Good phono pre with Ortofon 2m Bronze

Good to know. Plus, there is a mono switch on rear. I guess a rumble filter really is not necessary.

 

Rumble filters aren't necessary but may be helpful in certain situations. They are really a band aid fix for other problems, like warped records, cart/arm mismatch, speaker placement constraints, etc. I've used one in the past but do not have one on my main deck now.

 

Besides Ortofon, Rega MM carts, like the Exact produce voltage in the range of "Output: 6.8 - 7.2mV" and they are used with MF phono preamps all of the time.

All of these statements are silly. MM phono preamps typically will have gain in the neighborhood of 40-dB.

 

Good to know

 

I run the 2M bronze on my 1200mkii through a Parks Budgie tube phono stage and luuuuurve it. Upgraded the tubes last week and its now perfection. $450ish on the secondary market now.

 

The lowest gain on the MoFi is 40. I guess this is a situation where people are just looking at specs and not listening. I wonder if anyone has actually heard distortion with the MoFi using a high output cartridge that would not be there with another phono pre that was more forgiving.

 

Has anyone measured what input voltage causes the MoFi to saturate at the 40dB gain setting?

 

Not to my knowledge, if you're talking about a real bench test. It would need to go on an AP analyzer or similar equipment. ASR or Miller Audio Research could do it.

 

I heard the distortion. I did not come to the conclusion from just looking at specs. The phono stage was making more distortion than usual with a Goldring 1042 cartridge, which is nominally spec'd at 6.5mV output. When I contacted MOFI, there was some back and forth and they concluded that the cart was too hot for their phono stage. This is due to the design of the MOFI, which uses a 2 stage gain system and was never designed with a hot cart like that or other hot carts in mind. It was designed with MOFI carts in mind, and maybe for some common MCs.

The problem sent me shopping for another phono stage. I emailed a number of different manufacturers about this issue before considering what phono stage to try and buy next. A number of manufacturers gave me wishy-washy answers, and since barely anyone bench tests phono stages anymore, I couldn't find many brands and models that I was willing to take a leap of faith on. I narrowed the search to a few models, but some of them were impossible to try before buying. When I found GS and their home loan program, I spent some time on the phone with their loan coordinator, who also has decades of engineering experience. I set up a loan and tested the product at home for about a month. When I plugged it in with the Goldring, the level of distortion I could plainly hear from the MOFI was gone.

Now I'm not saying the MOFI SP is a bad product. I think it's a good product but it has some real world limitations like every product ever made. One should be aware of those limitations when matching a cart with it, or you're likely to be disappointed, especially when you plug in a really hot cart and put on a loudly cut record (I have many of these).

Bottom line is that phono stage manufacturers ought to put their gear through more robust tests before bringing these units to market. If there are limitations, they need to be stated in specs as recommendations at the very least. Nowadays many companies don't bench test their stuff, don't stress test it in the real world either. Testing takes time and costs money. Companies have an incentive to rush things to market, then leave the customers to sort out the problem, which may or may not get solved down the line when version 2.0 comes out.

Some of the problems that have appeared in the last few years, due to manufacturers not testing products properly:

-A DAC with poor USB implementation and higher levels of noise than it should have.

-A 3D printed tonearm that would "melt" and break down in warm climates indoors.

-A phono stage that was very prone to RFI issues if you lived near radio/TV stations.

-A turntable with a fixed headshell arm, whose headshell did not have enough clearance to mount common cartridges.

-A pair of high-end headphones that were improperly assembled, and had to be recalled/fixed.

And on and on.

 

I don't think any fancy equipment is needed. Just run a 1KHz sinewave in at known RMS voltage. Monitor the output spectrum until severe harmonics pop up. I may try this soon. I can just monitor the MoFi output with my PC sound card ADC using ARTA software.

 

There has been a request at the ASR board for a full test, nothing yet. I would be curious as well about the level where the MoFi overloads. I'm sure Mofi made the pre with their, MoFi branded, version of AT cartridges in mind. However, Ortofon, I believe, sells the most cartridges in the world, so one would think that MoFi would make sure those cartridges sounded great on their unit.

Phono preamp review requests: Schiit Mani, Vincent Pho-8, MoFi StudioPhono / UltraPhono

 

Just be careful not to break the thing. At the very least, your sound card will need to have a much higher SINAD than the MOFI SP. ASR could probably advise you how to run these tests with the gear you have. It definitely won't be as good as testing on $40,000 AP analyzer but it may tell you something. Specs from MOFI are 78dB S/N and .01 THD. I believe that's at 40dB gain and A-Weighted, but you'd need to contact them to confirm. They never say what the overload margin is.

