Arguably not too interesting anymore as things have been evolving on the power amps front, just a very good and proven by now CFA solution with some solid engineering, there are better and mightier now from Sito and possibly others. I used to have KT88s push pull class A triode 20W+20W amp of my design with Audio Note OPTs, silent as a church mouse on 100dB horns even, but as my speakers have developed they needed more current at a point and I had to cover for that and also sell my tube amp so to replenish for my further experiments in the various system fronts.
Transducers are floating balanced sources (or loads), we very recently referred to that when analyzing the 2xDCG3 BAL modes.
Now I read this myth busting article about connecting and driving headphones that a friend e-mailed to me. Funny coincidence.
https://benchmarkmedia.com/blogs/application_notes/audio-myth-balanced-headphone-outputs-are-better
Now I read this myth busting article about connecting and driving headphones that a friend e-mailed to me. Funny coincidence.
https://benchmarkmedia.com/blogs/application_notes/audio-myth-balanced-headphone-outputs-are-better
If you look at my signature, You see i am coocking on
a scaled down Alephj.
Gives around 15w and is sensitiv at input.
I have attached a picture with datasheet from original
Alephj.
Attachments
The last thing I would like to do is to introduce myself as an expert. I can't even measure what I build or listen to. My limited level of knowledge on electronics and audio derives mostly from internet reading. This said I' m very carefull what to adopt and what to reject. I appreciate articles like the one above because the authors respect sience. In fact it's articles like this that made me understand the benefits of balanced driving! It all stars from the balanced nature of headphones and then it is a matter of power, distortion output impedance and damping factor all relative parameters...How many commercial products deliver the power of DCG3 @ 0 ohms?
Thanks Jesper! I was following the last posts your mimis thread. I' m going to read it all.
Just beware
... The "final" schematic is not updated with current components value (Don't differ much from schm. through!)Jesper.
A bridged channels amplifier works balanced from input to load. The article verifies the benefits of balanced connection between line and power electronics but busts the notion that balanced power drive is better for transducers. To the contrary it could be struggling in some situations.
When driving a load between bridged amplifiers its ideally four times the same type single amp's power due to the voltage it doubles. For types of headphones that are leaning to higher voltage & lower current (>120Ω) there will be not too heavy taxing of the amps although they still do see half the Ω each thus asked for double the current each. Its as like each side now drives a 60Ω headphone.
That should be kept in mind for bias choice when planning bridged headphone driving with 2xDCG3 for the range of headphone models in someone's collection. The headphones should have 4 wires (in stereo) connections.
When driving loudspeakers could be a heavy duty job nonetheless. Amplifiers running in bridged mode are usually doing so only with speakers that have impedance of twice the minimum impedance the amp is rated for when in two channel single ended mode. In other words, if an amp is rated to handle 4 ohm loads in stereo mode, the minimum load for bridged mode will be 8 ohms.
True for balanced and bridged amplifiers. But I think bridged amps are not balanced. They do not amplify antiphase signals. They take in phase inputs somehow in parallel and they give in phase outputs somehow in series. WRT psu modulation, a bridged amp stresses more the psu than a SE and a balanced amp much less. That is if I get it right of course!
Also as AndrewT points out in every given chance, it is not the balanced signal but the balanced impedance that deals with CMRR. I just try to understand where the balanced signal fits in the equation. My empirical conclusion is:
1. For common noise rejection impedance must be balanced or at least very low source impedance to very high load impedance.Common noise would hardly be an issue in home audio though.
2. Balanced signal is self compensated for low psu modulation.
3. For power stages - headphones or speakers - it's not only voltage swing but watts. Source/load impedance ratio is critical. Better start with very low source impedance and high enough load impedance both for balanced and bridged amps. Still, the amps will be stressed to deliver full power but OTOH if we need the same SPL as with SE mode then the volume control should be turned down relaxing the amps.
Coming back for a correction. Indeed I didn't get it right! Bridged amps work in antiphase mode. Still, not understand if this is just to make input and output floated but that's another thing. For the rest I can't see if I' m missing anything.
The thing is they need too much power sometimes. They have an opamp inside that reverses signal taken from input one. Drives input two with that when a bridge mode small switch is selected outside. Only input one is used for incoming mono signal. Many times done for driving high power in a big subwoofer both in pro audio and car audio. Or for main cabinets series combinations when short of enough dedicated amps. Not usual but it may come up.
They many times also have a parallel mode option for dumping big current in low impedance. There they drive both inputs in phase from a mono signal again and the load (few paralleled cabinets) hangs from both amps in SE mode to ground.
They many times also have a parallel mode option for dumping big current in low impedance. There they drive both inputs in phase from a mono signal again and the load (few paralleled cabinets) hangs from both amps in SE mode to ground.
I don't know, I have seen several wild claims in brochures, but your differential DCG3 arrangement can provide 1.6W to 300 Ohm headphones. With high enough gain set you may smoke them up for good if you choose so
I'm glad I'm not the only one alert to this myth.
A balanced amplifier will effectively bridge the load.
A bridged amplifier is not necessarily balanced unless it is DESIGNED to be balanced impedance.
It is necessarily antiphase the least. All installation worthy and tour worthy prosound amps use the XLR input and are well engineered to resist interference on signal lines. Its ok to have considered them correctly balanced bridge mono mode offering examples for the economy of discussion IMO. MagicBus's 2xDCG3 build is balanced source and bridged power when attaching headphones for sure anyway.
Do you live in Athens center? Maybe I could come around and listen to your open baffle speakers with NOS German ovals and 2xDCG3 balanced at a point?
Don't trust the DMM at mV AC level and full range signal. Most can only surely pick up a simple sinewave below 1kHz reliably when strong enough also.