Need some audiogon expertise


Hi all, I am having a little problem here with thin bass. I am not really sure where to start. Some help would be most apprecieated. I have heard some say tubes in preamp but i dont feel that 2 little 6922's can be causing the music to be so thin but maybe so. Heres my list of equipment.

California Audio Labs Icon/Powerboss
Audible Illusions L-1/matched pair of 6H23-EB
Aragon 4004 mkII
Sansui TU-717
Vmps Tower 2/R's
Acoustic Research 12 guage
Radio Shack fusion IC's throughout

Stand alone i've not heard of any of the components having the traits of thin bass. But obviously i have something causing this.

Room is 22 x 14 x 8. Speakers are on the short wall placed 2 1/2 feet from back wall and 3 feet from sidewalls toed in directly at my listening position which is 10 feet from speakers.

Thanks for the help.
kool39

Showing 2 responses by gunbei

Cables and cords are good way to tune a system, but it may be better to make sure everything else is matched first.

Tubes are also a good way to tune your system, but you seem to have everything dialed in and the bass may be tough to solve by changing 6922 tubes. In my system, changing 6922s have altered the sound in more than one area of the sound spectrum.

I checked the specs on the input sensitivity for your Aragon 400 mkII and it's rated at 22Kohm, which is in the same ballpark as the 23Kohm Pass Aleph 3 which I had trouble mating to my Blue Circle BC21 preamp. If the output impedance of your Audible Illusions L-1 is 2Kohm as Marakanetz says, that may be the reason right there. Previous A'Gon posters have mentioned a guideline range of 10 to 100 times [preamp output impedance to amp input impedance] and your set up is sitting on the very low end.

Do you lack dynamics if you turn the volume up? Along with the thin bass, this was another problem I experienced with the Aleph 3. A real shame because no amp has done guitars as well in my system as the Aleph 3.

Is it possible for you to substitute another amp in place of the Aragon just to see if that has an effect? Also, what's the output voltage on your CAL Icon? If that is too low it's possible the AI L-1 doesn't have enough gain to compensate for that.

Good luck and let us know how it goes.
Kool, from what you describe even though the specs say otherwise, it seems you might NOT be experiencing impedance mismatching with your preamp and amp.

I agree that experimenting with speaker placement would be the best place to start. Try pushing them closer to the back walls. Hopefully you can achieve a balance where bass fills out without becoming boomy or muddy, and soundstaging doesn't suffer.

Good luck.