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Correct Phono Preamp Gain Setting

I have a Blue Circle Audio phono preamp with fixed gain settings of 58 and 71db. My cartridge is an Ortofon Cadenza Red with an output voltage of .45uv.
The KAB parameters chart indicates the setting should be in the low to mid-fifties. However, the setting at 58db and specifically the volume is too low. It sounds great, but is anemic, has no punch, and is not loud enough for my listening. On the other hand, the setting at 71db provides more than adequate volume without distortion. Unfortunately, I cannot do a direct A/B comparison to gauge quality differences. Are my ears deceiving me at 71db or do I need to set at the lower gain and purchase an SUT?
cinellipro
hdm
1,062 posts
 
With what you describe I would doubt that the 71 dB setting is optimal and I would in fact venture an educated guess that the 58 dB setting, as long is it is not presenting you with hiss/hum levels that are obtrusive at the maximum SPL's you want to achieve, would in fact provide you with better sound quality.

Bear in mind also that most volume pots are much more linear and provide their best sound quality when they are close to maxed out; I'd expect that to be the case with your Cayin as well.

What you've described in terms of the volume discrepancy is not unusual and is, in fact, pretty normal.
cinellipro OP
26 posts
 
I played a little bit of the Acoustech 45rpm recording of Horace Silver's Tokyo Blues at both settings. First with the phono gain set at 71db. Then again at 58db. At 58db I noticed a lot less hissing, more front to back depth in the soundstage, and everyhting the sound seemed more open, or less compressed. Thanks for the expertise and great advice. Now I just need to be okay with the volume knob cranked to 3.
Cheers!
hdm
1,062 posts
 
Bingo. What you just described is exactly what I would have expected based on the numbers. Especially with low output MC's, getting the gain right is extremely important. Both too little and too much gain (even 3-4 dB in my experience) can really compromise sound quality. You're actually quite fortunate as, at least in theory, 58 dB of gain should be just about absolutely perfect for your Cadenza Red. Glad it worked out for you!!
czarivey
5,946 posts
 
at 58db you get larger dynamic headroom. at 71db you compress signal lots.
i have to turn volume '3 hours later' vs. digital playback. as previous posters mentioned, it's normal.
mattmiller's avatar
mattmiller
1,497 posts
 
Cinellipro, Plain and simple....you need a phono preamp with better settings....a Musical Surroundings Phonomena would solve all these problems you describe. It has infinite # of settings to dial in your Ortofon,it also sounds awesome! punch, slam, detail, dynamics all there. I purchased one used on the Gon for around $325. It is amazing what a good phono preamp does.
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