2. analog
  3. 143944-86974

Phono Preamp Gain

Hi all,

I am in the process of getting a new cartridge and I want to make sure the output voltage is a good fit for my system. First off here's what I'm working with:

VPI Prime
Schiit Mani (30dB, 42dB, 48dB, 59dB gain options)
Prima Luna Dialogue Premium Integrated (239mV input sensitivity using KT88 tubes) (S/N ratio 81)
JBL L100

My question is what do I use for Vout in this equation to calculate the correct gain to choose on the Schiit Mani phono preamp??


20log(Vout/Vin)


Using the input sensitivity of the integrated and the output voltage of the  Soundsmith Otello ES Moving Iron Cartridge I get 

20log(.239V/.00212V) = 41dB gain

Is this correct?
My main issue is I dont know if my assumption to use .239V is correct.

Cheers



nmo25
bdp24's avatar
bdp24
9,815 posts
 

My Herron mm phono amp provides 42dB of gain, which works fine (to use understatement ;-) with my 5mV output London cartridges. I don’t know how Schitt came up with 30dB for Deccas, but remember, 5mV is the cartridge’s nominal output, not it’s maximum. Transient peaks may produce even higher output, right?

Another phono amp incorporating a setting specifically for Decca/Londons is the Andros by Zesto Audio, whose impedance switch includes 15K ohms (the cartridge likes to be loaded down, to electronically damp it’s high frequency resonance). Zesto designer/owner George Counnas told me he put that in the Andros specifically because of all his friends and industry colleagues who use Decca/Londons, a cult favorite!

jperry
2,449 posts
 
Go to vinylengine.com and use the tools there to calculate gain requirements.
tablejockey
3,912 posts
 
nmo25,

I HAVE the PL HP, a VPI,and used a Schiit Mani, while my main unit was in the shop.

Don't drive yourself mad figuring what is "absolute" on paper.

One of the 2 first MM settings will be fine. Using your ears, in this instance, won't damage anything. 

The Mani is a great entry level, cheap unit. In my case, it served as something to get by with, while waiting for my "proper" phonostage to be repaired.

Your system is being underserved. With that amp,table/cart and speaker setup, you're  only hearing 60-70% of what it's capable of.

Consider a  Chinook or Herron, they seem to be the 2 most popular tube based units here. Use a tube phonostage to keep the tube vibe(realistic/convincing) presentation. You have that PL(tubed) for a reason.

Naturally, this is IMHO.
mulveling's avatar
mulveling
1,913 posts
 
I’d agree that he’d realize huge performance gains going to one of those fine tube/hybrid phonos over a budget SS like the Schiit. I have the Herron and a VAC Renaissance after upgrading through phono stages for years; both are absolutely fantastic. The Rogue Ares (and probably their new Triton 2) is also very very good for much less money, but those more expensive units are certainly better.
nmo25 OP
2 posts
 
Tablejockey,

Of course! I wanted to see if I was in the right ballpark before messing around and finding out what sounds best. I haven’t bought the soundmith cart yet, but the compliance works well with the lighter VPI arm so my next bet was to see if the output would be close to one of the gains on the mani. 

Obviously my phono stage is the bottleneck in the system, and eventually I would like to upgrade that. I appreciate the tube preamp recommendations because that’s definitely the path I’ll be going down. I’m not sure if the JBLs are anywhat of a good match for the Primaluna but I got them for dirt cheap at an estate sale so they are staying for a while. 


More to discover