is considering, It is not known if a from scratch build is something they would consider.

My encounters with Pure Copper Low Eddy RCA's in use, is generating the notion making the use of such connectors is a must for any DIY Builds or Upgrade Works undertaken.

To get the full benefits, Cables used with the Chassis Mount Low Eddy RCA's are noticeably better when terminated with Low Eddy RCA's as well. 

@rmdmoore When using a SUT there is a possibility Hum can occur.

One cause of this can be using a RCA Connection that does not have a good bite.

The most simple method to try to remove/ substantially reduce a Hum, is to move the SUT around in relation to the Phon' and TT. Typically a movement away from both will start to create a change to the level being heard.

As short Cables are recommended between SUT > Phon' the movement of the SUT with a short cable may not be enough to have an effective control.

It has been a very long time since I done this, but in the past have also had good success using a very small gauge earth wire to bridge across connectors on the SUT. From recollection the Bridging has been done in line and not across channels. 

As for Cable selection, for quite some time now I have been an advocate of a Cable using PC Triple C wire for the Signal Path. My recommendation for RCA Connectors are outlined in a earlier post.    

@dogberry In a earlier post on in this thread, I make it known how impressive the Sculpture A SUT has been as a Copper Winding and produced as an ideal match for a 0.2mv Cart'.

In the same session a Silver Winding SUT from Sculpture A that was not the ideal match, was also used on the same 0.2mv Cart', which proved to be equally impressive for different reasons for how it produced a sonic.

From all of my experiences had using SUT's, these are the most attractive I have from recollection.

Using ones ears to assess whether the interface is an attraction or not, really does seem to be the method. 

I have had SUT's demo'd that are ideal matches for the Cart' in use, where there is noticeable overbearing perception of Bass Weight being produced, as well as a unattractive Looseness of the Bass Notes. Certainly not my flavour of choice.

@rmdmoore I would have to get it confirmed by the individual who loaned the SUT's for the Demo's but do believe the Sculpture A with a Copper Winding was 1:26 Ratio.

The nano crystalline core is not too commonly seen on audio, and it is this material, that certainly seems responsible for a proportion of the standout impression made.

Lundhal are offering this Core Type on some of their designs for a Tranx. 

Amorphous is not Crystalline.

The following is a bit of other forum talk on the subject.

"According to Per Lundahl, writing by email, "Choice of core material is a question of taste. Our top-of-the-line MC transformers are available with either our uncut amorphous strip core (like the LL1931) or with a conventional mu-metal lamination core (like the LL1933). As it has turned out, the amorphous-core transformer is most popular, but the mu-metal lamination transformer is still preferred by some audiophiles. In THD ... and linearity measurements, the mu-metal lamination version outperforms the amorphous core version, but in listening tests, the amorphous core usually wins."

"I asked Per to explain the metallurgical differences between mu-metal, amorphous cobalt, and nanocrystalline transformer cores."

"In true amorphous material, there should not be any crystal structure. Atoms are randomly oriented, and there is no repeated structure such as you find in most solid metals. To achieve this, the melted metal is cooled so rapidly that atoms get stuck in their random positions. ... This very rapid cooling requirement is the reason why amorphous metal is only available as thin film, about 1 mil (0.025 mm) thick.

"To achieve nanocrystalline material, special amorphous iron is carefully heat treated at very controlled temperatures. In this process, very small [nano]crystals are formed."

 

@rmdmoore As stated in a earlier post in this thread and in another thread very recently.

I am a user of Valve equipment who much prefers the end of a Valves produced  Sonic that leans heavily towards transparent.

This has made me inquisitive and searching for items that assist with keeping the sonic where I prefer. As stated, I have been demo'd numerous SUT's across many years and state with full conviction in my system and in other systems, SUT's add Richness to the Sonic being produced.

In some cases it is a subtle underpinning of the Sonic, and at the other extreme, the sonic can be Bass Laden and very very loose in its shape and roll off.

My 'Gut Intuition' strongly leaves myself feeling the use of a Nano Crystalline Core has reduced the perception of Richness using a Copper Winding to the least I have detected it. Also the impact it had on the Cart' was quite something, the sense of effortless function and the projection of the sonic, had one feeling the system had gone through a very expensive upgrade. The system it was demo'd on has been via a Valve Phon' close to my own in use design, a Pre Amp' that shares very similar design to the Model I am having produced, EAR Valve Power Amp's and ESL Speakers. This system has similarities to my own inclusive of the ESL's.

As stated the Nano Crystalline Core with the Silver Winding that was not a ideal match for the Cart' in use, was equally impressive for other reasons. This had the most voluminous Sonic, extra pumps of Volume were seemingly added to the Soundstage. I am no stranger to this perception, but using older experiences and recollection this came at the expense of a undesirable colouration, one that is way beyond what I seek. The Structure A Silver Winding, offered all this Voluminous perception, as well as maybe being the most Transparent SUT ever heard.

Hence, this Brand is Shortlisted for Home Demo's.

It is good to see that other Companies have become aware of the value of adding the nano crystalline cores to their range and individuals like yourself have become interested in the notion of adding it to a SUT.

All SUT users, who prefer the Transparent End of the sonic that can be produced, will have to wait for patiently for the time when PC Triple C Wire Wound Tranx's are being made, to get to the next exciting level of sonic that can be created.

I'm hoping for Cart' Coils, Lead Out Pin's, Wand Wire (Already Achieved), SUT Windings to be produced in PC Triple C Wire. My World of interest in Audio will become a place with new enthusiasm to encounter such items. 

Interconnects, Power Cable, Speaker Cable, Internal Speaker Wire and Internal Hook Up Wire are all uses for PC Triple C Wire that I have now experienced in use.

Internal Speaker Wire being the only device not able to be A/B compared as a Demo' to a Typical version.

PC Triple C Wire has proved as a result of Demo's to be the correct choice made as a Copper Wire.                

I just visited my Old Group Buy Thread for 1254's.

The Fourth GB was not gaining much momentum, and interest party posted the following.

"I ended up buying them directly from Cinemag. $175 each as of Jan 20th, 2023."

Add to this cost Low Eddy RCA Chassis Connectors and Low Eddy RCA's for Cables, and I am confident the experience had of the 1254's will be quite different for the better, producing a sonic that is improved over the ones reported on without such connectors used.

One other way from recollection used by myself as a method to discover what might be contributing to producing Hum, is to put a finger on the Metal of the Input RCA. Use the Spare Finger to touch the other Metal Parts, other RCA's, SUT Chassis, SUT Covers is external mounted, Phon' Chassis, Pre RCA's and any visible screw heads on any device local to the finger in contact with the RCA. 

If one of the contacts being made substantially reduces Hum and it is in-line, a small gauge wire used as a earth bridge might make the Hum inaudible at listening levels with a ear about a metre from a speaker. 

I have a single wire removed from a Telephone Extension Cable used as a Earth Bridge, a friend soes very similar, but also has pure copper crocodile clips attached to make an improved contact that a loose wrap.