Step Up Transformer Question
Ok, so bear with me as this is new terrain for me. I was quite happy with how things were sounding and then I accidentally bumped the stylus of my Cadenza Black and snapped the cantilever clean off. I did some research and ultimately decided to have Steve at VAS at fix my cartridge but it was going to take a few weeks and there was going to be no way to play the Christmas vinyl that my wife loves so much. She told me to buy another cartridge so we could have Christmas records. I was stunned. I found a great deal on a Winfeld Ti on this site and pulled the trigger. I've got it on my table and it sounds amazing.
After speaking with Steve though, I'm going to trade in my Cadenza and have him build me a wood body cartridge to have something different. It will also be 0.2mv output. I think I've got the 2nd arm situation sorted (gonna buy a Wand and a pod to mount it on) which leaves the phono pre. I love my Rogers PA-2 and it is switchable between MC and MM with 2 different inputs in the back. Finally got the SUT part. I've been looking and trying to figure things out. I spoke with Roger and he said the transformer built into the PA-2 is 1:10 and with that I can achieve 70 or so dB of gain. I did a lot of reading and looking and while I'm sure a 4k+ SUT is amazing that's just not where I'm at with all the other expenses at the moment. I saw the Bellari MT502 was a stereophole recommended component for many years and Amazon had one on sale for like $349 or something. Figured can't hurt to try it, it's Amazon so I can always return it. I plugged it in with some admittedly questionable interconnects I had lying around and when I put the phono stage k there was a bit more hum than I'm used to but I said let's have a listen. Holy shit. This little thing blew my mind. Better impact, tighter bass, more space around instruments so better staging, improved transients. This puts me in an interesting place.
This is an extremely inexpensive piece and it has changed my system quite a bit. I think the little extra gain I get even at 1:12 brings the cartridge to life. My question is where do I go from here? Bob's makes the sky 30 which is switchable from 1:15 to 1:30 which I like because I can play with the gain tubes in my preamp and potentially go to a quieter 12au7 than the 12ax7 that's currently in there. Will that be a real improvement? Less hum? Had also considered ordering a Rothwell from jolly old England but can't find much on them. Thoughts? I'd like to keep this sub 1k or so for now. Maybe I'll save up for a big boy SUT later.
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. |
@mulveling I appreciate your input. I spoke with Roger at Roger's High Fidelity who makesy phono stage and he said that the 20db I'd get with 1:10 will get me a total of 70db of gain which is what I'm currently using with the built in SUT. It seems quite good with my Windfeld Ti. Ralph from Atma-Sphere also mentioned, as did Roger, that a lower ratio will be less prone to noise. I'm waiting on some new cables to come next week to see if I can eliminate some of the hum I'm getting with the Bellari. As you said, might need to try different grounding schemes. I feel like that's a whole other thread, lol |
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. |
@rmdmoore I enthusiastically disagree with this part. With a SUT, it's a given that you absolutely have to get the grounding and cable shielding right - whatever the ratio. Once you do, hum noise will disappear and the only noise you should be hearing is a "hisssssss" or "shhhhhh" noise from the active RIAA stage of your phono (the noise part of its signal-to-noise spec). Using a higher ratio SUT allows you to lower preamp volume while attaining the same signal SPL, which pushes this noise DOWN. It's not so much a matter of total gain (yes everyone agrees 70dB is high), as it is about optimizing the *structure* of that gain. The actual signal levels hitting each part of your analog chain up to the preamp volume control - this is what matters! Of course it's a balancing act - if you push SUT ratio too high you risk loading the cartridge too heavily (which will cause loss of signal), overloading your RIAA stage (bad distortion), and of course the SUT itself will distort more at higher ratios (all else being equal). Higher quality SUTs will distort less at the same ratio. A good rule of thumb, for most MC cartridges (coils wound on iron), is to choose a SUT so that your "calculated" signal coming out of it is ideally 5mV (this is what hits your MM / RIAA stage). But anywhere in the range of 3.5mV - 7.5mV is usually considered good (I listen loud and like to ride on the high side of that, personally). So your 0.2mV Windfeld into a 10X SUT is only 2mV. That sucks, IMO. I can't believe people are recommending that lol. A 20X would give you 4mV and a 30X would be 6mV. I'd choose the 30X there, but either would work great. If your 2nd wood cartridge is also 0.2mV that would be great, and the same SUT would likely be optimal for both. But that's also why many SUTs come with 2 or 3 taps. The Sky 30/15 for example, would work great with a 0.2mV cart at 30X and a 0.4mV at 15X. |
@mulveling it's funny, that's what I was initially thinking. I messaged Ned Clayton about an SUT that would have some adjustability so I can play with different gan ratios and then I can adjust my tubes in my phono pre accordingly. I'll probably end up doing that. |