 

AhhhI wasn't sure you heard the distortion...I so there you go. Maybe others are not hearing it due to the recordings or do not recognize it when they do hear it. As an OCD person, I would always wonder if theer were any shortcomings with the Ortofon/MoFi combo. The MoFi sounds fantastic. I am now leaning toward the PPA-2 (Elac) over the GS. I'm not really going to need specil EQ for &* rpms. The ones I have actually sound fine with standard RIAA eq. All of mine are from the 50's.

 

Pretty sure AT sells more carts than Ortofon. Ortofon is definitely up there though. Not fully testing their unit was a big oversight, IMHO.

RE: the above, the recent version of the Mani was already tested here:

Review and Measurements of Schiit Mani Phono Stage

I had an older version at one point and eventually grew to hate it due to high noise from RFI.

 

I don't have any records that require special EQ either. I have some mono records from the 50s and 60s as well as mono reissues. All are standard RIAA eq'd.

RE: the Elac, no idea about that really. If it's like most higher end phono stages it was probably designed with top MC performance in mind. Most companies that make $1,000+ phono stages are pretty much banking on the end user having an MC cart. It does look nice.

If it were me I'd try to get both the Elac and GS on loan/return window and compare in your system at home before making a decision.

 

Good idea.

 

You simply are not going to overload a MM phono preamp with a few millivolts. Typical Rega, Ortofon and other manufacturer's make MM cartridges the run from 5.0V to 7.5V. Unless a phono preamp was designed for a very specific low output MM cartridge, it will not overload.

Of course, MoFi and just about every manufacturer on the planet will design their phono preamp to work with these cartridges.

BTW... I have used the Exact with a MoFi X-LPS on a Rega RP6 turntable. The X-LPS is in the rear, on the right.



I have the Ortofon Bronze/Black and I use it on the vintage Vinyl Nirvana Thorens TD-160 Super, with a Decware ZP3 tube preamp.



If you consider all of the technical specifications that are published, with relation to audio gear. You never see a MM phono-pre state the input overload voltage. This is because it is such an unimportant specification,

The reason again, is that MM phono preamps just don't overload unless you put about ten times the voltage that a typical MM cart is going to put out.

AT sells WAY more carts than Ortofon. I doubt if anybody outsells AT, with regard to carts.

 

What do you think is the cause of the distortion Patient_OT is hearing above?

 

Have no idea.

People all over the world use MoFi phono preamps and other phono preamps, with carts by manufacturers like Ortofon and Rega, without any issues.

Including many members on this forum, where Rega and Ortofon MM cartridges are very popular.

The Decware tube phono-pre that I have is for MM cartridges and has 42-dB gain.

Most MM phono preamps will not hit an input overload until they hit about 40-mV or more. While this might occur with a click or pop, that is an extreme transient and not normal program material.

 

FYI, you don't have a Mo-Fi preamp; you have a Musical Fidelity preamp. Mobile Fidelity and Musical Fidelity are two different companies. AFAIK, Musical Fidelity designs its own products and does indeed have a good reputation for quality, but Mobile Fidelity is just a marketing outfit that has others make stuff they feel that they can sell.
-Bill

 

You’re saying Musical Fidelity makes the MoFi?

 

No. I am saying that they are not the same company... I don't know who designed the Mo-Fi unit.
-Bill

 

Oh. Just wondering why Musical Fidelity was brought up

 

Because the other fellow was using the names interchangeably and I wanted to mention that they were distinctly different companies, despite their similar names. He owns a Musical Fidelity piece and I guess he just assumed that was what others were talking about here. Easy enough to confuse the two brands since the names are so similar.
-Bill

 

Graham Slee has some stuff about this, how a MM/MC preamp can't handle higher output MM cartridges all that well.

I have a Great Jazz Trio "Love for Sale" album that, combined with my 5mv Audio Technica cartridges, will seem to make my Radio Shack 42-2109 phono preamp produce a little midrange pop on some higher-level bass transients.

I'm not sure if the problem is actually clipping in the phono preamp, or something actually on the vinyl.

One of these days I'll find a different preamp to try. Or maybe a lower output cartridge. Or maybe both. Or maybe neither.