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Why should I use two amps and how? Newb questions!

J

jchouston

Well-Known Member
Layman warning!

What, if any, is the benefit of running two similar amps from one preamp to one set of speakers?

I have a Rotel RC 870 pre and an Adcom GFA 535 amp (my sources are a Denon cd and Pro-Ject RM5) running to a pair of B&W 602’s.

If I were to get another GFA 535, would there be any benefit to incorporating it into my system and, if so, how do I do it? One amp per speaker? Or, one amp to the tweeters and one to the woofers? The 602’s do have two sets of posts per speaker, but I’ve never known why.

I’m just confused on how it would make a difference.

Two other factors: I have a pair of B&W 601’s that aren’t hooked up, but I don’t have wife approval for that yet. Also, would it make a difference if the second amp was an Adcom GFA 5300 instead of a GFA 535?

Thanks, everyone!
 
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unless you have two of the same amps one per speaker. but if you have two different amps. try one on the woofer and the other for the tweeters. it really makes a difference in sound quality. and try each amp on the tweeter and woofer posts. sound will change slightly as the amps are different...happy experimenting, i gotta go to work now.
 
budgetaudio6 said:
unless you have two of the same amps one per speaker. but if you have two different amps. try one on the woofer and the other for the tweeters. it really makes a difference in sound quality. and try each amp on the tweeter and woofer posts. sound will change slightly as the amps are different...happy experimenting, i gotta go to work now.
Click to expand...

I'm doing the one amp for the bottom/one for the top thing as of this morning and am thrilled with the results (see my post for details). Having dissimilar amps can work quite well that way it seems.
 
Vertical bi-amping you can use different amps, horizontal, you need to have matched amps. If you do both, you can get even more benefits..
 
So, if I am to understand correctly:

My B&W 602's have two sets of binding posts connected by a brass "bridge" or jumper and are powered by one amp.

Remove the jumper and use, say, the GFA 535 for the top set of posts and the GFA 5300 for the bottom posts. The result is one small step closer to audio nirvana?

BUT...it appears my pre-amp (which I have not yet picked up) only has one set of outputs. Does that negate everything?

I feel like I skipped out on school or something.
 
similost said:
Vertical bi-amping you can use different amps, horizontal, you need to have matched amps. If you do both, you can get even more benefits..
Click to expand...
Actually that is incorrect. It is the exact opposite. Its imperative the amps are the same for a vertical bi-amp configuration.
 
jchouston said:
So, if I am to understand correctly:

My B&W 602's have two sets of binding posts connected by a brass "bridge" or jumper and are powered by one amp.

Remove the jumper and use, say, the GFA 535 for the top set of posts and the GFA 5300 for the bottom posts. The result is one small step closer to audio nirvana?

BUT...it appears my pre-amp (which I have not yet picked up) only has one set of outputs. Does that negate everything?

I feel like I skipped out on school or something.
Click to expand...
some pre-amps do have 2 outputs.
Like the NAD C-162 it has 2 and even has variable output level on one of the outs.
But if yours pre does not you can use a y splitter....BUT
I looked up your amp and it has an A / B speaker selection
You could get away with one amp (I think) that this amp is biamp ready and you will not need a splitter
From Left channel pre-amp out to left channel in on the amp then to the speaker (with jumpers removed) run A to one of the binding post and B to the other
repeat for Right channel
 

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jchouston said:
So, if I am to understand correctly:

My B&W 602's have two sets of binding posts connected by a brass "bridge" or jumper and are powered by one amp.

Remove the jumper and use, say, the GFA 535 for the top set of posts and the GFA 5300 for the bottom posts. The result is one small step closer to audio nirvana?

BUT...it appears my pre-amp (which I have not yet picked up) only has one set of outputs. Does that negate everything?

