Amplifier Voltage Gain matching your Preamp and Amplifier

[Irvrobinson]

Irv what about the 2002, and where would it be ?

The AT2000 and the AT3000 do not have gain controls. On the AT602 and AT1202 they have small screwdriver controls on the rear panel.

 

[cpp]

The AT2000 and the AT3000 do not have gain controls. On the AT602 and AT1202 they have small screwdriver controls on the rear panel.

Thanks Irv for a moment I thought I had missed out on something....

 

[seanpatrick]

Hey all - Boy this level of understanding is WAY beyond mine when it comes to audio. With that in mind, perhaps someone could offer some advice. I've picked up a Denon X 4000 and recently added height channels ( as the wides are not really feasible with my room layout ) to bring my total to 9.2 Speakers. The Denon needs a amp to power the extra speakers, so I picked up ( got a deal used ) an Audiosource Amp - 100. It puts out 60wpc x 2 @ 8 ohms ( which my speakers are ), and I've got it connected to the pre -amp out of the receiver to power my heights. Funnily enough, though 60wpc should be more then enough to power heights, I've still got to max the volume on the amp to match the rest of my speakers within +/- 3db when running room calibration software. I'm wondering if A) it would be worthwhile to pick up a matching amp and run them bridged, ( 160wpc ) and have them power my fronts, thus freeing up the AVR to power the surrounds or possibly sell it and pick up a more powerful stereo amp to do the same? Would I notice a difference? More to the point, if I were to do so, how could I make sure there were no sonic differences between the amp I pick up for the fronts, and the amps in the Denon? or is this really a non issue. Thanks in advance!!!

 

[Grador]

Hey all - Boy this level of understanding is WAY beyond mine when it comes to audio. With that in mind, perhaps someone could offer some advice. I've picked up a Denon X 4000 and recently added height channels ( as the wides are not really feasible with my room layout ) to bring my total to 9.2 Speakers. The Denon needs a amp to power the extra speakers, so I picked up ( got a deal used ) an Audiosource Amp - 100. It puts out 60wpc x 2 @ 8 ohms ( which my speakers are ), and I've got it connected to the pre -amp out of the receiver to power my heights. Funnily enough, though 60wpc should be more then enough to power heights, I've still got to max the volume on the amp to match the rest of my speakers within +/- 3db when running room calibration software. I'm wondering if A) it would be worthwhile to pick up a matching amp and run them bridged, ( 160wpc ) and have them power my fronts, thus freeing up the AVR to power the surrounds or possibly sell it and pick up a more powerful stereo amp to do the same? Would I notice a difference? More to the point, if I were to do so, how could I make sure there were no sonic differences between the amp I pick up for the fronts, and the amps in the Denon? or is this really a non issue. Thanks in advance!!!

Maxing the volume on the amp is in fact appropriate. Remember that your denon is providing volume control [pre-amp] so when you connect the pre-amp outs of the denon you would only be adding more volume control by having the audiosource set to anything but max.

 

[Zereth]

Power amp an preamp

Ok this is confusing since I'm not a math wiz. I'm new to power amps and pre amps. I picked up a peavey rockmaster tupe preamp and a crown xls 402. Now how would I set up the wattages , db's and all that good stuff with out clipping . I also have an ampeg 4x12 200W, each speaker is 16 ohm.
Please help.

Zereth

 

[AbbyDaddy]

Has anyone tested or seen the input/output/gain specs of a Yamaha RX-A3050 in relation to what external amps it is capable of powering? I connected my Rotel RMB-1075 and it sounded like junk compared to the AVR powering the same speakers. I am now leaning towards either an Emotiva XPA-7 or ATI AT3007, but don't really know if the Yamaha can handle it. I have emailed Yamaha to get the spec on that, but to no avail.

 

[TLS Guy]

Has anyone tested or seen the input/output/gain specs of a Yamaha RX-A3050 in relation to what external amps it is capable of powering? I connected my Rotel RMB-1075 and it sounded like junk compared to the AVR powering the same speakers. I am now leaning towards either an Emotiva XPA-7 or ATI AT3007, but don't really know if the Yamaha can handle it. I have emailed Yamaha to get the spec on that, but to no avail.

A gain mismatch is not going to make an amp sound like junk. If it did sound like junk then there is something seriously wrong with that Rotel Amp.

Pretty much all amps will sound fine with your receiver, even if the position of the volume control will be different between amps.

