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MM Phono pre better in MM/MC pre?

Donal64

Donal64

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Been thinking of a phono pre, and looking and figuring. I am interested in MM phono pre only. I have no interest and probably never will have an interest in MC cartridges. I've noticed that most phono pres under $100 are MM. It seems most phono pres over $100 are MM/MC. Wondering would the MM of the MM/MC have better sound quality than the lower priced pres with MM only? Seems like I was wondering something else , but can't think what it was right now. Taking a break.
 
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To answer your question, most (but not all) MM/MC preamps consist of a MM preamp, preceded by (occasionally) a step-up transformer (SUT), but most often, a MC head amp (pre-preamp). When they are switched to MM, they bypass the MC stage. Usually, the ones with SUT’s cost a lot more, since transformers of similar quality are much more expensive than the electronics in MC head amps.

So most times, a MM/MC preamp will sound similar to a MM preamp of the same circuitry. So if you’ve got the choice between a MC/MM preamp, and a MM one from the same manufacturer with identical MM specs, then they’ll probably sound very similar – probably identical. So you can save money if you don’t have a MC cartridge.
 
ETI_5000 said:
To answer your question, most (but not all) MM/MC preamps consist of a MM preamp, preceded by (occasionally) a step-up transformer (SUT), but most often, a MC head amp (pre-preamp). When they are switched to MM, they bypass the MC stage. Usually, the ones with SUT’s cost a lot more, since transformers of similar quality are much more expensive than the electronics in MC head amps.

So most times, a MM/MC preamp will sound similar to a MM preamp of the same circuitry. So if you’ve got the choice between a MC/MM preamp, and a MM one from the same manufacturer with identical MM specs, then they’ll probably sound very similar – probably identical. So you can save money if you don’t have a MC cartridge.
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Thanks Don. I kinda figured that would be the case.
 
I've one with Nichicon caps. Doesn't sound bad at all. Might see if it can be redone with Dueland JAM caps at some point.

Other mates are running them with Vishays or stock. Definitely much better after a recap.
 
mjw21a said:
I've one with Nichicon caps. Doesn't sound bad at all. Might see if it can be redone with Dueland JAM caps at some point.

Other mates are running them with Vishays or stock. Definitely much better after a recap.
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Are there any phono pre's that you could compare them to, as far as being about as good as, or not as good as, or maybe better than? The only comparison I could make is to a couple of mid 1990s Technics receivers. Would rather not spend $100 only to find there is no improvement in sound.
 
With Vishays installed its even with the EAR 834P with about a $800 complement of NOS tubes. Quite impressive really.
 
ETI_5000 said:
To answer your question, most (but not all) MM/MC preamps consist of a MM preamp, preceded by (occasionally) a step-up transformer (SUT), but most often, a MC head amp (pre-preamp). When they are switched to MM, they bypass the MC stage.
Click to expand...
I'd say the configuration you describe - MM phonostage preceded by a headamp - is the "next level up". The basic level for an MM/MC phonostage is just a circuit with a switch to change a feedback resistor for more gain in the MC mode. It's pretty common with lower priced phonostages and is why the signal-to-noise ratio leaves something to be desired. Also, since the high gain is achieved by using reduced feedback the performance suffers.
If you look at page one of the thread linked-to in post #2 above, you'll see a typical MM phonostage. A cheap way to turn it into an MM/MC phonostage would be to have a switch to change the 150 ohm resistor in the feedback loop of the first stage to about 15 ohms. Lots of cheap phonostages do it this way.
 
rothwellaudio said:
I'd say the configuration you describe - MM phonostage preceded by a headamp - is the "next level up". The basic level for an MM/MC phonostage is just a circuit with a switch to change a feedback resistor for more gain in the MC mode. It's pretty common with lower priced phonostages and is why the signal-to-noise ratio leaves something to be desired. Also, since the high gain is achieved by using reduced feedback the performance suffers.
If you look at page one of the thread linked-to in post #2 above, you'll see a typical MM phonostage. A cheap way to turn it into an MM/MC phonostage would be to have a switch to change the 150 ohm resistor in the feedback loop of the first stage to about 15 ohms. Lots of cheap phonostages do it this way.
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Yes, I’m aware of that, but wouldn’t recommend them. I also didn't want to complicate things too much, so ignored them.:)

Incidentally, there are good examples of the switched-gain MM/MC phono stage, and Sony used an excellent example in one of their greatest (hugely expensive) preamplifiers, the TA-E77-ESD, which had IEC signal to noise ratios of 83dB (A-weighted) on MC, and 95dB on MM.
 
