Accuphase Pre / Power gain settings
 

Hi everyone,
I have an Accuphase set - C-2120 + A65 which I have been enjoying for a couple of months now. As you know - both pre and power have selectable gain switches.
Since I do not trust my own ability to decide by ear yet, I was wondering what friends here choose for these settings.
Right now i'm on +18db on the Pre (which is the default) and on -12db on the power (just because I saw in the specs that the SNR is better in this setting).

I would be glad to hear your opinion,

Thanks,
Simon

Simon:
I keep my C-2420 in 18db. My older A-50V doesn't have gain adjustment so I can't comment on that. I didn't notice any quality difference between the setting so I just left it in -18db.

In this review about the C-2120 ("Stereo" magazine from Germany, translated by Accuphase) http://accuphase.com/review_pdf/STER...0_01_2015e.pdf

they say:

(...) It also defines the sound character of the C-2120 and validates simultaneously the HiFi wisdom, which warns from little accentuation. Then the Pre-amp only offers in the “12 dB” position maximum, roomy, light and fanned out sound patterns. Already at “18 dB” it sounds a little tighter and more compact, what can be exciting with pop music, but doesn’t transfer as exhilarating and airy as before, furthermore the mid tones gain a little more severe diction.
“24” dB might allow to enhance consumptively pale sources such as Portis, but the C-2120 in turn looses much of its audiophile qualities

And about the Gain selector on P-4200, also reviewed, they say:

It’s gain selector with the positions “MAX”, “-3 dB”, “-6 dB” and “-12 dB” lowers just the input signal and not the tonal brisance of the “GAIN” – switch of the Power amp.


I keep the gain setting on the C-2420 at 12 dB, and if needed also lower the gain on A-46. I think the gain on the A-46 works by applying more or less negative feedback, so in theory something should change in the presentation, but honestly I never noticed striking differences between the settings.

I try to put myself in a preamp volume range range where the noise is theoretically minumum (not that I think you can actually ear any differences regarding noise in any position). Normally now I am between -30 and -40 on the volume, depending on the source.

Here is a noise graph from an Accuphase C-2120 paper:

https://c2.staticflickr.com/8/7351/2...e2bdf768_b.jpg

I keep my C-3850 in +18dB and my A-200 in MAX.
In addition I changed the level display reading to Gain Mode (default is Attenuator Mode).
This way, the approx. levels used fall between -20dB (corresponds to -38dB in Attenuator Mode) and -32dB (corresponds to -50dB in Attenuator Mode) and the scaling of the level control becomes less coarse.

Martin

Pre at +18dB and power at MAX is what Accuphase recommended to me as well.

Gain settings
 

What gain you would set for PRE and AMP.

Not basic recomendation from Accuphase with 18 on pre and Max on Amp

But with your own speakers and listening levels

Since I run my Arye QX 5 Twenty direct to my A 65 I have the gain set to -12 db so that the average listening level is around 70 to 80 on the QX 5 this sounds best on my room and set up.

Running dac direct to amp with a lower signal to noise ratio is clearly audible and most dac,s running direct sound better in the higher volume range then the lower half. When I had the matching C3800 I was running max on the amp and - 18 on the pre as I recall.

Attenuator vs GAIN
 

W-if i understand you well in Gain mode the volume control is used more widely meaning indicator to 3 o clock ?


I am at 12 on PRE and -12 on the Amp but volume is at max 11 o clock

I’d suggest doing some research on gain structure in a system. The goal is to minimise the needless amplification of noise.

Accuphase has already done this in more recent models (e.g. A-250) by shifting the formerly equally divided up voltage gain between signal input and power amplification stage towards a higher amount of voltage gain in the signal input stage (A-250: 22dB) and lower voltage gain in the power amplification stage (A-250: 6dB) with the goal to optimize the noise figures (A-250: 127dB for gain selector at max position).
Though there are also further measures applied to improve s/n.

Martin