 

[fmw]

It is none of that. Nearly every preamp output will drive nearly every power amp to full output.

Bingo. Why fetter audio enthusiasts with things that don't matter? It is like complaining about inaudible distortion.

 

[fmw]

Has anyone tested or seen the input/output/gain specs of a Yamaha RX-A3050 in relation to what external amps it is capable of powering? I connected my Rotel RMB-1075 and it sounded like junk compared to the AVR powering the same speakers. I am now leaning towards either an Emotiva XPA-7 or ATI AT3007, but don't really know if the Yamaha can handle it. I have emailed Yamaha to get the spec on that, but to no avail.

It is a non issue. It will drive whatever you connect to it.

 

[Irvrobinson]

Bingo. Why fetter audio enthusiasts with things that don't matter? It is like complaining about inaudible distortion.

Actually, it can matter. The combination of a Sony BD player, an Outlaw 975 prepro, an ATI AT602 amp, and relatively inefficient bookshelf speakers, caused me very annoying gain structure problems. The 975 can't drive the AT602 to anything like full output, and often couldn't play many DVDs and BDs loud enough to enjoy. Personally, I do feel the 975 is poorly designed and should have greater output into lower impedance, but I'm using it as an example because your blanket statement isn't correct, fmv, and there are combinations possible that don't work that well together. Just saying.

 

[TLS Guy]

Actually, it can matter. The combination of a Sony BD player, an Outlaw 975 prepro, an ATI AT602 amp, and relatively inefficient bookshelf speakers, caused me very annoying gain structure problems. The 975 can't drive the AT602 to anything like full output, and often couldn't play many DVDs and BDs loud enough to enjoy. Personally, I do feel the 975 is poorly designed and should have greater output into lower impedance, but I'm using it as an example because your blanket statement isn't correct, fmv, and there are combinations possible that don't work that well together. Just saying.

That was bad luck. Unfortunately there is no agreement on what line level is. However the vast majority of line level outputs are from 1 to 2 volts full modulation with headroom over that.

Most unbalance line level input are the same. So if you had an output of 1 volt and input requirement of 2 volts full modulation you would only be off 3db.

So I think your problem is unusual.

Again Peter Walker made his preamps flexible providing a choice of 0.5 volt, 1.6 volt and 5 volts out. As usual he had the customer covered!

 

[fmw]

Actually, it can matter. The combination of a Sony BD player, an Outlaw 975 prepro, an ATI AT602 amp, and relatively inefficient bookshelf speakers, caused me very annoying gain structure problems. The 975 can't drive the AT602 to anything like full output, and often couldn't play many DVDs and BDs loud enough to enjoy. Personally, I do feel the 975 is poorly designed and should have greater output into lower impedance, but I'm using it as an example because your blanket statement isn't correct, fmv, and there are combinations possible that don't work that well together. Just saying.

OK let me rephrase it to say that problems mating preamps to amps are so rare as to be ignored. In more than 1/2 a century of audio I have never encountered a single one, even in two years of doing bias controlled tests on hundreds of products. Yours is the first one I've ever heard of. I think you might have had a defective product somewhere. I agree completely with what AVengineer posted.

It could be hard for a home audio preamp to drive a pro audio amp which expects a 2 volt signal to full power, but certainly it can drive it far enough to handle a home audio environment. I don't read any complaints about people driving pro audio amps with home audio preamps. In your case you were using home audio amps. There should not have been the slightest problem unless you had a defective product.

 

[Steve81]

Why fetter audio enthusiasts with things that don't matter?

Articles like this tend to get written specifically because people have had problems / asked questions on the subject.

 

[Irvrobinson]

I think you might have had a defective product somewhere.

No, I don't. I tested the AT602 in my primary system, and that pre-amp easily drove it to clipping; the AT602 just has only 28db of gain, while most inexpensive amps these days have 32db of gain. I talked to Outlaw, and they seemed to have a procedure all ready for trying to mitigate the problem. The Sony worked fine previously with a Sony AVR. Fortunately the problem was solved by just using much more efficient speakers, which I'm guessing are over 10db more sensitive than the previous pair.

I think my case is unusual, good thing, but I also think being dismissive of the problem is incorrect.

