Specific SUT with unusual case scenario question from a LOMC N00b


I tried posting this over at Steve Hoffman forums and got crickets so I am trying my luck here as well as I am also new to this forum for posting although i have been reading off of it for years so nice to finally meet you all and I would like to thank you for your time as my question is kind of specific and a bit numbers nerdy beyond my physics calculation capabilities so I am hoping I can get some expert opinions here. To ask this question I have to give the details on my system setup and the vinyl wing of it is a new addition I am putting together but haven’t yet been able to assemble because the salamander designs AV furniture it will be sitting on in my living room is on backorder which is kind of an exercise in patience I hadn’t planned on… leading me to obsess over ideas and post on forums like this one in the meantime while I wait.

So my system has to do double duty as home theater and audiophile listening meaning some of my choices had to blend the two along with the WAF since it is in my living room but here’s the phono path in it’s entirety as it stands:

Hana Umami Red LOMC Cart (with wallytools custom brass mounting shim) —>
Bergmann Magne turntable / tonearm —>
Morrow Audio series 5 DIN to RCA phono interconnect cable —>
PrimaLuna EVO 100 tube phono preamp (with upgraded tubes) —>
Morrow Audio series 5 RCA interconnect —>
Marantz AV10 preamp/processor —>
XLR balanced output —>
Emotiva XPA HC-1 Monoblock SS Amps —>
DIY assembled 10 awg speaker wire —>
Martin Logan hybrid electostat speakers paired with a Deep Sea Sound Mariana 18” subwoofer

So the primaluna phono preamp has all tubes including the gain boost for the MC cart before it enters the signal pathway like a MM cart would through the rest of the tubes. It has 3 selectable gain settings for the MC mode but it’s right at the limit for my Hana Umami Red. I haven’t heard this combo yet due to the furniture backorder snafu but from what I have read online others that have paired that cart and phonostage seem overall satisfied. I upgraded all the tubes in the phonostage including the quietest I could get from Uncle Kevin at Upscale Audio for the MC gain tube complement.

So with all that in mind, here is my question:

If i want to retain the upgraded MC tubes in my signal pathway but minimize (if even possible) how much gain i need to apply with that to keep the noise to a minimum, is there any role for a small SUT boost between my turntable and the phonostage but into the MC (not the MM as would be more typical) signal pathway? My rationale is that a small boost from a SUT might allow me to continue to use these tubes in the pathway but minimize the gain i have to apply with them and possibly keep noise down while expanding the soundstage. I was thinking something like the Bob’s Devices Sky 10 SUT might be suitable for this if it is possible. But maybe I have no idea what I’m talking about here and that won’t work at all which is why I’m asking.

Any thoughts from those more experienced with SUTs and that know how to crunch the numbers applicable to my setup would be much appreciated. If exactly which tubes I got matters I could list them but i was thinking that’s probably unnecessary detail for this calculation but again maybe I know nothing (John Snow). Any thoughts on this or recommended SUTs that would work in that (apparently) uncommon usage scenario? I couldn’t find much info about if you can (carefully) feed a SUT into the MC pathway if you want to retain those tubes in the path in an all tube phonostage.

I know that was rather long-winded so again I appreciate anyone taking the time to read all of that.

Cheers & Thank you!
 
 
128x128xceilidhx

Showing 6 responses by xceilidhx

@mulveling : What do you think about pairing my kit with Bob’s Sky 20-S? There is no 30-S at this time as far as I know but the 10 and 20 ratio SUT is also pretty much in the range you are recommending (rather than 15 and 30) and offers improved quality (in theory). Just wondering if you have an opinion.

 

Cheers

You guys rock. Thanks so much for the thoughtful replies. Much food for thought and extremely helpful.

So if you have a 40 ohm load for for a 60+ rated cart, what is the (theoretical or actual) sonic impact of that being on the low side, AKA marginal territory? Forgive my ignorance. Just not sure what the downside of that is in practice.

The included math is very much appreciated.

 

And the Marantz is adding nothing because i'm passing though it with a regular line input on pure audio mode so it shuts off everything else that could interfere inside the pre/pro and I'm not using the Marantz phono input.  So the PrimaLuna is currently doing all the work +/- SUT which I'm trying to consider how to integrate. 

 

Cheers

 

Wow.  Thanks for taking the time to type that all out.  You just summarized a lot of cart physics in a way I can actually grasp.  Bravo.  You may have just achieved the impossible :)  And I appreciate the specific recommendations for my kit because going back to practical application, now I have some real food for thought and numbers I can use to compare products depending on how I want to try and tweak this to get a little less noise and a little more dynamics / soundstage.   

 

Cheers again. 

Indeed.  And thank you for chiming in as well.  I really appreciate the time you all took to respond.  

Thanks again all for this truly priceless advice and your time and effort in replying.  It is helpful to hear from fellow listeners with experience as I dive back into high end analog so i don’t just waste my time and money on components that won’t give me what I am looking for.  Of note, it looks like Bob’s actually recently did release the 30-S so if i did go that route and wanted to buy from him i would have the 1:15 option now that may be more of a sweet spot for my cart but of course in the end there is a subjective listening aspect fudge factor that is hard to anticipate ahead of time before purchase.  

Also, thanks for the link to the Lundahls. I’ll check them out as well.

Cheers!