Help with increasing gain on pre amp or options?


I've just recently paired an AR LS15 tube preamp with a pair of Cary V12 Monoblocks and need to increase the gain from the preamp to get more volume....probably around 30% including some headroom.
What is the best was to do this?
The LS15 has the remote volume control so I'm guessing it's not as simple as changing a couple of resistors?
The issue seems to be with the V12's, since I had the same problem with lack of volume when driving them directly from a Monarchy DAC, and I've driven other amps directly from the DAC without issue (both LS15 and V12 are new to me, so I haven't had experience with these issues before now).

Is it possible to change output tubes in the LS or input tubes in the V12 to increase gain?

I don't want to open up the V12's if possible.

Any help would be appreciated.


The gain of either the preamp or the power amp could be easily increased slightly by trivial circuit changes. Why not consult with the manufacturers?
If your cdp and the Cary have the outputs, switch to XLR which typically carry an additional 2volts over single-ended connections.

Given the right right mix of things, those additional 2 volts could grant you your wish.

The LS15 was sold offering two different gain choices at time of purchase. You should contact Audio Research and give them the serial number and they should be able to tell you which version you have.
It may be an issue of voltage sensitivity instead of gain.
On my ARC pre (SP-9), there was a trace to cut on the PCB that would change (reduce) the gain. Maybe it was cut on yours.
One note of caution regarding preamps that provide two different gain settings. Sometimes, selecting the higher gain option can also increase the distortion to unacceptable noise levels.

What is the output of you CDP? maybe it is time or an excuse to upgrade that and get the gain increase you need.

I have a Gamut CD1R and it has a 4 volt gain and I'm actually looking to reduce my gain because it is too much for my high sensitivity amplifier inputs.
Thanks for comments so far, however, I just installed a high-gain mod from Audio Research (2 resistors lift the output from 12 to 18 db) and it's still not enough.
It changes from disc to disc, but on most discs I can't get more than about 88db (at the desired 14' listening position') from my Mag 3.6's. The amps don't sound particularly strained, so I'm assuming more volume is possible given more volts on the inputs.
What concerns me is that looking at Cary's preamps as a possible 'synergistic' option, they range in gain from only 17db to 20db, which I don't beleive will be enough, based on what I've just seen going from 12 to 18db.

I'm using balanced outs from the LS15, although they are quite long at 20'. I would estimate based on the step from 12-18db, that I need about 25db gain to get the volume up without having the volume pot fully clockwise.
My front end is Audio Alchemy DDS Pro Transport into AA Dti Pro 32 into MF A3/24 upsampling DAC.
I don't know if there is any way to lift the output from the Dti or the MF?
I really don't want to ditch the LS15, but ARC are saying that any additional increase in gain would result in excessive noise and degraded sound quality.

Can anyone suggest an option that doesn't involve ditching equipment, if not, please recommend a pre with balanced outputs that has 25+db of gain.

Many thanks