2. analog
  3. 1035010362

Phono Preamp Help - 47K Ohms - 100 Ohms .. Huh?

I am relatively new to analog and therefore have little experience matching a cartridge with a phono preamp. I currently have a Shelter 901 which the user manual specs at "within 100 Ohms" as the recommended load impedance for the head amp. I've been shopping for a new phono pre and find that many top phono pre's are all rated at 47K Ohms and are not switchable.

This got me thinking that maybe 47K Ohms was the right setting for ALL phono stages and sounds the best... So since I currently use a Black Cube which IS switchable between 47K Ohms and 100 Ohms I decided to play around.

When in the 100 Ohm setting, I feel the sound is crystal clear - nearly perfect - yet the midrange seems recessed ever so slightly causing some recordings which I know should have heft and body to be somewhat recessed sounding and maybe thin. Also, at 100 Ohms, the sound is not quite as involving as I like. It's not exactly bright but quite close.... really close - in fact, as extended as I've ever heard a system be without being able to confirm it as being bright.

Switching das cube over to 47K Ohms gives a dynamite midrange. Very impressive vocals. Solo instruments seem incredibly lifelike - highs are ever-so-slightly rolled when compared to the 100 Ohm but during complex music, and even not-so-complex music the mids seem somehow congested as if the notes are bumping into one another slightly - perhaps muddy - more or less "confused". This sucks because everything else seems to be close to perfect.

Each setting has its virtues but I feel the 47K Ohm setting would be ideal without the midrange confusion.

Now for the questions...

If my Shelter 901 is designed for "within 100 Ohms" what the heck does that mean? Within? Does this mean I need to stay at 100 Ohms for the best match to the cartridge?

When switching to 47K as I said above, there are some advantages and clearly a few disadvantages. Are the downfalls more related to the phono preamp, the cartridge or even the impedance match? I mean, could the congestion be a result of the black cube itself vs. a direct result of the impedance settings?

What's more important - the preamp or the impedance setting?
bwhite

Showing 5 responses by bwhite

bwhite OP
807 posts
 
Hi Twl, Okay.. now.. the VTA is that the adjustment I can do with the hex bolt? or is that the knob on the arm? I think if I remember correctly its the hex bolt... So I'll try that.

My Ittok is the BLACK Ittok which is/was released right before the Ekos and is essentially an Ekos without the integrated arm rest. This Black Ittok is damped unlike the silver Ittok arms and it does not ring like 'em.

The brightness I referred to is not actually "bright". It is however, as close to being bright as I've ever heard without being bright.

I'll try to raise the VTA slightly and see what happens.
bwhite OP
807 posts
 
Okay... I messed with the VTA. Quite frankly I don't know if it went up or down but the bass is better, the highs are nice and the mids are much more accurate. This is what I was trying to acheive.

Thanks all who helped!

This brings me to the phono stage question regarding various loadings. I guess from what I've read, its best to match the output of the cartridge however it is difficult to find a better phono pre (the kind without the toggle switches) that is at 100 Ohms. The Linn Linto is at 150, the LAMM is at 40, Jadis is at 47K, The Joule's are at 47K, the Lukaschek is at 22K.... I cannot find one at 100 Ohms What gives?
bwhite OP
807 posts
 
Gregm, I was looking at getting a Jadis and the guy told me, "It is fixed at 47K. Every modern moving coil is optimized for 47K". That was VERY confusing for me and the catalyst which sent me into my latest fervor regarding my analog rig.

All my research tells me that his comment, "Every modern moving coil is optimized for 47K" is asinine. Perhaps he blundered by saying moving coil vs. moving magnet but given we were discussing the DPMC I presumed he knew what he was talking about. The name DP"MC", kind of implies its for MC cartridges but I could perhaps be wrong.
bwhite OP
807 posts
 
Viridian - analog rigs seem to be a wee-bit tweeky to set up correctly but the sound is for the most part, exactly what I always hoped digital could be. And it was easy to get to that level vs. spending 10's of thousands on digital + associated cables and stuff. Analog is so good that I haven't listened to a single CD since I got my TT.

However, as much as I like the TT and vinyl, I am leaning toward using my digital system for classical. I am a bit frustrated with the quality of classical recordings (at least those that I've listened to on vinyl, they just don't seem to be as fulfilling). The crackle/pop at lower levels is very, very distracting for this genre - not to mention the "short" play time of a single side of an LP.

As I am finding out, it seems that many newer LPs from the late 80's through current were recorded digitally. The advantages of an analog version of a digital recording are debatable. Also during this time period, it seems the vinyl was a bit "rough-cut" and cheezy. So this may be a time period where I prefer digital as well.

Pre 80's music (all the way back), and some early 80's analog recordings are outrageously good sounding. So for this era, I will certainly use my analog rig.
bwhite OP
807 posts
 
Consttraveler - how is the Coph Nia??? I've read a bit about them and I'm curious to know what you've compared it to. Care to share?
More to discover