Lil' Knight
Headphoneus Supremus
- Joined
- Sep 16, 2007
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Even though the beta22 itself IS a discrete op-amp?
Overkill is my middle name
Nah, a truly good amplifier should be able to drive anything from sensitive IEMs all the way to Speakers right?
I'm a fan of Jensen Transformers, but that might just be because I've worked with them more than any other company, it's funny how we form favoritism like that...
http://www.jensen-transformers.com/ln_in.html
And TBH, toroidal transformers provide some degree of self-shielding in the first place, the electromagnetic radiation coming from the transformer is probably very small compared to other current-carrying wires in the system.
With that said, I cannot empirically prove that what I just said is correct because I don't have the necessary equipment to do so. If you just happen to have a EM radiation meter laying around then by all means, take some measurements of toroidal transformers when they're operating and see if they will cause EMI in amplifiers.
I lean towards the school of thought that headphone amps should be "high power pre amps" not "low-power speaker amps."
There is something to say for both design methods, but I prefer an elegant solution to brute force.
Nobody gets my subtleties, congrats.
I lean towards the school of thought that headphone amps should be "high power pre amps" not "low-power speaker amps."
There is something to say for both design methods, but I prefer an elegant solution to brute force.
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What's the difference?
Looks great!
How did you make that silver PCB?
. The issue with the 2-box B22 (or even one-box if you're not careful) is that DCR and inductance between the power supply and amp boards has been linked to a few B22 failures.
Learn the maths!
Bigger transformer ≠ more magnetic field.
I lean towards the school of thought that headphone amps should be "high power pre amps" not "low-power speaker amps."
There is something to say for both design methods, but I prefer an elegant solution to brute force.
The 2-box B22 was a very popular solution to transformers leaking EMF into what should have been a quiet amps. The issue with the 2-box B22 (or even one-box if you're not careful) is that DCR and inductance between the power supply and amp boards has been linked to a few B22 failures.
There is another good reason to use an appropriate transformer for the job. An underloaded tranny will typically put out a higher voltage than spec, giving your regulators a harder time (=more heat and other problems down the line).
I can't think of any advantages to using an oversized transformer at all.
The rated output voltage is usually given as the unloaded one.
Just to be clear, the only reason I'm a 300VA transformer is because I ripped it out of one of my older builds so I don't have to buy a new one.
I will never do stupid things for the hell of it.
Likewise, the only reason why a person like me who thinks headphones amps should be nothing more then a few op-amps is even making a 4-channel beta22 is because I got most of the stuff for free.
To be completely honest, I think the beta22 is an absolutely stupid design.
You do get the point that a beta22 is just an over blown discrete opamp, right? So, if you think a headphone amp should be nothing more than a few op-amps, then why would you be opposed to one that is just a large op-amp?
Well, it's not the opamp architecture but rather how the design wastes so many components for the sake of being overkill an no real advantage in boosting the performance at all.....
That depends on what you mean by performance. The amp was designed to excel in performance metrics (measurements), and therefore (according to the theory) also sound great. You can see this from the "specifications" pages on the website - I haven't yet seen better specs in ANY amp. The B22 beats everything by large factors, often by orders of magnitude. It's a shame it hasn't been retested with some serious test kit yet, but I believe this on the "to do" list, as it far exceeds the audio interface it was tested with.
Whether this approach automatically leads to something that sounds good isn't known. But by putting together a discrete amp you definitely have more control over its performance. More than anything it's a great example of simulation-driven circuit design.