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Understanding Gain in the ARC Ref Phono 2 SE


On my ARC Ref Phono 2 SE, it has a high gain and low gain setting. I am having
to use the high gain setting for adequate volume output. The low gain is just
too quiet, even when I turn up my Rowland Synergy IIi volume all the way. Now, this was different on my Rowland Cadence where I could use the low gain settings on it and the volume would be just fine. Although the high gain setting in the ARC Ref Phono 2 SE is fine, I would like to use the low gain setting if at all possible as it optimizes the lowest electrical noisefloor.

So here is some info/technical data on my system:

Cart:

Dyna XV-1s:
Output 0.3 mV; resistive loading recommended > 30 ohms

Here was the typical settings I would have on the Rowland Cadence:

Low gain: 64 dB (high would be 74dB). Cart loading ranges from 30-400 ohms


Here is the ARC Ref Phono 2 SE: (I run SE from tonearm to phono pre, balanced out of phono pre)

Gain: 51 dB low gain, 74 dB high gain (BAL) ; 45dB low gain, 68 dB high gain
(SE)

Cart loading: 50-200 ohms

Output impedance: 400 ohm balanced out (recommended load 50K-100K ohm)

I'm guessing my volume in low gain on the ARC is due to running BAL (51dB)
compared to BAL on the Rowland Cadence at 64 dB. On to
something there?

Then I wonder despite the above if the pre amp specs may still play a role:

Rowland Synergy IIi

Input Impedance: BAL at 36K ohms or 600 ohms. This is switchable and default
is 36K ohms. Never tried the other lower ohm setting.

Output Impedance: Balanced at 80 ohms

Eventually if I purchased an ARC REf 5SE preamp, here are the ARC Ref 5SE preamp specs:

Input Impedance: 120K ohms balanced

Output Impedance: 600 ohms balanced; 20K ohm resistive load

So I'm guessing again its the difference in output in the BAL configuration low gain settings from the Cadence (64 dB) to the ARC low gain BAL (51dB). Any way to use the low gain setting in the ARC through my Rowland Synergy IIi to get adequate volume output without turning up the volume to maximum settings? Changing the input impedance of the Synergy to the lower ohm setting? Eventually would a new ARC Ref 5SE preamp help this?

Any input or advice would be appreciated as I would like to use the low gain setting in the ARC as I did in the Cadence.

philb7777

Showing 4 responses by philb7777

philb7777 OP
401 posts
 
Thanks for the responses and info.

The noise floor in the high gain setting on the ARC is just slightly more noticeable than the low gain setting. This is not audible at the listening position, just next to the speaker.

What you are saying makes sense - gain is gain! I will try to increase the gain setting on the input in the Synergy and experiment.
philb7777 OP
401 posts
 
Thanks Gpgr4blu!
philb7777 OP
401 posts
 
I prefer the ARC over the Cadence in my system. The Cadence is fanstastic. Super quiet but with my system a tad on the dark side. The ARC give much better continuity to the soundstage and all the good tube- stuff. Plus much better dynamics and ambient retrieval of space and info. Imaging density slightly better with the Cadence, but imaging in the ARC more 'realistic' if that makes sense.

I'm keeping both, but using the Cadence around 10% of the time to the ARC 90% of the time. When I get a second arm and cart for my table, I can have active use of both.

Good to know others with low output carts are using high gain in the ARC.
philb7777 OP
401 posts
 
Dctom -

The Ref 2 SE is super quiet. At a volume turned up to a meter level of 40/60 on my Rowland Synergy IIi and the high gain setting noisefloor is only audible when placing your ear a few inches away from the tweeter/mid. In low gain, still silent at those volume levels. Being used to solid state, I was amazed at how quiet tubes can be. The SE upgrade is probably well worth it.

My next carts will be in the 0.5 mV levels so I can utilize the low gain settings in the Ref 2Se more.
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