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FS: Single Op-Amp MM/MC Phono Stage

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Single op-amp phono stage. Negative feedback RIAA. 4-pole 2-way switch to swap loading resistor and gain to switch between MM and MC. Resistors are Dale RN60, caps are WIMA and SILMIC and TDK X7R. Op-amp is OPA2134.

Tested and working. You just need a bi-polar power supply and wire it up.

$40 plus shipping
 

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MC cart noise performance?

Never measured it. Basically a single OPA2134 with negative feedback and all gain in a single stage. Not the best stage for MC in my opinion but a good all-around versatile stage that is a great addition to an integrated or a newbie in vinyl. Beats most modern commercial integrated built-in stages hands down.
 
So the modern times(starting with the 1950's I guess) gave us just 50 lousy phono preamplifiers... Would you make a list of them so that we'd know what to avoid or is it just good to know that "most or all modern phono preamps", except yours of course, are complete disasters?
 
So the modern times(starting with the 1950's I guess) gave us just 50 lousy phono preamplifiers... Would you make a list of them so that we'd know what to avoid or is it just good to know that "most or all modern phono preamps", except yours of course, are complete disasters?

Do you have a hobby or are you normally just an arrogant *******?
 
I just like to quote future high end audio equipment sellers:

Well since you obviously are an *******, here you go ... I'll put a "+" afterwards if mine is better and a "-" afterwards if not better and "=" if there is no discernible difference:

Yamaha receiver ~2017 +
Yamaha C-4 -
Luxman LV-100 +
McIntosh MA3100 =
JVC receiver ~2000 +
JVC A-X3 -
Onkyo TX-41 +
Rotel RX-303 =
Sansui 500 +
Denon receiver ~2000 =
APT Holman Preamp -
Hafler 915 + (Hafler sounds better but mine is quieter)
Pioneer receiver ~2005 +
NAD PP-2 +
Grado PH-1 +
RCA "Classic" tube phono +
RCA "Eli Duttmann modified" tub phono -
OPENAMP1 -
Pass Pearl II -
Modified EAR 834P -
WAD Phono -
Hagerman Bugle -
Thorsten DC Phono + (His sounds better but mine is quieter)
Dynaco PAT4 +
Dynaco SCA35 (stock) +
Dynaco SCA35 w/custom Passive RIAA tube stage -
Telefunken Empress II +
Motorola SK-73W +
Clairtone S-301 +
Bottlehead Seduction -
Analogue Addicts Preamp -
Boozehound Labs -
Doug Self ~2012 -
Rotel RQ960BX -
AudioNote phono -
Wright FVP5 -
RH Design Phonostage -
Budgie -
Hagerman Cornet -
DogStar Phono +
Juicy Music Peach -
Lafayette M65 +

Sorry ... you got me ... not 50 is it?! All I could think of going through my notes but I have missed many and heard maybe another 20 or so at about 5 audio shows including the now defunct AK Fest and AXPONA. :rolleyes:
 
nice parts in that preamp - some say a single op-amp with feedback RIAA EQ is better (and makes more sense for MM) than passive RIAA between two op amps

It's all about compromise to me. Due to the amount of gain in phono, the less active devices the better to keep overall noise down, so a single amp with active feedback is the best from a noise perspective. For MM, I prefer a FET-input op-amp like the OPA627, OPA2134, etc. vs a BJT-input amp. However, when done properly, split passive RIAA are some of my favorite designs! Getting them quiet is another issue! :D

To date, my favorite as far as "overall quality of sound" is the WAD clone. The best bass is the OPENAMP1 (no surprise being DC-coupled). Now if I could combine the 2 ... ;)

Sorry but I don't do measurements. I judge by my ear. If I listen and get tired after 30 minutes and turn it off, it goes in the trash. If I get goosebumps when I hear certain passages and find my toe tapping on every song, that is a keeper worth further investigation! It is well known that even harmonic distortion is pleasing to the ear in low doses. How low depends on the individual and there is no "one size fits all" for everyone. For example, not to go off on a tangent but audio fests always amaze me! Sorry if I am stereotyping or calling anyone out but it is typically attended by older gentlemen who flock towards brand names when I am pretty sure that they cannot hear much above 10KHz when they all sit in a room in amazement and I have to leave because the system sounds like a cheese grater on my ear drums! :p
 
However, when done properly, split passive RIAA are some of my favorite designs! Getting them quiet is another issue! :D
I did two passive valve based and hybrid(valve-discrete transistor) preamps that showed no audible noise at max volume 2vRMS obtained in only 2 stages and a passive network.Decoupling the mm cart from the input gave some audible noise, but extremely low.Well...at the time i did it, a d3a valve was just 10 euros!!! now it's 5 times more expensive :) .
The full valve design had a high impedance passive riaa network, the hybrid one had a very low impedance passive riaa netwok(3k ohms). Both were dead quiet, but i preferred the same passive network values used in lme49710 datasheet even though i couldn't see any difference on the scope until 25khz square wave at max 5v rms output on 1k2 and 550 ohms.
Split riaa is actually better with active op-amp designs than with passive designs. In passive designs you need to get the most gain in each of two stages and that is not easy to get linear too!
 
I did two passive valve based and hybrid(valve-discrete transistor) preamps that showed no audible noise at max volume 2vRMS obtained in only 2 stages and a passive network.Decoupling the mm cart from the input gave some audible noise, but extremely low.Well...at the time i did it, a d3a valve was just 10 euros!!! now it's 5 times more expensive :) .
The full valve design had a high impedance passive riaa network, the hybrid one had a very low impedance passive riaa netwok(3k ohms). Both were dead quiet, but i preferred the same passive network values used in lme49710 datasheet even though i couldn't see any difference on the scope until 25khz square wave at max 5v rms output on 1k2 and 550 ohms.
Split riaa is actually better with active op-amp designs than with passive designs. In passive designs you need to get the most gain in each of two stages and that is not easy to get linear too!

Sounds like we are on the same page! I just finished up a PCB design for a tube phono that utilizes split passive RIAA. The first stage is a JFET cascode in MC mode and standard voltage gain stage in MM mode. The first stage is also a Mu follower to resolve the poor PSRR of cascode. PS is a simple HV series pass regulator with regulated heaters also. I used a similar PS in my WAD clone and it was dead quiet, so I have high hopes for this one! <fingers crossed>
 
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