Noob phono stage question.

Ricardo

I have a Dynavector 10x5 cartridge; it's a high output MC (2.5 mv).

I am having too much gain using the MC input on my preamp, so here's my question:

My preamp's MC input is a "head amplifier for moving coil phonograph cartridges with a separate RCA jack input for cartridge loading". This means that there are two sets of input jacks; one for the RCA's coming from the TT, and one for cartridge loading. The pre came with several RCA plugs that have a resistor, with several values ( going from 1 ohm to 200 ohms). Will this help me play with the gain? Right now I don't have anything plugged there (the cartridge has a recommended load impedance > 1,000 ohm, and Dave Belles told me that the pre without any load would work fine). So, what will happen if I plug resistance to these load jacks???

Probably a very basic question...:o

cmy330go

Changing load does not change gain. Adjusting load is just a way to fine tune a phono pre to a cartridge. So by changing the plugs the most you will notice is a change in sound.

cmy330go

Is this on the Belles 28a? If so you should be able to switch to the MM input and be just fine. That MC is pretty close to the typical level of a MM.

EDIT: I realize you have probably already tried this, but just thought I would mention it in case you haven't.

Ricardo

Thanks Dave; yes. it's the 28a. I thought of doing that, but according to the specs, the MM's gain is higher (40db vs 26db). Does this make sense? maybe a typo? I'll try it and see what happens.

cmy330go

No prob!

I'm pretty certain that's a typo.

MM's typically have higher output & therefore require less gain.

Ricardo

Changed to MM and that did it. So, difference between MM and MC is just gain? I really thought there was something else about it. Anyway, easy fix.

cmy330go

Ricardo wrote: »

Changed to MM and that did it. So, difference between MM and MC is just gain? I really thought there was something else about it. Anyway, easy fix.

Glad it worked!

There is more of a difference than just gain. I believe typically MM phono stages are set to load at 47k. It seems to be the general belief that this is usually the best setting for a MM cartridge. I suppose since most people using MM cartridges aren't audio freaks like us, that works fine for the majority. Most audio junkies seem to end up with higher-end MC cartridge that will typically benefit more from an adjustable Pre-amp.

I'm sure there is even more to it than that, but I'll have to leave that to the real freaks.:D

Ricardo

Well, after listening a bit I switched back. Gain was perfect, but it sounds a bit dull. Or maybe it's just my brain...No way of doing a blind test though

billbillw

Ideally, with that high output MC, you would want MM type gain, but with a lower loading (47k is too high for that one). I'm not sure if the preamp lets you adjust loading for MM, but that is probably why it sounded duller on MM. Something between 1000 and 10k might be good. Maybe ask Belles and see what they have to say.

SCompRacer

Ricardo, think of cartridge loading as electrical damping. Loading also influences the noise level, frequency response and output of the cartridge. Could be what you heard is exactly what is happening. It is best to start loading at what the manufacturers suggest, then adjust up/down to find that sweet spot. And yes, I would say the specs are a typo error. My MM is ~45 and MC is 68.

Does your pre have capacitance loading along with resistance, or just resistance loading?

Maybe it is time for a low output MC. I've had both high and low output MC. For me, the magic is with low output.

Ricardo

Only resistance loading. I'll play with the RCA plugs I have available and see how that affects the sound.

I've been thinking on a low output cartridge. On my short list, though I also think that my TT is not good enough to spend too much in tweaks. We'll see

SCompRacer

Well, that settles it then. A new cartridge and a table.;)

cmy330go

I'm pretty sure the loading on that Belles only effects the MC input.

What do you have for a table Ricardo? You might consider a Benz Micro Ace. Great cartridge for the money!

Ricardo

I have a Pro-ject RM5; that benz Ace costs more that the TT

I need to stop looking at Troy's thread on the FM......

cmy330go

WTH???? When did that thing jump to $700 it used to be somewhere between $400 and $500.

Apparently our money just isn't good anymore.

SCompRacer

Ricardo wrote: »

I need to stop looking at Troy's thread on the FM......

You really need to buy that table!

His VPI is a nicely configured table. It has all the right stuff.

Buy! Buy! Buy!

You cannot resist this subliminal SOPA message!

SCompRacer

cmy330go wrote: »

Apparently our money just isn't good anymore.

Dem upgrade dollars sure don't go as far as they used to......