Stereo bridged or Mono amp

jakelm

Was brought up breifly in another thread, that there is a difference.

Besides ohm handling, what the difference between a stereo amp that is bridge and a mono amp?



Jake

thejck

yeah i'd like to know that too

unc2701

Depends on the design of the mono amp. A bridged stereo amp will always be push-pull. Some mono amps are, some aren't.

venomclan

A bridged amp, is a 2 channel amp that is essentially combining both channels to create 1 more powerful channel. Not all amps can be bridged.


The mono amp, is just a single channel amp.

General concensus is to avoid bridging amps, as some results show added distortion going that route. It would best to get 1 more powerful stereo or mono amp pair.
V

heiney9

unc2701 wrote: »

Depends on the design of the mono amp. A bridged stereo amp will always be push-pull. Some mono amps are, some aren't.

This is not nec true. A perfect example is the Monarchy SM70. It's a stereo amp that is single ended mono when bridged. Balanced also. This is the exception however as most (95%) are as you say "push-pull" when bridged.

This is an excellent article it's a bit technical but it should get the basic idea across of bridging. It's more for car stereo application but the concept holds true for all bridgeable stereo amps.

http://www.bcae1.com/bridging.htm

I'm pressed for time but I'll revisit this subject over the weekend to try and help explain the difference between true mono blocks and stereo bridging.

H9

jakelm

But I always thought, when bridging an amp, your using only 1 channel, but both L/R MOSFETS and both sides of power supply. I thought the actual signal is not used in one of the channels, but just the voltage.

In a plate amp for a sub, you have seperate left and right inputs. (Reason for the 3dB increase in output when using both inputs). So is a plate amp concidered a bridged amp?

In a bridged system, the single signal is looped through the intire amp instead of just one half?

Flows from positive left into posistive right (acting as ground)?


Link not working for me H9.....

jakelm

I just read this article: http://www.digitaldj.ws/mediawrite/Tech%20pages/Bridged-Mono.htm

Am I missing something, or since my Hafler has a common ground between output left and right. All I would have to do is take the input wires (coming out the back of the input RCA jacks), split them in 2 (2 pos wires, 2 neg wires), cross them (positive to negative on one board) , Diconnect the inpout wires completely from input 2, then hook my speaker from speaker out 1 positive to speaker output 2 positive, and its bridged?

It cant be that simple.

thejck

so if you have speakers that are biampable would it be better to use 2 amps in stereo and biamp them than use each in mono for each speaker??
i know you shoudnt go with numbers but amps that are bridgebale usually have really high mono watts rating.

AndyGwis

Am I missing something, or since my Hafler has a common ground between output left and right. All I would have to do is take the input wires (coming out the back of the input RCA jacks), split them in 2 (2 pos wires, 2 neg wires), cross them (positive to negative on one board) , Diconnect the inpout wires completely from input 2, then hook my speaker from speaker out 1 positive to speaker output 2 positive, and its bridged?

It cant be that simple.

Man, that doesn't sound simple to me. I'm lost just reading it. . .

jakelm

AndyGwis wrote: »

Man, that doesn't sound simple to me. I'm lost just reading it. . .

It sounded simpler in my mind...lol:D

The amp does require a phase inverter board to bridge...shoot..I thought i could just swop some wires...

jakelm

Anyways back to original question......

I'm starting to think the answer to my stereo/mono question is harder than just jotting notes down in a forum.

heiney9

jakelm wrote: »

Anyways back to original question......

I'm starting to think the answer to my stereo/mono question is harder than just jotting notes down in a forum.

You got it! I wouldn't recommend trying what you stated in your earlier post. I'll try to shed more light when I have time.

H9

jakelm

My original question, was brought up on the fact that my center channel will soon get its own dedicated amp. Now wether to go bridged or mono, I dont know.

There are alot of great stereo amps out there that are very inexpensive and can be bridged for that wattage I need. Also when an upgrade bug hits again, I could always unbridge the amp and put it on surround duty.

I know this might sound wierd, but having a stereo amp and only using one channel, for center speaker, for maybe years, just doesnt sit right with me. I would much prefer bridging it and have the same hours used on all of the components within the amp.

But not if sound quality will suffer or life of the amp will suffer. Then I will go with a mono amp. But if I go with a mono amp, then I am stuck with a mono amp.

Questions, questions...decisions decisions

heiney9

jakelm wrote: »

My original question, was brought up on the fact that my center channel will soon get its own dedicated amp. Now wether to go bridged or mono, I dont know.

