Simply, approximately twice the amount required for a mono (i.e. single channel) amplifier. Follow the recommended values shown in table 3 of the magazine article. There it shows, for example, 2 X 8R speaker loads require 5,000uF in a simple power supply and the regulated version in fig.8(a). http://www.sound-au.com/tcaas/jlh1969.pdf
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Use as R any bigger trafo. Shorting the primary winding, use the secondary as wirewoundresistor, highly loadable. Later disconnect the shortening: the inductivity will the sound of a JLH support tonally appropriately;-)
Capacitors sound as different as beers or wines taste. Unfortunately, the capacitance values do not provide any information about, for example, quietness or depth or blackness or clarity of the sound. Finding the right capacitors can be a lot of work.
If I understand you right, that you want to use the secondary of a transformer as a choke. Be very careful in this statement because you need an air gap in the core to prevent saturation. When a core become saturated, it is simply turns into an electromagnet and behaves like a lossy resistor. I also agree that capacitors sound different and one should view the capacitor as part of the output circuit because the audio signal passes through it. It should be very low ESR and low inductance, else the HF will be rolled off. It is of good practice to bypass the reservoir caps with smaller film type caps of say 100nF allowing HF to pass through. The power capacitors should also allow high ripple current because all the signal current is passed through them. In simple terms, if the signal current can reach 1.4 amp, the reservoir capacitor should be able to handle at least twice that current to pass through it. This is true for the output coupling cap as well. Good caps for the purpose are normally expensive it is not brand related it is application related and selecting the right capacitor for the task is important.
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Let us just assume for a moment you designed your amp for say a 4 ohm load, but your capacitor at some frequency has a ESR of 1 ohm then your amp will effectively see a 5 ohm load. That is almost a 2 dB loss of power. People in general give so much attention to what make or type of transistors they use, but you will be surprised at how the passive components can affect your sound quality.
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Some audiophiles believe in an A/B testing in order to find the best of the best. I don't necessarily agree with this theory. If you go out for dinner one night, and you are served this fantastic tasting steak, you know that it is good, you don't need the waiter to bring you a sh!t piece of steak as well for comparison. Once you found the sound that works for you, you know it and appreciate it and you stop wanting better because all you will get is different.
Regarding the transformer as choke: the primary winding switch will provide information.
EVERYTHING is "signal pass". The choice of power supply capacitors also has a considerable influence on sound. The one sound character of components can be heard in all places and functions of a circuit.
Never bridge capacitors with smaller ones or other types of construction. Not in audio electronics! This is how you create audible distortion mirrors like those at fun fairs, for example. And sometimes these bridges are even visibly detectable as oscillating circuits. If it sounds better with bypassing little caps, then do search for reasons at other places.
EVERYTHING is "signal pass". The choice of power supply capacitors also has a considerable influence on sound. The one sound character of components can be heard in all places and functions of a circuit.
Never bridge capacitors with smaller ones or other types of construction. Not in audio electronics! This is how you create audible distortion mirrors like those at fun fairs, for example. And sometimes these bridges are even visibly detectable as oscillating circuits. If it sounds better with bypassing little caps, then do search for reasons at other places.
{Never bridge capacitors with smaller ones or other types of construction.}
I think you should explain your theory to some of those dumb people like Nelson Pass, Bob Carver, John Curl, Peter Walker, David Berning. David Hafler. Stan Curtis, Saul Marantz, and many more who made their mark in the audio industry. I think any electronic design engineer will appreciate this revealing information. Who am I to dispute this fact.
I think you should explain your theory to some of those dumb people like Nelson Pass, Bob Carver, John Curl, Peter Walker, David Berning. David Hafler. Stan Curtis, Saul Marantz, and many more who made their mark in the audio industry. I think any electronic design engineer will appreciate this revealing information. Who am I to dispute this fact.
Hi Mr Ras. I hope you are fine. I made your RAS10 single ended class A circuit about 10 years ago and it sounded very good.But it is lost/stolen in apartment roof.It surprised me when i heard double bass drum in the song (i heard it as single drum) If you permit i can share it here. I have 2x8v transformer and maybe you can advise something on the circuit (maybe an upgrade) Thanks in advance.Regards
Hi Veysel, yes, I remember this amp well. Thank you for your kind remark. It is an extremely simple amplifier and making it more sophisticated, for instance changing the long tail pair, tail resistance for a 1.2mA constant current generator and adding a 10uF cap between the emitters of the tail pair will drop the THD a by an order of magnitude, but I doubt very much if it would be audible, only measured. You could increase the rail voltage as well as the bias current, making it more powerful, but this would increase the heat generated and requires inspecting the heat sink not to get too hot to touch. Then if you change to higher power bigger capacitors would be needed and a higher rating transformer. Is the extra expense worth a few watts, that is something to decide.