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rothwellaudio said:
I'd say the configuration you describe - MM phonostage preceded by a headamp - is the "next level up". The basic level for an MM/MC phonostage is just a circuit with a switch to change a feedback resistor for more gain in the MC mode. It's pretty common with lower priced phonostages and is why the signal-to-noise ratio leaves something to be desired. Also, since the high gain is achieved by using reduced feedback the performance suffers.
If you look at page one of the thread linked-to in post #2 above, you'll see a typical MM phonostage. A cheap way to turn it into an MM/MC phonostage would be to have a switch to change the 150 ohm resistor in the feedback loop of the first stage to about 15 ohms. Lots of cheap phonostages do it this way.
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Agree.

Some of the more basic ones use op amp circuits and you set the gain by selecting/ switching the feedback resistors. Even seen this in mid priced units.
 
ETI_5000 said:
Yes, I’m aware of that, but wouldn’t recommend them. I also didn't want to complicate things too much, so ignored them.:)

Incidentally, there are good examples of the switched-gain MM/MC phono stage, and Sony used an excellent example in one of their greatest (hugely expensive) preamplifiers, the TA-E77-ESD, which had IEC signal to noise of 83dB (A-weighted) on MC, and 95dB on MM.
Click to expand...


I know what you mean but Vista Audio makes a very nice one. I’ve heard it compete with much more expensive phono stages and it holds it own. It’s my recommendation for new and $300 or less for people that don’t do kits. Would love to hear the stock Radio Shack and then tweak it a bit.
 
The more you have to amplify a signal the more distortion and noise gets introduced into the music stream. If you ar egoing to only use MM cartridges then use a MM pre.for the reasons above. If you look at specs on pre-amplifiers and receivers you will see that the SN ratio is always better for the MM verses the MC inputs.
 
bobins08 said:
Cool. Can you post it once you get it in and set up.
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Sure.

bobins08 said:
I know what you mean but Vista Audio makes a very nice one. I’ve heard it compete with much more expensive phono stages and it holds it own. It’s my recommendation for new and $300 or less for people that don’t do kits. Would love to hear the stock Radio Shack and then tweak it a bit.
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There was one listed for like $12.99 plus shipping yesterday. Was a different model #, but still an old Realistic.
 
Is an over under shot gun better than a side by side. It all depends on who made the particular gun and who is using it. But I would say most of the better MM/MC units are better than the MM units.

Maybe I misunderstood you. Is the MM section of a MM/MC better than a MM unit. Depends again on the MM section of the pre-amp and the MM section of the pre-preamp. I don't think you can give a general answer. Its like asking is the MP 100 better than the phono section of a C-47, C-48 or C52. I would hope its at least equal. I know from experience they do sound different. It might be in one case and not the other. IS a MP 1100 better than the phono section of a C-1100? Well, its certainly more flexible with more features and the features that are there make it a better Pre-preamp for me. So it again depends on the individual units. You either have to believe what reviewers and friends tell you or trust the measurements made and/or the manufacturers specs.
 
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twiiii said:
aybe I misunderstood you. Is the MM section of a MM/MC better than a MM unit. Depends again on the MM section of the pre-amp and the MM section of the pre-preamp. I don't think you can give a general answer.
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This is pretty much what I was getting at:
ETI_5000 said:
So most times, a MM/MC preamp will sound similar to a MM preamp of the same circuitry. So if you’ve got the choice between a MC/MM preamp, and a MM one from the same manufacturer with identical MM specs, then they’ll probably sound very similar – probably identical. So you can save money if you don’t have a MC cartridge.
Click to expand...
 
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