There are alot of great stereo amps out there that are very inexpensive and can be bridged for that wattage I need. Also when an upgrade bug hits again, I could always unbridge the amp and put it on surround duty.

I know this might sound wierd, but having a stereo amp and only using one channel, for center speaker, for maybe years, just doesnt sit right with me. I would much prefer bridging it and have the same hours used on all of the components within the amp.

But not if sound quality will suffer or life of the amp will suffer. Then I will go with a mono amp. But if I go with a mono amp, then I am stuck with a mono amp.

Questions, questions...decisions decisions

I would think for an HT center either one would be just fine. Not too much of a load on the amp and not so worried about superior sound reproduction. If you can get a bridgeable amp much cheaper (same quality) as a mono I see no reason in this application why it wouldn't work out with great results.

Most of the time my POV and comments come from a purely 2 channel POV and the quest for superb sound reproduction. HT is a whole other ball game and I just haven't spent the time getting beyond the basics for HT set-up, etc. Frankly the expectations for HT are different too.

H9

jakelm

In my experience in HT, the center channel in under major duty, so IMO a quality powerful amp is deffinatly needed.

With that fact that my center is close to 4ohms and is driven as hard as a movie theater, I feel my HK is working overtime keeping up with Most movies

Dialog clarity, is critical. Vocals are one of the hardest things to reproduce, if not reproduced accuratly, it can be quite disturbing. So IMO, the center channel is one of the most important channels in a HT. Being one of the most important channel, taking the amp that drives it, lightly, can ruin the whole HT experience.

Ever been to a movie theater and could barely hear the dialog? Result of bad center speaker or bad amp. It does ruin the entire movie.

heiney9

jakelm wrote: »

In my experience in HT, the center channel in under major duty, so IMO a quality powerful amp is deffinatly needed.

With that fact that my center is close to 4ohms and is driven as hard as a movie theater, I feel my HK is working overtime keeping up with Most movies

Dialog clarity, is critical. Vocals are one of the hardest things to reproduce, if not reproduced accuratly, it can be quite disturbing. So IMO, the center channel is one of the most important channels in a HT. Being one of the most important channel, taking the amp that drives it, lightly, can ruin the whole HT experience.

Ever been to a movie theater and could barely hear the dialog? Result of bad center speaker or bad amp. It does ruin the entire movie.

I understand but it certainly isn't as critical as trying to reproduce music correctly was my only point. Dialog is a lot different (to me) than vocals. Now if you are using this for some sort of ultra high end multi channel music thing then perhaps better gear and speakers are warranted.

I do agree 100% the center channel needs the most attention as far as calibration and power to keep up with the rest of the front stage. But a less expensive bridgeable stereo amp will certainly be more than good enough to give you excellent results.

H9

jakelm

heiney9 wrote: »

I understand but it certainly isn't as critical as trying to reproduce music correctly was my only point. Dialog is a lot different (to me) than vocals. Now if you are using this for some sort of ultra high end multi channel music thing then perhaps better gear and speakers are warranted.

I do agree 100% the center channel needs the most attention as far as calibration and power to keep up with the rest of the front stage. But a less expensive bridgeable stereo amp will certainly be more than good enough to give you excellent results.

H9

Absolutly, SACD/DVD-A rules as much as DD/ DTS in my home.

When I said dialog/vocals. To me they are the same, both refering to the human voice.

The reason behind myself believing it is harder for a system to reproduce vocals/dialog, is the fact that instruments (music) is machanical in nature, as is the equipment amplifying it, vocals on the other hand are biological, in which the best reproduction of a human voice, is only another human voice. Which it take s a much more of a strain for a mechanical peice of equipment to reproduce a biological sound.

If that makes any since. Just my opinion.

unc2701

heiney9 wrote: »

This is not nec true. A perfect example is the Monarchy SM70. It's a stereo amp that is single ended mono when bridged. Balanced also. This is the exception however as most (95%) are as you say "push-pull" when bridged.

This is an excellent article it's a bit technical but it should get the basic idea across of bridging. It's more for car stereo application but the concept holds true for all bridgeable stereo amps.

http://www.bcae1.com/bridging.htm

I'm pressed for time but I'll revisit this subject over the weekend to try and help explain the difference between true mono blocks and stereo bridging.

H9

I still haven't figured out WTF is up with that SM70, but it's definitely the exception to the rule.:) Been meaning to shoot them an email, just to satisfy my curiosity.

heiney9

unc2701 wrote: »

I still haven't figured out WTF is up with that SM70, but it's definitely the exception to the rule.:) Been meaning to shoot them an email, just to satisfy my curiosity.

