sakis. i have done that. i use a F5 daily. and it is NO PROBLEM. also tryed with aleph2. but those amps are a little too laidback for my taste.
techno, metal, hiphop. no problem. i still use the F5 insted of the hypex UcD400HG.
techno, metal, hiphop. no problem. i still use the F5 insted of the hypex UcD400HG.
Last edited:
Why do audio amplifiers have to be "warm" or "hot" to sound their best ? Always strikes me as kind of odd tbh. If an amplifier can be reliably differentiated audibly as to whether its hot or cold then it strikes me as a pretty poor design, a design with some wildly varying and thermally unstable internal conditions. On the other hand, can a listener reliably differentiate if the listener was unaware whether the amp were hot or cold 😀
Medical and instrumentation electronics often need to be cooled to perform their best. Why do we not cool our RIAA stages to get the best possible noise figures for example ?
Just a wonderin'
Medical and instrumentation electronics often need to be cooled to perform their best. Why do we not cool our RIAA stages to get the best possible noise figures for example ?
Just a wonderin'
Answer is not that simple Mooly but of you want to generallize it i am willing to sahre an opinion ....
The average semi will play better if pushed hard ( voltage and current ) that will produce heat
Though expect decrease of speed
Class AB lovers get to get some of both some HK stages driven hard in class A while output rests in minimal idle
The juice lays in the balance of the above different topology and approach will produce different result
Let us take away from the picture devices with problems and behavior depending in the room temperature ....
The average semi will play better if pushed hard ( voltage and current ) that will produce heat
Though expect decrease of speed
Class AB lovers get to get some of both some HK stages driven hard in class A while output rests in minimal idle
The juice lays in the balance of the above different topology and approach will produce different result
Let us take away from the picture devices with problems and behavior depending in the room temperature ....
That is why I always prefer class A/B amplifiers. I try a few times with Class A, but I saw they were very inefficient. They have to use huge heatsinks and some of them I have seen with exhaust fans to dissipate the heat aagggg!!!. and I bet you if I put a good amp class A/B against a good amp class A you will not hear the difference!
PS: if I need a heater....I will get a class A amplifier 😛
PS: if I need a heater....I will get a class A amplifier 😛
lol...I guess you are "stocked" with a heater too 😛 Do not worry you can still build a good class A/B 😉
Member
Joined 2009
Paid Member
It's simple, in the winter use Class A and in the summer use Class D. For me, the biggest benefit of Class A is the ease of design and construction - it lends itself nicely to DIY. I do not believe in high powered Class A amplifiers because of the power dissipation so I willingly trade off dynamic headroom when using Class A and find this no issue. For home theatre where dynamic headroom is more important for me, then I use Class AB because I can build that fairly easily too. Of course, high power Class AB can waste as much energy as low powered Class A. Long term I will not be shy to use Class D - the technology is elegant and has huge potential yet to be unlocked.
🙂
Thanks Sakis. For me, I'm a non believer that a good competent amp will sound different when hot vs when cold.
I know many others disagree though 😀
is anyone aware of dynamic / active bias systems where all output devices conduct for 360 degrees of the input cycle yet have low idle current? I'm aware of non switching / square law amps and current dumping (sort of) but to me they are not pure class A.
I think many commercial amps claim "Class A" followed by some marketing speak such as sliding/dynamic bias etc. Simple answer is they are not Class A by the accepted definition of the term.
If any amplifier conducted for less than 360 degrees the output would be distorted with the possible exception of a true current dumping amp where there is a small Class A amp "to fill in the missing bits".
I actually proposed a technique that would allow for an amp to have a "variable" bias to always allow true Class A operation at all times,
http://www.diyaudio.com/forums/solid-state/154396-new-idea-low-dissipation-class-amplifier.html
If any amplifier conducted for less than 360 degrees the output would be distorted with the possible exception of a true current dumping amp where there is a small Class A amp "to fill in the missing bits".
I actually proposed a technique that would allow for an amp to have a "variable" bias to always allow true Class A operation at all times,
http://www.diyaudio.com/forums/solid-state/154396-new-idea-low-dissipation-class-amplifier.html
looks like i've got some reading to do but tracking the input signal volume would only work for a fixed (known) value resistive load? BTW some excellent articles on tubecad.com i have to say..
Same would apply to a conventional fixed bias Class A amp.
Use a load impedance below its design spec and the amp will either leave Class A before its rated maximum voltage swing or it will current limit (distort).
Use a load impedance below its design spec and the amp will either leave Class A before its rated maximum voltage swing or it will current limit (distort).
I believe that the output topology (where the emitters of the drivers are connected to the output) is the limitation. Only Krell and no other brands that uses this old topology at high level.
I have never found an amp based on Linn topology that is measured really high end. Many class-B amps are measured better than class-A, especially in term of THD, hence the detailed sound. But some class-A amps like a variation of Aleph-J is measured really well. So assuming that bias current, simplicity and measurement are 3 unrelated things, then it is for me something to keep.
I think he does.
Nothing wrong with voltage. Just found lead/acid battery doesn't suit my ears. But may be different if the battery is followed by high quality capacitors like in traditional power supply (in this case, short term high current is supposed to be supplied by the caps).
True.. I have one of it, even in class B. it uses around 110dB negative fedback to linearize the outputs. Sounds better than SE triodes😱. It also with switchable sound stage, light, weighted, and deep soundstages. it has around 1ohm output impedance with selective damping phase.
Class A Amp
You don't get owt for nowt! Done a lot of work with power amps.For REALLY top quality sound,Nothing beats Class A.but at the expense of power dissipation,max possible efficiency is only 25%.For in-depth info.see the writings of the late,great audio guru,John Lindsley-Hood,Various articles in Wireless World and his book "The Art of Linear Electronics"If you are into Classical at home,you'll be surprised how little power you actually NEED! I drive a pair of transmission line speakers with a pair of 10 Watt monoblocks,more than adequate for a med.sized lounge.For more amp details,see Graham Maynard "Gem Amp".
If you need more power,Class AB run with a hefty Iq ,say 60-100mA.but DO make sure the heatsinks are adequate.The best MOSFET amps.I have encountered are based on the Hitachi design note.B.K. Electronics make a range of amps.100 - 1K Watt based on the Hitachi design.They are very reasonably priced,but do need a case and a heatsink.
You don't get owt for nowt! Done a lot of work with power amps.For REALLY top quality sound,Nothing beats Class A.but at the expense of power dissipation,max possible efficiency is only 25%.For in-depth info.see the writings of the late,great audio guru,John Lindsley-Hood,Various articles in Wireless World and his book "The Art of Linear Electronics"If you are into Classical at home,you'll be surprised how little power you actually NEED! I drive a pair of transmission line speakers with a pair of 10 Watt monoblocks,more than adequate for a med.sized lounge.For more amp details,see Graham Maynard "Gem Amp".
If you need more power,Class AB run with a hefty Iq ,say 60-100mA.but DO make sure the heatsinks are adequate.The best MOSFET amps.I have encountered are based on the Hitachi design note.B.K. Electronics make a range of amps.100 - 1K Watt based on the Hitachi design.They are very reasonably priced,but do need a case and a heatsink.
- Status
- Not open for further replies.