I've noticed that some High-End Amplifiers use 2 Power Transformers for the Power Supply; a separate Transformer for each channel.
Is this something quite new? I've always only seen 1 Power Transformer used in most Amplifier Power Supplies.
Are 2 Transformers used only on Higher-Power Amps? Or is it a matter of better separation between the 2 channels to acheive a higher-level of Sound Quality?
I'm referring to Solid-State Amplifiers only.
Is this something quite new? I've always only seen 1 Power Transformer used in most Amplifier Power Supplies.
Are 2 Transformers used only on Higher-Power Amps? Or is it a matter of better separation between the 2 channels to acheive a higher-level of Sound Quality?
I'm referring to Solid-State Amplifiers only.
Nothing new. Generally two would be used in a higher-quality amp, to achieve two monoblock type designs in a single chassis. You are correct that this leads to better separation and sound quality (in theory).
tiroth said:
Thanks. So, are you saying that it's the "Separation" of both channels and an independent Power Supply for both the left & right channels that really makes the difference?
It's not an issue of Power (Watts) that this kind of design is necessary? Another words: Is it a better design regardless of whether the Amp is designed to put out only 1 Watt or 500 Watts?
Tom D said:
You can buy VERY large transformers. If you were building a VERY powerful amp, then you could need to use 2 tranformers. Only in very extreme cases would two tranformers be a "necessity".
Using two smaller transformers will almost always be more expensive.
If the amps have a high enough PSRR, then the benefits of two separate supplies will be minimal.
All told, two separate supplies are theoretically better than one, but in most cases, I don't see the benefit.(considering the cost)
Tom
It's basically about reducing intermodulation distortion to a minimum. If one channel is sucking a lot of power from the supply, and if your supply is a little weedy, your rails will then sag, and the other channel has a lower voltage to work with.
It's quite common to have two sets of smoothing caps and bridge rectifiers as once your caps are charged, you should be okay. Doubling transformers provides less benefit. Some people even have two power cords! You could take independent cables back to your fuseboard. The channels have to meet somewhere. As with all audio, how far do you want to go?
Separation is a bit misleading: intermodulation can affect one channel on its own. The interesting thing to compare is two separate supplies versus one twice the size. I would be surprised if you could hear a difference, as long as the supply is big enough.
Two transformers look impressive and it's a good sell.
It's basically about reducing intermodulation distortion to a minimum. If one channel is sucking a lot of power from the supply, and if your supply is a little weedy, your rails will then sag, and the other channel has a lower voltage to work with.
It's quite common to have two sets of smoothing caps and bridge rectifiers as once your caps are charged, you should be okay. Doubling transformers provides less benefit. Some people even have two power cords! You could take independent cables back to your fuseboard. The channels have to meet somewhere. As with all audio, how far do you want to go?
Separation is a bit misleading: intermodulation can affect one channel on its own. The interesting thing to compare is two separate supplies versus one twice the size. I would be surprised if you could hear a difference, as long as the supply is big enough.
Two transformers look impressive and it's a good sell.
You could always use a transformer for each rail (if using both positive and negative rails) then you'd look even better to those you're trying to sell to 🙂...
If you won't want to buy two transformers (expensive) you could always get a transformer with dual secondaries.
If you won't want to buy two transformers (expensive) you could always get a transformer with dual secondaries.
2 xformers
What the two last corresponders wrote, coundn't be more true!
Yes, somewhere there has to be fixed a limit. The quest for absolute channel separation is wrong. Now that CD provides more than 60 dB separation, people have started to realise that music is better heard if the two channels are deliberately mixed (there are "black boxes"sold which do this thing)! Cartridges were providing 30-40 dB separation. Then, we were satisfied! I wonder, how much live music do we hear, in order to understand that more than 20-30dB channel separation is never heard, even if are sitting on the first row.
In the past, i was was trying to separate everything. By the time, i realised that i was doing more harm than good. 2 xformers=2 sources of 50Hz electromagnetic radiation.Also more space. Also, they had to be positioned 90 degrees to each other. Also double mains wiring. So, what's the use? The most you have to do, is to use two separate bridges and caps. Simple is correct.
What the two last corresponders wrote, coundn't be more true!
Yes, somewhere there has to be fixed a limit. The quest for absolute channel separation is wrong. Now that CD provides more than 60 dB separation, people have started to realise that music is better heard if the two channels are deliberately mixed (there are "black boxes"sold which do this thing)! Cartridges were providing 30-40 dB separation. Then, we were satisfied! I wonder, how much live music do we hear, in order to understand that more than 20-30dB channel separation is never heard, even if are sitting on the first row.
In the past, i was was trying to separate everything. By the time, i realised that i was doing more harm than good. 2 xformers=2 sources of 50Hz electromagnetic radiation.Also more space. Also, they had to be positioned 90 degrees to each other. Also double mains wiring. So, what's the use? The most you have to do, is to use two separate bridges and caps. Simple is correct.
When using 2 xformers (or dual secondaries/single xformer) there is always the earth connection that is common. The channels can be wired directly or through a few ohms and I believe this causes interference as well. One only have to hear a bad earthed amp to feel this!
One possible advantage of using two transformers is when you can't use toroidal core transformers (for whatever reason, such as cost or availability), putting two smaller E-I transformers in place of one can reduce the minimum height requirement of the amplifier's case. Of course, smaller transformers will sag more, and are also less efficient. They put less of a strain on the filter caps, with respect to their ripple current ratings.
Thanks to everyone for all the informative responses!