 

[fmw]

No, I don't. I tested the AT602 in my primary system, and that pre-amp easily drove it to clipping; the AT602 just has only 28db of gain, while most inexpensive amps these days have 32db of gain. I talked to Outlaw, and they seemed to have a procedure all ready for trying to mitigate the problem. The Sony worked fine previously with a Sony AVR. Fortunately the problem was solved by just using much more efficient speakers, which I'm guessing are over 10db more sensitive than the previous pair.

I think my case is unusual, good thing, but I also think being dismissive of the problem is incorrect.

I hear you. Hopefully you will forgive my being dismissive because I still am.

 

[fmw]

Articles like this tend to get written specifically because people have had problems / asked questions on the subject.

That is certainly a thought. I'm not criticizing the writing of the article. I am agreeing with someone who criticized its content.

 

[PENG]

No, I don't. I tested the AT602 in my primary system, and that pre-amp easily drove it to clipping; the AT602 just has only 28db of gain, while most inexpensive amps these days have 32db of gain. I talked to Outlaw, and they seemed to have a procedure all ready for trying to mitigate the problem. The Sony worked fine previously with a Sony AVR. Fortunately the problem was solved by just using much more efficient speakers, which I'm guessing are over 10db more sensitive than the previous pair.

I think my case is unusual, good thing, but I also think being dismissive of the problem is incorrect.

I just checked Outlaw website and found the 975's pre outs are rated 2V, 2.7V maximum so I don't know what it can't drive your AT602 that only needs 0.9V for the rated 60W output, according to the manual and my calculations back that up too.

http://www.ati-amp.com/manuals/at1202manual.pdf

Did Outlaw give you any reason why their 2V is a problem? Assuming it is 2V rms I just can't see that being a problem.

 

[Irvrobinson]

I hear you. Hopefully you will forgive my being dismissive because I still am.

I can't say that I'm surprised. As for being forgiving, the last time that topic came up I was called "demanding and uncompromising". Make of that what you will.

 

[Irvrobinson]

I just checked Outlaw website and found the 975's pre outs are rated 2V, 2.7V maximum so I don't know what it can't drive your AT602 that only needs 0.9V for the rated 60W output, according to the manual and my calculations back that up too.

http://www.ati-amp.com/manuals/at1202manual.pdf

Did Outlaw give you any reason why their 2V is a problem? Assuming it is 2V rms I just can't see that being a problem.

Outlaw never gave me a technical reason for the gain problem, and I almost sent the silly thing back, but the only alternative for a prepro in that price range was the Emotiva, and I already had a bad experience with that company. And other than the remote control design being unbelievably lame, and slower than average HDMI switching times, the 975 does perform very well within its limited output. It also looks good, is easy to set up, and has been reliable.

As you might have expected of me, PENG, I read the specs before ordering. I suspect the problem is one or more of the following:

- The 975 doesn't have an output level problem; it has an input sensitivity problem, and has substantially less than unity gain.

- The 975 has an unusually low input impedance, perhaps because of a design defect, and is somehow stressing the cheap output devices of certain components, like the cheap Sony BD player. (I doubt this is the reason, but I don't know.)

- The 2V output spec is simply incorrect, or wasn't met in the first version of the product, which I have. (I suspect this is the real reason.)

- The ATI AT602 gain is not 28db, it is only 24db, which is woefully low. If you look at the ATI web site, which was my reference, gain is listed at 28db. If you read the owners manual, I just noticed it is listed at 24db. 24db, if correct, is the lowest gain I've ever encountered for a power amplifier. (24db of gain in conjunction with less output from the 975 than advertised could be a double whammy.)

So, I'm thinking this is a genuine case of components that are just incompatible, especially when the electronics chain is paired with a set of JBL speakers that are probably 82db/2.83v/m, sensitivity-wise. And I'm also thinking that y'all ought to consider the silliness of being so dismissive of a situation that when discussed gets an immediate match from an audience with such a small population.

 

[slipperybidness]

- The ATI AT602 gain is not 28db, it is only 24db, which is woefully low. If you look at the ATI web site, which was my reference, gain is listed at 28db. If you read the owners manual, I just noticed it is listed at 24db. 24db, if correct, is the lowest gain I've ever encountered for a power amplifier. (24db of gain in conjunction with less output from the 975 than advertised could be a double whammy.)

Yeah, 24dB seems unlikely to me. More likely that it's a misprint.

Voltage Gain (Av) is pretty easy to measure with a function generator, dummy load resistors, and an O-scope.

I mentioned in another thread, when I build an amp, I typically shoot for 29dB. That seems to be about the sweet spot from what I've seen.