pre amp suggestions

Before you give up on your Lamm, I would look to the amp. I would think the 14.87db gain provided by the L2 should be enough with that amp. From Rowland's website on the Model 5 specs;
Overall Gain Selectable: 20, 26, 29.5, 32 dB
Sensitivity 36 mV, 1 watt, 8 ohms
Input Impedance Selectable: 100k, 20k, 600 ohms
It appears you can select your gain (maybe by internal dip switches or jumpers?) and also your input impedance. Start by checking the input impedance. Although the output impedance of the Lamm is stated as "nominally" 130 ohms, the actual output impedance could be much higher at low frequencies. You should make sure your amps are not set at the 600 ohm input impedance, then try both the 20K and 100K ohm settings to hear the differences. You should also check to verify your amps are not set at the lowest gain setting, and adjust the amp's gain setting as needed to achieve the best sound. Hopefully, you can resolve the problem without the expense of changing equipment. Good luck.

I would also suggest to raise the input impedance of the JRDG model 5 to 28K Ohms, or even better to 100Kohms. This should be probably attempted before raising the amp gain.

Thanks very much but I tried before but this rowland amp doesn't seem to have any adjustments. I spoke to Jeff Rowland and he said that this model didn't have the adjustments like the later ones. In the past I had the sevens and they had the adjustments as described. You all are correct I believe because as I think about it the amp seems to be the problem.

Hmmm, the spects for JRDG model 5 are on the following page:
http://jeffrowland.com/ClassicSpecs.htm
The manual is at:
http://jeffrowland.com/Docs/Model5Manual.pdf

In particular, here is what the manual states about input impedance and gain selection:

"Input Impedance Selection
Your amplifier is provided with user-adjustable input impedance. A four (4) position
D.I.P. switch for each channel is located and clearly marked on the back panel. Jeff
Rowland Design Group has chosen 3 values of input impedance to cover the majority of
applications. If you want to change your input impedance, please turn off the front panel
power before doing so. Selecting from the switch codes shown below will provide the
specific input impedance desired by the user.
The "low" setting is for use with most direct-coupled solid-state preamplifiers such as
those made by Jeff Rowland Design Group; the "medium" setting is for use with most
solid-state, hybrid and some tube preamplifiers; the "high" setting is for use with most
tube preamplifiers. We have provided these different settings so that you may find which
one provides the best sonic results in your system. Your amp comes set from the factory
at the "medium" (20 k ohms) adjustment.
Adjustable Gain
The overall gain structure of your Model 5 amplifier can be adjusted to one of four
different values, 20, 26, 29.5 or 32 dB. (Your amp comes set from the factory at the 26
dB adjustment.) The Model 5 can thus be used with dissimilar-gain preamplifiers, as well
as with a wide variety of analog and digital sources (since many digital sources [compact
disc players, digital to analog converters] have high output voltages relative to tuners,
tape decks, etc.). This feature allows the volume control of your preamp to be used in its
optimum position. It also permits you to tailor the gain structure for use with high or
low-efficiency speakers.
The gain switches are located on the underside of the plug-in modules and should only
be adjusted by your Jeff Rowland Design Group dealer. Incorrect installation of these
modules will result in damage to the amplifier circuitry which cannot be covered under
warranty."

Your amp may still be on the factory set 20KOhms input impedance. It is also possible that early Model 5 production runs lacked these adjustments.

Guido

A few months ago a friend and I adjusted the impedance and it sounded best at the factory setting I think. However it sounded best at it's current setting, then we tried adjusting the gain and removed the module but there wasn't any adjustment controls and that's when I contacted Rowland and was told that the gain could not be adjusted on this particular series. I guess that I would have to start looking around for another power amp e.g the Rowland 8t, krell evo 402 or some other s s amps. Feel free to make suggestions. Currently the system sounds ok but to me and some of my friends it's a bit dark and I believe it's from the Rowland.

Before suggesting any amp alternatives, here are a couple more questions for due diligence:

1. Have you checked the status of your pre tubes? Is there the possibility that they are depleted? Here is what Lam says about them:

"NOTE: we recommend replacing 6C19P and both 12AX3 tubes about once a year
to maintain the best performance of the preamp"

2. Are you using balanced ICs? Both L2 and JRDG M5 seem to provide XLR connectors. M5 appears to be symmetrically balanced and should yield higher performance in a balanced configuration.

What power cords are you using on your system?

Bery old thread but i cant help but notice not 1 person thought of reccomending the OP insert an Active gain control in the loop that would have added +12 db which is a massive jump in gain, its how i solved the same problem with my Rowland 501 amps,a decent quality gain control can be bought well under $100.