Step Up Transformers….Are they Worth the Trouble?

interesting, @br3098 . users of both often state this in their preference for SUT. what headamp does such for hana ML?

"a really good head amp had an airiness and delicacy that SUTs can't match. You need to test."

Does anyone have a direct experience with Thöress ‘Phono Enhancer’. I was reading late last night about it and kinda digging its design and features. A purely active phono circuit – no step-up transformers – that uses three NOS (new-old-stock) tubes – one PCC88 and two 6J5GT.

@lalitk I'm running the Thoress, reason I purchased was the unique design and features. Don't have a great deal of experience with phono stages, but Thoress plays at a different level than my ModWright SWP9.0SE and prior custom build tube stage with step up trans.

I'm at point where I exclusively use only point to point wiring, short signal paths in all components, Thoress fits my preferences. I also believe performance could be raised further still with cap and resistor mods I'm contemplating. Thoress pretty much unknown in US, overlooked by many. In researching my purchase the Thoress competes against some much more expensive phono stages.

I am making no value judgement, but be aware that Thoress uses a JFET in addition to tubes in order to develop sufficient gain with LOMC cartridges. Not that there’s anything wrong with that; the Steelhead does it too. What’s the big deal about the 6J5? It’s equal to one half (one section) of a 6SN7, which is a great medium mu tube and easier to find. I’d advise against choosing gear based on content of seemingly exotic parts.

@lalitk 

You have inspired me to finally pull the trigger on a new SUT for my Koetsu - have been Hamlet-ing the decision for almost a year and a half now.  So thank you.  I went with the Swissonor, will report back.

Re SUT vs. active stage, I had a great discussion (email) with Andrew Rothwell before I bought one of his units several years ago.  Here’s a portion of his thoughts:

“Hi Steve.  Yes, noise is indeed a potential problem with headamps - but noise is a potential problem with any audio electronics. Actually, there are various types of noise and various ways it can infest an audio signal.  The type of noise most likely to plague a headamp is Johnson noise, aka thermal noise, which is a hissing sound.  With a step-up transformer you're unlikely to have any hiss problems, but you're more likely to have hum problems. Anyway, without getting too deep into the topic of noise, let me assure you the Headspace has very low noise - way below vinyl surface noise.  I leave the choice between headamp and SUT to the customer, but with your system being valve-based the transformer option seems more fitting - no transistors  :-). Btw, no the battery doesn't address the issue of Johnson noise at all.  It addresses the issue of mains-borne noise and potential ground loops.  Regards. Andrew”