• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

OTL PS question!!

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
diyAudio Senior Member
Joined 2002
Hi,

A good reason why you should stay away from sound scientific persuits like electronics.

The only thing you've proven so far is that once again you're working with the wrong assumptions just picking up on something I said and taking it out of context to suit your argument.

My point as initially stated was that the Ciuffoli OTL amp specifies 2H 2A chokes with a DCR of 0.5 Ohm max., upon which I remarked that those values aren't readily available.

Cheers, ;)
 
So how you calculate 0.8 A continous current?

RMS current is as you say SQRT(Pout/RL) = 1.77A which gives an average current drawn from the power supply, (assuming a sinus shaped signal) of 1.77/1.1 ~1.6A but as we have one postive and one negative half they only give current half of the time, thus the average current drawn is 1.6/2 = 0.8A

If you push out 25W continous power the current draw is 0.8A, capacitors can handle peaks that is correct but only for a few milliseconds which is of no use for continous power, the conclusion is that the power supply must be designed for 0.8A continous ciurrent otherwise it is not a 25W amplifier. I have run my OTL amp for full power 25W for 24hours just to see what happened but everything was OK but very warm.

The problem with your regulator design is not the thermal noise from the zeners but bad regulation due to zener resistance and zener temperature drift, this can be marginally better by using many zeners in series but it is not a perfect solution, when your amp start to draw current the raw power supply voltage will drop and that directly affects the current trough the zener, this is not a good design. Try to use a normal regulator design with a feedback loop where the voltage reference is derived from the output instead.

What do you all think about it?

I still think you should drop the regulator idea and use only one of your 6000uF caps per side, it is enough if you build the rest of the amplifier in a good way.

Regards Hans
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.