Do share, I did send them an e-mail to see if it's common ground when run in stereo because since no one ever seems to sell their used Pass Labs pieces (alephs in particular) I might pick one of these up and run it in stereo for my SDA's. I got no response which is unusual because C.C. Poon has been very quick to answer questions in the past.

H9

Systems

jakelm wrote: »

In my experience in HT, the center channel in under major duty, so IMO a quality powerful amp is deffinatly needed.

Agreed,on some movies I have found there to be some effects along with dialog that can place some big demands on the center.For this reason I recently did a big upgrade of my center speaker and amplification because the previous setup sonically fell apart trying to handle movies like Master and Commander etc.

Systems

On the subject of bridged amps some high power units are specifically designed and optimised with bridged (also refered to as balanced) output stages.For instance the mono block Bryston 7B SST has 2 complete channels but they are permanentlyconnected in bridge mode so that it can achieve its high power output.

Ron Temple

jakelm, what kind of budget, what kind of power? I was bridging an Audiosource Amp One to 200w vs the HK and it definitely improved performance, especially for MCH vocals. Since it was bridged and it's a pretty dinky amp, I decided to put the center on 1 channel of a TFM35, 250w. A little better, punchier yes, but not miles of improvement. Both are 2 ohm stable and used are pretty cheap. I'm sure can do you do as well.

jakelm

Hi Ron, The budget is yet to be determend. The upgrade will probably take place sometime next month as I am still dishing out money getting the kids back to school (geeezzz "public" schools are expensive, between BETA, Band and their sports, I am currently broke).

Budget will probably be around the $150-$200 mark. As for power, the HK is doing a pretty good job with its 90-100watt @ 6 ohms. So Im thinking no less than 150 -200 watts. Something similar to if I bridged out my Hafler.

jakelm

Question, Common ground, my Hafler has the both speaker grounds connected together between the PS caps. Is this concidered common ground? Does an amp half to have common ground to be bridged?

Systems

jakelm wrote: »

Question, Common ground, my Hafler has the both speaker grounds connected together between the PS caps. Is this concidered common ground? Does an amp half to have common ground to be bridged?

Yes your Hafler is common ground.
When you bridge an amps two channels it is no longer common ground because the negative output is not at ground potential in fact it is usually the two positive (hot)terminals that are used.

jakelm

GV#27 wrote: »

Yes your Hafler is common ground.
When you bridge an amps two channels it is no longer common ground because the negative output is not at ground potential in fact it is usually the two positive (hot)terminals that are used.

Because the phase between the 2 channels is 180 degrees which makes a ground.

Why would Hafler and many other manufacutrs make a phase inverter board, when you could just swop the polarity of the input on one chanel? Wouldnt that change the phase also? Does the entire circuit have to be phase reversed or just the input voltage before the amp?

Systems

jakelm wrote: »

Because the phase between the 2 channels is 180 degrees which makes a ground.

Why would Hafler and many other manufacutrs make a phase inverter board, when you could just swop the polarity of the input on one chanel? Wouldnt that change the phase also? Does the entire circuit have to be phase reversed or just the input voltage before the amp?

The inverter is needed to shift 1 channel 180 degrees out of phase with the other.
I ll try to make this make some sense.
Non bridged the amps AC voltage output potential is measured between positive and ground.When you take the second channel and invert its phase its potential is the same as the positive cycle but it is below ground.So now you have twice the voltage swing because you have the potenial between pos and neg (ground is in the middle)and not just pos to ground.Picture it as an AC sinewave that is twice as big.

frreo1

When most amps are bridged, their ability to handle impedance is halved. What that means in the practical sense is that if an amp could normally handle a 4 ohm load. bridging it means that now it's limit would be 8 ohms instead. Given the fact that many modern speakers often provide nominal 4 ohm loads, bridging is not a good idea for those type of speaker loads.

jakelm

GV#27 wrote: »

The inverter is needed to shift 1 channel 180 degrees out of phase with the other.
.

I understand the concept of bridging. But my question is, wouldnt changing the posistive and negative input wires on the amp board, create a 180 degree shift in phase and voltage, therefore, the posistive output post becoming the negative?

Then why add a board, when the input wire swop be easier?

My diagram kinda explains what I'm talking about

Early B.

jakelm wrote: »

Budget will probably be around the $150-$200 mark.

For your budget, spend $150 and get yourself a Marantz MA500 monoblock (150 wpc) or spend $200 for an MA700 (200 wpc) and you're done. Great sound quality for the price.

Systems

Oh will it work without the inverter?Probably not as it would just short the signal to ground.The best solution is the external inverter.