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Adcom GFP 555II Preamp Bass Lacking

I recently acquired an Adcom GFP 555II for 50 bucks. When I first tried it I noticed that it sounded very flat, had virtually no bass at all (lab output) and a slight amount of bass with the contour on. I replaced all the old capacitors with ELNA caps. It sounds much better now, however it still has a weak bass output. Any ideas on what could be wrong or is this what I should expect from Adcom? I'm running an Adcom GFA 5200 Mosfet power amp as well. Running four 10" bass drivers but the bass is just not there. Thanks for any help, -Keith
128x128moviemakerkeith
philjolet's avatar
philjolet
2,306 posts
 
Slikric, isn't the bypass the lab output?

the Adcom should have bass

try different wire for starters
slikric3000
638 posts
 
The bypass is just that, uses minimal electronics, bypasses tone controls, has a much more fuller sound. I have had this model, close to 20 years ago.
slikric3000
638 posts
 
Besides that, 4-10 inch drivers with a 50 wpc amp, cmon already. There is a Monster Cable, I forget which 1, I have several pairs at home that will add noticable bass, but I am in Denver right now 1200 miles away.
philjolet's avatar
philjolet
2,306 posts
 
"bypasses tone controls"

that is what the lab out does
slikric3000
638 posts
 
Where are you getting the lab output, in the manual the bypass is stated to use minimal electronics including bypassing tone controls. There is no mention that I can remember of it being a lab output. The 565 has 3 sets if I remember right. What would be the the 3rd output be ?? 3rd leg output ??
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