I feel like I skipped out on school or something.
Click to expand...
This topic has been beat to death and opinions vary. The 2 sets of binding posts are tied together with a jumper yes. By removing the jumper it seperates your speakers passive crossover. The top binding posts will connect to the MF&HF (mids and tweets) and the lower posts for the LF (woofers) (unless otherwise marked but I have NEVER seen different). Since you have 1 set of preouts, use some Y-adapters to split them. The amp hookup as you describe above will be what I would call a horizontal passive bi-amp configuration. Try searching the site on bi-amping, and you will get more info and opinions than you will have time for. HERE is some good reading for you.

IMO and for the most part if you really want improvements, look into REAL bi-amping or active bi-amping by filtering BEFORE the amplifiers taking the passive crossover's out of the equation. Keeping in mind there ARE some speakers that are best left using the speakers crossover. After you have researched and your head stops hurting have some fun experimenting. :D
 
BalancedXLR said:
Actually that is incorrect. It is the exact opposite. Its imperative the amps are the same for a vertical bi-amp configuration.
Click to expand...

You lost me Balanced.. Vertical is high's and lows.. different amps can be used, but a crossover is a must.. Horizontal is left and right, and need to be matched... Or I missed something long ago...
 
similost said:
You lost me Balanced.. Vertical is high's and lows.. different amps can be used, but a crossover is a must.. Horizontal is left and right, and need to be matched... Or I missed something long ago...
Click to expand...
No sir, you have missed something long ago :) An example of vertical bi-amp is using a stereo amp for the left channel and speaker with 1 channel of the amp output connected to the HF and the other channel connected to the LF of the speaker. The amp would be getting the left channel signal output fed to BOTH L/R signal inputs on the amp. The right channel would be the same obviously except that the amp would be getting the right channel signal fed to BOTH L/R inputs and would require the amp to be the SAME. An example of Horizontal bi-amp would be using any 2 stereo amplifiers with L/R signal inputs hooked as normal and the amplifier outputs hooked as normal to the speakers (L to L and R to R). Only that 1 amps L/R outputs would hook to the L/R speakers top terminals and the other amp in the same manner but to the lower terminals. Again the amps do not have to be the same in a horizontal bi-amp config just balanced.
 
OK balanced.. I see where I'm getting confused.. You're talking stereo amps, and I'm talking about using mono amps to bi-amp..
 
similost said:
OK balanced.. I see where I'm getting confused.. You're talking stereo amps, and I'm talking about using mono amps to bi-amp..
Click to expand...
Still some confusion then; because in that case you STILL could use a SET of monoblocs for the highs and another completely different SET of monoblocks for the lows (example: tube set of blocs on the MF&HF and SS blocs on the LF).
 
right.. then that would be both vertical, and horizontal correct? Left to right, would be horizontal, and high and low would be vertical.. correct?
 
Autobot said:
some pre-amps do have 2 outputs.
Like the NAD C-162 it has 2 and even has variable output level on one of the outs.
But if yours pre does not you can use a y splitter....BUT
I looked up your amp and it has an A / B speaker selection
You could get away with one amp (I think) that this amp is biamp ready and you will not need a splitter
From Left channel pre-amp out to left channel in on the amp then to the speaker (with jumpers removed) run A to one of the binding post and B to the other
repeat for Right channel
Click to expand...

Huh?

:saywhat:

:headscrat

I think you're describing bi-wiring, but I'm really not sure.

:confused:

je
 
To the original poster- this is something that I've found is MUCH easier to work out in an actual real-time conversation- typing out this stuff without knowing your resources (knowledge, testing tools, components) ends up confusing & frustrating. Any chance you know somebody locally that could work through this with you? If not, feel free to hit me with a PM & maybe we can start with a quick conversation.

Good luck...

je
 
Nailer said:
Seperate amp for the woofers will typically require a crossover if amps aren't the same.
Click to expand...

That depends- if there are strapped inputs on the speakers, chances are that all of the passive crossover circuitry stays in line once the straps are removed (no internal/external crossover switch on the speakers).

Don't know how the if-amps-aren't-the-same part enters into the equation...

je
 
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