RS2B : Which amp to use for best performance

ygorali

New Member
I'm wondering if someone can help me on this. I have a pair of RS2B speakers with the Low Freq Equalizer. They are good condition with no issues. The rest of the equipment is as follows.

* A custom-built tube preamp
In biamped mode;
* Two custom built tube power amps for the mids and highs
* ADCOM GFA-555 PRO for the low end

Previously ADCOM's successors were two other custom built tube power amps. Since I had found the bass sluggish back then, I replaced them with ADCOM. And now what I ended up with is the boomy bass.

I would like to get your thoughts and insights to get things right. I am also open to any suggestions including other options for replacing power amps.

Thanks !
 
Welcome to AK.

Assuming the Adcom is operating properly the first thing I would look at would be the speaker placement/room interaction.

The best speaker in the world can sound like crap if you are having issues with
boundary reflections and standing waves etc.

How far out from the side walls and the rear wall are they placed?

Make an effort to look at your room then if still having issues move on to the gear.
 
A friend replaced his Adcom GFA 555's with an MC300. The Mac's highs and mids are much clearer and less grainy but the bass is louder with the GFA's. Not better just louder.
 
It could be a balance issue - too much power to the bass is overpowering the
highs & mids. Reduce the gain on the Adcom until the balance sounds good.

Have you tried running the speakers full range with just the Adcom? If it doesn't sound boomy it's a balance issue. It it still sounds boomy then it's a room or speaker setup issue.
 
I like the Adcom gfa 555. Don't have one anymore but never thought they made speakers boomy. Very good slam. If it is too spec i would look elsewhere for the problem. Check the tubes in your pre amp along with what the other guys said.
Jim
 
Room is the first place to look for something that doesnt sound good provided all the components are working OK. RS2B should not be boomy
 
Both my RS-IIIa's and II's show boominess when close to the corner (see my Avatar), but this is fixed to a large degree when I move the speakers to the middle of the room when listening for real. So try to move the speakers 3+ ft away from the back wall and 2-3 ft from the side walls for starters.
 
Both my RS-IIIa's and II's show boominess when close to the corner (see my Avatar), but this is fixed to a large degree when I move the speakers to the middle of the room when listening for real. So try to move the speakers 3+ ft away from the back wall and 2-3 ft from the side walls for starters.

I agree. Assuming the EQ is working properly, I would suspect placement / room. Its not the Adcom. I've used both a 555 ii and a 5502 to drive the bottoms. Very tight and tuneful bass using either. My 2Bs are 3 ft from the back wall and 4-5 ft from the side walls / corners.
 
These speakers are designed to be out in the room. Mine are almost 6' into the room, and the difference is HUGE. Better bass, MUCH better soundstage and imaging. As below:
 

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Some details about the listening environment

All,

As someone who is rarely into the forums, I got amazed when I saw your close interest to this matter. I should say that I am very thankful of your helping hand indeed.

Well, let me give you some details about the listening room.

Distance between speakers : 185 cm
Distance from the wall : 90 cm
Distance to the listening seat : 410 cm

Also note, that there is a good space on the sides of the speakers.

See also the attached picture.

So, any new thoughts ?

Thanks in advance,
 

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nice setup indeed. I would myself pull the speakers out a little from the cabnet. but other then that,.looks good to go. I had a pair of these speakers. one of the best out there for the money. and decent amp will drive them. you do not need a $10,000 amp. I used b&k 202+ for top. soundcraftsmen for bottom. adcom 5500 for both. parasound 3500 for bottom. jolida 502p in mono for top, and a few others. all worked well. if you get a decent 150 wpc an up you should be good to go. no 50 wpc receivers will do. enjoy
 
Very nice room and set up. Have you ever tried a ss pre amp or another tube pre amp? I've found the bass to be much better with my ls7 compared to my sp6. The sp6 has a looser bottom end. Both are Audio Research but around twenty years apart with the ls7 to be newer. Maybe burrow another preamp and see if it makes any difference. Perhaps synergy is a problem as with the two pre amps I mentioned many would rate the sp6 above the ls7 but not with my setup. Anyone with ears could tell the ls7 to be superior with the associated eqipment.
Jim
 
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