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gcph phono stage gain settings

i just bought a ps audio gcph and i'm using it with an mm cartridge that is rated at 3.3mV (clearaudio virtuoso). i have to have the input gain on the back panel turned all the way up to 66, the highest setting, to get decent volume, and even then i have to have the output gain knob on the front of the unit turned to 1 o'clock. this goes against what the manual says, namely that for mm cartridges the input gain on the back should be at the lowest setting.

i'm concerned that if i ever get an mc cartridge with 1/10 the output of my current cartridge, the gcph will not be able to handle it.

does anyone with a gcph and an mm cartridge need to turn the input gain to the highest setting? what are your experiences?

thanks in advance!
tanglewood
axelwahl
788 posts
 
Hi,
y.s.:
>>> i'm concerned that if i ever get an mc cartridge with 1/10 the output of my current cartridge, the gcph will not be able to handle it.<<<

Your fear is completely unfounded. I used the GCPH with a 0.3mV cart. Setting in this case was 1kohm or 500ohm load and 60db RCA (=66dB with XLR which I used).

As far as the MM goes: The GCPH volume knob set at 3:00 is just fine with no sound degradation i.e. just a tad off the full volume (1:00 if FAR too low!). Close the volume all the way, put a small pencil mark at ~ 7:00 (as it does not do a full 360deg turn) then open the volume until your pencil mark is at ~ 3:00.

Setting for MM is 47k (a MUST!) and you will probably find that 60/66 dB is by far too loud! --- and so you can go down to a more appropriate 40dB RCA = 46dB XLR.
tanglewood OP
29 posts
 
thanks for the responses. yes, i have the impedance set at 47.
someone at ps audio initially said not to turn the front gain knob past 1 o'clock, but i don't get much sound if i do.

also, i get essentially no sound until the front knob is at 12. seems like a silly design to not start getting sound until the knob is half way around.
axelwahl
788 posts
 
Tanglewood:
I think in fairness to PS Audio, you also can connect the unit straight to a power amp. I have done that too, but preferred going true my Levinson 326S after all.
If you connect it straight to a power amp, it will start to make sense why it works that way. It's a good attenuator from 0 all the way up, and 1:00 will be about where it is at elevated room spl -- depending on your cart of course. Going into a pre-amp it's 3:00pm and not 1:00pm, at least in my experience... :-)
A.
tanglewood OP
29 posts
 
thanks axel.

and i did not mean to be critical of the gcph in general--i thought that perhaps my particular unit has a defect (it is b-stock). but it seems from your response that it is working as intended.

j
axelwahl
788 posts
 
Hi,
y.s.: >> (it is b-stock) <<
What makes it b-stock? I only know the answer to such in the shoe industry and there it'd mean some blemish/mark with the finish. You’d still get 2 soles and 2 laces, upper, insoles etc. :-)
So it maybe a scratch or such?
A.
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