Recap a Yamaha C-2X preamp

C2-x phono gain:

I've done some testing and have some data.
I fed aux, DAD, and MM inputs with a 1000Hz sine wave at their specified levels and measured Vout @pre-out and rec-out. The input voltages were set with the signal generator loaded by the respective input. The output voltages were unloaded/only DMM across the output. Measured w/Fluke 88 DMM.
(pre-out spec @full volume: 1.5V; rec-out spec .15V)
MM: (2.5mV in)1.426V out (spec 1.5V)
MM w/-10db cut button selected: (7.9mV in) 1.42V out (spec 1.5V)
Aux/DAD: (.150Vin) 1.50V out (1.5Vspec)
Then I tested the output of the Bang & Olufsen 8002/MMC-1 cartridge and the PX-2/AT440MLa cartridge, unloaded/meter direct which probably yields slightly higher than actual output voltages. The first track of Miles Davis "Straight No Chaser" was sampled for avg and peak V.
MMC-1 (spec: 2.12mV@5cM): avg .7mV/2.8mV peak
AT440MLa (spec 4.0mV@5cM): avg 1.4mV/5.2mV peak
CD output w/jazz record, fairly dynamic: avg .35V/.75peak
Tuner, jazz station/calm announcer: avg .27/.50peak.
I'm assuming that normal peak levels=specified input levels, in which case actual input levels are much higher than specd-in the case of CD by a factor of 5! (14db), tuner: 3.3 (10.4db)
This explains why I need to attenuate line inputs to match levels, especially with MMC B&O carts. And my high output Adcom MM VandenHul, although rated at 2.5mV into 47K-higher than the B&O-has less "snot" than the B&O. Neither of these cartridges can fully drive my system to "party" levels. If I select MC and <10db> phono cut, then I can drive the hell out of it, but now the situation is reversed: the MC input is too "hot" compared to line ins (without attenuaters-to solve the imbalance I'm running <10db> attenuaters on tuner and DAD inputs) and the MM is now unusable in that the back panel <10db phono> button affects all phono inputs.
If anyone's interested: MM phono gain is 55db, 45db w/<10db> button selected. (measured) calculated from spec: 55.6db
Line inputs: 20db (measured/specd)
MC, calculated from spec: 83.5db.
Using calculator @ www.muzique.com/schem/gain.htm
phil

ps: Mandak-did the discussion of low-cost carts on VE lead you to the AT440 as well?
 
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pfcs49 if I understant you correct, then you compair the sound level (SPL) of you're system running a vinyl recording, then switching to a CD-P signal (on the DAD or AUX input) and then to Tuner indput.

And you're problem is that they are not the same level, is this correct?

ps. No I did not read the discussion, what is VE?
 
c2x level matching

Yes-using Yamaha MC 705 or Adcom Crosscoil high output MCs or B&O MMC-1 moving iron (2.12mV) cartridges, the system is much louder when switched to CD or tuner inputs. I spend much time playing my horn to the system and tend to switch back and forth from 2 TTs/CD/tuner. Before attenuating the line inputs, the volume level jumped profoundly when switching from a turntable to CD or tuner. By trial and error I ended up with -14db in-line attenuater to CD, and -10db to tuner, which matches the source levels very closely to each other. Testing the preamp electrically confirms this.
What would work much better would be if the phono section had another 10db of gain in the MM inputs. As it is now, if I want to "get down" with some loud rock n roll, there isn't enough gain. With the hi output MC carts, I can select the MC input and the -10db phono trim and experience what my system is truly capable of-and it's pretty capable! But by doing that, the second (B&O) TT is now rendered useless (-10db from already poor gain), and the line inputs, even without the attenuaters are weak compared to the MC phono level.
VE=Vinyl Engine=wwwvinylengine.com. There is a current thread 27pgs long: "Further on rediculously low cost cartridges" which discusses excellent cartridges that are inexpensive. A month ago I read that thread and purchased an AT440MLa based on what I read. It raises the phono level somewhat compared to my other cartridges, but I'd still like the full 10db.
I want to try a lo-output MC thru the pre and see where that takes me. phil
 
I would say it is quite normal that the phono section is not as loud as the CD-Player, tuners can varry and some also have normal + high output (the T-85 has this).

Acctually the CD's them self varry quite a bit in level, if you play a cd from mid 80's and then play in a new pop CD, you will get quite a surprice when the SPL goes up. This is in general known as the "loudness war", witch started in the 70's radio mastered records.

To mach the CD-P and phono section I use the vaible output from the CD-P and tune this at the same level as the TT. This way I can switch without a jump in SPL, but this is not without cost. The signal from the CD-P can suffer a bit depending on the quality of the varible output, for critical listning i use the normal output.

Regarding carts, I think you overdrive you're MC input by running a high output MC into it, the high output carts was made to run on systems that was not capable of using MC carts (sytems with only MM indput). If you run the B&O MMC1 (0.6mV) into the MC indput, krank the volume all the way and still don't have a high SPL level, then you have to look at the combination of pre amp and power amp (and speakers of curse).
 
Running a high output MC (2-3mV) thru lo MC input probably gets to near overload (C2x MC limit is 20mV) but seems to be an OK bandaid for lack of gain.
If I run the MMC1 moving iron thru the MC input, there's MUCH gain (as there is when running Hi output MCs also), but it is not useful because the low impedance of the input ruins the frequency response of MM/MI carts.
 
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