2. amps-preamps
  3. 1057037362

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
gunbei
2,327 posts
 
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.
kool39 OP
53 posts
 
Gunbei, thanks for the advice. I was looking at my audible illuions L-1 manual and it states that the output impedance is 1.2Kohm. The aragon 4004 mkII does have an input impedance of 22Kohm. This tells me i am on the low side of the of the guidline range but also i am well within it at 18 times. Not completely sure that some of the problem doesnt lie in this area but with the dynamics as such i highly doubt it.
marakanetz's avatar
marakanetz
5,473 posts
 
Output impedance usually is correctly specified in the manuals but the freequency range sometimes isn't or if even specified the levels usually hidden.
Preamp might be at fault of not having "full-enough" range and needs either internal upgrade or replacement.
I'd increase negative feedback or introduced the global feedback if one is absent in the amp. Also I'd replace stock volume control on alps pots.
For a replacement I'd look for Audio Research older units that are far more superior than L1.
kool39 OP
53 posts
 
Marakanetz, The frequency response is specified in the manual and it is within 1dB from 2 to 100khz. So i do believe it has the audible range covered. The preamp seems to be working perfectly absolutely dead quiet. Music comes out of the blackness. There is no noise present when i turn the volume controls. Not sure what you are talking about with global or negative feedback. The aragon is an ss amp by the way. Thanks for the input.
redkiwi
1,092 posts
 
I have had one experience where the 4004 MKII had such a high damping factor that the bass was swallowed by a 'floppy' room. By 'floppy' I mean suspended wooden floor or thin walls etc. In the same room a fairly basic tube amp managed much 'better' bass than the Aragon simply by being less damped.
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