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
gregm
3,021 posts
 
Bwhite I, too, think that the sales rep was thinking of MM or hi-output MC. Zaike gives good advice on choosing quality resistors & Twl's tip on capacitance loading is a valuable trick... But do focus on resistance for now!
viridian's avatar
viridian
4,184 posts
 
Aah, TWL suggests raising the VTA, Oldears suggests lowering, some think 47K and other lower. Is there any better illustration of why so few new converts are being brought into the analog fold and why so many have defected to the silver disc?
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.
twl
3,251 posts
 
Viridian, we can't help unless we post what we think, right? There are conflicting posts on just about every thread on the forum, including the Digital page. It's not just analog that is suffering from this problem of conflicting answers.

Bwhite, at least with the TT, you CAN adjust something to change the sound. With a CD player all you can do is buy a new one.
zaikesman
3,017 posts
 
Agree with Twl, except I wouldn't even call 'conflicting' answers a 'problem' (unless they're posted by the same individual!). If there was no sincere difference of opinion or experience to be found in this hobby, we wouldn't really need this forum, would we? Vive la variety! :-)
More to discover