Well, it seems to me from most of the responses; that it's really not a "necessity" to use 2 transformers unless it's a special design(not sure if I'm saying this right) or a very High-Powered Amp. But; a couple of people said; It makes for a good sell. It "looks" impressive and a designer "can" use 2 transformers and the manufacturer can claim superior performance even though in reality there would be no audible benefit.
Hope I'm making sense?
Well, it seems to me from most of the responses; that it's really not a "necessity" to use 2 transformers unless it's a special design(not sure if I'm saying this right) or a very High-Powered Amp. But; a couple of people said; It makes for a good sell. It "looks" impressive and a designer "can" use 2 transformers and the manufacturer can claim superior performance even though in reality there would be no audible benefit.
Hope I'm making sense?
What's anyone's take on this one. HeadRoom Max Headphone Amp. 2 Avel-Lindberg Transformers. Uses OPA627 Op-Amps. Good design or (possibly) just a good sell?
http://www.headphone.com/images/InsideMaxBig.JPG
🙄
http://www.headphone.com/images/InsideMaxBig.JPG
🙄
Not even one comment or opinion on this Amp??
The thread was going along very well and I appreciate all the responses.
Tom
The thread was going along very well and I appreciate all the responses.
Tom
Headroom Amp
Same goes for this headphone amp. They have done just about everything "extra" you could possibly do to an amp. Dual supplies, fanciest connectors, etc. Again, here the dual transformers probably make the amp 0.01% better, even though it doesn't make much economic sense. (Look at the price - if you had much economic sense, you probably wouldn't spend that much on a headphone amp!)
Same goes for this headphone amp. They have done just about everything "extra" you could possibly do to an amp. Dual supplies, fanciest connectors, etc. Again, here the dual transformers probably make the amp 0.01% better, even though it doesn't make much economic sense. (Look at the price - if you had much economic sense, you probably wouldn't spend that much on a headphone amp!)
Re: Headroom Amp
seangoesbonk,
Thanks. It does seem to be overkill in most respects. This amp probably puts out less than 1 Watt of power, since that would be more than sufficient to drive headphones. I suppose it "is" better performance-wise opposed to some other headphone amps. But, going back to some earlier posts in this thread:
Is it really "necessary" or just a good sell marketing-wise; Like you said about "economic sense".
seangoesbonk said:
seangoesbonk,
Thanks. It does seem to be overkill in most respects. This amp probably puts out less than 1 Watt of power, since that would be more than sufficient to drive headphones. I suppose it "is" better performance-wise opposed to some other headphone amps. But, going back to some earlier posts in this thread:
Is it really "necessary" or just a good sell marketing-wise; Like you said about "economic sense".
My experience is that there can be quite dramatic improvements from going from a single power transformer to duals. Naturally, whether a change is described as "dramatic" or not is entirely subjective. But in general, I have found that changes to power supply busses and grounding schemes can yield sonic differences that are considerably more obvious than most component changes (and the differences are usually easily measurable). Changing normal electrolytics to Black Gates or industrial-grade opamps to audiophile-approved devices is nothing compared to the differences that you can obtain by re-routing busses, or for that matter, revising circuit-board layouts.
Some of the benefits of dual transformers can be accomplished by going from a single, shared secondary winding to dual secondaries - one per channel (for the sake of simplicity assuming one winding for both voltage polarities with a center tap ground). But my experience is that there is still enough modulation occurring through the transformer core that there is a further benefit in moving from dual secondaries to dual transformers.
Theoretically, if you had a granite-solid constant current source and used one pair per channel to feed the regulators and amplifiers, the constant-current nature of the sources should fully isolate the channels and make it immaterial whether you were using one transformer or two. But this is easier said than done. Definitely one of the areas that I intend to work on in the future.
regards, jonathan carr
Some of the benefits of dual transformers can be accomplished by going from a single, shared secondary winding to dual secondaries - one per channel (for the sake of simplicity assuming one winding for both voltage polarities with a center tap ground). But my experience is that there is still enough modulation occurring through the transformer core that there is a further benefit in moving from dual secondaries to dual transformers.
Theoretically, if you had a granite-solid constant current source and used one pair per channel to feed the regulators and amplifiers, the constant-current nature of the sources should fully isolate the channels and make it immaterial whether you were using one transformer or two. But this is easier said than done. Definitely one of the areas that I intend to work on in the future.
regards, jonathan carr
I could not agree more with what Jonathan has mentioned here. The use of separate Transformer per channel is always the first tweak I would considered. (if possible). I do this even for my power amp, pre-amp, and even DAC. I use separate transformer for my left and right BB1704. Try it to experient the differences.
So; I think it's coming down to the importance of the Power Supply. Whether the sonic differences are audible are of course subjective, like someone else said.
And of course the price of the amp goes up because of the extra parts, and/or better quality parts.
And of course the price of the amp goes up because of the extra parts, and/or better quality parts.
Even if I quite agree with the dramatic differences two transformers can make, I believe the most dramatic improvement can happen when you split from one transformer to separate bridges and separate capacitors for each channel.
The key there is to use a big transformer that will not lag down when power is demanded. In my opinion that is what kills dynamics and is more evident than channel separation.
Crosstalk shouldn't happen if you use good star earthing, big transformers (EI or toroidal), big bridges and good size capacitors. On the latter, too big can be a problem sometimes.
Carlos
The key there is to use a big transformer that will not lag down when power is demanded. In my opinion that is what kills dynamics and is more evident than channel separation.
Crosstalk shouldn't happen if you use good star earthing, big transformers (EI or toroidal), big bridges and good size capacitors. On the latter, too big can be a problem sometimes.
Carlos
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