If it's a toroid, you can remove some of the secondary windings, or add turns to the primary. You can do the same thing with an EI transformer, you just have to cook it a bit to soften the varnish which holds the thing together.
I hate giving up musical watts for watts of heat.
The regulator from the Zen V5 might be just the ticket.
http://www.passdiy.com/pdf/zen-v5-hires.pdf
It needs about an 8 volt drop to work reliably.
An F5-V5 should be quite special.
Doug
http://www.passdiy.com/pdf/zen-v5-hires.pdf
It needs about an 8 volt drop to work reliably.
An F5-V5 should be quite special.
Doug
What about a simple regulator circuit using a zener as reference and a BJT to take the current.
You could even use MOSFETs like IRFP240/9240 bearing in mind the gate voltage will be about 3-4 volts. Clearly they would need to be on a heatsink.
I am the type of forum participant that can read a schematic, order from Digikey, and solder. Would you have a moment to refer me to a model of this circuit and the values that would achieve an output of 24v. I have all the room and heat sink to implement about anything. I am just of little brain and can't find a schematic of this circuit at present.
Bruce
Bruce
My scanner isnt working to input a circuit diagram.
Hopefully someone else can help.
Hi Bruce,
Have you considered these two options:
http://sound.westhost.com/project15.htm
http://www.datasheetcatalog.com/datasheets_pdf/L/M/3/3/LM338K.shtml
The LM338K (T03 steel Case) is good for 1.2 - 30V dc @ 5A. with adequate heastinking....
Just be aware @ 24v AC you are looking at 33.936V-24=9.936*2A (X 2 Rails)
~ 39.744 W of heat in the regulator(s) per channel (if you run the amp at +/- 24V, 2A bias)
so if you used a minimum of 2 x LM338K you would have 79.488W of heat dissipated in each.
Hope this is useful....
-Dan
PS nobody said class a was efficient
Have you considered these two options:
http://sound.westhost.com/project15.htm
http://www.datasheetcatalog.com/datasheets_pdf/L/M/3/3/LM338K.shtml
The LM338K (T03 steel Case) is good for 1.2 - 30V dc @ 5A. with adequate heastinking....
Just be aware @ 24v AC you are looking at 33.936V-24=9.936*2A (X 2 Rails)
~ 39.744 W of heat in the regulator(s) per channel (if you run the amp at +/- 24V, 2A bias)
so if you used a minimum of 2 x LM338K you would have 79.488W of heat dissipated in each.
Hope this is useful....
-Dan
PS nobody said class a was efficient
you should know that it was your Super Hiraga that sent me packing for 25v Toroidals in the first place. So it is only karmically fitting that you have helped me adapt them to the F5. I had seen the ESP design and can't think of a reason not to substitute it for the PSU spec'd with the F5. My only worry is that it will be a bit noisy but the description of the project answers this.
Do you or anyone else see a problem with this substitution. It was originally an option for the JLH Class A so it is no stranger to the current demand(s).
As I already have 8x15000uF for the F5 PSU and I see where I can use these, the addition of some active parts is no expense to speak of.
But what value resistor, other than the 12k would I use to take my 33.6vdc down to 24vdc?
Thanks again.
Bruce
Do you or anyone else see a problem with this substitution. It was originally an option for the JLH Class A so it is no stranger to the current demand(s).
As I already have 8x15000uF for the F5 PSU and I see where I can use these, the addition of some active parts is no expense to speak of.
But what value resistor, other than the 12k would I use to take my 33.6vdc down to 24vdc?
Thanks again.
Bruce
Hi npapp
sorry for the late reply.
For a single output pair I get a damping factor of 56 into 8 ohm load.
For 3 pairs I get a damping factor of 162 into 8 ohm
So if you have 2 pairs you will have a damping factor of about 110.
However Nelson said the damping factor is 80 for the original version so if his measurements are correct then you will have a damping factor of 160.
sorry for the late reply.
For a single output pair I get a damping factor of 56 into 8 ohm load.
For 3 pairs I get a damping factor of 162 into 8 ohm
So if you have 2 pairs you will have a damping factor of about 110.
However Nelson said the damping factor is 80 for the original version so if his measurements are correct then you will have a damping factor of 160.
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Hi T,
now go and model your speaker with that added resistance and see what happens to the LF frequency response.
Compare the
1.)[theoretical (no added resistance)] to the
2.)[amp + speaker] to the
3.)[amp + cables + speaker] to the
4.)[ cables + speaker]
I think you will be surprised how close 1 & 2 are and how close 3 & 4 are
an amp with a low output impedance makes almost no difference. It's the cables that can potentially be used to tune the bass response.
An amp with a high output impedance mimics what high resistance cables can do for your LF tuning. Very short low resistance cables ranging to long high resistance cables gives a quite different LF sound.
now go and model your speaker with that added resistance and see what happens to the LF frequency response.
Compare the
1.)[theoretical (no added resistance)] to the
2.)[amp + speaker] to the
3.)[amp + cables + speaker] to the
4.)[ cables + speaker]
I think you will be surprised how close 1 & 2 are and how close 3 & 4 are
an amp with a low output impedance makes almost no difference. It's the cables that can potentially be used to tune the bass response.
An amp with a high output impedance mimics what high resistance cables can do for your LF tuning. Very short low resistance cables ranging to long high resistance cables gives a quite different LF sound.
Tnt audio article
Quote from http://www.tnt-audio.com/clinica/ssps2_e.html :
"Also, please note the two symmetrical RC networks. They serve to get rid of the residual capacitor inductance, which should improve high frequency performance. In my experience, it always does, though to what extent remains open to debate, trial and error. No matter how good the capacitors may be, they always have some inductance left over; the better they are, the lower the value, and vice versa. Therefore, this is always good to have, even if its greatest effects will show up with the worst of capacitors. A side benefit is that the amp will tend to be even more stable with complex loads, although this is primarily something the amp design should deal with."
Have any one tried this in the F5 power supply and report on the listerning test ?
Thanks
kp93300
Quote from http://www.tnt-audio.com/clinica/ssps2_e.html :
"Also, please note the two symmetrical RC networks. They serve to get rid of the residual capacitor inductance, which should improve high frequency performance. In my experience, it always does, though to what extent remains open to debate, trial and error. No matter how good the capacitors may be, they always have some inductance left over; the better they are, the lower the value, and vice versa. Therefore, this is always good to have, even if its greatest effects will show up with the worst of capacitors. A side benefit is that the amp will tend to be even more stable with complex loads, although this is primarily something the amp design should deal with."
Have any one tried this in the F5 power supply and report on the listerning test ?
Thanks
kp93300
Krisfr,
There was one 'optional' change to the final schematic. The values of R21 and R22 are officially 10k, but 22k may work better.
First mentioned here (by Nelson):
http://www.diyaudio.com/forums/showpost.php?p=1643840&postcount=1946
Rick