AndrewT said:
you try doubling the Ampere capacity of any amp beating that specification.Progg70 said:
It's IMPOSSIBLE.
Now reduce the load resistance/impedance to a non sensical 0r1 or 1uF and near zero resistance and find the peak transient current before or with limiting. That is a completely different spec. I have no way of deciding whether this affects sound quality and in particular bass quality.
Nop.
40V * 10A it's only 400VA take this x2 (Double winding) and you have a transf. on 800VA.
36V* 26,8A it's only 1037VA take this x2 (Double winding)and you have a transf. on 2000VA. Not so common use two 1000VA instead.
Abrahamsson Audio has 3000VA and about 2x24V for each channel. Then the sound is alright.
There is always a problem to have high effect and good sound. I think max effect and good sound is about 100W…
A&O Audio have their No. 1 at 16W with 800VA on each channel.
40V * 10A it's only 400VA take this x2 (Double winding) and you have a transf. on 800VA.
36V* 26,8A it's only 1037VA take this x2 (Double winding)and you have a transf. on 2000VA. Not so common use two 1000VA instead.
Abrahamsson Audio has 3000VA and about 2x24V for each channel. Then the sound is alright.
There is always a problem to have high effect and good sound. I think max effect and good sound is about 100W…
A&O Audio have their No. 1 at 16W with 800VA on each channel.
Try and listening is the only way to go. You always got different views on how things are going to be made.
Anyway the energy must be there and as always the speaker
should se the transformer as good it can be.
Then we are talking cables, prints, transistors and of course the transformers wire thickness, capacity.
You can never get a nice amplifier with pore transformers.
Try to start a car with a MC battery… Energy is needed.
A transformer is not a rocket science but most of it is copper who is expensive… this is often the most
expensive part in a amplifier. Not strange they try to save on this component…
Anyway the energy must be there and as always the speaker
should se the transformer as good it can be.
Then we are talking cables, prints, transistors and of course the transformers wire thickness, capacity.
You can never get a nice amplifier with pore transformers.
Try to start a car with a MC battery… Energy is needed.
A transformer is not a rocket science but most of it is copper who is expensive… this is often the most
expensive part in a amplifier. Not strange they try to save on this component…
post13 and post15 moved the enquiry to amplifier power.
I went on to show that simply quoting 100W into 8ohm tells us insufficient to make comparisons.
One needs to know how well the amplifier drives a lower impedance load.
Using Cordell and my own opinion it seems that nominal impedance/2 or nominal impedance/3 are useful resistances to start making that comparison.
From there we can define what is required of the PSU to allow the amplifier to do it's job.
An amplifier that can drive Xwatts into Rohms that is pure resistance, proves nothing about it's ability to drive a speaker. How it delivers current into varying loads starts to tell us a lot more.
I went on to show that simply quoting 100W into 8ohm tells us insufficient to make comparisons.
One needs to know how well the amplifier drives a lower impedance load.
Using Cordell and my own opinion it seems that nominal impedance/2 or nominal impedance/3 are useful resistances to start making that comparison.
From there we can define what is required of the PSU to allow the amplifier to do it's job.
An amplifier that can drive Xwatts into Rohms that is pure resistance, proves nothing about it's ability to drive a speaker. How it delivers current into varying loads starts to tell us a lot more.
OK I was a litle bit single track there. 
My experience is that even if you have pore impedance handling in the output stage, transistors, tubes… the dominant component
is still the transformer.
A good transformer is the most important component.
In A&O Audio No. 1 you only have one transistor on the output but a really good transformer. The load handling is really good. Read the review here: http://aoaudio.se/Artikeln_Highfidelity_eng.pdf
My experience is that even if you have pore impedance handling in the output stage, transistors, tubes… the dominant component
is still the transformer.
A good transformer is the most important component.
In A&O Audio No. 1 you only have one transistor on the output but a really good transformer. The load handling is really good. Read the review here: http://aoaudio.se/Artikeln_Highfidelity_eng.pdf
Without throwing any math about, I've also always found that a silly large transformer sounds better. Ditto a regulated PSU. Ones that have much more current delivery than makes sense for amp/load.
Just what I've heard listening to and working with stuff. Good strong current ability always seems to sound better.
Just what I've heard listening to and working with stuff. Good strong current ability always seems to sound better.
This is the main tragedy of modern recordings
We had much more than that in the past..now a days no more dinamics...music inside a can.
The main advantage we had with digital was the 100 db dinamic range..what people did..compressed and variation does not go higher then 20 decibels... terrible that!
The media could give us noiseless pianissimo moments into the music and outstanding peaks.... but they mess with all that..and suck kind of things started (here) with the FM stations, the figth to play louder than others..because louder means quality to the average listener.
Carlos
We had much more than that in the past..now a days no more dinamics...music inside a can.
The main advantage we had with digital was the 100 db dinamic range..what people did..compressed and variation does not go higher then 20 decibels... terrible that!
The media could give us noiseless pianissimo moments into the music and outstanding peaks.... but they mess with all that..and suck kind of things started (here) with the FM stations, the figth to play louder than others..because louder means quality to the average listener.
Carlos
Applying some of the info I've gleaned from this thread:
For the NAP-140 clone kit (using TIP41/42) which can put out 70W into 4 ohms (I'm assuming use of 4 ohm speakers here), I'd come up with a 70VA (35V w/ 2 amps) continous demand capability, double that to end up with 150VA toroids for each mono. This should address any peaks. This would be a reasonable "rule of thumb" approach for selecting transformers for an audio amp? As a point of reference, the commercial version of this amp uses a single 200VA transformer for both channels.
As far as capacitance, it appears the amps I'm seeing have roughly 200-300uF/watt. Therefore, I'd use 20,000uF for each mono.
Understanding that this approach is quite crude, does it end up with transformer and capacitance values that are in the reasonable range?
For the NAP-140 clone kit (using TIP41/42) which can put out 70W into 4 ohms (I'm assuming use of 4 ohm speakers here), I'd come up with a 70VA (35V w/ 2 amps) continous demand capability, double that to end up with 150VA toroids for each mono. This should address any peaks. This would be a reasonable "rule of thumb" approach for selecting transformers for an audio amp? As a point of reference, the commercial version of this amp uses a single 200VA transformer for both channels.
As far as capacitance, it appears the amps I'm seeing have roughly 200-300uF/watt. Therefore, I'd use 20,000uF for each mono.
Understanding that this approach is quite crude, does it end up with transformer and capacitance values that are in the reasonable range?
It's quite simple to see a graph of dynamics of your favourite music. Just run any old freeware "wave" editor and view the waveform of your favourite music. No mystery or science, just scroll through and look at the graph of dynamics vs time.
My intuition says Andrew's last recommendation is a great approach, anything more would see fairly diminished returns.
..Todd
My intuition says Andrew's last recommendation is a great approach, anything more would see fairly diminished returns.
..Todd
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